Survival Comparisons for Breast Conserving Surgery and Mastectomy Revisited: Community Experience and the Role of Radiation Therapy

Abstract

Objectives: Evidence suggests superiority of breast conserving surgery (BCS) plus radiation over mastectomy alone for treatment of early stage breast cancer. Whether the superiority of BCS plus radiation is related to the surgical approach itself or to the addition of adjuvant radiation therapy following BCS remains unclear. Materials and Methods:We conducted a retrospective cohort study of women with breast cancer diagnosed from 1994-2012. Data regarding patient and tumor characteristics and treatment specifics were captured electronically. Kaplan-Meier survival analyses were performed with inverse probability of treatment weighting to reduce selection bias effects in surgical assignment.Results: Data from 5335 women were included, of which two-thirds had BCS and one-third had mastectomy. Surgical decision trends changed over time with more women undergoing mastectomy in recent years. Women who underwent BCS versus mastectomy differed significantly regarding age, cancer stage/grade, adjuvant radiation, chemotherapy, and endocrine treatment. Overall survival was similar for BCS and mastectomy. When BCS plus radiation was compared to mastectomy alone, 3-, 5-, and 10-year overall survival was 96.5% vs 93.4%, 92.9% vs 88.3% and 80.9% vs 67.2%, respectively. Conclusion:These analyses suggest that survival benefit is not related only to the surgery itself, but that the prognostic advantage of BCS plus radiation over mastectomy may also be related to the addition of adjuvant radiation therapy. This conclusion requires prospective confirmation in randomized trials.

Breast conserving therapy and mastectomy revisited: Breast cancer‐specific survival and the influence of prognostic factors in 129,692 patients

“…Our results further support the hypothesis that BCT might be the preferred choice for breast cancer patients when both BCT and mastectomy are suitable treatment options . A previous observational study that also investigated survival outcomes following both types of surgery hypothesized that the prognostic advantage of BCT over mastectomy may be related to the effects of RT as a component of BCT while early stage mastectomy patients in general receive no RT5.…”

“…A possible explanation for the differences in BCSS between the two time cohorts, apart from the difference in the applied chemotherapy regimens, is the length of follow‐up. Recurrence peaks (including local/locoregional recurrences and distant metastases) are described to occur 2, 5 and 9 years after diagnosis . Since the 2006–2012 cohort had a median follow‐up of 7 years, this cohort may have had too short follow‐up to reveal the effect of BCT and mastectomy after 7 years.…”

“…Large randomized controlled trials (RCTs) in the 1980s have shown equal survival for breast‐conserving therapy (breast‐conserving surgery plus radiation therapy, BCT) and mastectomy in early stage breast cancer . Over recent years, however, multiple observational studies have challenged this equivalence, showing superior survival for patients treated with BCT compared to those treated with mastectomy . The use of population‐based observational studies in studying treatment effects can be of additional value on outcomes obtained through RCTs.…”

Intensity-modulated radiation therapy for early-stage breast cancer: is it ready for prime time?

“…Breast conserving surgery (BCS), followed by adjuvant radiation therapy (RT), is an essential arm in the treatment management of women with early-stage breast cancer 2. Onitilo et al3 demonstrated that the judicious use of adjuvant RT post-BCS improves survival outcomes compared to radical mastectomy alone 3. Adjuvant RT also halves the recurrence rate thereby significantly improving survival rates 4,5.…”

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“…Although how much this extends into clinical and long term survival benefit is still a matter of debate. Clinical trials exist for both invasive and in situ carcinoma in which no significant difference in survival was found in patients treated with BCT or mastectomy [24][25][26]. Both radiation therapy and adjuvant systemic chemotherapy contribute to low rates of cancer recurrence in treated breast.…”