Increased sectioning of pathologic specimens with ductal carcinoma in situ of the breast: are there clinical consequences?

To assess if there has been increased sectioning of pathologic specimens with ductal carcinoma in situ (DCIS), identify sources of this change, and consider the clinical consequences, pathologic data from patients who underwent initial excisional biopsies at our institution and were referred to the radiation oncology department with DCIS from 1992-2002 were retrospectively reviewed. One hundred forty-four of 480 patients with DCIS were eligible for review. Specimen size was recorded as length, to the nearest 0.1 cm, in 3 dimensions. Specimen volume was approximated by the product of the 3 dimensions of the specimen. The primary endpoint was the number of microscopic sections taken from gross specimens, corrected for specimen size. Other analysis included margin status, use of a previous stereotactic needle biopsy, and whether a subsequent repeat excision was performed. Over time, there was an increase in size of the excisional biopsy specimens (mean of 49 cm3 from 1992 to 1994 and 90 cm3 from 2001 to 2002; P = 0.045). Mean numbers of slides per centimeter of specimen were 2.5, 2.7, 3.9, and 5.8 for the intervals 1992-1994, 1995-1997, 1998-2000, and 2001-2002, respectively (P < 0.001 for 1992-1997 vs. 1998-2002). Adjusting for volume, the increase over time in the number of slides per specimen was statistically significant (parameter significance, P < 0.001). For a given volume, the number of slides increased approximately 9.1% per year, on average, during the study period. The positive margin rates were 52%, 46%, 23%, and 25% from 1992 to 1994, from 1995 to 1997, from 1998 to 2000, and from 2001 to 2002, respectively. The degree of sectioning, corrected for specimen length and volume, increased over time.