Frequency of benign and preinvasive breast diseases

The importance of benign proliferative and non-invasive breast lesions as a risk factor preceding the development of invasive mammary carcinoma is well established in the literature. The objective of this study is to estimate the magnitude of benign proliferative diseases as well as mammary intra-epithelial neoplasia in the Western region of the Kingdom of Saudi Arabia (KSA), in order to encourage nationwide breast cancer screening programs for early detection of the high risk proliferative and pre-invasive breast lesions.

We reviewed histopathology records (reports and slides of selected cases) of 2129 breast cases including mastectomies and breast biopsies from January 1985 to December 2002 in King Abdul-Aziz University Hospital and King Khalid National Guard Hospital, Jeddah, KSA. All the cases and diagnosis are listed and reclassified using systematized nomenclature of medicine (SNOMED) coding system and then regrouped based on the associated risk factors of developing breast carcinoma.

Two thousand one hundred and twenty-nine reports were reviewed and 2343 diagnosis were identified as some cases had more than one diagnosis. The total of benign diagnosis were 1504 after exclusion of malignant diagnosis (558), normal breast tissue, gynecomastia, and non-mammary tissue (281). All diagnosis (1504) were reclassified based on anatomical prognostic indicators into non-proliferative (1283/1504), proliferative (140/1504), atypical hyperplasia (AH) (8/1504), and carcinoma in situ (CIS) (73/1504). We compare our findings with the literature and we found that the percentage of benign non-proliferative diagnosis was 85.3% that is higher than the literature 69.7%. Proliferative diseases were 9.3% and atypical hyperplasia was 0.5%, which was lower than the literature 26.2% and 3.6%. On the other hand, CIS diagnosis was 4.9%, which is much higher than the reported literature 1.7%. The study findings could be explained on the basis of higher prevalence of benign breast lesions in our population, or it is related to the number of cases studied, or to the diagnostic criteria followed initially.

These findings should encourage us to refine our diagnostic criteria of proliferative diseases, AH and CIS (mammary intraepithelial neoplasia [MIN]). In addition, we strongly encourage a breast cancer screening program, nationwide.