Overall survival according to type of surgery in young (≤40 years) early breast cancer patients: A systematic meta-analysis comparing breast-conserving surgery versus mastectomy.

OBJECTIVES Young age is an independent risk factor for local recurrence after breast conserving surgery (BCS) and whole breast radiotherapy (WBRT) for breast cancer. The aim of this study was to carry out a systematic meta-analysis to address the issue as to whether type of surgery might have an impact on overall survival (OS) of young patients with early breast cancer. MATERIAL AND METHODS We summarized six studies comparing OS between BCS + WBRT vs. mastectomy in young patients (≤40 years) with T1-T2 N0-N + M0 breast cancer. Primary endpoint was OS or distant metastasis free survival (DMFS). Only studies with fully adjusted Hazard Ratios (HR) were analyzed. Summary HRs were calculated through random effects models. We investigated publication bias and heterogeneity by means of sensitivity analyses and meta-regression models. RESULTS Five population-based studies and a pooled study of two clinical trials, for a total of 22598 patients 40 years old or younger, were considered: 10898 patients underwent BCS and 11700 underwent mastectomy. After all the adjustments, including nodal status and tumor size, no difference in risk of death was found between the two groups (10% not significant risk reduction in patients who underwent BCS compared to mastectomy; summary HR = 0·90; 95%CI: 0·81 to 1·00). Between-study heterogeneity was not statistically significant (I(2) = 34% and Chi-square P = 0·15). Heterogeneity investigation did not find any variable influencing results. No indication for publication bias was found (P-value = 0·37). Excluding the only study presenting DMFS the results did not change (HR = 0·88; 95%CI: 0·78 to 1·01). CONCLUSION Considering all the limitations, from the present meta-analysis carried out on 22598 patients it appears unlikely that mastectomy provides better OS compared to BCS + WBRT in early breast cancer patients aged 40 years or younger.