Mary Koshy, MD

Squamous cell anal cancer remains an uncommon entity; however,the incidence appears to be increasing in at-risk populations, especiallythose infected with human papillomavirus (HPV) and human immunodeficiencyvirus (HIV). Given the ability to cure this cancer using synchronouschemoradiotherapy, management practices of this disease arecritical. This article considers treatment strategies for HIV-positive patientswith anal cancer, including the impact on chemoradiation-inducedtoxicities and the role of highly active antiretroviral therapy in the treatmentof this patient population. The standard treatment has beenfluorouracil (5-FU) and mitomycin (or cisplatin) as chemotherapy agentsplus radiation. Consideration to modifying the standard treatment regimeis based on the fact that patients with HIV tend to experience greatertoxicity, especially when CD4 counts are below 200; these patients alsorequire longer treatment breaks. Additional changes to the chemotherapydosing, such as giving 5-FU continuously and decreasing mitomycin dose,are evaluated and considered in relation to radiation field sizes in an effortto reduce toxicity, maintain local tumor control, and limit need forcolostomy. The opportunity for decreasing the radiation field size andusing intensity-modulated radiation therapy (IMRT) is also considered,particularly in light of the fact that IMRT provides dose-sparing whilemaximizing target volume dose to involved areas. The impact of the immunesystem in patients with HIV and squamous cell carcinoma of theanus and the associated response to therapy remains unknown. Continuedstudies and phase III trials will be needed to test new treatment strategiesin HIV-infected patients with squamous cell cancer of the anus todetermine which treatment protocols provide the greatest benefits.

The fusion of 18-fluorodeoxyglucose (FDG) positron-emission tomography(PET) with computed tomography (CT) offers both anatomicand physiologic delineation of head and neck cancers. PET-CT is usefulin the staging of head and neck carcinomas and may identify unsuspecteddistant metastasis that may alter treatment. PET-CT may alsohelp in target volume delineation during radiotherapy (RT) treatmentplanning. Better characterization of the target may improve local controlas well as spare normal tissues from RT sequelae.

The article by Drs. Bendell andRyan reviews the associationbetween anal cancer and humanpapillomavirus (HPV) infectionand discusses current managementstrategies for patients with squamouscell carcinoma of the anal canal. Theauthors should be complimented ona thorough review of the literature,which supports that association andthe use of chemoradiation as the goldstandard for treatment of this groupof patients.