The benefit from 5 years of tamoxifen therapy persists through 10 years of follow-up. No additional advantage is obtained from continuing tamoxifen therapy for more than 5 years.

One of the most important factors associated with local recurrence after lumpectomy in breast cancer patients is the status of the surgical margin. Standard surgical practice is to obtain clear margins even if this requires a second surgical procedure. It is assumed that reexcision to achieve clear margins when positive margins are present at initial excision is as effective as complete tumor removal at a single procedure; however, the efficacy of reexcision in this context has not been well studied. A retrospective search of the Henrietta Banting Breast Centre database from 1987 to 1997 identified 1430 patients who underwent lumpectomy for invasive breast cancer: 1225 patients (group A) had negative margins at the initial surgery and 152 patients (group B) underwent one or more reexcisions to achieve negative margins. Fifty-three patients had positive margins at final surgery, but no reexcision was done (group C). Logistic regression was used to identify factors that were predictive of a positive margin; predictors of local recurrence in women whose tumors were completely resected were determined using Cox's proportional hazards model. Patients in groups A, B, and C differed with respect to mean age at diagnosis (58 years, 51 versus, and 56 years, respectively, p < 0.0001), mean tumor size (19 mm, 16 mm, and 26 mm, respectively, p < 0.0001), node positivity (30%, 22%, and 41%, respectively, p = 0.004), and the presence of a ductal carcinoma in situ (DCIS) component (60%, 64%, and 79%, respectively, p = 0.007). The mean follow-up period was similar for the three groups (8 years, 8 years, and 9 years, respectively, p = 0.17). Young age was the only variable predictive of positive margins. Among patients undergoing complete tumor excision, there was a suggestion of a higher 10 year local recurrence rate in reexcision group B, but the difference did not reach statistical significance (11.6% versus 16.6%, p = 0.11). Cox's multivariate regression analyses identified older age, smaller tumor size, receiving radiation therapy, and tamoxifen use as significantly decreasing the rate of local recurrence in patients with negative margins at initial surgery or after reexcision. Our data confirm the results of previous studies indicating that young age is an independent predictor of positive margins after lumpectomy for invasive breast cancer. The only independent predictor of local recurrence in our study cohort was large tumor size. There was a trend toward a higher local recurrence rate if more than one procedure was required to secure clear margins, although this effect was not independent of other factors. Reexcision to clear involved margins is an important surgical intervention for both younger and older women.

There has been a recent increase in the diagnosis of in situ duct carcinoma of the breast (DCIS) as a result of mammographic screening. DCIS is heterogeneous in appearance and likely in prognosis. There is no generally accepted model to predict progression to invasive carcinoma. We investigated the prognostic effect of clinical presentation and pathologic factors for women diagnosed with primary DCIS. A cohort of 124 patients was accrued between 1979 and 1994 and was followed to 1997; 78 had DCIS detected mammographically, and 88 underwent lumpectomy alone. In this article, we provide details about characteristics affecting the choice of primary therapeutic modality, and we examine the effects of factors on progression for the two patient subgroups. Presentation with bloody nipple discharge was associated with a significant increase in DCIS recurrence (p=0.07). The pattern of duct distribution was important: DCIS in which the involved ducts were more widely separated had a significantly greater recurrence of DCIS than when the involved ducts were more concentrated (p=0.08 for mammographically detected DCIS, p=0.07 for patients who underwent lumpectomy alone). For mammographically detected DCIS, younger patients had more DCIS recurrence (p=0.07). We found considerable heterogeneity in nuclear grade; 50% of patients exhibited more than one grade. Nuclear grade, necrosis, and architecture were not significantly associated with either recurrence of DCIS or development of invasive carcinoma. Longer follow-up will allow further evaluation of the prognostic relevance of the factors assessed.

The biological significance of occult metastases in axillary lymph nodes of breast cancer patients is controversial. The purpose of the study was to determine the prognostic significance of occult micrometastases using the current American Joint Committee on Cancer (AJCC) staging system in a cohort of women with node-negative breast cancer, of whom 5% received adjuvant systemic therapy and who all had long-term follow-up. We studied a cohort of 214 consecutive histologically node-negative breast cancer patients with a median follow-up of 8 years. Blocks of the axillary lymph nodes were assessed for occult micrometastases by examination of an additional hematoxylin-eosin-stained slide and by immunohistochemical staining using an antibody to low molecular weight keratin. Occult metastases were classified according to the sixth edition of the AJCC cancer staging manual. We examined the prognostic effects of occult micrometastases and other clinicopathologic features on recurrence outside the breast with disease-free interval (DFI) and survival from breast cancer with disease-specific survival (DSS). Cytokeratin-positive tumor cells were identified in the lymph nodes in 29 of 214 cases (14%). Two cases had isolated tumor cells and no cluster larger than 0.2 mm [pN0(i+)], whereas 27 of 214 (13%) had micrometastases (larger than 0.2 mm and