Evaluating the Rationality of the International Guideline's Recommendations Regarding Selective Coverage of Level Ib in Node Clinical Target Volume With Nasopharyngeal Carcinoma: Results From a Real-World Series

Level Ib-sparing IMRT should be safe and feasible for patients who only had involvement of level II LNs with ECE, and/or had a MAD of greater than 2 cm in level II LNs, and/or Ib involvement with negative pathological results. Further well-designed multi-center prospective trials should be conducted to confirm our results.