Everyone has days when they’re low on energy, but you should feel refreshed after a good night’s sleep or two. If you notice you’re tired every day for more than a month, or experience shortness of breath when you didn’t before, see a doctor, says Dr. Wender. “Most of the time it won’t be cancer, but get it checked because you never know.” Leukemia and lymphoma commonly cause persistent fatigue. These are other medical reasons you could be tired all the time.
If you’re not prone to migraines and never get headaches, but suddenly find yourself popping ibuprofen every day, it could be a brain cancer symptom, which causes pain by pressing on nerves.
Blood in the stool
Most likely it's something benign, like hemorrhoids. But this can be a sign of colon cancer. Cases are increasingly common in people under the age of 50—the age at which colon cancer screening is typically first recommended—Dr. Wender says it’s important to get checked out. “It’s easy to dismiss it as hemorrhoids or constipation, and if the problem comes and goes, people reassure themselves that nothing’s wrong, especially younger people,” he says. “But blood in a bowel movement is never normal, so get it checked out.”
Noticeable skin changes
iStock/Willie B. Thomas
Skin cancer is the most common cancer in America, but it’s also one of the trickiest to recognize the early signs, says Dr. Wender. “Skin cancer is a tough one—many people think freckles, moles, or a darker age spot is just like the others they’ve had,” he says. Dr. Wender says if you notice a mole getting darker, larger, or becoming raised, get it checked out. Melanoma skin changes are easier to identify because those spots are often irregularly shaped as opposed to round, significantly darker in color, or even two distinctly different colors within one spot, he says. “Melanoma is far less common than other skin cancers but has the potential to be more deadly,” says Wender. “However, many melanomas have a long period where they’re not invasive and easy to cure, as long as they’re caught early.” These are sneaky places you didn't realize you can get skin cancer.
Sores or pain in the mouth
A cold sore that heals is probably nothing to worry about—Try one of these homemade cold sore remedies to resolve the issue—nor is a toothache that goes away after a trip to the dentist. But if you notice sores that don’t heal, pain that sticks around, white or red patches on the gums or tongue, and any swelling or numbness of the jaw it could be a sign of some mouth cancers. If they persist for longer than two weeks, the American Cancer Society suggests seeing a doctor.