Evaluating The Survival Benefit Following Ovarian Function Suppressionin Early Breast Cancer Patients

BACKGROUND: It has been over a century since Beatson demonstrated that oophorectomy was effective for treating advanced breast cancer.With the development of adjuvant therapy, its using was gradually faded. Along with the produce of LHRH, ovarian function suppression or ablation(hereafter, OFS) aroused people's attention gradually. Several trials have been done to assess treatment of OFS in hormone receptor positive early breast cancer patients, but results have been inconclusive. In order to clarify the survival benefit of OFS, a meta-analysis of relevant randomized trials was performed.METHODS: PUBMED, GOOGLE SCHOLAR, EMBASE, OVID and COCHRANE were searched for published randomized trials assessing the function of OFS versus no OFS in hormone receptor positive early breast cancer patients. Through duplicate removal, reading the title and abstract, and reading relative literature, eventually we included 11 articles. Disease free survival(DFS) and overall survival(OS) at the end of the study was the primary outcome and the second outcome is the side-effects of OFS. Meta-analysis was used to assess the survival benefit of OFS. At the same time, we performed subgroup analysis to assess the most appropriate crowd of OFS and its side-effects.RESULTS: A total of 11 studies contributed to the analysis. The use of OFS was more effective than no OFS on DFS(the pooled relative risk(p RR)=0.86; 95%CI: 0.75-0.96) and on OS(p RR=0.79; 95%CI: 0.70-0.89). In subgroup analysis, we found evidence that increased DFS was positively associated with patients who had received chemotherapy(p RR=0.85;95%CI: 0.74-0.96), who were lymph node negative(p RR=0.74; 95%CI: 0.61-0.91) and were less than 40 years old(p RR=0.71; 95%CI: 0.59-0.83). There was a significant difference in OS between the groups receiving chemotherapy(p RR=0.73; 95%CI: 0.58-0.89) or for patients less than 40 years old(p RR=0.52; 95%CI: 0.18-0.87). The use of OFS also produces some side-effects, such as mide to severe hot flashes, hypertension, weight gain and diabetes, but having statistical differences between the groups are severe hot flashes(p RR=2.32; 95%CI: 1.36-3.97), and hypertension(p RR=1.54; 95%CI: 1.12-2.12).CONCLUSIONS: OFS should be considered as one treatment option for hormone receptor positive premenopausal early breast cancer patients who have received chemotherapy and are less than 40 years old. At the same time, we also should pay attention to the side-effects and weigh the advantages and disadvantages of each before deciding on using OFS or not.