KEY POINTS
- The retrospective MERLIN study included 305 patients with nasopharyngeal carcinoma treated at nine German centres between 2004 and 2023. Median follow-up was 61.7 months, and 90.8% received concurrent chemoradiotherapy.
- Central imaging review confirmed medial retropharyngeal lymph node involvement in 9 of 305 patients (2.95%; 95% CI 1.05–4.85%), compared with a historical rate of 0.2% in an endemic cohort.
- The observed rate exceeded the study’s prespecified noninferiority threshold of 2.2%, meaning noninferiority to the historical endemic rate was not demonstrated.
- The medial retropharyngeal region was included in the elective clinical target volume in 198 of 282 evaluable patients (70.2%). No recurrence occurred in this region among patients whose elective volume omitted it.
- Only one medial retropharyngeal recurrence occurred in the entire cohort. That region had been irradiated, and the recurrence developed alongside primary-site recurrence and lung metastases.
CLINICAL TAKEAWAY
Elective omission of the medial retropharyngeal region may be reasonable in carefully staged patients with nasopharyngeal carcinoma from non-endemic populations, particularly when reducing dose to the swallowing pathway is a priority. However, the evidence remains retrospective, imaging was heterogeneous, functional outcomes were not measured, and the prespecified noninferiority threshold was not met.