Q: During a check-up last week, my doctor discovered a small lump in my thyroid gland. The possibility of thyroid cancer was suggested, and I made an appointment to see a specialist. What is the chance that a thyroid lump is cancerous and how is the diagnosis made?
A: Thyroid lumps (nodules) are quite common. In adults they are present in about 6 percent of women and 2 percent of men; they are more frequent in elderly individuals. Approximately one thyroid nodule in 20 is malignant.
A thyroid nodule is more likely to be malignant in men, in younger people, in those with a family history of thyroid cancer, and especially in people who had irradiation treatment to the head and neck during childhood or adolescence. Rapid growth of the nodule, pain, hoarseness or difficulty in swallowing also suggest cancer.
Usually, the first diagnostic step is a thyroid scan, which is carried out by administering a radioactive substance that concentrates in normally functioning thyroid tissue. If the nodule takes up the radioactivity, it is benign. However, 90 percent of nodules fall into the category of not taking up the radioactivity. In that case, the next step is to obtain cells for examination (biopsy) under the microscope; this is quite safe and an experienced cytologist can determine when cancer is present about 90 percent of the time.
Surgical removal is the treatment for thyroid cancer. When the needle biopsy does not show cancer, patients are treated with thyroid in an effort to suppress further growth of the nodule. A repeat needle biopsy is often done in about six months if the nodule continues to grow or fails to shrink. Surgery may be recommended instead if the initial biopsy was suspicious or there is a history of prior irradiation to the neck.
Q: Last year my mother died of ovarian cancer and I am afraid that I may acquire the same kind of cancer. What do you advise?
A: All women have reason for concern about ovarian cancer because no other cancer of the female reproductive system causes as many deaths. Some added concern on your part is warranted; women whose mothers or sisters have ovarian cancer are at moderately increased risk to develop the disease.
Ovarian cancer can be cured if detected and treated early enough. For several reasons, however, ovarian cancers are usually discovered only after they have spread and cannot be totally removed.
In the first place, there are no early warning symptoms of ovarian cancer. In addition, no effective tests are available for the detection of early ovarian cancer. The Pap smear, for example, cannot detect ovarian cancer. The most effective way to discover possible ovarian cancer is a pelvic examination. The American Cancer Society recommends a yearly cancer checkup for all women over the age of 40.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for faculty affairs at the school.