Clear survival benefit is achieved if all or most (< 1 cm remaining) of the tumour after primary surgical treatment for advanced epithelial ovarian cancer is removed

Ovarian cancer is a cancerous growth arising from different parts of the ovary. It is the sixth most common cancer among women. Most ovarian cancers are classified as epithelial. Ovarian epithelial cancer is a disease in which malignant (cancer) cells form in the tissue covering the ovary and most cases are epithelial. Primary surgery is performed to achieve optimal cytoreduction (surgical efforts aiming at removing the bulk of the tumour) as the amount of tumour that remains after surgery (residual disease) is one of the most important factors that is taken into account when determining a prognosis (prognostic factor) for survival of epithelial ovarian cancer. Optimal cytoreductive surgery remains a subject of controversy to many practising obstetric gynaecologists who specialise in the diagnosis and treatment of women with cancer of the reproductive organs (gynae-oncologists). The Gynaecologic Oncology Group (GOG) currently defines 'optimal' as having a small aggregation of remaining cancer cells after surgery (residual tumour nodules) each measuring 1 cm or less in maximum diameter, with complete cytoreduction (microscopic disease) being the ideal surgical outcome. Although the size of residual tumour masses after surgery has been shown to be an important prognostic factor for advanced ovarian cancer, there is limited evidence to support the conclusion that the surgical procedure is directly responsible for the superior outcome associated with less residual disease. This review assessed overall and progression-free survival of optimal primary cytoreductive surgery for women with advanced epithelial ovarian cancer (stages III and IV). We found 11 retrospective studies that included more than 100 women and used a multivariate analysis (used statistical adjustment for important prognostic factors) and met our inclusion criteria. Analyses showed the prognostic importance of complete cytoreduction, where the residual disease is microscopic with no visible disease, as overall (OS) and progression-free survival (PFS) were significantly prolonged in these groups of women. PFS was not reported in all of the studies but was sufficiently documented to allow firm conclusions to be drawn. When we compared suboptimal (> 1 cm) versus optimal (< 1 cm) cytoreduction the survival estimates were attenuated but remained statistically significant in favour of the lower volume disease group, but there was no significant difference in OS and only a borderline difference in PFS when residual disease of > 2 cm and < 2 cm were compared. There was a high risk of bias due to the retrospective nature of these studies. Adverse events, quality of life (QoL) and cost-effectiveness were not reported by treatment arm or to a satisfactory level in any of the studies. During primary surgery for advanced stage epithelial ovarian cancer, all attempts should be made to achieve complete cytoreduction. When this is not achievable, the surgical goal should be optimal (< 1 cm) residual disease. Due to the high risk of bias in the current evidence, randomised controlled trials should be performed to determine whether it is the surgical intervention or patient-related and disease-related factors that are associated with the improved survival in these groups of women.