Mammography and physician breast exams after the diagnosis of breast cancer in a twin or non-twin sister.

Reports of breast-cancer-screening behavior were collected from 591 twin sisters of women with breast cancer and 182 non-twin sisters of the same women, and compared with the patterns found by national surveys. Timeline plots indicate that prior to the diagnosis of breast cancer in a sister, these women were being screened at prevailing rates. In the year after diagnosis, the annual frequency of use by them of both mammograms and physician breast exams increased by approximately 25 percent, but in subsequent years these rates dropped to a plateau no more than 10 to 15 percent higher than the baseline. The sisters over age 60 were screened with unusually low frequency, as were those with no partner in the home, those with no regular source of medical care, and especially the siblings of cases that died soon after the diagnosis. The relatively infrequent adoption of a long-term, annual, screening pattern in the face of certain knowledge of personal high risk gives cause for concern about the effectiveness of any intervention program requiring recognition of personal high risk for effectiveness. One cause for optimism is that higher screening rates prevail among those with co-twins diagnosed since 1980, suggesting that the increase in publicity and public education in recent decades has had a beneficial impact.