Intensity-modulated radiation therapy versus para-aortic field radiotherapy to treat para-aortic lymph node metastasis in cervical cancer: prospective study.

AIM To compare dosimetry, efficacy, and toxicity of intensity-modulated radiation therapy (IMRT) with para-aortic field radiotherapy in patients with para-aortic lymph node (PALN) metastasis of cervical cancer. METHODS This prospective study examined 60 patients with cervical cancer with PALN metastasis who underwent whole-pelvis radiotherapy followed by brachytherapy between November 1, 2004 and May 31, 2008. After 3 cycles of chemotherapy, patients were serially allocated into two groups and treated with IMRT or para-aortic field RT at doses of 58-68 Gy and 45-50 Gy, respectively. Treatment response was evaluated and toxicities were assessed. Patients in the IMRT group were treated with both para-aortic field RT and IMRT in order to compare the exposure dose of organs at risk. RESULTS In the IMRT group, the mean dose delivered to the planning target volume was 67.5 Gy. At least 99% of the gross tumor volume received effective coverage and radical dose (median, 63.5 Gy; range, 54.5-66) during treatment. IMRT plans yielded better dose conformity to the target and better sparing of the spinal cord and small intestine than para-aortic field RT. The IMRT patients experienced less acute and chronic toxicities. The IMRT group also had higher 2- and 3-year survival rates than the para-aortic RT group (2-year, 58.8% vs 25.0%, P = 0.019; 3-year, 36.4% vs 15.6%, P = 0.016). However, no significant difference was found in 1-year survival (67.7% vs 51.3%, P =0.201). The median survival in the IMRT group was 25 months (range, 3 to 37 months). The actuarial overall survival, disease-free survival, and locoregional control rates at 2 years were 67%, 77%, and 88%, respectively, in the IMRT group. CONCLUSIONS IMRT provides better clinical outcomes than para-aortic field radiotherapy in patients with PALN metastasis. However, cervical local and distal recurrence remain a problem. Long-term follow-up and studies involving more patients are needed to confirm our results.