3512 - Clinical Outcomes and Patterns of Failures of Patients with Oligometastatic Anal Squamous Cell Carcinoma Treated with Definitive-Intent Chemoradiation and Metastasis-Directed Therapy
Presenter(s)
R. Ravella1, E. K. Liu1, Z. Chakrani1, M. Reyngold1, V. M. Williams1, V. Hristidis1, E. Pappou2, P. Paty2, A. J. Wu1, M. Zinovoy1, M. Weiser2, L. Saltz3, J. J. Cuaron1, R. Yaeger3, A. Cercek3, J. Garcia-Aguilar2, J. J. Smith2, C. H. Crane1, D. A. Roth O’Brien1, and P. B. Romesser1; 1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 2Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, 3Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY
Purpose/Objective(s):
Although stage I-III anal squamous cell carcinoma (ASCC) is highly curable with definitive chemoradiation (CRT), metastatic ASCC carries a poor prognosis and is often treated palliatively. We evaluated the impact of definitive CRT and metastasis-directed therapy (MDT) in patients with oligometastatic ASCC, hypothesizing that aggressive local treatment to both the primary tumor and limited metastatic sites may enable durable disease control—or even cure—in a select subset of patients.Materials/Methods:
We performed a single-institution retrospective review of patients treated from 2010 to 2024 with ASCC and solid organ metastases (i.e., liver, lung, bone) who received definitive-intent CRT plus MDT. Patients with isolated non-regional abdominopelvic nodal metastases were excluded. We collected clinical data, including local control of metastatic site, distant failure (DF), progression-free survival (PFS), overall survival (OS), and patterns of failure. Failures were analyzed using competing risk methods, whereas survival endpoints were estimated using the Kaplan–Meier method. Statistical analyses were performed using Prism and R.Results:
Among 35 patients (8 male, 26 female), 27 had synchronous metastatic disease, and 8 had metachronous disease diagnosed at a median of 11 months (range, 7-36) from initial presentation. Most patients had 1 (n=14, 40%) or 2-3 (n=12, 34%) metastatic lesions. Thirteen patients (37%) received induction chemotherapy prior to CRT and MDT. MDT was administered with radiation (n=22, 63%), surgery (n=3, 9%), or ablation (n=1, 3%).The median follow-up was 22 months (range 1-101) after completion of MDT. The 3-year OS was 53% (95% CI 33–69%)—56% (95% CI 34–73%) for synchronous disease vs 32% (95% CI 1–74%) for metachronous disease (p=0.30). The 3-year PFS was 30% (95% CI 15–47%)—32% (95% CI 1–74%) for synchronous vs 0% for metachronous (p=0.05). DF was most common, with a 3-year DF rate of 52%, while isolated failure within the initial metastatic organ occurred in 20% of patients at 3 years. Local control at the treated metastatic site was 87% at 3 years. At last follow-up, 18 (51%) patients remained alive of which 11 (31%) were without evidence of disease recurrence.
Conclusion:
In this cohort of oligometastatic ASCC, definitive CRT coupled with MDT led to encouraging long-term outcomes, with over half of patients alive at 3 years and nearly one-third free of disease. These results suggest that intensive treatment of both primary and metastatic sites may offer an opportunity for meaningful disease control, and possibly cure, in carefully selected patients.