Patients with localized rectal cancer classified as low risk can skip neoadjuvant chemoradiotherapy (nCRT) with an acceptably low risk of local relapse, new research suggests.
A prospective study of patients with stage cT2-4 rectal cancer classified into high- and low-risk groups based on a mix of factors, which dictated treatment.
Overall, 530 low-risk patients (tumor-free mesorectal fascia) underwent upfront total mesorectal excision (TME) and 354 high-risk patients received nCRT followed by TME.
The primary endpoint was 5-year locoregional recurrence; 5-year distant metastases was a secondary outcome.
A subgroup analysis divided 570 patients with tumors in the lower and middle rectal third, classified as clinical stages II and III, into low- and high-risk groups.
The overall 5-year locoregional recurrence was 4.1% for protocol-treated patients, 2.9% for low-risk patients who had upfront TME, and 5.7% for high-risk patients who had nCRT followed by TME.
The 5-year rates of distant metastases were 15.9% for low-risk patients and 30.5% for high-risk patients.
In the subgroup, low-risk patients had slightly higher rates of 5-year locoregional recurrence (3.8%) and distant metastases (16.8%).
In the subgroup, high-risk patients with involved mesorectal facia and/or cT4 tumors who received nCRT then TME exhibited the highest risk of metastases (34.5%).
“These data support de-escalation of nCRT in low-risk patients and escalation of neoadjuvant therapy in high-risk patients to improve long-term outcomes,” the authors write.
The study, led by Reinhard Ruppert, MD, with Municipal Hospital of Munich-Neuperlach, Munich, Germany, was published June 19 in the Journal of Clinical Oncology.
This study was nonrandomized and lacked a true comparator group. There was a high percentage of protocol deviation.
The study had no commercial funding. Ruppert reported no relevant disclosures. Some authors disclosed relationships with Intuitive Surgical, Johnson & Johnson/Janssen, Serag-Wiessner, Merck Serono, and AbbVie.
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