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Maintenance chemotherapy for ovarian cancer.

BACKGROUND
Epithelial ovarian cancer accounts for about 90% of all cases of ovarian cancer. Debulking surgery and six courses of platinum-based chemotherapy results in complete clinical remission (CCR) in up to 75% of cases. However, 75% of the responders will relapse within a median time of 18 to 28 months and only 20% to 40% of women will survive beyond five years. It has been suggested that maintenance chemotherapy could assist in prolonging remission. To date, there has not been a systematic review on the impact of maintenance chemotherapy for epithelial ovarian cancer.


OBJECTIVES
To assess the effectiveness and toxicity of maintenance chemotherapy for epithelial ovarian cancer and to evaluate the impact on quality of life (QoL).


SEARCH STRATEGY
We searched the Cochrane Gynaecological Cancer Review Group Specialized Register, The Cochrane Central Register of Controlled Trails (CENTRAL, The Cochrane Library Issue1, 2009), MEDLINE, EMBASE, PubMed, CBMdisc, CNKI and VIP (to May 2009). We collected information from ongoing trials, checked reference lists of published articles and consulted experts in the field.


SELECTION CRITERIA
Randomised controlled trials (RCTs) comparing maintenance chemotherapy with no further intervention, maintenance radiotherapy or other maintenance therapy.


DATA COLLECTION AND ANALYSIS
Two review authors independently assessed trials for eligibility and quality and extracted data. We analysed overall survival (OS) and progression free survival (PFS) rates as dichotomous variables. Toxicity and QoL data were extracted where present. All analyses were based on intention to treat (ITT) on the endpoint of survival. We also analysed data by subgroups of drugs.


MAIN RESULTS
We included six trials(902 women). When all chemotherapy regimens were combined, meta-analysis indicated no significant difference in 3, 5 and 10-year OS or PFS. For 5-year OS, the combined relative risk (RR) was 1.07 (95% confidence interval (CI) 0.91 to 1.27) and for the 5-year PFS the combined RR was 1.18 (95% CI 0.88 to 1.58). Results were very similar when trials of different regimens were analysed. Comparing chemotherapy with radiotherapy, only the RR for 10-year PFS in pathological complete remission was in favour of whole abdominal radiotherapy 0.51 (95% CI 0.27 to 1.00), while 3 and 5-year OS rates have no significant difference between the two groups.


AUTHORS' CONCLUSIONS
There is no evidence to suggest that the use of platinum agents or doxorubicin used as maintenance chemotherapy is more effective than observation alone. Further investigations regarding the effect of paclitaxel used as maintenance chemotherapy are required.