TIME TREND OF FEMALE BREAST-CARCINOMA IN-SITU BY RACE AND HISTOLOGY IN CONNECTICUT, USA

A rapid increase of female breast cancer has been reported in many are as of the world and the reasons are not fully understood. While some h ave attributed the increase to the increasing detection of early stage breast cancer through mammography screening, few studies have directl y examined the time trend of in situ breast cancer specifically. This study included all incident cases of female breast carcinoma in situ r eported to the Connecticut Tumor Registry between 1973 and 1992. The a ge-adjusted incidence rates and age-specific incidence rates were calc ulated by histology and by race. The age-adjusted incidence rates were standardised to the 1970 United States standard million population. T he study found that the overall age-adjusted incidence rate of in situ breast cancer has increased dramatically, from 3.53/100 000 in 1973-1 975 to 17.51/100 000 in 1991-1992. The increase was not uniform during the past two decades of cancer registration. In fact, most of the obs erved rise has occurred since the early 1980s. This increase was found in both Caucasians and Blacks. The results by histology indicate that the dramatic increase in carcinoma in situ is mostly attributable to an increase in ductal carcinoma in situ. The increase was also observe d in all age groups 40 years and over. These results are consistent wi th the use pattern and the reported effect of mammography screening. T herefore, these results are qualitatively consistent with the idea tha t mammography screening is largely responsible for the recent upsurge in female breast cancer incidence in this population. The study also f ound that the age group 40-49 years in whites experienced a rapid incr ease in incidence that began in the same time period as the older age groups, but it has since levelled off. The potential impact of the hig hly publicised debate regarding the efficacy of mammography in this ag e group in recent years is discussed. (C) 1997 Elsevier Science Ltd.