The short answer
NCI states that after a lung cancer is removed, there is a 1% to 2% risk per patient per year that a second lung cancer will occur. That is a separate new cancer, not the old one returning, and it is a large part of why scanning continues for years.
NCI states that after a lung cancer is removed, there is a 1% to 2% risk per patient per year that a second lung cancer will occur.
Surgery is not one operation. NCI describes lobectomy along with segmental, wedge and sleeve resection, and notes people with impaired lung function are candidates for the smaller ones.
NCI reports radiation pneumonitis in fewer than 10% of people treated with focused radiation for early lung cancer. It is not the same as ordinary scarring.
Smoking cessation reduces precancerous changes and lowers risk, and former smokers still keep an elevated risk for years after quitting.
Choose how you want to understand this
The full explanation.
How much lung was taken out
Surgery for lung cancer is not one operation. NCI describes lobectomy, and also segmental, wedge and sleeve resection.
The smaller operations exist partly for a reason that matters after treatment. NCI notes that people with impaired lung function are candidates for a segmental or wedge resection instead.
So ask which one you had. Then ask what your breathing tests showed before, and what they show now.
The 1 to 2 percent a year problem
This is the number few people are told.
NCI states that after a lung cancer is removed, there is a 1% to 2% risk per patient per year that a second lung cancer will occur.
That is a separate new cancer, not the old one returning. It is a large part of why scanning continues for years.
Radiation, the lung and the cough that follows
Radiation can inflame lung tissue. NCI calls this radiation pneumonitis, and reports it in fewer than 10% of people treated with focused radiation for early lung cancer.
It is not the same as ordinary scarring. Ask which of your symptoms would count as pneumonitis, and who to call at 2am.
Late effects from drugs you have already stopped
Immunotherapy can leave the thyroid underactive. NCI lists hypothyroidism among the common side effects of pembrolizumab and of atezolizumab combinations.
Platinum-based chemotherapy can leave numbness in the hands and feet. NCI lists peripheral neuropathy among common reactions to chemotherapy combinations for lung cancer.
Ask which blood tests would catch a late thyroid problem.
Questions for your lung clinic visit
- Which operation did I have, and how much lung capacity should I expect back?
- What did my pulmonary function test show, and when is the next one?
- How do I tell radiation scarring from radiation pneumonitis?
- I finished immunotherapy. Should my thyroid still be checked, and how often?
- Is the numbness in my feet from chemotherapy likely to improve?
- Am I being watched for a new second lung cancer as well as for this one coming back?
- Can you refer me to a program that helps with breathing and exercise?
Quitting still changes your numbers
NCI puts it flatly. Smoking cessation reduces precancerous changes and lowers lung cancer risk.
It also gives the honest caveat. Former smokers keep an elevated risk for years after quitting.
Both things are true at once. Ask for real quit support, not a leaflet.
When to ask a second lung team
Worth doing if your follow-up plan has no end date, if a new nodule is being watched without a stated trigger for action, or if breathlessness is being treated as inevitable.
Related pages
Try these next: Watching for Cancer Recurrence, Fear of Recurrence, Cancer Staging, and Questions to Ask Your Doctor.
Where this comes from
Words to know
Tap any term to see what it means.
Common questions
Is a second lung cancer the same as a recurrence?
No. A second lung cancer is a separate new cancer, not the old one returning. NCI puts that risk at 1% to 2% per patient per year after a lung cancer is removed. Ask whether you are being watched for both.
What is radiation pneumonitis?
Inflammation of lung tissue after radiation. NCI reports it in fewer than 10% of people treated with focused radiation for early lung cancer. Ask which of your symptoms would count as pneumonitis, and who to call at 2am.
Should my thyroid still be checked after immunotherapy?
Ask. NCI lists hypothyroidism among the common side effects of pembrolizumab and of atezolizumab combinations, so ask which blood tests would catch a late thyroid problem.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Your next step
Turn this topic into questions for your next appointment.
Speak With Trained Specialists & Human Navigators
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Immediate emergency guidance for fever (>100.4°F during chemo), severe pain, or shortness of breath.
Help Us Improve This Guide
Did this explanation answer your question and help you determine your next step?
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Sources last checked: 2026-07-30 what this meansLast updated: 2026-08-16Next planned review: 2028-07-30
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status — Source checked. This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
Related articles
Still have questions?
Educational answers, plain language
Free to print and share