Carboplatin and Paclitaxel Chemoradiation for Localized Anal Cancer in Patients Not Eligible for Mitomycin and 5-Fluorouracil

TL;DR

This study shows that carboplatin and paclitaxel chemoradiation is a promising treatment for anal cancer patients who cannot tolerate the standard therapy.

Contribution

The study introduces a new treatment regimen for anal cancer patients ineligible for the standard mitomycin and 5-fluorouracil therapy.

Findings

89% of patients achieved a complete clinical response with the new regimen.

The regimen was completed for 78.3% of the intended treatments with manageable toxicity.

67% of patients were alive and without recurrence after a median follow-up of 25.8 months.

Abstract

Squamous cell carcinoma of the anus or anal cancer is increasing in prevalence, and the standard treatment of mitomycin and 5-fluorouracil is too toxic for many patients. Unfortunately, there is currently no standard of care for what to do for this disease when someone is not a candidate for this aggressive treatment. Here, we demonstrate the promising preliminary toxicity profile and efficacy of the combination of weekly carboplatin and paclitaxel chemotherapy for patients with localized anal cancer. This regimen was able to complete 80% of the intended treatments with anticipated toxicities, and 89% achieved a complete clinical response. This combination is a promising regimen and is already being investigated further in a clinical trial.

Background: Although squamous cell carcinoma of the anus (SCCA) is a relatively uncommon malignancy in the United States, it continues to increase in incidence. Treatment for locoregional disease includes mitomycin and 5-fluorouracil with radiation. This combination is associated with significant toxicity, limiting its use in patients who are older or have certain comorbidities. Carboplatin and paclitaxel (C/P) is an accepted treatment regimen for metastatic SCCA. We aim to evaluate the efficacy and toxicity of weekly C/P given with radiation for patients unable to receive standard chemoradiation for SCCA. Methods: From our cancer registry, adult patients who received weekly intravenous C/P concurrent with standard-dose radiation for localized SCCA were included in this study. Clinical response was determined based on the evidence of disease on imaging and/or anoscopy. Toxicities were graded according to the CTCAE v5. Results: Ten patients were included; eight were female, and the median age was 75.5 years (54–87). Six had T2 disease, and four had T3 tumors. Four had node-positive disease. The majority (70%) of patients were dosed at standard C (AUC 2) and P (50 mg/m2), with a limited subset requiring dose reduction for baseline performance status. Patients completed a mean of 78.3% (40–100%) of the intended treatments. A total of 89% of the patients achieved a complete clinical response. With a median follow-up of 25.8 months (3.4–50.4 months), 67% of the patients are alive and without recurrence. Two patients have had local recurrence, and one patient had metastatic progression. The most common toxicities of any grade included leukopenia (100%), anemia (100%), radiation dermatitis (100%), diarrhea (100%), and fatigue (100%). Grade 3 or higher toxicities included neutropenic fever (20%), neutropenia (30%), and anemia (30%). Conclusions: This study demonstrates promising tolerability and efficacy for weekly C/P chemoradiation for patients with anal cancer unable to receive mitomycin and 5-fluorouracil. This regimen merits further investigation in prospective clinical trials.

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