The short answer
You do not need to worry about every ache. The symptoms most worth checking are those that are new, last more than a couple of weeks, keep getting worse, or are unusual for you. Getting checked early brings peace of mind and, if needed, earlier treatment.
Most symptoms are not cancer, so there is no need to panic over every change.
Check symptoms that are new, lasting, worsening, or unusual for you.
Blood in the stool or urine, a new lump, or a changing mole are always worth checking.
Getting checked early brings peace of mind and, if needed, earlier treatment.
Choose how you want to read this
The whole article, with every detail and caution.
The simple version
This page helps you decide when a symptom is worth getting checked. It is not helpful, or possible, to worry about every ache and cough. The goal is to know which changes matter. Then you can act on those and let go of the rest.
When to get help sooner
NCI says to see a doctor if symptoms do not get better after a few weeks. This page uses a cautious two-week guide for slow symptoms. It is the wrong tool for the ones below.
- Call 911 or go to an emergency department if… you have severe difficulty breathing, or your lips and skin look blue, grey or pale.
- Call 911 or go to an emergency department if… you have chest pain or discomfort, or pain in an arm, shoulder, jaw, neck or back (CDC lists these as heart attack signs). Do not drive yourself.
- Call 911 or go to an emergency department if… bleeding will not stop, you vomit blood, or your stools are black and tarry.
- Call 911 or go to an emergency department if… your face droops, an arm goes weak or numb, speech slurs, or you suddenly lose balance or vision, or have a sudden severe headache or confusion. Call even if it passes (CDC stroke signs). Do not drive yourself.
- Call 911 or go to an emergency department if… you have sudden severe pain in one testicle, or a seizure. MedlinePlus calls pain in the testicles an emergency.
- Call your care team the same day if… you see blood in your urine, bleed after menopause, or cough up any blood. MedlinePlus advises contacting a provider any time you cough up blood. Get help right away if it is more than a few teaspoons, or comes with chest pain or severe shortness of breath.
Waiting suits many symptoms and none of these.
The pattern that matters
For almost any symptom, the same pattern signals it is worth checking:
- New — something you have not had before.
- Lasting — it does not go away after a couple of weeks.
- Worsening — it keeps getting worse.
- Unusual — it is not normal for you.
Always worth checking
A few symptoms should always be checked, even if they are brief:
- Blood in the stool or urine.
- A new lump.
- A changing mole.
- Unexplained weight loss.
- Unusual bleeding.
These do not always mean cancer, but they should be checked.
Your doctor would rather see you for something minor than have you wait on something serious.
Checking early helps
Many cancers are easier to treat when found early. And even when a symptom turns out to be harmless — which it usually is — getting it checked brings peace of mind.
Sources
Common questions
How do I know if a symptom is serious?
The pattern matters more than any single symptom. Symptoms worth checking are new, last more than a couple of weeks, keep getting worse, or are unusual for you.
Which symptoms should never be ignored?
Always get checked for blood in the stool or urine, a new lump, a changing mole, unexplained weight loss, or unusual bleeding. These do not always mean cancer, but they should be evaluated.
What if I'm worried it's nothing?
Doctors would much rather check something minor than have you delay on something that turns out to be serious. Getting checked is reasonable, not an overreaction.
Why does checking early help?
Many cancers are easier to treat when found early. Even when a symptom turns out to be harmless, getting it checked brings peace of mind.
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).
Talk with a trained specialist or navigator
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
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
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: 2026-07-21 what this meansLast updated: 2026-10-02Next planned review: 2027-07-21
Review details and limits
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. 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.
Words to know
Tap any term to see what it means.
Knowledge check
0 of 3 answered
This self-assessment checks understanding of educational content only. It is not medical advice.
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. 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.