A recent phase 3 study presented at the American Society for Therapeutic Radiology and Oncology (ASTRO) 2020 Annual Meeting found that patients with cervical cancer undergoing postoperative adjuvant conventional radiation are more likely to develop late bowel toxicity than those undergoing image guided intensity modulated radiotherapy (IG-IMRT).
For this study, results of which are published in the International Journal of Radiation Oncology, Biology, Physics, 300 patients aged 18 to 65 years old with cervical cancer who were planned to receive adjuvant pelvic radiation (CRT) were enrolled. Patients were randomly assigned to be administered either IG-IMRT or three-dimensional conformal radiation (3D-CRT) after stratification for type of hysterectomy. Those in the 3D-CRT group received a dose of 50 Gy/25 fractions/5 weeks with or without weekly cisplatin (40 mg/m2), followed by 2 fractions of high dose rate brachytherapy of 6 Gy.
After a median follow up of 49 months, the 4-year grade ≥2 late bowel toxicity was significantly lower in the IG-IMRT arm compared with the 3D-CRT arm (19.2% vs 36.2%). The 4-year grade >3 late bowel toxicity was also decreased in the IG-IMRT arm (2.0%) versus the 3D-CRT arm (8.7%). In the IG-IMRT group, 17.2% of patients reported acute grade ≥2 diarrhea, and 27.2% reported this treatment side effect in the 3D-CRT arm. There was no significant difference in disease-free survival observed (73% vs 68%).
The study authors, led by Supriya Chopra, MD, from the Department of Radiation Oncology, Advanced Centre for Treatment Research and Education in Cancer, Homi Bhabha National Institute, Mumbai, Maharashtra, India, conclude "IG-IMRT results in significantly lower incidence of late grade ≥2 bowel toxicity in patients receiving adjuvant post-operative RT or CTRT for cervical cancer with no difference in disease-free survival. IG-IMRT should be considered as the new standard of care for postoperative pelvic radiation."
For More Information
Chopra S, Dora T, Gupta S, et al (2020). Phase III randomized trial of postoperative adjuvant conventional radiation (3DCRT) versus image guided intensity modulated radiotherapy (IG-IMRT) in cervical cancer (PARCER): final analysis. Int J Radiat Oncol Biol Phys, 108(3):S1-S2. DOI:10.1016.j.ijrobp.2020.07.2069
Image courtesy of Haymanj