Clinical outcome of intensity-modulated radiotherapy versus two-dimensional conventional radiotherapy in locally advanced nasopharyngeal carcinoma: Comparative study at SKIMS Tertiary Care Institute.

Abstract

The management of nasopharyngeal cancer (NPC) at present is based primarily on radiotherapy, but the technique by which radiation therapy is delivered is different such as intensity-modulated radiotherapy (IMRT) and two-dimensional conventional radiotherapy (2D-CRT). In our study, IMRT and 2D-CRT were compared for their treatment outcome in locally advanced nasopharyngeal carcinoma (NPC) patients. Patients with Stage II to IVA nasopharyngeal cancer (NPC) as per the American Joint Committee on Cancer 7th and 8th edition 2017 treated with IMRT (n = 30) and 2D-CRT (n = 30) between October 2016 and October 2020 were retrospectively analyzed. We matched our patients by using the propensity-score matching method. OS was the primary endpoint of our study. The secondary endpoints were local relapse-free survival (LRFS), regional relapse-free survival (RRFS), disease-free survival (DFS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). Acute and late radiation toxicities between IMRT and 2D-CRT were also compared. In the propensity-matched cohort of 60 patients, 30 patients received 2D-CRT and 30 patients received IMRT. Compared with the treatment of 2D-CRT, the IMRT group is associated with a better 3-year OS (70% vs. 85% P = 0.045), LRFS (78% vs. 96% P = 0.047), RRFS (78% vs. 95% P = 0.015), DFS (80% vs. 95% P = 0.034), and PFS (84% vs. 90% P = 0.024), while as DMFS (85% vs. 85% P = 0.147) were comparable in both the groups. IMRT was also associated with a lower incidence of late toxicities such as xerostomia and trismus. Our study demonstrates that IMRT yields better long-term overall survival and local control including LRFS, RRFS, DFS, and PFS. In addition, late toxicities induced by irradiation in nasopharyngeal carcinoma (NPC) are lower with IMRT. IMRT may be an effective treatment in nasopharyngeal cancer (NPC) as compared to 2D-CRT, but further studies are needed to establish the association.