Rectal bleeding likely due to radiation

Dear Dr. Roach: I am an 84-year-old man. I had an enlarged prostate that was treated by radiation in 2018 for 15 days.

I had no problems, but for the past few months, I have had some rectal bleeding that lasts for a day, then nothing for two to three days. Sometimes I bleed when I pass gas.

Is this normal for someone my age? What could be the problem?

D.K.

Answer: This not normal, by any means. This is very likely to be radiation damage from your treatment back in 2018.

Radiation is not used to treat benign enlarged prostate, but it is used to treat prostate cancer. It’s a common treatment that generally has fewer side effects than surgery; however, radiation proctitis is a problem that can result. Sometimes, the symptoms begin right after radiation (within six weeks), but chronic radiation proctitis usually shows up about a year after the treatment.

Symptoms include diarrhea, rectal pain, a sense of urgency to defecate and bleeding. The risk is higher with higher doses of radiation. The diagnosis should be confirmed. This includes being sure there are no other likely causes. You’ll need a colonoscopy, preferably with biopsies. If the diagnosis is confirmed, treatment for the chronic form of radiation proctitis with recurrent bleeding may include medicated enemas. More severe bleeding may require endoscopic treatment. You should see a gastroenterologist.

Dear Dr. Roach: I am a 77-year-old woman. I am extremely allergic to mercury, and all products that have it as a preservative, such as lotions, makeup, etc. My pharmacist made sure my flu shot was safe for me to get. Can you tell me if the COVID-19 vaccines contain mercury? I am also concerned about the shingles vaccine.

D.K.

Answer: Thiomersal is a mercury-containing preservative used in some vaccines, such as the multidose flu vaccines. However, there is no thiomersal in either the Pfizer or Moderna COVID-19 vaccines. There is also no thiomersal in the available shingles vaccines.

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