Cancer Symptom Checker

Understanding Cancer Warning Signs

Early detection is one of the most important factors in successful cancer treatment. When cancer is found early — before it has had a chance to spread — treatment is more likely to be effective. The American Cancer Society estimates that regular screening and early detection could prevent tens of thousands of cancer deaths each year.

General Red Flags Across All Cancers

While each cancer type has specific symptoms, these general warning signs apply across many cancers:

• Unexplained weight loss: Losing 10+ pounds without trying may be the first sign of cancers of the pancreas, stomach, esophagus, or lung
• Persistent fatigue: Extreme tiredness that doesn't improve with rest
• Unexplained pain: Persistent pain that has no clear cause
• Skin changes: Darker, yellowish, or reddish skin, itching, or excessive hair growth
• Changes in bowel or bladder function: Long-term constipation, diarrhea, or change in stool size
• Sores that don't heal: Persistent sores on the skin or in the mouth
• Unusual bleeding: Blood in cough, stool, urine, or abnormal vaginal bleeding

When to See a Doctor

Don't wait for symptoms to become severe. See your doctor if any symptom persists for more than 2-3 weeks, gets progressively worse, or is unusual for you. Having one or more of these symptoms does not necessarily mean you have cancer — many conditions cause similar symptoms. But early evaluation is always the safest approach.

Cancer Screening vs. Symptom Checking

Symptom checking helps you recognize potential warning signs, but it is not a replacement for regular cancer screenings. Screenings (like mammograms and colonoscopies) can detect cancer before symptoms even appear, which is when treatment is most effective. Use our Cancer Screening Guide to find which screenings are recommended for your age and gender.