Comparison of intensity-modulated radiation therapy and 3-dimentional conformal radiotherapy plansfor cervical carcinoma with recurrence and metastasis

Abstract

Objective To compare the treatment effects,dosimetry,and toxicities to organs at risk of intensity-modulated radiation therapy (IMRT) and 3-dimentional conformal radiotherapy (3DCRT) plans for cervical carcinoma patients with recurrence and metastasis. Methods 62 cervical carcinoma patients with recurrence and metastasis were analyzed retrospectively, and divided into two groups including intensitymodulated radiation therapy group (n=29) and 3-dimentional conformal radiotherapy group (n=32).Patients were performed with 6 MV-X ray.The regimen was 1.8-2.2 Gy/f,1 f/d,18-33 times in total.Prescribed dose was 40-60 Gy and median dose was 52.8 Gy. At the same time for the IMRT group 29 cases were performed with 3DCRT, which was designed using the same prescribed dose to compare radiation dose distributed in organs at risk (OAR).Results The maximum dose of the two plans showed that bladder and small intestine in IMRT plans were lower than that in 3DCRT (P＜0.05), showing the IMRT's protective advantage. The maximum dose of PTV in IMRT plans were significantly higher than 3DCRT (P＜0.05). In the group of IMRT plans, the overall 1-,2-,and 3-year survival rates were 65.5 ％(19/29), 42.1％(8/19), and 25.0 ％(2/8),respectively,the median survival time was 19 months,of 28 deaths,21 patients died of tumor progression,7 patients died of distant metastases.In the group of 3DCRT plans,the overall 1-,2-,and 3-year survival rates were 60.6 ％(20/33),35.0 ％(7/20),and 14.3 ％(1/7),respectively,the median survival time was 17 months,of 32 deaths, 24 patients died of tumor progression, 8 patients died of distant metastasis. There were no significant differences in overall 1-, 2-, and 3-year survival rates between the two groups (P＞0.05). The incidence rate of toxicity in the IMRT plans was significantly lower than that in the 3DCRT plans, especially for patients with Ⅰ level and Ⅱ level.Conclusion The treatment effects of the IMRT plans are better than the 3DCRT plans for cervical carcinoma patients with recurrence and metastasis. IMRT plans can improve radiation dose in tumors and reduce the dose distributed in normal issue and reduce the incidence of the side effect. Key words: Uterine cervical neoplasms; Recurrence; Neoplasm metastasis; Radiotherapy,intensity-modulated; Radiotherapy, conformal