Objective:

To evaluate the feasibility and safety of a target-prioritized IMRT strategy for locally advanced nasopharyngeal carcinoma (NPC) with tumors close to the cervical spinal cord.

Approach:

• Patient Selection: Retrospective review of 909 patients with stage III–IVB NPC treated with IMRT from 2012 to 2022, focusing on 145 patients with tumor-cord proximity.
• Dosimetric Analysis: Extraction of dosimetric parameters from dose-volume histograms and evaluation of predictors using logistic regression.
• Outcome Analysis: Outcomes analyzed using Kaplan-Meier and log-rank test.

Key Findings:

• No clinically diagnosed radiation myelopathy (RM) was observed in the overall cohort (upper one-sided 95% CI, 0.33%).
• 5-year local relapse–free survival (LRFS) and overall survival (OS) rates were 92.8% and 86.8%, respectively.
• The cumulative burden score, based on occipital base, occipital condyle, and atlanto-dental interval involvement, was associated with target-prioritized planning (trend OR, 1.906; P = 0.001).
• In the target-prioritized cohort, median cord Dmax was 56.2 Gy, with 20.8% of patients having a Dmax >60 Gy.
• 5-year LRFS and OS rates in the target-prioritized cohort were 87.9% and 74.2%, respectively, with no clinically diagnosed RM (upper one-sided 95% CI, 2.8%).

Interpretation:

Limitations:

• Retrospective design may introduce bias.
• Findings may not be generalizable to all NPC patients.

Conclusion:

With strict dose-volume control and image guidance, a target-prioritized strategy can be implemented in selected cases of NPC.