Abstract 160P
Background
Malignant phyllodes tumor is a subtype of fibroadenomas but with invasive behaviors that accounts for 1% of all breast cancers. About one in every 4 phyllode tumors is malignant. The available treatment modalities for malignant phyllode tumors are wide excision or mastectomy with adjuvant radiotherapy and in case of distant metastasis, adjuvant chemotherapy is added. However, Due to its scarcity, there are no enough data about the best treatment modality and that is the what our study aims to find.
Methods
We extracted the data of 1971 female patients from Surveillance, Epidemiological, and End Results (SEER) database. All of them had Malignant Phyllode tumor. We divided the patients into 3 groups; Conservative surgery, simple mastectomy, and radical mastectomy. For each group we further subdivided them into 3 more groups, surgery with no systemic therapy, adjuvant radiotherapy, and adjuvant chemotherapy. For each subgroup, we measured the relative 5-year survival. We also performed Kaplan-Meier curve and log rank test using SPSS 25 for survival analysis.
Results
The 5-year relative survival of conservative surgery, simple mastectomy and radical mastectomy were (98.1%, 86.2%, 77.5% respectively; P<0.001). With sub stratification of the 3 available surgeries, we compared the 5 year-relative survival of adjuvant therapy with each group; adjuvant radiotherapy with conservative surgery, simple mastectomy and radical mastectomy were (94.9%, 83.2%, 64.7% respectively; P<0.001) and for Adjuvant chemotherapy, they were (50.8%, 66.4%, 22.1% respectively; P<0.001).
Conclusions
The results of this study highlight that conservative surgery with no adjuvant therapy to be the treatment modality of choice as it has the best survival outcome. However, If the tumor is abnormally large, simple mastectomy is recommended instead. Regarding adjuvant therapy, Adjuvant radiotherapy shows better survival than adjuvant chemotherapy but both shows no survival benefit compared to surgery. So, we recommend that adjuvant radiotherapy to be cautiously used with selective patients. Additionally, adjuvant chemotherapy should be avoided to avoid unnecessary side effects.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.