Upper-Neck Irradiation and Whole-Neck Irradiation Yielded Similar Regional Control in Nasopharyngeal Carcinoma

Less radiation toxicity and comparable regional control were observed in patients with N0 to N1 nasopharyngeal carcinoma who received in elective upper-neck irradiation (UNI) compared with whole-neck irradiation (WNI), according to findings from a phase 3 study (NCT02642107) published in The Lancet Oncology.

For those who received UNI, the 3-year regional relapse-free survival rate was 97.7% (95% CI, 95.7%-99.7%) vs 96.3% (95% CI, 93.8%-98.8%) for those who underwent WNI; the group difference was –1.4% (95% CI, –4.6% to 1.8%; non-inferiority P <.0001). The stratified HR was 0.73 (95% CI, 0.25-2.09; log-rank P = .85). The median follow-up was 52.0 months. The intent-to-treat analysis yielded the same results seen in the per-protocol analysis.

A total of 446 patients were randomly assigned 1:1 to either the UNI group (n = 224) or the WNI group (n = 222). In total, 122 patients received induction chemotherapy, 367 received concurrent chemotherapy, and 1 patient in the UNI group received adjuvant chemotherapy.

Follow-up was 41.0 months for the last patient enrolled in the study. Of 446 patients, 431 underwent regular examinations and followed up at participating centers until death or last scheduled assessment. The median follow-up was 53.0 months. The 3-year follow-up data were available for 218 patients in the UNI group and 210 in the WNI group.

At the last follow-up, overall, 13 patients had regional nodal relapse, 12 in the retropharyngeal or upper-neck regions, 1 was without relapse in the lower neck, and 1 in both the upper and lower neck region.

At the time of the last follow-up, 14 patients the UNI group and 10 in the WNI group died from primary cancer (n = 13), and non-cancer-related dermatomyositis (n = 1). No patients died during treatment. Eighteen patients had local relapse, and 27 had distant metastases.

The 3-year overall survival (OS) in the UNI group was 99.1% (95% CI, 97.9%-100%) vs 96.4% (95% CI, 93.9%-98.9%) in the WNI group (HR, 0.39; 95% CI, 0.12-1.25; P = .10). The 3-year distant metastasis-free survival was 94.6% (95% CI 91.7%-97.5%) in the UNI group and 93.5% (95% CI, 90.2%-96.8%) in the WNI group (HR, 0.85; 95% CI, 0.40-1.78; P = .15). Finally, the 3-year local relapse-free survival in the UNI group was 97.3% (95% CI, 95.1%-99.5%) vs 95.4% (95% CI, 92.7%-98.1%) in the WNI group (HR, 0.88; 95% CI, 0.36-2.16; P = .67). The per-protocol analysis yielded similar results, as well.

Between both groups, there were not any significant differences in acute radiation-related toxic effects. Patients in the UNI group had lower incidence of late toxicities vs the WNI group, respectively, including hypothyroidism (30% vs 39%), skin toxicity (14% vs 25%), dysphagia (17% vs 32%), and neck and tissue damage (23% vs 40%).

At the beginning of the study, 334 patients completed a EORTC QLQ-C30 questionnaire after starting treatment, and 324 completed the QLQ-H&N35 questionnaire. Both groups did not have differing results, except for the QLQ-C30 item of physical functioning, where patients in the UNI group had a higher baseline score than those in the WNI group.

At year 3, of those who were disease-free, 360 patients completed the EORTC QLC-C30, 353 completed the QLQ-H&N35, with the remaining patients not answering because of language constraints.Investigators did not find the results of the 3-year quality of life (QOL) analysis to differ greatly. Patients in the UNI group had significantly better QOL scores than the WNI group which included global health status, emotional functioning, and fatigue. Investigators reported an improvement in the swallowing domain, with a mean change from baseline of 10.1 points.

Reference

Tang LL, Huang CL, Zhang N, et al. Elective upper-neck versus whole-neck irradiation of the uninvolved neck in patients with nasopharyngeal carcinoma: an open-label, non-inferiority, multicentre, randomised phase 3 trial. Lancet Oncol. 2022;23(4):479-490. doi:10.1016/S1470-2045(22)00058-4