Addition of concurrent chemotherapy to adjuvant radiotherapy versus radiotherapy alone for resected salivary gland cancers: A systematic review and meta-analysis.

Abstract

e17563 Background: Surgery remains to be the standard definitive treatment for malignant tumors of the salivary gland. Post-operative radiotherapy (RT) is warranted for high risk individuals having tumors with high grade, advanced disease or inadequate resection, showing local control and survival benefit. Despite lack of evidence, adjuvant chemoradiation (CRT) has been suggested for worse prognosis patients. Two recent population-based studies showed that adding chemotherapy to RT did not demonstrate a survival advantage, and no randomized study answers this question. Our aim is to review current evidence comparing RT with and without concurrent chemotherapy in non-metastatic, resected salivary gland cancer. Methods: Literature was searched using: CINAHL plus, EBSCOhost, Medline Complete, Science Direct, Proquest, Scopus, and Pubmed. Eligible studies were experimental or observational which compare adjuvant radiotherapy alone versus radiotherapy with concurrent chemotherapy after primary surgery. Pooled analysis for eligible studies was conducted utilizing the Mantel-Haenzel model (random effects) for the outcomes of interest. The NHMRC of Australia Body of Evidence Framework was used to provide an overall evidence recommendation. Results: Eight retrospective studies were included in the qualitative analysis and two were cancer database studies. Pooled analysis from 4 studies showed inferior 3-year overall survival in patients receiving adjuvant CRT(RR 2.15, 95% CI 1.23-6.75). There were no significant differences in 3-year LRC, DMFS or PFS between both groups, although a trend for worse 3-year DMFS and PFS was observed in the CRT group. G3 hematologic toxicity was worse in patients receiving adjuvant CRT vs RT alone (RR 8.63, 95% CI 1.69-44). Critical appraisal revealed that more patients with adverse risk features (T3-T4, node positive, LVSI, PNI, close or positive margins) received CRT. Conclusions: The addition of concurrent chemotherapy to RT in resected salivary gland cancer does not improve overall survival is associated with worse outcomes and greater toxicity.