Lung cancer

Lung cancer begins in the lung. A cancer from another organ that spreads to the lung is treated according to its original type, so finding a lung mass is only the start of the diagnosis. A nodule on a scan can also be benign. Imaging estimates the likelihood of cancer and its extent; pathology usually identifies what it is.

Smoking is a major risk factor, but people who have never smoked can develop lung cancer. Radon, occupational exposures, air pollution and other factors also matter. A smoking history helps plan care and prevention; it should not replace a complete diagnostic assessment or determine whether someone deserves treatment.

• Persistent or changing cough, blood in sputum, chest discomfort or breathlessness.
• Unexplained weight loss, fatigue, hoarseness or recurrent chest infections.
• Symptoms outside the chest, including persistent bone pain or new neurological changes, may need assessment for spread or another cause.

Large amounts of coughed-up blood, severe or rapidly worsening breathlessness, new weakness, seizures or marked swelling of the face and neck require urgent medical assessment. These symptoms are not suitable for waiting on a routine online consultation. Less dramatic symptoms can still deserve investigation if they persist.

Neuroendocrine lung tumors are not all small cell cancers. Carcinoid tumors and large-cell neuroendocrine carcinoma require appropriate pathology interpretation. A tumor of the pleura, such as mesothelioma, is also a separate diagnosis. If a report says only 'carcinoma' or 'malignant cells', ask whether further typing is possible before a treatment decision.

Plan the biopsy around the decision

A biopsy may be taken through bronchoscopy, ultrasound-guided sampling of chest lymph nodes, a needle through the chest wall, pleural fluid sampling or another accessible site. The safest useful sample is not always the largest lung lesion. A sample that establishes both diagnosis and spread can avoid another procedure. The team should also consider whether enough material will remain for relevant molecular tests.

Scans and fitness assessment answer different questions

CT, selected PET-CT and brain imaging help assess disease extent. Suspicious lymph nodes sometimes require sampling because inflammation can also produce an abnormal scan. Lung function, heart health, organ function and day-to-day activity help determine whether a proposed operation, radiation course or medicine is tolerable.

TNM records the primary tumor (T), regional lymph nodes (N) and distant metastases (M). Current IASLC/AJCC lung staging uses the ninth-edition/version 9 framework. Older reports and trials may use an earlier edition, so ask which system was used rather than assuming an apparent stage change means the cancer has grown. The full T, N and M findings are useful when comparing opinions.

Small cell lung cancer also uses limited-stage and extensive-stage descriptions for treatment planning. In any lung cancer, 'not suitable for surgery' does not by itself mean there is no active treatment. A tumor may be technically unresectable, or an operation may be too risky for the patient's lung function; these are different problems with different alternatives.

In appropriate NSCLC settings, molecular testing looks for tumor changes that can make a matched medicine relevant. PD-L1 assesses a protein and helps with certain immunotherapy decisions; it is not the same test as a gene panel. The exact alteration matters: a gene name alone does not establish that a particular drug will work.

A result described as 'negative' should be read with the method, genes covered, sample quality and timing. Tumor profiling is different from inherited-risk testing, and a tumor mutation does not automatically mean relatives carry it. Ask what each proposed test would change before paying for more testing.

Localized disease

When disease is confined and treatment is feasible, the plan may aim for cure using surgery, precisely delivered radiotherapy or a combination with systemic medicines. For selected early NSCLC patients who cannot undergo surgery, stereotactic body radiotherapy can be considered. Surgery is not the usual pathway for most small cell cancers.

Locally advanced and metastatic disease

Locally advanced lung cancer often needs a coordinated plan involving medical oncology, thoracic surgery and radiation oncology. Metastatic disease generally needs systemic treatment, with local procedures for selected disease sites or symptoms. Treatment may include chemotherapy, immunotherapy or a biomarker-matched medicine. A drug that is appropriate for metastatic cancer is not automatically suitable before or after surgery.

Breathlessness can have several causes, including fluid around the lung, infection, airway obstruction, blood clots or treatment-related inflammation. Report new or worsening symptoms rather than assuming the tumor alone is responsible. Supportive care can address pain, appetite, fatigue, anxiety and practical needs while anticancer treatment continues.

Ask about pulmonary rehabilitation, activity suited to your capacity, nutrition and smoking-cessation support if relevant. Palliative care is an additional layer of symptom and decision support and can begin alongside active cancer treatment; it is not restricted to the final days of life.

Low-dose CT screening is intended for eligible people without symptoms, based on the screening program's risk criteria. It is different from investigating symptoms or monitoring a known cancer. Screening can detect disease earlier, but can also lead to false alarms, additional procedures and overdiagnosis. A blood test or routine chest X-ray is not an interchangeable substitute for an evidence-based low-dose CT screening program.

A nodule follow-up interval depends on its size, appearance, growth and the person's risk. Keep prior scans for comparison. Do not use a general screening interval to decide how long to wait after an already suspicious finding.

• The original pathology report and information on where tissue or slides are stored.
• Recent CT and other staging images, reports and earlier scans for comparison.
• Complete molecular and PD-L1 reports, including the sample type, date and testing method.
• Previous surgery, radiotherapy plans and medicine history, with response and important side effects.
• Lung function, other medical conditions, current medicines and the main question you want the review to answer.