Response to Induction Chemotherapy as a Predictor of Clinical Outcome After Chemoradiation in Locally Advanced Head and Neck Squamous Cell Carcinoma Patients: A Retrospective Study.

Abstract

Introduction: Concurrent chemo-radiotherapy is standard of care for locally advanced Head and Neck squamous cell carcinoma. Induction chemotherapy is given to reduce locoregional relapse, distant metastases and tumor shrinkage. Response to induction chemotherapy can predict response to radiotherapy, but impact of IC response to survival benefit after radical treatment is less studied.

Materials and methods: We conducted a retrospective study of patients with locally advanced Head and Neck squamous cell carcinoma receiving induction chemotherapy followed by radical chemoradiotherapy. Clinico-radiological response to induction chemotherapy was recorded and further subjected to chemoradiotherapy. Overall, Disease free and distant metastasis free survival were analysed.

Results: 116 patients received induction chemotherapy followed by radical chemoradiotherapy. Post induction chemotherapy, response(down-stage) was, 48(41.37%) for T-stage, 46(36.65%) for N-stage and 45(38.79%) for Stage group, respectively. On follow up after chemoradiotherapy, 52(44.8%) had complete response, 61(52.6%) had failure of treatment, and 3(2.6%) died within three months. With median overall survival of 18.89 months, median follow up was of 10.8 months. Univariate analysis indicated significant benefits in Disease free survival for T-stage response (p < 0.04), but not for N-stage (p = 0.25) or stage group (p = 0.11). However, multivariate analysis identified stage group response as statistically significant predictor overall survival (p - 0.04, HR - 0.538). In subset analysis, younger population (< 50 year), despite being non-responder had significant benefit in distant metastasis free survival status (p - 0.04). For subsite, hypopharyngeal malignancies had significant benefit in overall survival status for N-stage (p - 0.002) and stage group (p - 0.008), and for laryngeal malignancies significant benefit in disease free survival status for T-stage response (p - 0.03).

Conclusion: In locally advanced Head and Neck squamous cell carcinoma, response to induction chemotherapy can be viewed as an indicator of potential survival benefit. Role of induction chemotherapy is recommended for laryngeal and hypopharyngeal malignancies, to preserve organ-function along with enhanced survival rates. In younger patients, even if they are non-responders, induction chemotherapy combined with concurrent chemoradiation is a viable option that may improve locoregional, and distant control of the disease.