In a Chinese phase III trial reported in The Lancet Oncology, Tang et al found that elective upper-neck irradiation sparing the uninvolved neck was noninferior in regional relapse–free survival vs standard whole-neck irradiation in previously untreated patients with nasopharyngeal carcinoma.

Study Details

In the open-label trial, 446 patients with N0-1 disease with no distant metastases from three Chinese centers were randomly assigned between January 2016 and May 2018 to upper-neck irradiation (n = 224) or whole-neck irradiation (n = 222). Total radiation doses of 70 Gy (for primary tumor volume and enlarged retropharyngeal nodes), 66 to 70 Gy (for involved cervical lymph nodes), 60 to 62 Gy (for high-risk target volume), and 54 to 56 Gy (for low-risk target volume) were administered in 30 to 33 fractions at 5 fractions per week. It was recommended that patients with stage II to IVA disease receive cisplatin-based chemotherapy as either induction chemotherapy followed by concurrent chemoradiotherapy or in concurrent chemoradiotherapy alone. Induction chemotherapy was received by 61 patients in each group. The primary endpoint was regional relapse–free survival in the intention-to-treat population. Noninferiority was established if the upper limit of the 95% confidence interval of the difference in 3-year regional relapse–free survival for the upper-neck irradiation vs the whole-neck irradiation groups was within 8.0%.

Regional Relapse–Free Survival

Median follow-up was 53 months (interquartile range = 46–59 months). Three-year regional relapse–free survival was 97.7% (95% confidence interval [CI] = 95.7%–99.7%) in the upper-neck irradiation group vs 96.3% (95% CI = 93.8%–98.8%) in the whole-neck irradiation group (difference = −1.4%, 95% CI = −4.6% to 1.8%, P < .0001 for noninferiority; stratified hazard ratio [HR] = 0.73, 95% CI = 0.25–2.09, P = .85).

At 3 years, overall survival was 99.1% vs 96.4% (HR = 0.39, P = .10), distant metastasis–free survival was 94.6% vs 93.5% (HR = 0.85, P = .15), and local relapse–free survival was 97.3% vs 95.4% (HR = 0.88, P = .67).

Toxicity

No substantial differences in acute radiation-related toxic effects were observed between the upper-neck irradiation and whole-neck irradiation groups. The most common of any grade in both groups were dry mouth (72% vs 73%) and mucositis (65% vs 69%); the most common grade ≥ 3 toxicity was mucositis in both groups (9% vs 10%). Late toxicity was less common in the upper-neck irradiation group, including any-grade hypothyroidism (30% vs 39%), skin toxicity (14% vs 25%), dysphagia (17% vs 32%), and neck tissue damage (23% vs 40%). The most common grade ≥ 3 late toxicity in both groups was dry mouth (5% vs 7%). No patients died during treatment.

The investigators concluded, “Elective upper-neck irradiation of the uninvolved neck provides similar regional control and results in less radiation toxicity compared with standard whole-neck irradiation in patients with N0-N1 nasopharyngeal carcinoma.”

Jun Ma, MD, of Sun Yat-sen University Cancer Center, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, is the corresponding author for The Lancet Oncology article.

Disclosure: The study was funded by Sun Yat-sen University Clinical Research 5010 Program, Natural Science Foundation of Guangdong Province, and others. For full disclosures of the study authors, visit thelancet.com.