Bulky nodal disease as distinctive prognosticator in anal cancer management.

Abstract

1 Background: This study aimed to investigate the prognostic value of bulky nodal involvement in patients with squamous cell carcinoma of anus treated with definitive chemoradiotherapy. Methods: Medical records of patients with anal squamous cell carcinoma receiving definitive chemoradiotherapy at three medical centers from 2004 to 2021 were retrospectively analyzed. Exclusion criteria were (1) distant metastasis including non-regional nodal involvement at diagnosis, (2) 2D radiotherapy, and (3) salvage treatment for local relapse. Bulky nodal disease was defined as node with long-diameter 2cm or greater. Results: A total of 104 patients were accrued, consisting of 51 patients without, 46 patients with non-bulky, and 7 patients with bulky nodal involvement. Median follow-up duration was 54.0 months (range, 6.4-162.2 months). Estimated progression-free survival (PFS), loco-regional recurrence free survival (LRRFS) and overall survival (OS) at 5 years for patients with bulky nodal disease were 42.9%, 42.9%, and 89.4%, respectively. Compared to without or with non-bulky nodal involvement, bulky nodal involvement was significantly related with poor PFS and LR RFS. New staging incorporating bulky nodal disease as N2 stage was devised: T1-2N0-1 as stage I, T3-4N0-1 as stage II, and N2 as stage III. Estimated PFS, LRRFS, and OS at 5 years were as follows: 83.5%, 85.9%, and 91.3%, 60.9%, 67.7% and 93.3%, and 42.9%, 42.9%, and 55.6% for patients with stage I, II, and III disease, respectively (p = 0.0024 for PFS, 0.0015 for LRRFS, and 0.28 for OS, respectively). Conclusions: Patients with bulky nodal disease receiving standard chemoradiotherapy had poor survival outcomes compared to the other patient groups, suggesting the need for further treatment intensification. Moreover, incorporating bulky nodal disease into the staging system improved the prognosis predictability.