The role of radiation therapy with 5-fluorouracil in anal canal cancer

Chemoradiotherapy for anal cancer: clinical trials past, present and future

SUMMARY

Anal cancer is a rare cancer whose incidence is increasing in the UK. It is associated with human papilloma virus infection and smoking and is more common in women and immunosuppressed individuals, including those with transplants and HIV infection. The current standard of care is chemoradiotherapy (CRT) to the pelvis with surgery reserved for patients where CRT is contraindicated or as salvage treatment for residual disease or recurrence post-CRT. Radiotherapy combined with mitomycin-C and 5-fluorouracil has emerged as the standard of care following a series of six well-conducted Phase III trials. Trials have shown no benefit for cisplatin-based combination regimens either concurrently, adjuvantly or neoadjuvantly.

Radiation Modifiers: Treatment Overview and Future Investigations

Many radiosensitizers are in current clinical use. In addition, a myriad of potential new targeted therapies, which may also interact with radiation, are in clinical development. The clinical utility of new targeted therapies, in combination with existing radiation sensitizers (chemotherapies) requires further evaluation, as does the understanding of their acute and late radiation effects. Free radical scavengers appear to show promise as radioprotectors, but data for mucoprotection are less convincing.

Carcinoma of the anal canal: a local experience and review of the literature

BACKGROUND

Through the 1970s patients presenting with anal canal carcinoma were managed with a surgical approach--abdomino-perineal resection. Since then, the pioneering work of Nigro et al. and a series of large clinical trials have clearly demonstrated that combined chemotherapy and radiotherapy result in greater local control, colostomy-free survival and increase in overall patient survival. The aim of the present study is to determine how widely the combined modality approach has been adopted in routine clinical practice and what outcomes are achieved in this setting.

METHODS

All patients with anal cancer treated at three tertiary referral centres over an 11-year period (1991-2001) were identified. Data were collected by a retrospective record review.

RESULTS

Our search identified a total of 50 patients: 22 men and 28 women, with a median age of 62 years. Four patients had metastatic disease diagnosed at presentation. Nine patients (18%) were at least 75 years of age and three were known to be HIV positive. Median potential follow up is 52 months. Of the 46 patients treated for cure, 38 received a combination of chemotherapy and radiation, with 79% achieving a complete response. Efficacy was maintained in treated elderly patients (> or =75 years). The 5-year survival of the 38 patients with local or locoregional disease who received combined chemoradiation modality was 63%.

CONCLUSIONS

Overall this series demonstrates that combined chemotherapy and radiotherapy has been adopted as standard treatment with outcome data similar to those reported in the randomized clinical trials. Where possible elderly patients should receive combined modality therapy.

Four Decades of Continuing Innovation With Fluorouracil: Current and Future Approaches to Fluorouracil Chemoradiation Therapy

Purpose

Chemoradiotherapy, the combination of external radiation therapy and concurrent chemotherapy, has been the basis for the oncologic management of many patients since its development in the 1960s. Fluorouracil (FU) chemoradiotherapy has demonstrated success in several organ sites with multiple dosing schedules that now guide the selection of oral analogs of FU to provide new chemoradiotherapy options.

Methods

This article reviews the metabolism and pharmacology of FU and the advantages of administration of FU by continuous infusion or bolus. The potential role and impact of the oral fluorouracil prodrugs UFT, S-1, BOF-A2, and capecitabine as replacements for intravenous administration are discussed. The results of recent chemoradiotherapy studies with FU from 2000 to 2003 are summarized in rectal, head and neck, esophageal, gastric, pancreatic, biliary, anal, and cervical cancers.

Results

Chemoradiotherapy with FU has the potential to widen the therapeutic window by minimizing normal tissue toxicity while maintaining effective tumor toxicity. Overall, FU chemoradiotherapy maximizes local control and, for some tumor sites (such as head and neck, pancreatic, biliary, cervical, esophageal, and gastric cancers), improves survival rates. Moreover, FU chemoradiotherapy results in improved organ preservation with excellent functional outcome in several anatomic sites including head and neck cancer, anal, and rectal cancer, with improved sphincter preservation.

Conclusion

FU chemoradiotherapy continues to play an important role in the management of many cancer sites. During the last four decades, optimal dosing schedules have produced a therapeutic gain. The introduction of oral prodrug analogs will likely further improve the results of FU therapy in several organ systems, such as the rectum, head and neck, and esophagus.

Carcinoma espinocelular de canal anal: análise de 11 casos

Racional - O câncer de canal anal é um tipo raro de neoplasia, sendo responsável por 4% dos tumores de intestino grosso. São descritos os aspectos clínicos e o tratamento dos pacientes com câncer escamoso desta região. Casuística - Analisaram-se, retrospectivamente, 11 pacientes com carcinoma espinocelular de canal anal. Nove pacientes eram do sexo feminino e dois do masculino. A idade média dos pacientes foi de 57,6 anos (variação 35-82 anos). Resultados - Os sintomas mais freqüentes foram sangramento retal, tumoração e dor local. Seis pacientes tinham lesão benigna prévia local e dois tinham doença metastática na ocasião do diagnóstico. Todos foram submetidos a quimioterapia sistêmica com 5-fluorouracil e mitomicina. Após o tratamento quimio e radioterápico, quatro apresentavam doença residual e foram submetidos a ressecção abdômino-perineal. Três pacientes apresentaram recidiva e quatro morreram pela evolução da própria doença. Conclusão - A maioria dos doentes era do sexo feminino. A químio e a radioterapia podem ser tratamentos curativos nos pacientes com doença localizada; no entanto, aqueles com doença residual devem ser submetidos a ressecção abdômino-perineal. Embora o câncer espinocelular de canal anal seja doença curável, quatro pacientes foram a óbito por terem sido diagnosticados em fase avançada.

[Conservative treatment of anal canal carcinoma with external radiotherapy and interstitial brachytherapy, with or without chemotherapy: long-term results]

PURPOSE

A retrospective analysis of conservative treatment of anal canal cancers with external radiation therapy and interstitial brachytherapy with or without chemotherapy.

PATIENTS AND METHODS

From 1986 to 1996, 69 patients were treated with external radiotherapy (40 Gy/20 fractions) and interstitial brachytherapy (20 Gy) after a mean interval of six weeks for a localized epidermoid carcinoma of the anal canal. Patients who did not complete the whole therapeutic sequence were not included. Forty-five patients received additional 5-fluorouracil- and/or mitomycin C-based chemotherapy regimen.

RESULTS

Acute toxicity was acceptable. Complete response rate was 81%. Actuarial local control rate was at two and five years, 65% and 59% respectively (median follow-up: eight years). At two, five and ten years, actuarial colostomy rate was 26%, 33% and 33% respectively, and colostomy-free survival rates 61%, 47% and 37%. Overall survival at two, five and ten years was 81%, 65% and 53% respectively. Distant metastases occurred in 11 patients (16%). Prognostic factors for overall survival were performance status (PS) (79% survival at five years for patients with PS 0 versus 50% for patients with PS 1-3, P = 0.04) and tumor stage (80% at five years for T1-T2 versus 53% for T3-T4, P = 0.03). Overall treatment time less than 12 weeks and time interval between external radiotherapy and brachytherapy inferior than six weeks were associated with a better local control (P = 0.05). In multivariate analysis, these prognostic factors were not significant.

CONCLUSION

These results confirm the efficacy of external radiotherapy and brachytherapy in the treatment of small anal canal cancers, and point out the need for improving treatment outcome of larger tumors.