Axillary dissection in breast-conserving surgery for stage I and II breastcancer: A National Cancer Data Base Study of Patterns of Omission and Implications for Survival

Background: Breast conservation (partial mastectomy, axillary node dissecti on or sampling, and radiotherapy) is the current standard of care for eligi ble patients with Stages I and II breast cancer. Because axillary node diss ection (AND) has a low yield, some have argued for its omission. The presen t study was undertaken to determine factors that correlated with omission o f AND, and the impact of the decision to omit AND on 10-year relative survi val. Study Design: A retrospective review of National Cancer Data Base (NCDB) da ta for 547,847 women with Stage I and Stage II breast cancer treated in US hospitals from 1985 to 1995 was undertaken. A subset of 47,944 Stage I and 23,283 Stage II women treated with breast-conserving surgery (BCS) was iden tified. Cross-tab analysis was used to compare patterns of surgical care wi thin this subset. Relative survival was calculated as the ratio of observed survival to the expected survival for women of the same age and racial/eth nic background. Results: The rate of BCS with and without AND increased steadily from 17.6% and 6.4% of patients from 1985-1989, to 36.6% and 10.6% of patients from 1 993-1995 respectively. AND was more likely to be omitted in women with Stag e I than women with Stage II disease (14.5% versus 5.5%). Similarly, AND wa s omitted more frequently in women with Grade 1 than women with higher grad es (Grade 1, 14.3%; Grade 2, 10.1%; Grade 3, 7.1%; Grade 4, 7%). Although t he rate of BCS with AND varied considerably according to location in the br east, the overall rate of BCS without AND appeared independent of site of l esion. Women over the age of 70 years were more than twice as likely to hav e AND omitted from BCS than their younger counterparts. Women with lower in comes, women treated in the Northeast, or at hospitals with annual caseload s < 150 were all less likely to undergo AND than their corresponding counte rparts. Ten-year relative survival for Stage I women treated with partial m astectomy and AND was 85% (n=1242) versus 66% (n=1684) for comparable women in whom AND was omitted. BCS with AND followed by radiation therapy for St age I disease resulted in 94% (n = 5469) 10-year relative survival, compare d with 85% (n = 1284) without AND. Addition of both radiation and chemother apy to BCS with AND for Stage I disease resulted in 86% (n = 2800) versus 5 8% (n = 512) without AND. In contrast, Stage II women treated with BCS with AND followed by radiation and chemotherapy experienced a 72% 10-year relat ive survival. Conclusions: A significant number of women with Stage I breast cancer do no t undergo AND as part of BCS. The trend is most pronounced for the elderly, but significant fractions of women of all ages are also being undertreated by current standards. Ten-year survival is significantly worse when AND is omitted. This adverse survival effect is not solely from understaging. (J Am Cell Surg 1999;188:586-596. (C) 1999 by the American College of Surgeons ).