Lung Cancer: Different Cancers Arising in the Lungs

Lung cancer is not one uniform disease. The main division is between non small cell and small cell lung cancer, which differ in growth, spread and treatment. Diagnosis combines imaging, biopsy, staging and molecular testing so that treatment matches both the cancer's extent and its biology.

What lung cancer is Lung cancer develops when abnormal cells within lung tissue grow without normal control. The cancer may begin in cells lining the airways, mucus producing glands, air sacs or specialised neuroendocrine cells. Cancer cells can invade nearby tissue, enter lymphatic channels or blood vessels and spread elsewhere. A cancer beginning in the lung is called primary lung cancer. Cancer that began in another organ and later spread to the lung is a secondary lung tumour, not a primary lung cancer subtype. One name covers several cancers Lung cancer is not one uniform disease. The first major distinction is between non small cell lung cancer, usually called NSCLC, and small cell lung cancer, usually called SCLC. These groups differ in microscopic appearance, typical growth pattern, likelihood of early spread and treatment response. Pathologists then identify more detailed subtypes and molecular features. This classification is fundamental because treatment suitable for one lung cancer may be ineffective or inappropriate for another. Non small cell lung cancer NSCLC accounts for most primary lung cancers. It is an umbrella group rather than one single biological entity. The principal histological categories include adenocarcinoma, squamous cell carcinoma and less common poorly differentiated carcinomas. NSCLC usually follows a different staging and treatment pathway from SCLC. Early NSCLC may be treated with surgery or radical radiotherapy, while advanced disease often requires systemic treatment selected by histology and biomarkers. Adenocarcinoma Adenocarcinoma develops from gland forming or mucus producing epithelial cells. It is now the most commonly diagnosed NSCLC subtype and often begins towards the outer part of the lung. It occurs in people who smoke, formerly smoked or have never smoked. Adenocarcinoma is the lung cancer subtype most often associated with targetable driver alterations, although these changes are not present in every tumour. Its behaviour varies greatly according to stage, growth pattern and molecular biology. Squamous cell carcinoma Squamous cell carcinoma develops from airway lining cells that have acquired squamous features. It is strongly associated with tobacco exposure and often begins in larger central airways, although it can arise elsewhere. A central tumour may obstruct an airway, cause recurrent infection, collapse part of a lung or produce haemoptysis. Some squamous cancers form a cavity within the tumour. Molecular and immune marker testing still matters because treatment cannot be selected from histology alone. Large cell and poorly differentiated carcinoma Large cell carcinoma has traditionally described an uncommon NSCLC made of large abnormal cells without clear glandular, squamous or neuroendocrine differentiation. Modern immunohistochemistry and molecular testing allow many previously labelled large cell cancers to be reclassified more precisely. The remaining category is therefore uncommon and represents a diagnosis of exclusion. These cancers are often high grade, but individual behaviour still depends on stage and biology. The term large cell does not simply mean that the tumour is physically large. Small cell lung cancer SCLC is a high grade neuroendocrine cancer. Its cells divide rapidly, and the disease commonly spreads to lymph nodes or distant organs early. It is very strongly associated with smoking, although an individual diagnosis should never be used to assign blame. SCLC is often initially sensitive to chemotherapy and radiotherapy. However, recurrence is common, and surgery is reserved for a small minority with very early localised disease. Why SCLC is treated differently SCLC frequently has microscopic spread beyond the visible primary tumour when it is diagnosed. Removing one lung lesion would therefore leave untreated disease in many cases. Systemic chemotherapy forms the backbone of treatment, often combined with chest radiotherapy or immunotherapy according to stage and fitness. Selected people may also receive treatment intended to reduce the risk of brain metastases. This treatment pattern differs fundamentally from early NSCLC, where surgical removal or stereotactic radiotherapy may be curative. Other primary lung tumours The lungs can develop rarer cancers that do not fit the common NSCLC or SCLC groups. Examples include carcinoid tumours, salivary gland type tumours and sarcomatoid carcinomas. Their biology and treatment can differ substantially from common lung cancers. Pleural mesothelioma begins in the lining around the lung and is not the same as lung cancer. A pathology report must therefore establish the actual tumour type before treatment is planned. Smoking is the dominant risk factor Tobacco smoking is the largest preventable cause of lung cancer. Risk generally rises with the amount smoked, the duration of smoking and cumulative exposure. Cigarettes are the main source, but cigars, pipes and other combustible tobacco products also expose the lungs to carcinogens. Passive smoke exposure increases risk. Stopping smoking reduces future risk, although risk does not immediately return to that of someone who has never smoked. Lung cancer in never smokers People who have never smoked can develop lung cancer. Never smoker lung cancer is not evidence that smoking is unimportant. It shows that smoking is not the only cause. Adenocarcinoma is the most frequent histological pattern in never smokers. Some driver alterations are proportionally more common in this group, but a person's past or current smoking cannot predict the tumour's molecular result. Symptoms in a never smoker require the same assessment as symptoms in someone with tobacco exposure. Other risk factors Radon is a naturally occurring radioactive gas that can accumulate within some buildings. Long term occupational exposure to asbestos, silica, arsenic, nickel, chromium, diesel exhaust and other carcinogens can increase risk. Air pollution makes a smaller but genuine contribution at population level. Previous chest radiotherapy, increasing age, chronic lung disease and health problems in the family may also influence risk. Most people with one risk factor do not develop lung cancer, and some people develop it without an identifiable exposure. Avoiding stigma A lung cancer diagnosis should not trigger blame. Nicotine dependence is a medical condition influenced by addiction, social circumstances, industry practices and health inequalities. People who smoke deserve the same timely investigation, compassionate care and treatment choices as everyone else. Never smokers should not have their symptoms dismissed because they appear to be at lower risk. Risk factors change probability. They do not confirm or exclude an individual diagnosis. Early lung cancer may cause no symptoms Small lung cancers can be present without causing noticeable symptoms. Some are found through targeted low dose CT screening. Others are discovered incidentally on imaging performed for trauma, heart disease, abdominal symptoms or another reason. A nodule or shadow found incidentally is not automatically cancer. Its size, shape, growth, previous imaging and the person's risk factors guide whether it needs surveillance, PET CT or tissue sampling. A persistent or changing cough A cough lasting more than three weeks is a recognised reason to seek assessment. A longstanding cough that changes in character, frequency or severity also matters. Cough is common and is usually caused by infection, asthma, chronic obstructive pulmonary disease, reflux or another non cancer condition. The symptom cannot identify the cause alone. Persistence, associated symptoms and risk factors determine the next investigation. Haemoptysis Haemoptysis means coughing blood from the respiratory tract. It may appear as blood streaked sputum or a larger volume of fresh blood. Possible causes include chest infection, bronchiectasis, pulmonary embolism, tuberculosis and lung cancer. Unexplained haemoptysis in a person aged 40 or over meets NICE criteria for a suspected cancer pathway referral. Large volume bleeding, breathing difficulty or circulatory collapse is an emergency at any age. Breathlessness Breathlessness can develop when a tumour obstructs an airway, collapses part of a lung or causes fluid around the lung. It can also result from infection, anaemia, pulmonary embolism, heart disease or pre existing lung disease. Gradual breathlessness is common in many conditions and does not diagnose cancer. Sudden severe breathlessness requires emergency assessment. New persistent breathlessness should be reviewed, particularly when accompanied by cough, weight loss or chest pain. Chest and shoulder pain A lung tumour can irritate the pleura, chest wall, ribs or nearby nerves. Pain may worsen when breathing or coughing. A tumour at the top of the lung can affect nerves supplying the shoulder and arm. Most chest and shoulder pain has a non cancer cause, including muscle strain, arthritis, infection and heart disease. Central pressure, severe pain or pain with sweating, collapse or acute breathlessness requires emergency assessment. Recurrent chest infection A tumour narrowing an airway can prevent normal drainage and cause infection to recur in the same region. Repeated pneumonia or an infection that does not resolve as expected can therefore prompt further imaging. Recurrent infection has many other causes, including aspiration, bronchiectasis and immune problems. A chest X ray that appears to show infection may need follow up imaging when symptoms persist. Treatment response and radiological resolution both matter. Weight loss, appetite and fatigue Lung cancer can cause reduced appetite, unintentional weight loss and profound fatigue. These symptoms may arise from inflammation, reduced intake, metabolic effects or advanced disease. They are non specific and can occur with infection, depression, thyroid disease and many other illnesses. Unexplained weight loss becomes more concerning when combined with persistent respiratory symptoms. A single normal blood test does not exclude lung cancer. Hoarseness and swallowing difficulty A chest tumour or enlarged lymph node can affect the recurrent laryngeal nerve and cause persistent hoarseness. Pressure on the oesophagus can contribute to swallowing difficulty. Hoarseness is more commonly caused by infection, reflux or vocal cord disease. Persistent unexplained hoarseness requires assessment. Progressive swallowing difficulty, aspiration or inability to swallow fluids needs urgent clinical review. Finger clubbing Finger clubbing changes the shape of the fingertips and the angle where the nail meets the skin. It can occur with lung cancer, bronchiectasis, lung fibrosis, heart disease and other conditions. Clubbing is a clinical clue rather than a diagnosis. New clubbing in an adult warrants investigation. People should not attempt to diagnose clubbing from one home finger test alone. Superior vena cava obstruction A tumour or enlarged lymph nodes can compress the superior vena cava, the large vein returning blood from the upper body. This may cause swelling of the face, neck or arms, prominent chest veins, headache, breathlessness or a feeling of fullness in the head. Symptoms can worsen when bending forwards or lying flat. Severe breathing difficulty, confusion or rapidly increasing swelling requires emergency care. Suspected superior vena cava obstruction needs urgent specialist assessment. Pancoast or superior sulcus tumour A tumour at the top of the lung can invade the chest wall and nearby nerves. It may cause persistent shoulder pain radiating down the inner arm. Weakness or wasting in the hand can occur. A drooping eyelid, small pupil and reduced facial sweating on one side can form Horner syndrome. These findings have other causes but require prompt neurological and chest assessment. Paraneoplastic effects Some lung cancers release hormones or trigger immune effects away from the tumour. SCLC can cause low blood sodium through inappropriate antidiuretic hormone secretion. Squamous cancer can sometimes cause high calcium levels through hormone like signalling. Other syndromes can affect nerves, muscles, skin or blood clotting. These abnormalities may precede respiratory symptoms but are not specific enough to diagnose lung cancer alone. Incidental pulmonary nodules A pulmonary nodule is a small rounded opacity within the lung. Most small nodules are benign scars, healed infection or non cancerous growths. Clinicians compare earlier scans and assess size, shape, density and growth. Some nodules need repeat low dose CT rather than immediate biopsy. A changing or high risk nodule may require PET CT, biopsy or surgical assessment. Targeted lung cancer screening England is rolling out a targeted NHS Lung Cancer Screening Programme. People aged 55 to 74 who currently smoke or previously smoked may be invited for a risk assessment. Those assessed at higher risk may be offered a low dose CT scan. Screening aims to find lung cancer before symptoms develop. A person with symptoms should contact a GP and should not wait for a screening invitation. Screening is not diagnostic assessment Screening is intended for eligible people who do not have concerning symptoms. A screening CT can find nodules, early lung cancer and unrelated incidental abnormalities. An abnormal screening result means further assessment is needed. It does not confirm cancer. A normal screening result cannot guarantee that cancer is absent or will not develop later. New symptoms require clinical assessment regardless of a previous screening scan. Primary care assessment A clinician asks about the duration and pattern of cough, breathlessness, bleeding and pain. They review smoking, occupational exposure, weight change, appetite, infections and previous cancer. Examination can assess oxygen levels, chest sounds, lymph nodes, clubbing and general condition. These findings guide urgency but cannot rule lung cancer in or out. The next step is often an urgent chest X ray or direct suspected cancer referral, depending on the presentation. The suspected cancer pathway The urgent suspected cancer referral pathway is commonly called the two week wait pathway. NICE recommends this pathway when a chest X ray suggests lung cancer. It is also recommended for unexplained haemoptysis in someone aged 40 or over. Other concerning symptom combinations in people aged 40 or over usually trigger an urgent direct access chest X ray first. A referral means cancer needs to be excluded promptly. It does not mean that cancer is already diagnosed. Urgent chest X ray criteria NICE advises an urgent chest X ray for people aged 40 or over with two or more unexplained symptoms from cough, fatigue, breathlessness, chest pain, weight loss and appetite loss. For someone who has ever smoked, one of these unexplained symptoms can be enough. An urgent chest X ray is also considered for recurrent chest infection, finger clubbing, suspicious chest signs, persistent neck nodes or raised platelets. These thresholds guide clinicians and are not a public self scoring tool. Clinical judgement and safety netting still apply outside the listed combinations. The limits of chest X ray A chest X ray is a useful first investigation but does not provide a definitive diagnosis. Cancer can be obscured by the heart, ribs, diaphragm or another lung abnormality. Small or central tumours may be missed. A normal X ray should not end investigation when clinical concern remains high or symptoms persist. CT provides much more detailed anatomical information. Contrast enhanced CT NICE recommends contrast enhanced CT for known or suspected lung cancer. The scan includes the chest, lower neck, liver and adrenal glands because these areas influence diagnosis and staging. CT shows the tumour's size, position, relationship to nearby structures and visible lymph nodes. It may identify possible distant disease or another explanation for symptoms. CT appearances alone usually cannot establish histological type or every site of spread. Planning diagnosis and staging together The investigation pathway aims to obtain the most useful information with the least risk. Clinicians may biopsy an accessible lymph node or distant lesion instead of the primary lung mass. This can confirm both the diagnosis and a more advanced stage in one procedure. CT is generally performed before biopsy so the team can choose the safest and most informative target. The plan also considers whether the person could receive treatment with curative intent. Bronchoscopy Bronchoscopy uses a flexible camera passed through the nose or mouth into the airways. It is particularly useful for a central lesion visible within or close to a large airway. The clinician can take biopsies, brushings or washings. Sedation and local anaesthetic are commonly used. A normal bronchoscopy does not exclude a peripheral lung cancer beyond the instrument's reach. EBUS and mediastinal staging Endobronchial ultrasound, usually called EBUS, combines bronchoscopy with ultrasound. It allows needle sampling of lymph nodes and lesions beside the airways. The result can identify cancer type and whether cancer has reached central chest lymph nodes. This information can fundamentally change whether surgery, radiotherapy or systemic treatment is appropriate. A negative sample may need further assessment when imaging remains strongly suspicious. CT guided lung biopsy A radiologist can guide a needle through the chest wall into a peripheral lung lesion. Local anaesthetic is used. The tissue can confirm cancer, determine subtype and support biomarker testing. Air leakage causing a pneumothorax is a recognised complication. The team balances diagnostic benefit against bleeding, lung function and procedural risk. Pleural fluid and other biopsy sites Lung cancer can cause fluid to collect between the lung and chest wall. Pleural aspiration can relieve breathlessness and provide fluid for cytology. A pleural biopsy may be needed when fluid testing is inconclusive. Accessible neck nodes, liver lesions, bone lesions or other metastases can sometimes provide safer tissue. The best biopsy target is not always the largest lung mass. Histology and immunohistochemistry A pathologist examines the tissue's structure and cell appearance. Immunohistochemistry uses antibodies to identify proteins that support adenocarcinoma, squamous, neuroendocrine or another origin. This prevents an undifferentiated tumour being assigned an inaccurate subtype. Small biopsy samples require careful use because tissue must also remain available for molecular testing. The final diagnosis integrates morphology, immunohistochemistry and clinical context. Molecular testing Current NICE guidance links lung cancer diagnosis to comprehensive next generation sequencing through genomic laboratory hubs. Testing can identify driver alterations that are maintaining cancer growth. Relevant examples include changes involving EGFR, ALK, ROS1, BRAF, MET, RET, KRAS and NTRK. The exact panel and eligibility depend on histology, stage and current national guidance. A negative panel does not mean that the cancer has no mutations. It means that no currently tested actionable alteration was identified. Driver mutations A driver alteration gives a cancer cell a growth advantage and contributes to maintaining the tumour. Some driver positive NSCLCs respond strongly to an oral targeted medicine. The alteration is tested in tumour tissue or, in selected situations, circulating tumour DNA from blood. A driver mutation found in the tumour is usually an acquired cancer cell change rather than an inherited family mutation. Treatment effectiveness and resistance patterns vary between alterations and medicines. PD L1 testing PD L1 is a protein that can suppress immune attack against cancer. Laboratories measure PD L1 expression on tumour cells using validated assays. The result can help select immunotherapy for some people with NSCLC. PD L1 is not a driver mutation and does not work as a simple positive or negative guarantee. Some people with low expression benefit from combination treatment, while some with high expression do not respond. Liquid biopsy A blood sample can sometimes detect fragments of tumour DNA circulating in plasma. This is called circulating tumour DNA testing or liquid biopsy. It may identify an actionable alteration when tissue is limited or a biopsy is unsafe. A positive informative result can guide selected treatment. A negative blood result cannot reliably exclude a driver alteration because some tumours release little DNA into the bloodstream. PET CT PET CT combines anatomical imaging with information about tissues using more glucose than expected. It is offered before potentially curative treatment to look for active lymph nodes or distant disease. Inflammation and infection can also appear active on PET. Very small or slow growing tumours may show limited uptake. Suspicious isolated findings may require biopsy or additional imaging before a curative plan is abandoned. Brain and bone imaging Brain imaging is selected according to stage, symptoms and treatment intent. People with neurological symptoms require urgent brain imaging. NICE recommends more intensive brain staging for stage 2 or 3 NSCLC being considered for curative treatment than for asymptomatic stage 1 disease. SCLC has a higher tendency to spread to the brain, so brain assessment is important. Bone imaging is guided by PET CT and localised symptoms rather than being identical for every person. Staging NSCLC NSCLC uses the TNM staging system. T describes the primary tumour's size and local invasion. N describes regional lymph node involvement. M describes spread to distant sites or separate malignant deposits. These components combine into stages I to IV, although detailed definitions change as staging systems are updated. Early stage NSCLC Stage I and selected stage II NSCLC may be confined sufficiently for treatment with curative intent. Surgery is preferred for many people who are fit enough. Stereotactic ablative radiotherapy can provide radical treatment when surgery is declined or unsuitable. Some people need chemotherapy, immunotherapy or targeted treatment before or after surgery. Early stage does not mean that every person receives the same sequence. Locally advanced NSCLC Stage III NSCLC includes several patterns of tumour and lymph node involvement. Some are operable within a multimodality plan. Others are treated with concurrent or sequential chemoradiotherapy with curative intent. Selected people receive immunotherapy after definitive chemoradiotherapy. Stage III is not automatically palliative, but treatment requires detailed thoracic multidisciplinary assessment. Metastatic NSCLC Stage IV NSCLC has spread beyond the region of the original lung cancer. For most people, treatment is non curative and aims to control disease, relieve symptoms and extend life. Systemic treatment is selected using histology, driver alterations, PD L1, general health and previous treatment. Some people with a small number of metastatic sites may receive radical local treatment as part of an individualised plan. Supportive and palliative care can begin alongside active cancer treatment. Staging SCLC SCLC is often described as limited stage or extensive stage disease. Limited stage disease can be encompassed within a radical chest radiotherapy field and has no distant metastasis. Extensive stage disease has spread beyond that pattern. TNM staging can also be recorded, especially when very early surgery is being considered. Because SCLC spreads early, its treatment strategy differs even when the visible chest tumour appears small. Treatment intent Curative intent treatment aims to eradicate all detectable and microscopic cancer with a realistic chance of long term cure. Palliative or non curative treatment aims to control cancer, reduce symptoms and prolong life when eradication is not achievable. Palliative does not mean that care has stopped or that treatment is only given during the final days of life. Intent can be influenced by stage, histology, tumour biology, fitness and personal priorities. The team should explain the intended goal clearly before treatment begins. Multidisciplinary planning Every suspected or confirmed lung cancer is reviewed by a specialist multidisciplinary team. The team commonly includes respiratory physicians, thoracic surgeons, radiologists, pathologists, oncologists and lung cancer nurses. Nuclear medicine specialists, palliative care clinicians and other professionals contribute when needed. The team combines diagnosis, stage, molecular results, lung function and general health. The person's preferences remain central to the final decision. Performance status and fitness Performance status describes how illness affects everyday activity and self care. It helps predict whether someone is likely to tolerate systemic treatment. Surgical decisions also require lung function, cardiac and exercise assessment. Age alone should not determine whether treatment is offered. Frailty, comorbidity, organ function and the person's goals provide more useful information than chronological age by itself. Surgery for NSCLC Surgery removes the tumour and regional lymph nodes when complete resection appears possible. Lobectomy removes one lobe and is the standard operation for many operable NSCLCs. Segmentectomy or wedge resection may be used for selected small tumours or limited lung reserve. Pneumonectomy removes an entire lung and is reserved for cases where a smaller operation cannot obtain clear margins. Pathological examination after surgery provides the final stage and may change postoperative treatment. Surgery for SCLC Surgery is not standard treatment for most SCLC. It may be considered when disease is very early, confined to the lung and without lymph node involvement. Thorough staging is essential before an operation. Chemotherapy is normally given afterwards because microscopic spread remains possible. This rare surgical pathway does not alter the overall principle that SCLC is primarily treated systemically. Radical radiotherapy and SABR Radiotherapy can cure selected lung cancers by delivering a high dose to the tumour. Stereotactic ablative radiotherapy, usually called SABR, delivers highly focused treatment over a small number of sessions. It is commonly used for early NSCLC when surgery is unsuitable or declined. Conventional radical radiotherapy or chemoradiotherapy is used for larger or node positive disease. Treatment planning aims to control the cancer while limiting damage to healthy lung, heart, oesophagus and spinal cord. Chemotherapy in NSCLC Chemotherapy uses medicines that damage dividing cancer cells throughout the body. It can be given before surgery, after surgery, with radiotherapy or for advanced disease. The drug combination depends partly on squamous or non squamous histology. Chemotherapy may reduce recurrence risk after complete resection in higher risk disease. It remains important even as targeted therapy and immunotherapy expand. Targeted therapy in NSCLC Targeted medicines block specific proteins produced by actionable driver alterations. Many are tablets taken daily, while others are given intravenously. They can produce substantial tumour shrinkage and symptom improvement in appropriately selected cancers. They do not work when the relevant target is absent. Resistance commonly develops over time, and repeat tissue or blood testing may identify a new treatment option. Immunotherapy in NSCLC Immune checkpoint inhibitors reduce signals that prevent immune cells attacking cancer. They can be used alone or with chemotherapy in selected early, locally advanced or metastatic NSCLC. Treatment choice depends on stage, PD L1, driver alterations and previous therapy. Immune related adverse effects can inflame the lungs, bowel, liver, skin, kidneys or hormone producing glands. New breathlessness or diarrhoea during treatment requires prompt oncology advice rather than self treatment. Treating limited stage SCLC Limited stage SCLC is usually treated with platinum based chemotherapy and chest radiotherapy. For people fit enough, radiotherapy is commonly given concurrently with chemotherapy. The aim may be curative. Selected people whose disease responds may receive prophylactic cranial irradiation after discussion of benefits and risks. More recent immunotherapy can be used after chemoradiotherapy in eligible adults under current NICE guidance. Treating extensive stage SCLC Extensive stage SCLC is treated primarily with platinum based chemotherapy. Immunotherapy may be added for eligible people. Treatment usually aims to control disease, improve symptoms and prolong life rather than cure it. Chest radiotherapy or brain directed strategies may be considered after a response in selected people. Response can be rapid, but recurrence is common and requires further specialist discussion. Prophylactic cranial irradiation SCLC has a strong tendency to spread to the brain. Prophylactic cranial irradiation uses low dose whole brain radiotherapy to reduce this risk in selected people whose disease has responded. It is not automatically appropriate for everyone. Possible effects on memory, thinking, fatigue and quality of life require discussion. Brain MRI surveillance may influence decisions in some settings. Palliative radiotherapy Radiotherapy can relieve pain, haemoptysis, airway obstruction or symptoms from bone and brain metastases. Palliative courses are often shorter than radical treatment. The aim is symptom control, not elimination of every cancer cell. Improvement may take days or weeks. Palliative radiotherapy can be used alongside systemic treatment and supportive care. Pleural effusion and airway obstruction Fluid around a lung can cause breathlessness and chest pressure. Drainage can provide relief and may be followed by pleurodesis or an indwelling catheter when fluid repeatedly returns. A tumour narrowing a major airway may be treated with radiotherapy, laser, debulking or a stent. These interventions can improve breathing even when the cancer is not curable. The treatment choice depends on urgency, anatomy and overall condition. Supportive and palliative care Supportive care treats symptoms and helps people maintain function throughout the illness. It can address breathlessness, cough, pain, fatigue, appetite, mood and practical needs. Palliative care specialists can work alongside chemotherapy, immunotherapy or radiotherapy. Early involvement does not shorten life or signal abandonment. The aim is to align treatment with what matters to the person. Smoking cessation after diagnosis Stopping smoking after lung cancer diagnosis can reduce surgical complications and support lung and cardiovascular health. It may improve tolerance of treatment and reduce risk of another tobacco related cancer. NICE advises offering stop smoking support as soon as lung cancer is suspected. Cancer surgery should not be postponed solely to create a period of abstinence. Support should be practical and non judgemental. Neutropenic sepsis Chemotherapy can reduce neutrophils, which are important infection fighting white blood cells. An infection can then become life threatening rapidly. Fever, shaking chills, confusion, sudden weakness or feeling acutely unwell requires immediate contact with the oncology emergency service. A normal or low temperature does not always exclude severe infection. Neutropenic sepsis is an emergency and needs prompt assessment and antibiotics. Immunotherapy toxicity Immunotherapy can activate inflammation in healthy organs. Pneumonitis can cause new cough, breathlessness or low oxygen levels. Colitis can cause frequent diarrhoea, abdominal pain or blood in stool. Hormone gland inflammation may cause severe fatigue, dizziness, thirst or confusion. Symptoms can develop during treatment or after it has stopped, so the oncology team must be told about previous immunotherapy. Brain metastases Brain metastases can cause headache, vomiting, seizures, weakness, speech change, visual disturbance or personality change. These symptoms have many other causes but require urgent assessment in someone with known cancer. Steroids can reduce swelling around symptomatic metastases while definitive treatment is planned. Treatment may include surgery, stereotactic radiosurgery, whole brain radiotherapy or systemic therapy. A first seizure or sudden neurological deficit requires emergency care. Spinal cord compression Cancer in a vertebra can press on the spinal cord. Warning features include new severe or progressive back pain, limb weakness, numbness, unsteady walking and bladder or bowel dysfunction. Pain can worsen when coughing, straining or lying flat. Metastatic spinal cord compression is an oncological emergency. Immediate assessment protects the best chance of preserving movement and continence. Hypercalcaemia Some lung cancers or bone metastases can raise blood calcium. Symptoms can include thirst, frequent urination, constipation, nausea, confusion, weakness or drowsiness. These symptoms are non specific and require a blood test. Marked confusion, severe dehydration or reduced consciousness requires urgent hospital care. Treatment addresses both the calcium level and its underlying cause. Treatment adverse effects Surgery can cause pain, reduced lung capacity, air leakage and infection. Radiotherapy can cause tiredness, oesophageal soreness, skin change and lung inflammation. Chemotherapy can cause infection risk, nausea, neuropathy, kidney injury and blood count abnormalities. Targeted medicines and immunotherapies have treatment specific effects. The oncology team provides written emergency advice because new symptoms may reflect treatment toxicity rather than cancer progression. Follow up after curative treatment Follow up assesses recovery, treatment effects and possible recurrence. Imaging schedules vary according to treatment and local protocol. People should know how to contact the lung cancer nurse between appointments. A new symptom should not wait for the next scheduled scan. Smoking cessation, rehabilitation, nutrition and psychological support remain relevant after treatment ends. Prognosis is not determined by one label Outcome depends on stage, histology, molecular biology, general health and treatment response. Early NSCLC can often be treated with curative intent. SCLC can respond dramatically to initial treatment but has a high risk of recurrence. Targeted treatments have changed the outlook for some driver positive NSCLCs. Population statistics cannot predict exactly what will happen to one person. Emotional and practical effects Lung cancer can affect breathing, mobility, work, finances and family roles. Stigma can intensify distress and discourage people from seeking support. Anxiety, depression and fear of breathlessness deserve active treatment. Lung cancer nurses, rehabilitation, welfare advice and palliative care services can provide practical help. Support should include relatives and carers when the person wishes. What this lesson should not be used for This lesson cannot diagnose lung cancer from a cough, chest pain, past or current smoking or CT report. It cannot determine histological type, stage or molecular treatment from imaging alone. Do not wait for screening when symptoms are present. Do not assume that a pulmonary nodule is cancer or that a normal chest X ray excludes cancer. Seek medical assessment for persistent respiratory symptoms and urgent help for severe bleeding, breathing difficulty or neurological deterioration.

Lung cancer includes several distinct diseases. The first major distinction is between NSCLC and SCLC because they spread and respond to treatment differently. Stage helps determine whether treatment can aim for cure, while histology, molecular drivers and immune biomarkers help identify which surgery, radiotherapy, chemotherapy, targeted therapy or immunotherapy is likely to help.