Factors Predictive of Local Disease Control after Intra-arterial Concomitant Chemoradiation (RADPLAT)

Objectives: To determine the relative risk of prognostic factors for local disease control following RADPLAT. Study Design: Prospective study, academic medical center. Methods: Analyses of nine categories of risk factors among 240 patients with Stage II-IV carcinoma consecutively treated with RADPLAT (cisplatin 150 mg/m² IA and sodium thiosulfate 9 g/m² IV, weekly ×4; radiotherapy 2 Gy/fraction/d, 5× weekly, 68-74 Gy over 6 to 7 weeks). Median follow-up: 58 months (range, 12-96 mo). Results: The percentage of patients who had local disease control was 87.5%. Univariant analysis showed T classification (P = .01), laterality of neck disease (P = .026), number of neck levels involved (P = .008), total dose of radiation greater versus less than 60 Gy (P = .027), and presence of pathologically positive lymph nodes following chemoradiation (P = .01) to be significant. Logistic regression analysis showed total dose of radiation (P = .03) and the presence of pathologically positive lymph nodes following chemoradiation (P = .05) to be significant. For Kaplan-Meier estimates of local disease control at 5 years, T classification (P = .038), number of levels with nodal disease (P = .006), and total dose of radiation therapy (P = .0001) were significant. The log-rank test identified as significant the total dose of radiation therapy (P < .0001), the presence of pathologically positive lymph nodes following chemoradiation (P = .005), and the number of neck levels with positive nodes (P = .006). The Cox regression model showed significance for the total dose of radiation (P = .001), the presence of pathologically positive lymph nodes following chemoradiation (P = .007), and the T classification (P = .029). Conclusion: Risk factors significantly associated with local disease control after RADPLAT appears to differ from more traditional therapy and is suggestive of a paradigm shift.