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, V45 dose percentage increased(95.2 ± 1.0)%vs (93.3 ± 2.0)%, intestinal bag dose of V40 decreased(24.4 ± 6.8)%vs (36.5 ± 15.9)%, rectal V40 dose percentage decreased(73.9 ± 12.3)%vs (85.4 ± 8.4)%, and lower rectal V45 dose percentage(32.8 ± 13.4)%vs (71.5 ± 13.7)%, bladder V40 dose percentage decreased(55.5 ± 13.0)% vs (84.4 ± 13.0)%. Bone marrow V20 lower:(67.9 ± 5.4)% vs (79.5 ± 6.6)%, V10 lower:(82.1 ± 6.0)% vs (86.3 ± 6.6)%; there were significant differences (all P0.05). (3) Acute radiation injury classification for IMRT vs 3D-CRT:big or small intestine:Ⅱ-Ⅲreaction [13%(11/85) vs 24% (24/98); χ2=3.925, P=0.048], there was significant difference. Bladder: Ⅲ reaction [19% (16/85) vs 26% (25/98); χ2=1.171, P=0.279], there was no significant difference. Radiochemotherapy of bone marrow suppression:Ⅲ-Ⅳreaction (14/20), the incidence rate [26%(14/54) vs 31%(20/65);χ2=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.