Mitomycin in anal canal carcinoma

Mitomycin and Fluorouracil With Concurrent Radiation (FUMIR) Regimen for Anal Cancer

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc, 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@aol.com; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Carcinoma of the anus: strategies in management

The management of anal cancer underwent an interesting transformation over the last two decades. Prior to this period, the standard definitive treatment for carcinoma of the anal canal was abdominal-perineal resection, which necessitated a permanent colostomy. The organ preservation concept appeared following the discovery of a high complete response rate from preoperative combined chemoradiation prior to abdominal-perineal resection. The organ preservation method of treatment rapidly gained popularity and ultimately saved a large number of patients from undergoing abdominal-perineal resection and colostomy. Chemoradiation treatment itself subsequently went through an evolutionary process. Several studies have sought to define the optimal chemotherapeutic regimen as well as radiation treatment dose and fractionation. Ongoing studies attempt to define an optimal treatment regimen that yields a higher cure rate while minimizing toxicity. We review the etiology, epidemiology, and treatment regimens for anal cancer.

Squamous cell carcinoma of the oesophagus treated with radiation and 5-fluorouracil, with and without mitomycin C

A retrospective analysis was performed of patients with squamous cell carcinoma of the oesophagus without evidence of distant metastases, who were treated with radical intent. Between 1981 and 1984, and 1989 and 1991, 98 patients were treated with radiation, 5-fluorouracil (5-FU) and mitomycin C; and between 1984 and 1989, 133 patients were treated with radiation and 5-FU without mitomycin C. Actuarial survival and local control were assessed, and prognostic factors were identified for both endpoints. The standard dose of radiation prescribed was 52 Gy to the 95% isodose in 20 fractions over 4 weeks. 5-FU was given by continuous infusion as 1 g/m2 (maximum 1.5 g)/day, for 4 days. Patients who received mitomycin C were given 10 mg/m2 (maximum 18 mg) on day 1. Survival and local relapse-free rates were estimated using the method of Kaplan and Meier, and the Cox proportional hazards model was used to evaluate possible prognostic factors, including the effect of mitomycin C administration. The median survival was 15.4 months (95% confidence interval 12.7-17.2) with 31% 2-year survival (standard error (SE) 3%), and 13% 5-year survival (SE 2%). In the multivariate analysis, lower radiation dose and younger age were the only statistically significant prognostic factors for reduced overall survival and reduced relapse-free rate respectively. There was no difference in survival (chi(2) = 0.07, 1 degree of freedom (df), P=0.79) or local relapse-free rate (chi2 = 0.39, 1 df, P = 0.53) between patients treated with or without mitomycin C. The treatment was well tolerated. Further studies are required to determine the most effective combination of radiation and chemotherapy or other radiation sensitizers for squamous cell carcinoma of the oesophagus.

Proliferation parameters in epidermoid carcinomas of the anal canal

PURPOSE

In a prospective study, we assessed the proliferation parameters in primary epidermoid carcinomas of the anal canal, and results were compared with those in cervical carcinomas.

METHODS

Between January 1992 and December 1996, 32 patients with primary epidermoid carcinoma of the anal canal were studied prospectively. Patients were given i.v. bromodeoxyuridine and proliferation parameters were obtained using flow cytometry. The treatment protocol consisted of radiation therapy (XRT) (24 Gy/12-3.5 week split-28 Gy/14) and concurrent 5-fluorouracil and mitomycin C. Proliferation parameters were not obtained in six patients, leaving 26 patients in the analysis. There were 16 females and ten males, with two T1, 16 T2, five T3 and three T4 lesions. Median follow-up was 3.6 years. There were 22 squamous cell and four basaloid carcinomas. Six tumors were aneuploid.

RESULTS

Median values for T(s) and S-phase fraction were 7.7 h and 8.2%, respectively. The median LI was 6.8% (0.9-35.7%), and the median T(pot) was 4.1 days (0.9-30 days). There was no correlation of LI or T(pot) with gender, age, tumor stage, size or histology. Local failure was observed in five patients (T(pot)>4.1 days, n=3; LI>6.8%, n=4). Isolated regional failure or distant disease in the absence of local failure was not observed. The small number of outcome events precluded a definitive analysis of the prognostic role of LI and T(pot). Values for the proliferation parameters were similar to those in our updated study of patients with carcinoma of the uterine cervix (n=107), median LI of 6.7% and median T(pot) of 5.5 days.

CONCLUSIONS

We conclude that proliferation parameters in anal carcinomas are similar to those in cervical carcinomas. Rapid tumor proliferation does not have an apparent adverse impact on outcome in anal carcinomas managed by split-course XRT with concurrent 5-florouracil and mitomycin C.

Enhanced cytotoxicity of mitomycin C in human tumour cells with inducers of DT-diaphorase

DT-diaphorase is a two-electron reducing enzyme that activates the bioreductive anti-tumour agent, mitomycin C (MMC). Cell lines having elevated levels of DT-diaphorase are generally more sensitive to MMC. We have shown that DT-diaphorase can be induced in human tumour cells by a number of compounds, including 1,2-dithiole-3-thione. In this study, we investigated whether induction of DT-diaphorase could enhance the cytotoxic activity of MMC in six human tumour cell lines representing four tumour types. DT-diaphorase was induced by many dietary inducers, including propyl gallate, dimethyl maleate, dimethyl fumarate and sulforaphane. The cytotoxicity of MMC was significantly increased in four tumour lines with the increase ranging from 1.4- to threefold. In contrast, MMC activity was not increased in SK-MEL-28 human melanoma cells and AGS human gastric cancer cells, cell lines that have high base levels of DT-diaphorase activity. Toxicity to normal human marrow cells was increased by 50% when MMC was combined with 1,2-dithiole-3-thione, but this increase was small in comparison with the threefold increase in cytotoxicity to tumour cells. This study demonstrates that induction of DT-diaphorase can increase the cytotoxic activity of MMC in human tumour cell lines, and suggests that it may be possible to use non-toxic inducers of DT-diaphorase to enhance the efficacy of bioreductive anti-tumour agents.

Ten-year results of chemoradiation for anal cancer: focus on late morbidity

PURPOSE

To evaluate (a) long-term survival and (b) the incidence and nature of long-term morbidity/ mortality related to chemoradiation using the anal cancer experience.

METHODS AND MATERIALS

From January 1979 to April 1987,34 consecutive patients with Stage I (5 patients), II (15 patients), and II (14 patients) cancers of the anal canal were treated definitively with a chemoradiation regimen combining 41.4 Gy pelvic radiotherapy with two concurrent cycles of 5-fluorouracil and mitomycin C. Cumulative actuarial survival was calculated at 10 years and long-term morbidity was categorized per RTOG/EORTC late toxicity criteria. Specific criteria to grade anal toxicity were devised.

RESULTS

Cumulative survival for all 34 patients was 92% at 5 years and 85% at 10 years. The most frequent late toxicity was chronic diarrhea in 17 (50%) patients. Five patients (15%) had Grade 3 or 4 late toxicities. Sexual dysfunction was present in 2 of 26 evaluable patients (7%).

CONCLUSIONS

Excellent long-term survival and colostomy-free survival is possible for anal cancer patients treated definitively by chemoradiation. Late effects do not appear to be frequent or intense enough to deter the use of chemoradiation in anal cancer. The biologically expected increase in long-term toxicity when combining radiotherapy and chemotherapy is not substantiated by the results of this study.