The results from the present study demonstrate high rates of overall survival, cause-specific survival, and freedom from distant metastases following the treatment of DCIS of the breast using breast-conserving surgery and definitive breast irradiation. These results support the use of breast-conserving surgery and definitive breast irradiation for the treatment of DCIS of the breast.

Mammary recurrences were studied in 1593 patients with Stage I and II breast cancer treated by macroscopically complete tumor excision followed by megavoltage radiotherapy, including a boost to the tumor bed (mean dose, 78 Gy). The actuarial freedom from mammary recurrence was 93% at 5, 86% at 10, 82% at 15, and 80% at 20 years. Seventy-nine percent of the recurrences were in the vicinity of the tumor bed, but with increasing time interval, an increasing percentage of recurrences was located elsewhere in the breast. A majority of recurrences after 10 years could be considered new tumors. Only ten of 181 patients with recurrence had prior or concomitant distant metastases, and 159 of 171 isolated mammary recurrences (93%) were operable. Uncorrected overall survival after operable recurrence was 69% at 5 and 57% at 10 years. Prognosis after late recurrence (after 5 years) was favorable (84% 5-year survival). Operable early recurrences retained a favorable prognosis if smaller than 2 cm and confined to the breast (74% 5-year survival). Disease-free interval and histologic grade also appeared to be important prognostic factors after early recurrence. Survival after recurrence did not depend upon the type of salvage operation. Locoregional control was 88% at 5 years after salvage mastectomy and 64% after breast-conserving salvage procedures. The role of adjuvant systemic therapy at time of local recurrence requires additional study. This experience illustrates the important differences between mammary failure and chest wall recurrence after mastectomy, in particular the protracted time course and more favorable prognosis associated with the former.

Of 586 unilateral stage I-II breast cancers treated with conservative surgery and radiotherapy, 61 patients were found to have two or more macroscopic tumor nodules, diagnosed either clinically (n = 20), mammographically (n = 2), or on gross pathologic examination (n = 39). After a median follow-up of 71 months, 15 of 61 (25%) of the patients with multiple tumors developed recurrence in the treated breast, compared to 56 of 525 (11%) of patients with single cancers (p less than 0.005). Local failure occurred in 6 of 37 (16%) of bifocal tumors and in 9 of 24 (35%) of patients with 3 or more tumor foci. Recurrence was more frequent for multiplicity diagnosed clinically or mammographically (8 of 22 patients, 36%) than when it was apparent only to the pathologist (7 of 39 patients, 18%). Only 1 of 21 bifocal tumors diagnosed on gross examination recurred. Local failure occurred in only 1 of 22 cases with clearly negative resection margins; the remaining recurrences were associated with positive (n = 3) or indeterminate margins (n = 11). In contrast with recurrences of unifocal breast cancers, local failures in these patients tended to be located at a distance from the original foci, to be multifocal, or to be diffuse, including skin involvement. Only four recurrences presented as a single focus in the vicinity of the original primary tumors. This study indicates that macroscopically multiple breast cancers are at higher local failure risk, especially if multiplicity is clinically apparent, or if three or more gross nodules are seen on pathologic examination. Negative resection margins appear to be essential for satisfactory results.

The influence of patient age on risk of recurrence in the breast was retrospectively studied in 496 stage I-II invasive ductal carcinomas treated by macroscopically complete primary tumor excision followed by radiotherapy. With a median follow-up of 71 months, local recurrence occurred in 13 of 62 (21%) patients younger than 40 years, compared with 48 of 434 (11%) older patients (P less than .025). Cox multivariate analysis of 18 parameters identified four that significantly determined risk: major lymphocytic stromal reaction (MCR), unsatisfactory resection margins, increasing histologic grade, and extensive intraductal cancer (DCIS) within the primary tumor. Compared with older patients, those younger than 40 years had tumors that more often exhibited MCR (36% v 20%, P less than .01), histologic grade 3 (42% v 28%, P less than .025), and very extensive DCIS (21% v 6%, P less than .001). The status of resection margins did not differ significantly between younger and older patients. Restriction of Cox analysis to patients younger than 40 indicated that risk was adequately described by MCR and percentage of DCIS, without consideration of grade or margins. For patients younger than 40, local failure occurred in four of five (80%) tumors with both MCR and more than 50% DCIS, in eight of 25 (32%) with either, and one of 32 (3.1%) with neither of these morphologic features. This study suggests that the higher local failure risk observed in patients younger than 40 years reflects the greater prevalence of certain morphologic characteristics in breast cancers in younger patients. Age itself does not appear to be an independent determinate of risk.

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