Objective: To study the frequency of ductal carcinoma in situ (DCIS) in a large pathology series. DCIS is a proliferation of non-invasive, malignant epithelial cells within the ductolobular system of the breast. It is a heterogeneous entity with several morphologic variants that differ in gross appearance, growth pattern, cytologic features, mammography, and malignant potential.
Methods: The data of The Aga Khan University' Pathology Department, diagnosed on the basis of histopathology, during a 6-year period (1st January 1998 to 31st December 2003) was reviewed, all cases of DCIS studied, and data was analyzed with the help of analytical software SPSS.
Results: Thirty-eight cases of DCIS were reported to the Aga Khan University Pathology Department, during a 6-year period (1998 to 2003), comprising approximately 1% of all breast cancers reported to the unit in the same period. The mean age of the patients at diagnosis was 48.95 years (CI 95% 44.6; 53.3). Approximately half the cases occurred in the 45-54 year age group (figure 1). Two cases (5.3%) were recurrences with previous lumpectomy scars. Comedo necrosis was observed in five (13.2%) cases, whereas 33 (86.8%) cases were non-comedo type. The clinical presentation was a palpable mass (92.1%), nipple discharge (5.3%) or clinically occult lesions diagnosed on mammography (2.6%). Approximately half the patients presented with a grade 2 disease. Atypical ductal hyperplasia was observed in a third of the cases, predominantly associated with a grade 1 and 2 disease. The estrogen and, progesterone receptor status was studied in 12 (31.6%) cases. Estrogen positivity was observed in 11 (91.7%) cases and progesterone positivity in 7 (58.3%) cases. Microcalcification was observed in four (10.6%) cases.
Conclusion: The cases reported in this study are the indolent grade 1 or 2 cases with a non-comedo pattern, and a positive estrogen and progesterone receptor status. If untreated, only 40% of these innocuous forms of DCIS become invasive over a time span of approximately 25-30 years. In Pakistan we are missing the more aggressive forms of DCIS which have a shorter transition to invasive carcinoma.