Chinese Academy of Medical Sciences, China
Du Xiao-meng has graduated from Weifang Medical College in 2012, and is now a Postgraduate in Peking Union Medical College. She majors in radiation therapy of gynecologic malignances, and has published one review on the new advances in external beam radiotherapy techniques for cervical cancer.
Aim: To study the difference and feasibility between intensity-modulated radiotherapy and conventional 2D radiotherapy for postoperative cervical cancer with the method recommended by ICRU83 report. Methods: Retrospectively analysis of the DVH parameters of 10 IMRT plans of postoperative cervical cancer and 10 conventional 2D plans simulated on the same planning CT. The DVH parameters reported include: D100(Dmax), D98(Dnear-min), D95, D50 (Dmedia), Dmean, D2(Dnear-max), D0(Dmax) for PTV, Dmax,V40,V50,D1cc,D2cc,D2 for rectum and bladder, V10, V20, V30 for pelvic bones, V10-40，Dmean，Dmax and D2 for small intestine. SPSS 19 was used for statistical analysis. Results: PTV D50 is raised by 4.47±3.62% in IMRT plans than 2D plans, the actual value was 200±157 cGy (t=4.2, p=0.001). HI in IMRT plans (0.13±0.04) was better than 2D plans (0.62±0.28), p=0.00. Deviation between D50 and prescribed dose, D98, D2 was 5.66±1.46%,-7.31±1.77% and 5.73±3.23% respectively. V10 and V20 for pelvic bones in IMRT was higher than 2D plans, 95.9±1.7% vs. 56.4±4%, p=0.000 and 77.9±7.2% vs. 47.5±5%, p=0.000. V30 for pelvic bones in IMRT and 2D plans showed no statistical significance. V10 and V20 for small intestine were higher and V40 was lower in IMRT plans than 2D plans. V40 and Dmean were reduced in IMRT plans, while there still remains small high dose regions. Conclusion: IMRT potentially increased dose to the target volume. IMRT reduced overall dose for bladder and rectum while still remained small high dose volume, but increased the volume irradiated with low-dose for small intestine and pelvic bones. With D50 as the prescribed dose for PTV for postoperative cervical cancer patients, it may be possible to reduce normal tissue complications while still achieving a relatively good tumor control rate.