A randomized study of intensity-modulated radiation therapy versus three dimensional conformal radiation therapy for pelvic radiation in patients of post-operative treatment with gynecologic malignant tumor

Abstract

Objective: To study the difference between intensity-modulated radiation therapy (IMRT) and three dimensional conformal radiation therapy (3D-CRT) for pelvic radiation of post-operative treatment with gynecologic malignant tumor. Methods: A prospective investigation study was conducted on 183 patients of post-operative patients with whole pelvic radiation therapy of cervical cancer or endometrial cancer in Zhejiang Cancer Hospital [IMRT group (n=85) and 3D-CRT group (n=98)] from Oct. 2015 to Oct. 2016. The two groups received same dose (45 Gy in 25 fractions). Comparison of two groups with radiation dosimetry:the score according to the Radiation Therapy Oncology Group (RTOG) acute radiation injury grading standards before and after radiotherapy reaction, the score from functional assessment of cancer therapy scale-cervix (FACT-Cx) scale and expanded prostate cancer index composite for clinical practice (EPIC-CP) scale were also analyzed. Results: (1) There were no significant effect with age, culture level, family economic condition and ratio of radiochemotherapy between two groups (all P>0.05). (2) Dosimetric comparison for IMRT vs 3D-CRT: the average dose of planning target volume (PTV) decreased (46.1±0.4) vs (46.4±0.5) Gy, V(45) dose percentage increased (95.2±1.0) % vs (93.3±2.0) %, intestinal bag dose of V(4)0 decreased (24.4±6.8) % vs (36.5±15.9) %, rectal V(40) dose percentage decreased (73.9±12.3) % vs (85.4±8.4) %, and lower rectal V(45) dose percentage (32.8±13.4) % vs (71.5±13.7) %, bladder V(40) dose percentage decreased (55.5±13.0) % vs (84.4±13.0) %. Bone marrow V(20) lower: (67.9±5.4) % vs (79.5±6.6) %, V(1)0 lower: (82.1±6.0) % vs (86.3±6.6) %; there were significant differences (all P<0.05). There was no significant difference between the dose of V(45) in the intestinal pouch and bladder (P>0.05). (3) Acute radiation injury classification for IMRT vs 3D-CRT: big or small intestine: Ⅱ-Ⅲ reaction [13% (11/85) vs 24% (24/98); χ(2)=3.925, P=0.048], there was significant difference. Bladder: Ⅲ reaction [19% (16/85) vs 26% (25/98); χ(2)=1.171, P=0.279], there was no significant difference. Radiochemotherapy of bone marrow suppression: Ⅲ-Ⅳ reaction (14/20), the incidence rate [26% (14/54) vs 31% (20/65); χ(2)=0.339, P=0.562], the difference was not statistically significant. (4) Quality of life scale by FACT-Cx scale in IMRT vs 3D-CRT: there were no significant difference before radiotherapy (82±16 vs 85±16; t=1.279, P=0.203), while there was significant difference after radiotherapy (76±14 vs 71±18; t=-2.160, P=0.032). EPIC-CP scale score: before radiotherapy they were (16±7 vs 15±6; t=-0.174, P=0.862),but after radiotherapy (18±7 vs 22±7; t=3.158, P=0.002), there was significant difference between them. Before and after radiotherapy, the increased EPIC-CP scale of the IMRT group vs 3D-CRT group were 3±4 and 6±4, the 3D-CRT group was significantly higher, the difference was statistically significant (t=5.500, P=0.000). Conclusion: IMRT has shown that there are a significant benefit for the post-operative patients with cervical cancer and endometrial cancer compared to 3D-CRT.