ANABASE.

Top Line: What are the real-world outcomes from modern therapy for anal squamous cell carcinoma?

The Study: While the overall treatment paradigm for anal squamous cell carcinoma has been well established for many years, there have been significant advances in imaging and radiation techniques.  How have these advances impacted treatment outcomes over time? FFCD-ANABASE is a large, prospective, multicenter observational cohort study from France that collected data on 1015 patients treated for anal SCC from 2015 to 2020. The majority were female (75.6%) and had workup with PET/CT (73%) and MRI (71.2%). Just over half (56.7%) had locally advanced disease (T3-4 or N+) with the rest having early stage disease (T1-2 N0). Most were also treated with IMRT (80.3%) and concurrent mitomycin and 5FU. The median total dose to the primary tumor was 60Gy with over a third of patients in both the early and advanced groups receiving >60Gy. These total doses are important to note as they underline the uncertainty regarding the optimal total dose to gross disease for anal SCC. A third of patients had treatment interruptions and of those 65.4% were treated with 3D conformal. At 4 to 6 months after treatment, the complete response rate was 82.4% for early stage disease and 68.1% for advanced disease. For early disease, DFS was 84.3% at 3 years and OS was 91.7%. This was significantly higher than the rate of DFS (64.4%) and OS (78.2%) seen in advanced disease. In multivariable analysis, male gender, poor performance status, and locally advanced disease were associated with worse survival outcomes. The use of IMRT was associated with better colostomy-free survival. In addition, patients treated with IMRT. The rate of recurrence was 19.9% with most of those being locoregional recurrences (56.9%) followed by distant recurrence (35.6%).

TBL: FFCD-ANABASE describes treatment outcomes from a large cohort of patients who had modern staging and treatment with modern radiation techniques for anal cancer. | Vendrely, Radiother Oncol 2023