The following is a summary of “Individualized delineation of clinical target volume for primary nasopharyngeal carcinoma based on invasion risk of substructures: a prospective, real-world study with a large population,” published in the February 2024 issue of Oncology by Wang et al.

In the context of primary nasopharyngeal carcinoma (NPC), the delineation of clinical target volume (CTV) remains contentious, with current international guidelines advocating a uniform approach irrespective of tumor extent. Addressing this discrepancy, the researchers conducted a prospective, real-world study aimed at assessing the clinical efficacy of an individualized CTV delineation method based on distance and substructure invasion risk. 

Initial investigations into local extension patterns of NPC in 354 newly diagnosed patients facilitated the categorization of surrounding structures into Level-1 to Level-4 substructures stratified by invasion risk. Subsequently, patients without distant metastasis were enrolled to evaluate their individualized CTV delineation protocol, with all subjects undergoing intensity-modulated radiotherapy. Primary endpoint evaluation focused on local recurrence-free survival (LRFS), with secondary endpoints including regional control and survival, analyzed using the Kaplan-Meier method. Their study, comprising 356 patients in the training set (January 2008 to December 2012) and 648 patients in the validation set (January 2013 to September 2019), demonstrated promising outcomes with a median follow-up of 104.6 and 51.4 months, respectively. 

Notably, the 5-year LRFS rates were 93.0% and 93.2% in the training and validation sets, with overall survival (OS) rates of 88.5% and 93.4%, respectively. Across the entire cohort (N=1004), with a median follow-up of 66.6 months, LRFS and OS at 5 years stood at 93.2% and 91.5%, respectively. Grade 3 late toxicities, including xerostomia, subcutaneous fibrosis, and hearing impairment, were observed in 1.5% of cases. Furthermore, the vast majority (97.1%) of local recurrences occurred within high-dose areas. 

In conclusion, their individualized CTV delineation approach yields favorable outcomes in terms of local tumor control and long-term survival, with acceptable rates of late toxicities.

Source: sciencedirect.com/science/article/abs/pii/S0167814024000756