Screening guide › Lung screening
Lung screening
The Ontario Lung Screening Program offers a risk assessment, and low-dose CT screening if eligible, to people 55–80 who have smoked commercial tobacco daily for at least 20 years in total.
- Referral criteria
- Age 55–80 (public summary), OHIP coverage, and daily commercial tobacco smoking for at least 20 years in total — not necessarily consecutive, not a pack-year threshold.
- Commercial tobacco
- Cigarettes, cigars, loose tobacco, pipes or bidi/beedi. Vaping, cannabis, chewing tobacco or second-hand smoke alone do not meet the criterion.
- Assessment vs screening
- Meeting referral criteria allows a risk assessment; screening (LDCT) happens only if the assessment finds you eligible.
- Access
- Clinician referral, or contact a program location to ask about assessment; a clinician referral is required before participation.
- Not routine
- Known lung cancer, lung nodule surveillance, or symptoms needing investigation.
What this page helps with
Lung screening uses a low-dose CT scan to look for early lung cancer in people at high risk who have no symptoms. This page explains the Ontario program's entry criteria, the difference between being assessed and being eligible, and how to get in touch. It does not estimate your risk — the program does that.
Symptoms are not screening. If you have new or concerning symptoms, arrange assessment rather than a screening test. Severe or life-threatening symptoms: call 911 or go to the nearest emergency department; otherwise a provider, walk-in or urgent care clinic, or Health811 (811).
Who the routine guidance is for, and who needs another pathway
Referral criteria. Public Ontario information describes ages 55–80 with OHIP coverage and a history of smoking commercial tobacco — cigarettes, cigars, loose tobacco, pipes or bidi/beedi — every day for at least 20 years in total. The 20 years do not need to be in a row, and the criterion is years of daily smoking, not pack-years and not time since quitting.
Assessment, then eligibility. Meeting the criteria allows a formal risk assessment by the program using several factors (age, smoking history, health history, family history and others). Only people whose assessed risk meets the program's threshold are eligible for screening. So contacting the program does not guarantee a scan.
Other exposures. Vaping, cannabis, chewing tobacco or second-hand smoke alone do not meet the listed smoking criterion. That is a statement about program entry, not that these exposures are harmless; symptoms still need assessment and quitting support is available.
Over 80. Public summaries describe 55–80, while the program's referral form also describes continued screening for some existing participants over 80. If you are already in the program, ask your OLSP team; if not, discuss with your provider. This site does not decide eligibility over 80.
Not routine. Known lung cancer, lung nodule surveillance, or symptoms such as coughing up blood or unexplained weight loss follow a diagnostic or follow-up pathway, not new screening.
How to access it in Ontario
A family doctor or nurse practitioner can refer you. You can also contact an Ontario Lung Screening Program location directly to ask about an assessment; a clinician referral is required before screening participation, and the program can advise on access for people without a provider. OHIP coverage is part of the criteria. See No family doctor?.
Potential benefits and limitations
In people at high risk, screening can find lung cancer earlier, when treatment is more likely to be effective. Limitations: many scans show nodules that are not cancer and need follow-up scans; there is a small radiation dose with each scan; and screening does not lower the risk that comes from continuing to smoke — quitting has a larger effect. Screening is not a way to investigate symptoms.
What the assessment and scan involve
The program contacts you for a risk assessment (usually by phone) and, if eligible, a conversation with a navigator about benefits and harms before you decide. The low-dose CT scan itself takes a few minutes, with no needles or contrast, lying on a table while it images your chest. Results go to you and your provider, with a repeat scan schedule if you continue in the program.
What happens after an abnormal result
Most nodules found are not cancer. Depending on size and appearance, the next step is usually a repeat CT after an interval, sometimes other imaging or a specialist review, and occasionally a biopsy. The program coordinates this; this page cannot interpret your result.
Questions to ask your provider or the program
- Do I meet the referral criteria, and what does the risk assessment involve?
- What are the chances of a false alarm and follow-up scans?
- I have quit — does that change anything?
- What support is there to stop smoking?
Sources and when they were checked
- R05 — Lung Cancer Screening (program information), Michael Garron Hospital, Ontario Lung Screening Program site. Current page describes commercial tobacco (cigarettes, cigars, loose tobacco, pipes, bidi/beedi).
- R06 — Lung cancer screening access, Ontario Health. Describes ages 55–80 and daily tobacco for 20+ years.
- R04 — OLSP referral form (January 2026), Ontario Health, hosted by Michael Garron Hospital. The PDF itself could not be retrieved during the 2026-09-15 check; criteria were confirmed from R05 and R06. Earlier 2025 forms said cigarettes only.