Reduced Risk of Lymphedema With Intensity-modulated Radiation Therapy Compared With 3-dimensional Conformal Radiation Therapy in Patients With Cervical Cancer Who Received Postoperative Pelvic Radiation Therapy

Objectives: To compare the long-term adverse events of intensity-modulated radiation therapy (IMRT) with those of 3-dimensional conformal radiation therapy (3D-CRT) in patients with intermediate-risk and high-risk uterine cervical cancer who underwent postoperative pelvic radiation therapy (PORT). Methods: We reviewed the medical records of 177 patients with cervical cancer who underwent radical surgery and PORT. IMRT and 3D-CRT were administered to 93 and 84 patients, respectively. Follow-up and toxicity assessments were then carried out. Results: The median follow-up period was 63 months (range: 3 to 177). There was a significant difference in the follow-up period between the IMRT and 3D-CRT cohorts (median: 59 vs. 112 mo, P<0.0001). The crude incidences of acute grade 2+ and grade 3+ gastrointestinal toxicities were significantly lower with IMRT than with 3D-CRT (22.6% vs. 48.1%, P=0.002, and 3.2% vs. 11.1%, P=0.04, respectively). The Kaplan-Meier estimates of late toxicities revealed that IMRT significantly reduced grade 2+ genitourinary (GU) toxicity and lower-extremity lymphedema ([LEL] requiring intervention) compared with 3D-CRT ([6.8% vs. 15.2% at 5-year, P=0.048] and [3.1% vs. 14.6% at 5-year, P=0.0029], respectively). IMRT was the only significant predictor of reducing LEL risk. Conclusions: The risks of acute gastrointestinal toxicity, late GU toxicity, and LEL from PORT for cervical cancer were reduced by IMRT. Lower inguinal doses may have contributed to a lower risk of developing LEL, which should be validated in future studies.