The impact of different cervical planning target volume designs on efficacy and toxicity in nasopharyngeal carcinoma: a single-center retrospective study.

Background: In nasopharyngeal carcinoma (NPC) patients, two radiation target delineation patterns are used for the cervical lymph node area.

Purpose: This study compares the efficacy and toxicity of two radiation target volume delineation patterns for planning target volumes (PTVs) in NPC patients.

Methods: This retrospective analysis included 387 non-metastatic NPC patients treated with concurrent chemoradiotherapy from January 2017 to December 2020. Patients were divided into two groups: the 2-PTV group with two dose gradients (50-54 Gy and 66-70 Gy) and the 3-PTV group with an additional 60-63 Gy dose.

Results: After a median follow-up of 51.2 months, the 3-year regional relapse-free survival (RRFS) showed no significant differences between the 3-PTV and 2-PTV groups (96.6% [95% confidence interval (CI): 96.5%-96.8%] and 96.3% [95% CI: 96.2%-96.3%]). In the N3 subgroup, the 3-year RRFS was also comparable between the 3-PTV and 2-PTV groups (96.2% [95% CI: 76%-99%] vs. 95% [95% CI: 69%-99%], p = 0.727). Importantly, the 2-PTV group demonstrated significantly lower rates of grade 3/4 dermatitis (5.1% vs. 16.5%; HR 0.88, 95% CI: 0.82-0.94, p = 0.002) and xerostomia (49.6% vs. 67%; HR 0.78, 95% CI: 0.72-0.84, p = 0.002).

Conclusions: The 2-PTV regimen achieved equivalent survival outcomes while significantly reducing treatment-related toxicities compared to the 3-PTV approach. These results suggest that the 2-PTV strategy may offer a more favorable therapeutic profile for NPC patients, particularly in minimizing severe dermatitis and xerostomia.