A total of 459 patients were enrolled in the study, all of whom had squamous cell carcinoma classified as high risk because the tumor met at least one criterion: invasion of two or more lymph nodes, extension beyond a lymph node capsule, or microscopic involvement of mucosal margins of resection. After all visible and palpable tumor was surgically removed, 231 patients were randomized to radiation therapy alone, with 228 randomized to identical radiation therapy plus cisplatin.

The two-year, local/regional control rate was 74 percent for the radiation group and 79 percent for the combination group. At three years of follow-up, 131 patients were alive, and 124 (95 percent) had no evidence of local or regional recurrence. Local or regional recurrence was the site of first treatment failure in 26 percent of the radiation patients and 19 percent of combination therapy patients. Distant metastasis was the first site of failure in 23 percent of the radiation therapy group and 19 percent of the combination therapy group. None of these differences are statistically significant.

However, 58 percent of patients who did not receive chemotherapy had some form of recurrent disease versus 45 percent of patients who did receive chemotherapy, a statistically significant difference.

"We primarily sought to learn whether the addition of cisplatin chemotherapy to post-operative radiation therapy would improve the likelihood of local-regional control of head and neck cancer for this selected subgroup of particularly aggressive resected tumors," said Jay S. Cooper, M.D., lead author of the study.

"We are disappointed to learn that despite added toxicity from the addition of chemotherapy, local-regional control, distant control, overall survival and disease-free survival were not significantly improved. On the bright side, we did demonstrate that we can reliably identify this aggressive group of tumors from features seen on pathology examination, which should improve selection of patients for future trials and treatments. We also have demonstrated that with modern techniques and meticulous attention to the details of our gold-standard treatment, surgery followed by radiation therapy, even for these high-risk tumors, we have reduced the rate of local-regional recurrence to the point that only one of four patients has treatment fail them in this fashion. Lastly, the significant difference observed for treatment failure of any type suggests that we are headed in the right direction, but need to identify more effective agents."