ASTRO: Radiotherapy safe for cancer patients with HIV

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Partially allaying concerns over limited treatment options in a population significantly more prone to cancer, researchers found that HIV patients with head and neck cancer tolerated radiotherapy without excessive side effects, according to a study published in the International Journal of Radiation Oncology, Biology and Physics.

Although patients infected with the HIV virus are known to face significantly higher risks of developing various cancers, including head and neck cancer, limited information exists as to how best to optimize treatment for these patients. Small studies have contributed to uncertainties over exaggerated toxicity due to immunodeficiency, leading some radiation oncologists to consider lower doses or CD4 count (an hematologic indicator of an individual's level of immunodeficiency) to be important conditions to treatment, according to Emily A. Klein, of the department of radiation oncology, and co-authors from the University of California Davis Cancer Center in Sacramento.

Klein and colleagues retrospectively reviewed the records of 12 HIV patients with head and neck cancer who were treated with radiotherapy, with a median dose of 68 Gy delivered over 2 Gy fractions. Six patients were treated concurrently with chemotherapy and nine were taking highly active antiretroviral therapy (HAART).

Three-year overall survival (median follow-up, 33 months) was 78 percent, with 11 of 12 patients experiencing complete responses to treatment. The three-year estimate of local-regional control was 92 percent. Three patients died within follow-up: one from local-regional cancer progression, one from distant metastasis to the lungs and one from intercurrent disease.

Acute grade 3 or greater toxicity occurred in 7 patients, including one patient who was not receiving HAART. The most common acute side effects were confluent mucositis (five patients) and moist skin desquamation (four patients). Two patients developed multiple grade 3 or greater toxicities.

Additional complications incurred during radiotherapy included severe arytenoid edema resulting in whispered speech, which resolved following the completion of treatment, and oral thrush in 25 percent of patients. Meanwhile, a mild drop in median CD4 count was observed in the whole cohort and the radiotherapy plus chemotherapy subcohort, dropping from 460 and 610 cells per microliter prior to treatment to 355 and 205 cells per microliter upon completion, respectively.

Although all patients completed the planned course of treatment, five patients experienced breaks in excess of 10 total days. "This is particularly relevant because prolonged treatment delays have been associated with adverse outcomes with respect to local-regional control and overall survival," Klein and co-authors wrote. The authors attributed this high rate of interruption to nonmedical and psychosocial reasons, which, because more prevalent in HIV patients, led the authors to suggest referrals for appropriate counseling in this population.

"Although our study demonstrates that chemoradiotherapy is well tolerated among HIV-positive patients with head and neck cancer, it is limited by the number of patients in the analysis and by selection bias," the authors acknowledged. Highlighting the reassuring findings that radiotherapy may not excessively increase toxicity, Klein and co-authors insisted on the importance of future studies consisting of larger samples, especially among patients with CD4 counts below 200 cells per microliter who have substantially worse immunodeficiency.

"Although this series is a nonrandomized comparison of a single institutional experience, the results demonstrate that radiation therapy can safely and effectively be administered to patients with HIV without an excessive rate of acute or late side effects," the researchers concluded. "These data are important because they alleviate concerns that toxicity may be intensified in this immunocompromised population."