In the Indian single-center phase III PARCER trial reported in the Journal of Clinical Oncology, Supriya Chopra, MD, DNB, and colleagues found that adjuvant image-guided intensity-modulated radiotherapy (IG-IMRT) was associated with less late grade ≥ 2 gastrointestinal toxicity vs three-dimensional (3D) conformal radiotherapy in women with cervical cancer, with no significant differences in disease outcomes observed.
Study Details
In the open-label trial, 300 patients at Tata Memorial Centre were randomly assigned between 2011 and 2019 to receive postoperative IG-IMRT (n = 151) or 3D conformal radiotherapy (n = 149). All patients received 50 Gy in 25 fractions over 5 weeks and high dose–rate vaginal brachytherapy at 12 Gy in 2 fractions over 1 week. The primary endpoint was 3-year grade ≥ 2 late gastrointestinal toxicity.
IG-IMRT results in reduced toxicity with no difference in disease outcomes.— Supriya Chopra, MD, DNB
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Key Findings
Median follow-up was 46 months (interquartile range = 20–72 months).
The 3-year cumulative incidence of grade ≥ 2 late gastrointestinal toxicity was 21.1% (95% confidence interval [CI] = 14.7%–29.7%) in the IG-IMRT group vs 42.4% (95% CI = 33.7%–52.3%) in the 3D conformal radiotherapy group (hazard ratio [HR] = 0.46, 95% CI = 0.29–0.73, P < .001). The cumulative incidence of grade ≥ 3 late gastrointestinal toxicity was 2.9% (95% CI = 1.1%–7.6%) vs 15.5% (95% CI = 9.9%–23.6%; HR = 0.22, 95% CI = 0.08–0.59, P < .003).
The 3-year cumulative incidence of any grade ≥ 2 late toxicity was 28.1% (95% CI = 20.7%–37.4%) in the IG-IMRT group vs 48.9% (95% CI = 40.0%–58.7%) in the 3D conformal radiotherapy group (HR = 0.50, 95% CI = 0.33–0.76, P < .001). Grade ≥ 3 toxicity occurred in 4.0% (95% CI = 1.6%–9.4%) vs 15.5% of patients (95% CI = 9.9%–23.6%; HR = 0.28, 95% CI = 0.12–0.66, P =.004).
No significant differences between the IG-IMRT vs 3D conformal radiotherapy groups were observed at 3 years for pelvic relapse-free survival (81.8%, 95% CI = 73.5%–87.7%, vs 84%, 95% CI = 76.0%–89.5%; HR = 1.17, 95% CI = 0.68–1.99, P = .55), disease-free survival (76.9%, 95% CI = 68.4%–83.4%, vs 81.2%, 95% CI = 72.9%–87.2%; HR = 1.03, 95% CI = 0.62–1.71, P = .89), or overall survival (82.9%, 95% CI = 74.6%–88.6%, vs 89.2%, 95% CI = 82.1%–93.6%; HR = 1.23, 95% CI = 0.71–2.14, P = .44).
The investigators concluded, “IG-IMRT results in reduced toxicity with no difference in disease outcomes.”
Dr. Chopra, of Tata Memorial Centre, Homi Bhabha National Institute, Kharghar, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the Department of Atomic Energy Clinical Trials Unit and Department of Science and Technology, India. For full disclosures of the study authors, visit ascopubs.org.
