HD and Cancer

Splitting cancer cells

I recently had my annual full body scan by my dermatologist for skin cancer.  When he entered the examining room I threw my hands up and said, “I plead guilty to running shirtless in the summer without sunscreen!” It was obvious from my perpetual upper body tan, which fades a little in winter.

In my defense, I mentioned the research that, contrary to conventional medical knowledge, exposure to natural sunlight protects against cancer. I have had 3 minor bouts with basal cell skin cancer in the past two years, my first. My doctor is amazed that I got to age 66 free of any kind of skin cancer. He sort of agreed with me that at age 68 it doesn’t make sense to slather myself with SP50 sunscreen every time I go outside.

I have wondered if having the HD gene is providing me with cancer protection. In 1999 a study in Denmark looked at a A total of 694 patients with Huntington disease who had survived at least to age 45 years during the period 1943-1993, and 695 individuals at risk and at least age 55 years during the same period, were selected from the Danish Huntington Disease Registry. The occurrence of cancer was determined from the files of the Danish Cancer Registry and compared with national incidence rates for various categories of tumors.

The overall incidence of cancer was significantly lower among patients with Huntington disease, but not among their healthy relatives. The standardized incidence ratio for the Huntington patients was 0.6, which means that HD patients would have had 60 cancers compared to 100 in the general population. The lower incidence was seen for cancers of all major tissues and organs except the buccal cavity and the pharynx.

This study gave rise to an anecdotal belief that there was one good thing about having the HD gene. A follow-up study of a much larger sample was done in Sweden in 2012 and the results were shocking.

Looking back over many years of data, the researchers found 1,510 cases of HD, 471 cases of SBMA and 3,425 cases of SCA. SBMA and SCA are also “CAG Repeat” diseases. Cross-referencing the cancer database revealed a surprising fact - all the mutation carriers examined had a lower incidence of cancer.

With cancer and the CAG-repeat diseases, researchers found an overall incidence ratio of between 0.4-0.7, depending on the mutation and tumor type studied. The ratio for HD was .47, which would mean that HD patients would have only 47 cancers compared to 100 in the general population.  Parents of gene carriers who did not carry the genes themselves had incidence ratios that were the same as the general public.

Outside of that minor basal cell stuff, I have been cancer free. I had my first colonoscopy at age 60 and it was clean, except for two small polyps which were snipped. I had a second one done about 3 years ago as part of an operation called Procedure for Prolapsed Hemorrhoid (PPH).  I’m glad I was put under for that. The machine used was about the size and shape of an artillery shell – no wonder my butt was sore. My gastroenterologist, a grandmotherly looking lady, said I should never have to worry about colon cancer.

I have been having regular prostate exams since I was 20. They have all been normal. I have been having PSA blood tests done for about the last 10 years and those have all been normal. My primary care doctor tells me the chances of developing prostate cancer seem very small. Speaking of small, my prostate examiner is a lady with very small fingers. The men reading this will understand why that’s a great feature in a physician.

My only sibling is a brother 3 years younger. His CAG count is 43, higher than mine of 40. Unfortunately, he is in the late stages of the disease as of this writing. However, he has NEVER had cancer of any kind.

My father was the gene carrier in our family. We never knew this until my brother began showing symptoms. He may have had behavioral and cognitive symptoms of HD, but the family blamed his alcoholism on his World War experience as a combat Marine. My mother died of old age in her late 80’s with no symptoms, so the gene had to have come from him.

Dad died at age 58 of cancer. He had had a growth removed from an ear in his early 40’s. It was cancerous and he had a bunch of lymph nodes removed from his neck and shoulder. That was supposed to eradicate the cancer, but it didn’t. His autopsy showed that the metastasis began there.

He had been a heavy smoker, which may have been a contributing factor. When he took sick, they did a very uncomfortable lung biopsy. When it was finished he asked the doctor, “What did you find in there, a Pack of Camels?” His Marine Corps black humor was alive and well.

So, the incidence rate for our family is .33 (one of 3). We may have the disease, but we beat the HD cancer odds of .47!!