Definitive S-1/mitomycin-C chemoradiotherapy for stage II/III anal canal squamous cell carcinoma: a phase I/II dose-finding and single-arm confirmatory study (JCOG0903)

BACKGROUND

Definitive chemoradiotherapy (CRT) with 5-fluorouracil plus mitomycin-C is a standard treatment for stage II/III squamous cell carcinoma of the anal canal (SCCA). We performed this dose-finding and single-arm confirmatory trial of CRT with S-1 plus mitomycin-C to determine the recommended dose (RD) of S-1 and evaluate its efficacy and safety for locally advanced SCCA.

METHODS

Patients with clinical stage II/III SCCA (UICC 6th) received CRT comprising mitomycin-C (10 mg/m² on days 1 and 29) and S-1 (60 mg/m²/day at level 0 and 80 mg/m²/day at level 1 on days 1-14 and 29-42) with concurrent radiotherapy (59.4 Gy). Dose-finding used a 3 + 3 cohort design. The primary endpoint of the confirmatory trial was 3-year event-free survival. The sample size was 65, with one-sided alpha of 5%, power of 80%, and expected and threshold values of 75% and 60%, respectively.

RESULTS

Sixty-nine patients (dose-finding, n = 10; confirmatory, n = 59) were enrolled. The RD of S-1 was determined as 80 mg/m²/day. Three-year event-free survival in 63 eligible patients who received the RD was 65.0% (90% confidence interval 54.1-73.9). Three-year overall, progression-free, and colostomy-free survival rates were 87.3%, 85.7%, and 76.2%, respectively; the complete response rate was 81% on central review. Common grade 3/4 acute toxicities were leukopenia (63.1%), neutropenia (40.0%), diarrhea (20.0%), radiation dermatitis (15.4%), and febrile neutropenia (3.1%). No treatment-related deaths occurred.

CONCLUSIONS

Although the primary endpoint was not met, S-1/mitomycin-C chemoradiotherapy had an acceptable toxicity profile and favorable 3-year survival and could be a treatment option for locally advanced SCCA.

CLINICAL TRIAL INFORMATION

jRCTs031180002.

A phase II study of concurrent chemoradiotherapy with 5-fluorouracil and mitomycin-C for squamous cell carcinoma of the anal canal (the JROSG 10-2 trial)

This study assessed the efficacy of chemoradiotherapy for squamous cell carcinoma of the anal canal (SCCAC). Patients with T1-4N0-3M0 SCCAC received chemoradiotherapy with 5-fluorouracil (5-FU, 800 mg/m2/day, 96-h infusion) and mitomycin-C (MMC, 10 mg/m2 bolus). Patients treated with 3-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) were administered 36.0 Gy in 20 fractions or 49.5 Gy in 33 fractions for elective nodal irradiation and 59.4 Gy in 33 fractions for primary tumor and metastatic nodal irradiation. The sample size was considered sufficient to estimate 95% confidence intervals (CIs) for the true 2-year disease-free survival (DFS) within a width of +15% when the expected true 2-year DFS was 70%. The primary endpoint was 2-year DFS. The secondary endpoints were 2-year overall survival (OS), locoregional control (LC), colostomy-free survival (CFS) and adverse events. Thirty-one patients were enrolled between January 2014 and July 2019. The median follow-up was 33.3 months (range, 16.2-65.8 months). Among the 31 patients, 13%, 32%, 16% and 39% had stage I, II, IIIA and IIIB disease, respectively. Thirty patients were treated with IMRT. Complete response (CR) was achieved in 27 patients. The 2-year DFS, OS, LC and CFS rates were 77.4% (95% CI, 58.4-88.5%), 93.5% (95% CI, 76.6-98.3%), 83.9% (95% CI, 65.5-92.9%) and 80.6% (95% CI, 61.9-90.8%), respectively. One patient experienced grade 3 late adverse events; however, no grade ≥ 4 late adverse events occurred. Good DFS with a low rate of late adverse events was observed. Chemoradiotherapy with 5-FU and MMC was effective for SCCAC.

Challenges of improving treatment outcomes for colorectal and anal cancers in Japan: the Colorectal Cancer Study Group (CCSG) of the Japan Clinical Oncology Group (JCOG)

Colorectal cancer is a major public health concern in Japan. While early-stage colorectal adenocarcinoma treatment entails radical resection of the primary tumor, the importance of perioperative treatment is growing as physicians seek to further improve treatment outcomes. For anal squamous cell carcinoma, definitive chemoradiotherapy is superior to radical surgery in terms of improved patient quality of life. The Colorectal Cancer Study Group of the Japanese Clinical Oncology Group was established in 2001 and has worked to provide answers to common clinical questions and improve treatment outcomes for colorectal and anal cancers through 15 large-scale prospective clinical trials. Here, we discuss the current state of perioperative treatment for early-stage colon, rectal and anal cancers in Japan and approaches taken by the Colorectal Cancer Study Group/the Japanese Clinical Oncology Group to improve treatment outcomes for these cancers.

Intensity-modulated radiotherapy for synchronous cancer of the anal canal and cervix

Due to recent advancements in diagnostic techniques, the incidence of multiple primary cancer has increased; however, synchronous cancer of the anal canal and cervix (SCACC) is rare, and no previous studies have investigated the treatment of this disease. The present study reports a case in which intensity-modulated radiotherapy (IMRT) was used to treat a 64-year-old female with SCACC, inguinal lymphadenopathy and anal pain. The patient was diagnosed with cT3N3M0 stage IIIb anal canal squamous cell carcinoma and cT1b1N0M0 stage Ib1 cervical squamous cell carcinoma, based on biopsy and imaging study data. According to the definitive treatment for advanced-stage anal canal cancer, outpatient treatment with chemoradiotherapy (CRT) using S-1 for SCACC was recommended, as the patient did not want to undergo resection of the anus. Considering the lymph node regions involved in SCACC and the necessary doses, the treatment plan was as follows: Whole pelvis and inguinal lymph node region radiation (36 Gy/20 fractions); a first booster radiation dose (9 Gy/5 fractions) for the whole pelvis; and a second booster radiation dose (14.4 Gy/8 fractions) for the primary lesions. The patient was prescribed S-1 at a dose of 60 mg/m²/day twice daily on days 1-14 and 29-42. The patient experienced grade 2 diarrhea and anal mucositis, but CRT was completed without discontinuation and hospitalization. The patient exhibited a complete response and remained disease-free without any treatment-associated complications at the 6-month follow-up. In conclusion, SCACC was successfully treated with IMRT in the present case. It is important to determine the treatment strategy for synchronous cancer types, taking into consideration the tumor stage, tumor location and patient situation.

Clinical endpoints in trials of chemoradiation for patients with anal cancer

This Review examines the reporting of endpoints in randomised controlled trials (RCTs) of radical chemoradiation for treatment of squamous cell carcinoma of the anus. The types, frequency, and definitions of clinical primary and secondary endpoints, and patient-reported outcome measures, reported in the methods and results sections of papers (and protocols, if available) were examined. Only six published RCTs comprising 2877 patients were identified. Primary outcome measures varied across the trials analysed: two used disease-free survival, one used progression-free survival, two used local failure, and one used colostomy-free survival. Secondary endpoints included overall survival, complete clinical response, quality of life, toxicity, and compliance. The definitions for primary and secondary endpoints were not consistent across trials, particularly for treatment failure (local, regional, and distant). We conclude that the quality of outcome reporting in RCTs of squamous cell carcinoma of the anus is inconsistent. A core set of outcomes, including clinical and patient-reported outcome measures with standardised definitions, is needed to improve the reporting of RCTs examining chemoradiation for treatment of patients with squamous cell carcinoma of the anus.

Anal cancer - What is the optimum chemoradiotherapy?

Radical concurrent chemoradiotherapy with 5FU and Mitomycin C is the standard-of-care for squamous-cell carcinoma of the anus (SCCA). Phase III trials combined radiation doses of 50-60 Gy with concurrent Fluoropyrimidines, Mitomycin C and Cisplatin in various doses and schedules. CRT is highly successful for early T1/T2 cancers, but results in appreciable late morbidities and still fails to control larger and node-positive tumours. Compliance to chemotherapy is important for local control. Modern radiotherapy techniques such as intensity-modulated radiotherapy (IMRT), rotational IMRT, image-guided radiotherapy (IGRT) have enabled smaller margins and highly conformal plans, resulting in decreased radiation doses to the organs at risk and ensuring a shorter overall treatment time. These advances offer the potential for integrating higher doses of radiation, escalation of the currently used drugs and the safe use of other more novel agents with acceptable toxicity. In this chapter potential novel approaches are discussed in the context of SCCA.