MHNC: Proton beam therapy shows promise in advanced sinonasal cancers

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Proton beam radiation therapy showed encouraging results for patients with locally advanced sinonasal malignancies, according to a study presented Feb.25 at the Multidisciplinary Head and Neck Cancer Symposium in Chandler, Ariz.

Between 1991 and 2003, 99 patients with newly diagnosed sinonasal cancers were treated with proton beam therapy at Massachusetts General Hospital in Boston. The histological subtypes were squamous cell carcinoma in 32 patients, esthesioneuroblastoma/ neuroendocrine tumors in 30, adenoid cystic carcinoma in 20, sarcoma in 11, and adenocarcinoma in 6, according to Annie Chan, MD, a radiation oncologist and the principal investigator of the study at Massachusetts General Hospital and Harvard Medical School in Boston.

The median total dose to the primary tumor was 72.8 GyE and the median percentage of protons was 57 percent--82 percent of patients received twice-daily radiation, 67 percent of the patients had surgery before radiation and only 2 percent of the patients had concurrent chemotherapy, said Chan.

The researchers found that after a median follow-up of 92.6 months for all surviving patients, the local control rates at 5 and 8 years were 87 percent and 83 percent, respectively. “There was no statistically significant difference in local control rate per histological subtype, T stage, and surgery vs. biopsy. Distant metastasis was the predominant pattern of relapse-- 56 percent and the distant-metastasis-free survival rate at 5 and 8 years was 69 percent,” noted Chan.

Chan and colleagues also found the rate of freedom from grade 3 or higher late toxicity at 5 years was 78 percent; in 5 years was 29 percent with surgery before radiation and 7 percent in patients without surgery before radiation.

"Due to the anatomical location of sinonasal cancers, conventional radiation therapy results in very poor local control rate and is associated with significant treatment-related toxicity," said Chan. "Proton beam radiation therapy, with its
superior dose distribution, allows the delivery of higher doses of radiation to the tumor while sparing more or the healthy surrounding tissues. This study showed very encouraging results for these patients and now prospective multi-institutional studies are being planned to further study the use of proton therapy in the treatment of this rare but aggressive malignancy."