PURPOSE: The local failure rate in patients with locoregionally advanced cervical cancer is 41-72% after radiotherapy (RT) alone, whereas local control is a prerequisite for cure. The Dutch Deep Hyperthermia Trial showed that combining RT with hyperthermia (HT) improved 3-year local control rates of 41-61%, as we reported earlier. In this study, we evaluate long-term results of the Dutch Deep Hyperthermia Trial after 12 years of follow-up. METHODS AND MATERIALS: From 1990 to 1996, a total of 114 women with locoregionally advanced cervical carcinoma were randomly assigned to RT or RT+HT. The RT was applied to a median total dose of 68 Gy. The HT was given once weekly. The primary end point was local control. Secondary end points were overall survival and late toxicity. RESULTS: At the 12-year follow-up, local control remained better in the RT+HT group (37% vs. 56%; p=0.01). Survival was persistently better after 12 years: 20% (RT) and 37% (RT+HT; p=0.03). World Health Organization (WHO) performance status was a significant prognostic factor for local control. The WHO performance status, International Federation of Gynaecology and Obstetrics (FIGO) stage, and tumor diameter were significant for survival. The benefit of HT remained significant after correction for these factors. European Organization for Research and Treatment of Cancer Grade 3 or higher radiation-induced late toxicities were similar in both groups. CONCLUSIONS: For locoregionally advanced cervical cancer, the addition of HT to RT resulted in long-term major improvement in local control and survival without increasing late toxicity. This combined treatment should be considered for patients who are unfit to receive chemotherapy. For other patients, the optimal treatment strategy is the subject of ongoing research.