Second Cancers After Prostate Cancer

Medically Reviewed by Melinda Ratini, MS, DO on May 25, 2022
5 min read

Your doctor may give you a clean bill of health after prostate cancer treatment, which is great news. The not-so-good news is there’s a chance you could get a different cancer unrelated to your prostate cancer. That's called a second cancer.

You can get any type of cancer after treatment. But prostate cancer itself puts you at higher risk for certain types. Some of them are more likely if you received radiation as part of your treatment.

It’s not always possible to prevent a second cancer, but lifestyle changes can lower your odds and boost your overall health and well-being.

You’re more likely to get a second cancer if:

  • You’re older.
  • You smoke.
  • You had radiation therapy that harmed nearby tissue, such as in the bladder or rectum.

You can get any type of second cancer, even in parts of the body far from the prostate. These cancers are among the most common:

Bladder cancer. Most bladder cancers start in cells in the deepest lining of your bladder. Cancer that grows into or through other layers is more advanced and harder to treat. If your doctor finds and treats the tumor early, you have a better chance of a good outcome.

Bloody urine is one of the first signs of bladder cancer. You may see just a little or enough to turn your urine pink, orange, or darker red. The blood might go away for weeks or even months. But it’ll come back if you have bladder cancer.

Keep in mind that many things can cause blood in your urine, including infections and kidney stones. Bladder cancer is much less common. Still, you should get checked if you see it, especially if you have trouble peeing or pee more than normal.

You should also be on alert for symptoms of bladder cancer if you had radiation to your prostate. Your bladder lies close to the prostate and can be affected by radiation treatments.

To help lower your risk:

  • Don’t smoke. (Research suggests about half of bladder cancers are caused by smoking.)
  • Drink plenty of water.
  • Choose a Mediterranean-style eating plan.

Study after study has shown that Mediterranean-style eating lowers your risk of cancer, along with several other conditions. It limits red meat, sugar, and processed foods. Instead, foods like fresh fruits and veggies, oily fish like salmon, and olive oil are recommended.

Rectal cancer. This type of cancer starts in the rectum, the last 6 inches of the large intestine. Most rectal cancers start as small growths called polyps, though many polyps never become cancer.

In some studies, radiation to the prostate upped the odds of rectal cancer as much as 70%, but not all studies found this. A lot depends on the type of radiation. Types that may raise your risk of rectal cancer are:

  • External beam radiation
  • Intensity-modulated radiation
  • Brachytherapy (internal radiation)

Your doctor will want to see you regularly for regular visits. They might also ask you to get a surveillance colonoscopy every few years.

Be sure to let your doctor know if you notice signs of rectal cancer, including:

  • A change in bowel habits such as diarrhea or constipation that doesn’t go away in a few days
  • Dark blood in your stool
  • Belly cramps and bloating
  • Weight loss for no reason

Cancer can start in any part of the small intestine, the longest section of your GI tract. Like rectal cancer, it usually begins with a small growth called a polyp. Common symptoms include:

  • Belly pain or cramps, especially after eating
  • Nausea and vomiting
  • Blood in your stool
  • Weight loss without trying

These symptoms can have many causes, but it’s important to tell your doctor about them to rule out cancer.

You can’t change some of the factors that make you more likely to get cancer in your small intestine, such as older age, being African American, and health problems passed down from parents and grandparents. But you can control other factors, including:

  • Smoking
  • Alcohol use
  • A diet high in red meat and salted or smoked foods

Almost everyone who receives radiation therapy has some skin damage. The kind and severity of damage depends on your age, your skin, the area treated, and the dose. During treatment, your skin might peel, bleed, and blister, and wounds may be slow to heal. Years later, cancer might form, including melanoma, the most serious type. While you receive radiation, do all you can to protect, cleanse, and heal your skin. Afterward, wear sun-protective clothing and see your dermatologist often for skin cancer checks.

Soft tissue sarcoma. This rare type of cancer can start in any of the body’s soft tissues, such as fat, muscle, nerves, and blood vessels. It’s often a side effect of radiation treatment, but may take up to 10 years to develop.

Soft tissue sarcomas start in the arms, legs or belly. You may feel a lump that grows over time. Some symptoms don’t come from the tumor itself but from problems it causes, such as bleeding or a blockage in your GI tract. Tell your doctor if you have:

  • A new or growing lump anywhere on your body
  • Belly pain that doesn’t go away or gets worse
  • Black or bloody bowel movements

Sometimes an injury or inflammation can cause a mass that looks like a soft tissue tumor, but the mass isn’t cancer and doesn’t grow or spread.

Cancer sometimes starts in endocrine glands like your thyroid or thymus – small glands that play a big role in your health. The thymus, located between your lungs, makes white blood cells that fight infection. The thyroid, a butterfly-shaped gland at the base of your neck, regulates blood pressure, heart rate, body temperature, and weight.

These cancers may not cause symptoms at first. Later, thyroid cancer may cause:

  • Hoarseness
  • Trouble swallowing
  • Pain in your neck or throat

Symptoms of thymus cancer include:

  • Cough
  • Trouble swallowing
  • Chest pain
  • Weight and appetite loss for no reason

The thyroid gland is especially sensitive to radiation, and even low doses may lead to cancer. Thymus cancers, while rare, are also more likely if you’re exposed to radiation.

You can’t completely prevent a second cancer, but these steps can help you stay as healthy as possible:

  • Maintain a healthy weight.
  • Stay active.
  • Try a mostly plant-based diet that includes lots of fruits, vegetables, and healthy fats like olive oil. Don't eat red meat, sugar, and processed foods.
  • Don't drink alcohol.