Combination short-term radiotherapy, chemotherapy suitable alternative treatment
Short-term radiotherapy combined with chemotherapy may be a suitable alternative to long-term radiotherapy for patients with advanced rectal cancer, according to data from a multicenter, randomized, phase 3 trial presented at ASCO21.
"Short pulse radiation combined with four pulses of chemotherapy is well-tolerable without increasing the incidence of surgical complications," Jing Jin, MD, an associate professor at the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing, China, said.
The multicenter, randomized phase 3 trial comprised 591 patients from 16 hospitals across China. Investigators randomly assigned patients to one of two groups; one group received short-term radiotherapy and chemotherapy and the other received only long-term chemotherapy.
Patients included in the study were diagnosed by MRI with distal or middle third T3-T4 or N+ rectal adenocarcinomas.
“Patients were diagnosed as stage 3, and overall, 85% of patients in each group were diagnosed as node-positive,” Jin said.
Investigators gathered patient data from August 2015 to August 2018.
"During the neoadjuvant treatment period, nearly 80% of patients in the experimental group finished the [chemotherapy]," Jin said. "However, full dose neoadjuvant treatment completion rates were only 75%, which was much lower compared with that in control group," she said.
The experimental group received short-term radiotherapy for 5 days followed by four treatments of capecitabine and oxaliplatin while the control group received 35 chemotherapy treatments.
“After surgery, 54% of patients in the experimental group finished two courses of [chemotherapy], and 40% in the control group finished the adjuvant six courses of chemotherapy with no significant difference between the two arms. It was tolerable during neoadjuvant treatment in both arms,” Jin said.
The combination of short-term radiotherapy and chemotherapy may lead to a higher complete clinical response and complete pathological response, as well as increased 3-year overall survival rates compared with long-term chemotherapy alone, according to the researchers. Jin noted that the advantage of overall survival in the experimental group should be followed up.
In addition, the investigators found a higher rate of grade 3 and 4 toxicities in the group receiving short-term radiotherapy.
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Jin J, et al. Abstract 3510. Presented at: ASCO Annual Meeting; 2021; June 4-8, 2021 (virtual meeting).
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