Predictive value of in vitro radiosensitivity parameters in head and neck cancers and cervical carcinomas: preliminary correlations with local control and overall survival.

PURPOSE: To determine whether in vitro radiosensitivity parameters are predictive of treatment outcome. METHODS AND MATERIALS: Biopsies were obtained from patients with head and neck cancers (57) and cervical carcinomas (20) and in vitro radiosensitivity parameters were obtained using the CAM plate assay. RESULTS: In most cases (75%) patients were treated with radiation alone. The median follow up was 461 days. When the whole group of head and neck cancers and cervical carcinomas was considered, patients with a SF2 value below 0.36 had a higher 2-year local control rate (93% versus 68%) and a higher 2-year survival rate (71% vs. 62%) than those with SF2 values above that threshold, but differences were not significant. These trends persisted when head and neck cancers were considered alone with a higher local control rate (86% vs. 67%) and a higher survival rate (75% vs. 52.5%) obtained for patients with a SF2 value below 0.36. When the alpha value was evaluated for the whole group of patients a significantly higher local control rate (80.5% vs. 40.5%) and overall survival rate (71% versus 37.5%) at 2 years were obtained for patients with alpha values above 0.07 Gy-1. When only the group of head and neck cancers was considered, local control rate was significantly higher (79% vs. 33%) but overall survival rate (65.5% vs. 33%) was not significantly higher for alpha values above 0.07 Gy-1. CONCLUSION: These results are encouraging but need to be confirmed with a larger number of patients with a longer follow-up.