Selecting the right chemotherapy in first-line advanced squamous cell carcinoma of the anus

Efficacy and tolerance of cetuximab in combination with 5 FU plus irinotecan based chemotherapy in metastatic squamous cell anal carcinoma

BACKGROUND

Squamous cell anal carcinoma (SCAC) is an uncommon neoplasia often cured by surgery and/or chemo-adiation therapy at the localized stage. Although the first-line treatment for metastatic anal canal cancer is now better codified with two validated treatment regimens, carboplatin-paclitaxel and modified docetaxel-cisplatin-5FU (DCF), there is little data and no consensus regarding subsequent lines [1-5]. In this study, we report the safety and efficacy of cetuximab (an epidermal growth factor receptor inhibitor) in combination with 5-FU plus irinotecan based chemotherapy.

METHOD

A retrospective analysis of patients with metastatic SCAC (mSCAC), who failed on at least one prior line of treatment, before being treated with the combination FOLFIRI and cetuximab between March 2015 and February 2022 at Gustave Roussy cancer center, was performed.

RESULTS

A total of 33 patients with a pre-treated mSCAC were analyzed. The combination of FOLFIRI and cetuximab provided a disease control rate (DCR) of 73%, and response rate of 30%. With a median follow-up of 38 months, the median progression free survival was 5.5 months, and the median overall survival was 13.7 months. Fourteen patients (42%) experienced grade III/IV adverse events that remained manageable.

CONCLUSION

Our study suggests that FOLFIRI and cetuximab is a promising combination in the management of mSCAC with a very good DCR and a manageable toxicity profile. Further prospective trials would be needed to confirm our results.

Long-Term Disease Control After locoregional Pelvic Chemoradiation in Patients with Advanced Anal Squamous Cell Carcinoma

Introduction

The incidence of metastatic squamous cell carcinoma of the anus (SCCA) is increasing. Even if systemic docetaxel, cisplatin, and 5-Fluorouracil (DCF) provide a high rate of long-term remission, the role of pelvic chemoradiation (CRT) is unknown in this setting. We reported the safety and efficacy of local CRT in patients with synchronous metastatic SCCA who achieved objective response after upfront DCF.

Methods

Patients included in Epitopes HPV01 or Epitopes HPV02 or SCARCE trials and treated with DCF followed by pelvic CRT were included. Concurrent chemotherapy was based on mitomycin (MMC) (10 mg/m² for two cycles) and fluoropyrimidine (capecitabine 825 mg/m² twice a day at each RT treatment day or two cycles of intra-venous 5FU 1000 mg/m² from day 1 to day 4). Primary endpoints were safety, local complete response rate, and local progression-free survival (PFS). Secondary endpoints were PFS, overall survival (OS), and metastasis-free survival (MFS).

Results

From 2013 to 2018, 16 patients received DCF followed by a complementary pelvic CRT for advanced SCCA. Median follow-up was 42 months [range, 11-71]. All patients received the complete radiation dose. Compliance to concurrent CT was poor. Overall, 13/15 of the patients (87%) had at least one grade 1-2 acute toxicity and 11/15 of the patients (73%) had at least one grade 3-4 toxicity. There was no treatment-related death. The most frequent grade 3-4 adverse effects were neutropenia (36%), dermatitis (40%), and anitis (47%). Eleven patients (73%) had at least one chronic grade 1 or 2 toxicity. One patient had a grade 4 chronic rectitis (7%). Complete local response rate was 81% at first evaluation and 62.5% at the end of the follow-up. Median local PFS was not reached and the 3-year local PFS was 77% (95%CI 76.8-77).

Conclusions

In patients with metastatic SCCA who had a significant objective response after upfront DCF, local CRT was feasible with high complete local response rate. The good local control rate, despite interruptions due to toxicities and low CT compliance, underline the role of pelvic RT. The high rate of toxicity prompts the need to adapt CRT regimen in the metastatic setting.