Radiation dose escalation using intensity modulated radiation therapy for gross unresected node-positive endometrial cancer

Abstract Purpose To determine rates of nodal control and survival in patients with endometrial cancer treated with intensity modulated radiation therapy (IMRT) with dose escalation to unresected nodal disease. Methods and Materials Between November 2005 and April 2011, 22 endometrial-cancer patients received IMRT with dose escalation to gross nodal disease with curative intent. Twelve were treated for recurrent disease (RD) and 10 in the primary setting, of whom 5 had a hysterectomy. The boost area included pelvic nodes in 9 patients (41%), paraaortic nodes (PAN) in 6 (27%) and both pelvic and PAN in 7 (32%). The median gross nodal dose was 63 Gy (range, 55-65). Rates of local control, disease-free survival (DFS) and overall survival (OS) were determined using the Kaplan-Meier method. Results Median follow-up time was 37.6 months (range, 10-88). Median nodal size was 2.25 cm (range, 1-6.9). The median time to first relapse after IMRT was 12 months (range, 6-49). Relapses occurred in 5/12 RD (42%), 1/5 hysterectomy (20%), and 5/5 inoperable cases. Nodal relapses occurred in-field in 3/12 RD and 1/5 hysterectomy patients. At 3 years, nodal control was 86%, DFS was 58% and OS was 68%. Three patients experienced grade 3 late hematologic toxicity (anemia). No late grade ≥3 gastrointestinal or genitourinary toxicity occurred. Conclusions In endometrial cancer, the use of IMRT for dose escalation to gross nodal disease is feasible with acceptable rates of toxicity. Patients with nodal recurrence or unresectable nodal disease after a hysterectomy may benefit from radiation dose escalation.