Forward-Planned Multisegmented Technique in Resource-Limited Settings: A Feasible Dosimetric Upgrade for 3D-CRT in Locally Advanced Nasopharyngeal Carcinoma

Abstract

In resource-limited settings, intensity-modulated radiotherapy (IMRT) is often unavailable, forcing reliance on three-dimensional conformal radiotherapy (3D-CRT) for advanced nasopharyngeal carcinoma (NPC). This limits curative potential due to challenges in sparing organs-at-risk (OARs) while covering complex target volumes. This study compared the forward-planned multisegmented technique (FPMS) and the multi-field technique (MFT) in 3D-CRT for NPC, focusing on OAR protection and target coverage. Conducted at two public centres in Dakar, Senegal, between January 2019 and September 2020, this retrospective dosimetric analysis included eight patients. For each, two treatment plans were generated for the initial 50 Gy phase: one using MFT and one using FPMS. Plans were assessed with dose-volume histograms, conformity and homogeneity indices. FPMS achieved superior OAR sparing, with lower mean maximum doses to the spinal cord (43 Gy vs. 45 Gy) and brainstem (52 Gy vs. 55 Gy). Parotid sparing remained inadequate with both techniques. Coverage of pathological lymph node volumes (PTVN70) was suboptimal in both approaches (80.5% vs. 78.9%). FPMS thus provides better OAR protection than MFT, but neither ensures optimal target coverage in locally advanced NPC. These findings support FPMS as a feasible, interim solution in African centres awaiting IMRT, while underscoring the urgent need for technological advancement. Keywords: radiotherapy conformal, low-resource setting, nasopharyngeal carcinoma.