[Squamous cell carcinoma of the anal canal treated with chemoradiotherapy in a patient with HIV].

Since the introduction of combination antiretroviral therapy (ART), the life expectancy has increased for patients infected with human immunodeficiency virus (HIV). This has been associated with reductions in the incidences of some AIDS-defining malignancies, such as Kaposi sarcoma and non-Hodgkin lymphoma, but has coincided with an increased incidence of non-AIDS-defining malignancies, such as anal cancer. However, anal cancers are rare in patients with HIV in Japan. We report the case of an HIV-infected patient with anal cancer treated with chemoradiotherapy. A 37-year-old man receiving ART for HIV infection presented with a 1-month history of left inguinal lymphadenopathy and anal pain. Magnetic resonance imaging and computed tomography revealed a 56-mm mass, left inguinal lymphadenopathy, and left external iliac lymphadenopathy. The mass had infiltrated from the anal canal to the right levator ani and corpus spongiosum. Colonoscopy revealed a tumor with an ulcer in the anal canal. Histological examination of the tumor biopsy specimens confirmed the diagnosis of squamous cell carcinoma. The patient was diagnosed with anal cancer (T4N2M1 stage IV), and he received 5-fluorouracil (1000mg/m(2) on days 1-4 and 29-32) plus mitomycin C (10mg/m(2) on days 1 and 29) and concurrent radiotherapy (total dose, 59.4Gy in 33 fractions) along with ART. The treatment-related adverse events were grade 4 leukopenia and neutropenia, grade 3 thrombocytopenia, and grade 2 radiation dermatitis. Moreover, CD4 suppression was observed:the CD4 count decreased from 190 cells/μl before chemoradiotherapy to 138 cells/μl after 3 months, but increased to 210 cells/μl after 1 year. Because of the grade 4 leukopenia and neutropenia, the dose of 5-fluorouracil was reduced to 800mg/m(2) on days 29-32. A complete response was confirmed on magnetic resonance imaging, and colonoscopy confirmed the disappearance of the anal cancer. The patient is living with no signs of recurrence at 2 years after chemoradiotherapy. When treating HIV-infected patients with anal cancer by chemoradiotherapy and ART, clinicians should be aware of the possibility of CD4 suppression.