Thursday, December 7, 2000 Older Editions

Study shows some elevated cancer rates

By Adam Groff

A significantly larger number of Andover women were diagnosed with breast and colon cancer during a five-year span than health officials expected, based on statewide data. In addition, a significantly larger number of Andover men were diagnosed with skin tumors.

Those are some of the findings in the 1993-to-1997 study of cancer rates in Massachusetts, presented at the last meeting of the Andover Board of Health, and released by the state Department of Public Health (DPH).

Health Director Everett Penney explained that the DPH keeps a cancer registry that tracks the number of cases of each type of cancer in the state each year. The expected rate of cancer in individual communities is then determined based on community population, and the expected rate is then compared with the actual rate within communities. There are 22 types of cancer listed in the study.

From 1993 to 1997, 144 cases of breast cancer were recorded in Andover. The expected rate was just under 121, amounting to a rate in Andover 19 percent higher than expected. There were 58 observed cases of colon and rectal cancer among women, compared with an expected 43, and the rate of melanoma, or skin cancer, among men was 19 cases, compared with an expected 11.

"When we find a statistically significant deviation in excess of what was expected," explains Penney, "we start to look at intervention strategies. We know some causes associated with various risk factors." For example, he said, in response to higher rates of melanoma, the town can work to alert people to the dangers of spending too much time exposed to direct sunlight, because it is known that exposure to the sun is linked to incidence of melanoma.

He pointed to an apparent success with regard to lung and bronchial cancer. The rate of this type of cancer in Andover is significantly lower than expected, at an observed rate of 81 cases in men and women compared with an expected rate of about 107. Penney believes that efforts in Andover to heighten awareness about the dangers of smoking are a factor in this lower rate. In 1994, Andover outlawed smoking in public places.

Penney also says that this study as a whole compares favorably with the previous five-year study, from 1990 to 1995, in which rates in Andover were high to a statistically significant degree in five categories instead of three: in addition to breast and colon/rectal cancer, brain, prostate, and testicular cancer rates were also high. Though Andover's cancer rates remain above the expected rate in each of these areas, the rates were lower in the most recent survey than they had been in the 1990 to 1995 survey.

In addition, lung cancer rates from 1990 to 1995 were lower than expected, but not to a statistically significant degree, as in the more recent study.

In the aggregate, from 1993 to 1997 the total rates of all types of cancer in Andover, at 729, were about the same as the total expected rates. In the earlier study, however, the totals were about ten percent higher than expected.

Penney is aware that local environmentalists are concerned about high breast-cancer rates, but he declined to jump to conclusions.

"This data is often referred to by people who are concerned about the incinerators and other environmental triggers," he said. "The problem with doing that is that we don't know the actual causes of breast cancer, so it's hard to assign the environmental triggers to them. Breast cancer may be associated with environmental triggers, but the case for association between breast cancer and family history is much stronger. You have to be very careful that you don't unilaterally make an association between environmental factors in the community and cancer."