Survival Outcomes of Surgical Resection of Metastasis to the Breast from Extra-Mammary Malignancies: An Individual Patient Data Analysis

Abstract

Background: It remains unclear whether surgical resection of in-breast metastasis from extra mammary malignancies would improve survival. Methods: There were 29 cases including 25 cases reported by 24 studies and 4 unreported cases from PUMC Hospital in this individual patient data (IPD) meta-analysis. The clinic pathological characteristics and overall survival (OS) were compared. The subgroup of patients who might potentially benefit from surgical resection of the metastatic lesion to the breast was identified. Results: The breast symptoms were 22 lumps (75.9%), 4 huge mass (13.8%), 3 inflammatory changes (10.3%), 1 ulceration (3.4%) and 1 non-palpable lesion (3.4%). There were 2 male patients (6.9%) with breast metastasis and 3 female patients (10.3%) with bilateral breast metastasis. The primary malignancy sites included 10 gastrointestinal (34.5%), 7 lung (24.1%), 4 urogenital (13.8%) and 3 trunk and limbs (10.3%). Adenocarcinoma (48.3%) was the commonest pathology. Twelve patients (41.4%) had metastases only to the breast. Seven breast metastases (24.1%) were diagnosed simultaneously with the primary malignancies, and 2 breast metastases (6.9%) were detected before the primary. The 12-month OS rate was 55.2% and the median survival was 5 month (1-60 months). 16 patients (55.2%) received surgical resection of the in-breast metastases, and their OS was not significantly different from those biopsy-only patients. Conclusion: Surgical resection of metastases to the breast from extra-mammary malignancies could achieve similar survival outcome compared to patients who only received core needle biopsy, with potential of improving the quality of life for patients with breast ulceration, huge mass and inflammatory changes.