The T-N tract involvement as a new prognostic factor for PORT in locally advanced oral cavity tumors

Objective: The space comprised between tumor and neck lymph nodes (T-N tract) is one of the main routes of tumor spread in oral cavity tumors. Aim of the study was to investigate the impact of T-N tract involvement on the postoperative radiotherapy (PORT) outcomes. Materials and Methods: Patients (pts) treated between 2000 and 2016 with indication to PORT were retrospectively retrieved. Inclusion criteria were: (a) locally advanced tumors of the oral cavity, (b) who received with indication to PORT (c) with a minimum follow-up of six months. Results: One hundred and fifty-seven pts met the inclusion criteria (136 pts treated with PORT and 21 pts not treated with PORT). In the PORT cohort, the T-N tract involvement had no impact on both OS (p =.09) and LRFS (p =.2). Among the non-PORT cohort, both OS (p =.007) and LRFS (p =.017) were worse for pts with positive T-N tract compared to those with negative T-N tract. PORT improved both OS (p =.008) and LRFS (p =.003) in pts with positive T-N tract but not in those with negative T-N tract (p =.36 and p =.37, respectively). Conclusions: Our results suggest that involvement of T-N tract should be considered as prognostic factors informing the indication to PORT.