Cytoreductive Surgery in the Management of Renal Tumours: Rationale, Current Evidence and Future Perspectives.

Renal cell carcinoma accounts for 3% of adult solid malignant tumours. Approximately 25% of the patients present with metastatic disease at presentation. In the era of immunotherapy (interferon alpha-2b and interleukin-2), studies showed significant survival benefit with cytoreductive nephrectomy (CRN) followed by interferon alpha-2b than interferon alpha 2-b alone. Introduction of targeted therapies (vascular endothelial growth factor receptor-tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors) in 2005 generated a great interest in the management of metastatic renal cell carcinoma (mRCC) as these drugs exhibited tumour shrinkage in the primary tumour as well as in the metastatic site/s. Though there is no level 1 evidence, many studies have shown the usefulness of cytoreductive nephrectomy along with targeted therapy as against to targeted therapy alone. This review is aimed at the rationale behind the cytoreductive nephrectomy in mRCC, the current evidence and what is in store for the future. A detailed search on the management of mRCC was carried out on MEDLINE, Embase, CANCERLIT and Cochrane Library databases using the key words "cytoreductive nephrectomy", "immunotherapy" and "targeted therapy" since 1980 till 2015. Original articles, review articles, monograms, book chapters on metastatic renal cancer and textbooks on urologic oncology, oncology and urology were reviewed. Various international guidelines on this issue were also studied. An identical search was performed using the American Society of Clinical Oncology Abstract database. Trials in the progress or recently completed that were relevant to this paper were identified through clinicaltrials.gov. The latest information for new articles ahead of publication was last accessed in November 2015. CRN has remained an integral part to the management of metastatic renal cell carcinoma mainly for the patients with good performance status, life expectancy of more than 12 months and in the absence of adverse prognostic factors. It had shown measurable survival benefit in the era of immunotherapy (CRN + immunotherapy vs. immunotherapy alone). In the era of targeted therapy, many studies have shown significant survival benefit with CRN + targeted therapy. However, there is no clear level 1 evidence to support this. The ongoing trials (CARMENA and European Organisation for Research and Treatment of Cancer SURTIME) would perhaps guide us in the way in which we should manage mRCC disease in the future. Maybe we may find some answers on the issues of the effectiveness of targeted therapy, the timing of CRN and sequencing these treatment arms once the results of these ongoing and future trials are through.