To analyze the prognosis and related factors of patients with giant breast tumors, whose chest wall defects was repaired by autologous tissue flaps after tumor resction.

The clinical data of 46 giant breast tumor patients in Sun Yat-sen Memorial Hospital of Sun Yat-sen University from April 2012 to May 2018 were retrospectively analyzed. They all underwent the resection of gaint breast tumor and defect repair by autologous tissue flap. Then the subgroup analysis was performed according to different pathological types, distant metastasis status, therapeutic responses and negative margin. Log-rank test was used to analyze the progression-free survival (PFS) and OS of different subgroups. Univariate and multivariate Cox proportional hazard regression models were used to analyze the related factors of PFS and OS.

Among the 46 patients, 7 patients had malignant mesenchymal tumors of the breast, and the other 39 patients had breast cancer (18 luminal B, 11 HER-2 positive, and 10 triple negative). Univariate analysis showed that: (1) the median PFS and OS were 28.5 months (18.1-38.7 months) and 28.5 months (18.1-38.9 months) in patients with malignant mesenchymal tumors, 17.2 months (14.1-20.3 months) and 25.1 months (13.7-36.6 months) in luminal B breast cancer, 15.6 months(12.9- 51.2 months)and 35.8 months(19.8-71.8 months)in HER-2 positive breast cancer, 8.6 months (4.6-12.5 months) and 18.5 months (5.8-43.5 months) in triple negative breast cancer. There were significant differences in median PFS and OS among the four types of malignant tumors (PFS: χ²=16.645, P=0.001; OS: χ²=8.617, P=0.035). (2) The patients with T₄ lesions alone (n=25) presented no significant differences in median PFS and OS compared with the patients with T₄ lesions and distant metastases (n=21) [PFS: 17.2 months (7.3-27.0 months) vs 9.8 months (8.6-11.1 months), χ²=1.369, P=0.242; OS: 28.5 months (14.1-42.9 months) vs 20.2 months (14.4-25.9 months), χ²=1.779, P=0.182]. (3) The median PFS and OS in patients with negative margin (n=35) were 22.1 months (10.8-33.4 months) and 22.2 months (11.3-33.2 months), respectively, significantly better than those in patients with positive margins(n=11)[5.1 months (3.0-7.2 months) and 10.2 months (5.4-15.0 months)] (PFS: χ²=17.794, P< 0.001; OS: χ²=6.192, P=0.013). (4) The median PFS and OS in patients with good response to systemic treatment were significantly higher than those in patients with poor response [PFS: 23.1 months (5.9-40.4 months) vs 8.7 months (7.8-9.8 months), χ²=9.868, P= 0.001; OS: 46.7 months (25.5-68.0 months) to 14.3 months (9.9-18.9 months), χ²=8.994, P=0.002]. The above-mentioned factors were included in the multivariate Cox proportional hazards regression model and the result showed that these factors were not independent prognostic factors affecting the PFS and OS of breast cancer patients.

The prognosis of the patients with giant malignant breast tumors is related to pathological types of tumors, negative margin and the response to systemic treatment, but none is an independent prognostic factor.