Clinical features and survival outcomes between ascending and descending types of nasopharyngeal carcinoma in the intensity-modulated radiotherapy era: A big-data intelligence platform-based analysis

Abstract

Purpose: To compare clinical features and survival outcomes in patients with ascending type (type A) and descending type (type D) nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era.

Materials and methods: A total of 5194 patients with type A and type D NPC treated at Sun Yat-sen University Cancer Center were randomly selected. Tumors that were mainly advanced local disease (T3-4 stage) with early stage cervical lymph node involvement (N0-1 stage) were determined as type A, while tumors with advanced lymph node disease (N2-3 stage) but early stage local invasion (T1-2 stage) were classified as type D NPC. Kaplan-Meier's analysis was used to evaluate survival rates, and log-rank test survival curves were used for comparison. In the multivariate analysis Cox proportional hazard models were developed.

Results: There was a larger proportion of type A tumors (82%) than type D tumors (18%). Compared to patients with type A tumors, those with type D tumors had increased likelihood of distant metastasis, regional recurrence, disease recurrence, and death (P < 0.001 for all), however, not for local recurrence (P < 0.001). The HR (hazard ratio) for death following recurrence of disease for type D tumors were 1.6 compared to type A tumors. Multivariate analysis revealed that elevated EBV DNA, elevated lactate dehydrogenase, alcohol consumption, and no family history of cancer attributed to the development of type D tumors. Annual hazard rate in type A patients increased, peaking at 12-18 months after initial treatment and downward thereafter. Similar trend also occurred in type D during the first 5 years following treatment. Notably, a minor peak was also observed 7-8 years post treatment.

Conclusions: In the IMRT era, recurrence patterns differed across tumor types. Type D NPC had a more aggressive clinical course and worse outcomes compared with type A NPC.

Keywords: Ascending type; Clinical features; Descending type; Intensity-modulated radiotherapy; Nasopharyngeal carcinoma; Survival outcomes.