Diagnosis and management of anal cancer.

During the past three decades, anal cancer has served as a paradigm for the successful application of chemoradiation to solid tumors. Since the early 1990s, the increasing incidence of anal cancer in homosexual men has highlighted the causative role of oncogenic human papilloma-virus infection. This review focuses on significant trends and developments in the management of patients with squamous cell carcinoma of the anal canal, emphasizing three major aspects of diagnosis and treatment: routine screening and eradication of premalignant lesions in high-risk individuals; outcome of chemoradiation therapy in HIV-positive individuals in the era of highly active antiretroviral therapy; and potential improvements in chemoradiation protocols through improved radiation delivery technique and the combination of mitomycin with cisplatin in current prospective randomized trials.

Chemotherapeutic options in the management of anal cancer.

During the past two decades, anal cancer has served as a paradigm for the successful application of chemoradiation to solid tumours; so far, it remains one of the few carcinomas of the gastrointestinal tract which are curable without the need for definitive surgery. Since the original contribution by Nigro in 1974, surprisingly few changes have been made to the standard of care in chemotherapy, which still consists of a combination of 5-fluorouracil and mitomycin C. However, many issues have yet to be clarified, such as the potential role of cisplatin as a substitute to mitomycin, as well as treatment-induced toxicity in HIV-positive patients.

Squamous cell carcinoma of the anus: another sexually transmitted disease.

During the past 30 years, there has been remarkable progress in our understanding of the pathogenesis of squamous cell carcinoma of the anus. It is now accepted that anal cancer is a sexually transmitted disease, which can be cured using a combination of chemo- and radiotherapy. The biology of anal cancer remains to be elucidated, as do the molecular mechanisms involved in resistance to chemoradiation.

A tale of two colons and two cancers. Distinct carcinogenesis and clinical outcome according to location proximal or distal to the splenic flexure.

The central hypothesis explored in this paper is that colorectal cancer (CRC) is a heterogeneous disease. The initial clue to this heterogeneity was provided by genetic findings; however, embryological and physiological data had previously been gathered, showing that proximal (in relation to the splenic flexure) and distal parts of the colon represent distinct entities. Molecular biologists have identified two distinct pathways, microsatellite instability (MSI) and chromosomal instability (CIN), which are involved in CRC progression.