Long-Term Survival following Trimodal Therapy Including Hyperfractionated Radiotherapy in Parotid NUT Carcinoma: A 29-Month Follow-Up Case Report.

INTRODUCTION

NUT carcinoma (NC) is a rare, aggressive malignancy with median survival below 1 year. Reports of long-term survival are exceptional and rare. While multimodal treatment strategies including surgery, radiotherapy, and chemotherapy have been attempted, evidence remains scarce.

CASE PRESENTATION: We report the case of a middle-aged female patient with parotid NC harboring a NSD3::NUTM1 fusion. Following surgical resection, rapid disease progression with newly evident lymph node metastases occurred within 3 weeks, prompting definitive hyperfractionated intensity-modulated radiotherapy using a simultaneous integrated boost technique (1.4 Gy/1.6 Gy to 56.0 Gy/64 Gy, twice daily, 40 fractions) with concurrent weekly cisplatin (50 mg/m2). Acute toxicities were limited to grade 2 mucositis and dermatitis; no severe late effects were observed. At 29-month follow-up, the patient remains disease-free, with preserved quality of life. This case adds to the limited body of literature documenting long-term survival in NC, in which parotid localization is rare and hyperfractionated radiotherapy has not yet been reported. Durable remission has only been reported in isolated cases and is often with significant treatment-related morbidity. Comparison with previously published cases suggests that multimodal strategies, when feasible, may provide a chance for long-term survival, although optimal regimens remain undefined.

CONCLUSION

The present case suggests that hyperfractionated radiotherapy, exploiting radiobiological advantages in rapidly proliferating tumors, may improve both tumor control and toxicity profile compared to conventional fractionation in NC, warranting further investigation. To our knowledge, this represents one of the very few reports of a parotid NC patient achieving disease-free survival beyond 2 years after trimodal therapy.