Lung Cancer Risk Calculator

Lung cancer risk reflects the combined influence of tobacco exposure, age, inherited susceptibility, environmental hazards, and other health factors. Cigarette smoking is the dominant preventable cause. A common way to summarize cumulative exposure is pack-years: packs smoked per day multiplied by years smoked. Twenty cigarettes are conventionally treated as one pack, so twenty cigarettes daily for thirty years equals thirty pack-years. Pack-years simplify a complex history and do not capture inhalation depth, tobacco type, interruptions, or changes over time. This calculator presents an educational index rather than a percentage probability. It gives increasing weight to older age and greater pack-year exposure, and notes first-degree family history plus radon or occupational exposure. Examples of occupational hazards include asbestos, silica, diesel exhaust, arsenic, chromium, and nickel compounds. The index deliberately remains transparent, but it is not a substitute for validated models such as PLCOm2012 or for national screening criteria. Low-dose computed tomography can reduce lung cancer mortality in selected people at high risk, but screening also has potential harms. These include false-positive findings, incidental findings, anxiety, radiation exposure, and invasive follow-up of benign nodules. Eligibility differs by country and can change as evidence evolves. In the United States, current recommendations commonly consider age, pack-years, and whether a person currently smokes or quit within a specified period. A clinician should confirm the applicable criteria, overall health, willingness to undergo treatment, and individual benefits and harms. Stopping smoking lowers risk at every age and is the most important action for people who smoke. Risk falls over time after quitting, although it may remain above that of someone who never smoked. Radon testing and workplace controls can reduce additional exposure. Symptoms such as coughing up blood, a persistent or changing cough, unexplained weight loss, chest pain, breathlessness, recurrent pneumonia, or new hoarseness require medical review and should never be routed through a screening calculator. Screening is intended for people without symptoms. Use the result to organize a conversation with a qualified professional, not to reassure yourself or predict whether cancer is present.