In the past five years, I have lost both parents, two uncles and both grandparents to cancer. My sister was diagnosed three years ago with ovarian cancer (she is now 49). Ten years ago, I had my right ovary removed because of a tumor that was benign. Two years ago, my uterus was removed, but my doctor refused to remove the left ovary. My concern is our family history of cancer. Ovarian cancer is hard to detect. Why should I take that risk?
My sister just had surgery for a ruptured colon. My mother had colon cancer in 1988, and one of my older sisters and I had breast cancer two years ago. My sister and I are in our 50s, and our mother is in her 70s. Are our other siblings also at risk for cancer?
There are now quite a few inherited cancer syndromes known. Most, thankfully, are fairly rare, but a couple are common and have been in the news in recent years: the BRCA I and II mutations, and the hereditary nonpolyposis colon cancer (HNPCC) mutations.
Current estimates are that 5 to 10 percent of breast cancers can be attributed to an inherited gene mutation. The mutation called BRCA I is found in about 1 in 500 people (the incidence is higher in Ashkenazi Jews). Women carrying this mutation have a high risk, perhaps as high as 85 percent, of developing breast cancer during their lifetime, and perhaps a 50 percent risk of developing ovarian cancer. They often develop the cancers at a young age. Men carrying the mutated gene have an increased risk of prostate cancer, and tend to develop the disease at an earlier age.
There are estimates that 1 in 200 people carry one of the mutations leading to HNPCC. This syndrome is usually suspected if colon cancer occurs in at least three first-degree relatives in at least two generations, with at least one case in a person under 50 years of age. (First-degree relatives are parents, children, brothers and sisters. Aunts, uncles, cousins, etc. are not considered to be first-degree relatives.)
Since cancer is now the second most common cause of death in the United States, there are many families who have several members with cancer purely by chance. Even if one looks only at breast cancer, the disease is so common, with a woman’s lifetime risk of developing it estimated at 1 in 8, that it is not at all unusual to see families with two first-degree relatives with breast cancer purely by chance. The likelihood of an inherited cancer syndrome increases if the affected people are young, since cancers that are not inherited remain predominately a disease of older people.
Do the families of our two writers today seem to have an inherited cancer syndrome? I don’t have enough information about either family to say what that likelihood might be. The first family has an impressive number of cancer cases in it, but we only know specifically about the writer’s sister, who did have ovarian cancer at an early age. If her mother had breast or ovarian cancer, or her father prostate or colon cancer, then the likelihood of a familial syndrome would be high, and it would perhaps be useful for her to be tested for the BRCA I mutation. If positive, that would make me much more willing to advise her to have that other ovary removed, and to be followed closely with breast exams and mammograms to catch any breast cancer early. Some doctors are now advising female carriers of a BRCA I mutation to have both breasts and both ovaries removed, but there is much controversy over this. As one authority points out, having both breasts removed is quite mutilating compared to having a lumpectomy if cancer develops.
It has been known for many years that taking birth control pills when young greatly reduces a woman’s risk of getting ovarian cancer (and endometrial cancer, a cancer of the lining of the uterus). A recent study was done to see if taking birth control pills would reduce the risk of ovarian cancer for carriers of a BRCA I mutation (Modan, B., Hartge, P., Hirsh-Yechezkel, G. et. al. Parity, Oral Contraceptives, and the Risk of Ovarian Cancer Among Carriers and Noncarriers of a BRCA I or BRCA II Mutation. New England Journal of Medicine. July 26, 2001;345:235-240). Unfortunately, the incidence of ovarian cancer was not reduced in the women with the mutation who took birth control pills, although it was halved in the women without the mutation.
The status of our second writer’s family is harder to determine since we were not told if the sister with the rupture of the colon had that because of cancer, and because her mother’s cancer developed after the age of 50. Therefore, the family would not fit the definition for HNPCC, nor do the two breast cancers necessarily point to a BRCA mutation, since it is not uncommon to have two such cancers occur by chance, particularly if she and her sister were over 50. That said, the remaining members of the family would probably be advised to have colonoscopies, and the female members of the family should be regular and thorough in their breast exams and mammographies. Although the U.S. Public Health Service in its evaluation of PSA testing for prostate cancer does not recommend such testing on a routine basis, I would be more aggressive myself in ordering such testing for the male members of her family.