A report from the German OCUM study published by Ruppert et al in the Journal of Clinical Oncology details long-term locoregional recurrence outcomes with risk-adapted neoadjuvant chemoradiotherapy plus total mesorectal excision and total mesorectal excision alone in patients with rectal cancer.
In the multicenter study, patients with rectal cancer (cT2–4, any cN, cM0) were classified according to minimal distance between the tumor, suspicious lymph nodes or tumor deposits, and mesorectal fascia on pelvic magnetic resonance imaging (mrMRF); distance of ≤ 1 mm was considered positive for mrMRF involvement (mrMRF+), whereas minimal distance of > 1 mm was considered negative (mrMRF–). Patients with distance > 1 mm underwent upfront total mesorectal excision (low-risk group); those with distance ≤ 1 mm and/or cT4 and cT3 tumors in the lower rectal third received neoadjuvant chemoradiotherapy followed by total mesorectal excision (high-risk group). The primary outcome measure was 5-year locoregional recurrence.
A total of 884 patients of 1,099 enrolled were treated according to protocol and were included in the analysis. Of these, 530 underwent upfront total mesorectal excision and 354 underwent neoadjuvant chemoradiotherapy followed by total mesorectal excision.
On Kaplan-Meier analyses, 5-year locoregional recurrence rates were 4.1% (95% confidence interval [CI] = 2.7%–5.5%) in the total per-protocol population, 2.9% (95% CI = 1.3%–4.5%) among patients receiving upfront total mesorectal excision, and 5.7% (95% CI = 3.2%–8.2%) among those receiving neoadjuvant chemoradiotherapy and total mesorectal excision.
The 5-year rate of distant metastasis was 21.8% (95% CI = 19.1%–24.5%) in the total per-protocol population, 15.9% (95% CI = 12.6%–19.2%) with total mesorectal excision alone, and 30.5% (95% CI = 25.4%–35.6%) with neoadjuvant chemoradiotherapy plus total mesorectal excision.
A subgroup analysis of 570 patients with lower and middle rectal third cII and cIII tumors showed that 257 (45.1%) were low risk. The 5-year locoregional recurrence rate in this low-risk group was 3.8% (95% CI = 1.4%–6.2%) after upfront total mesorectal excision, and the 5-year rate of distant metastasis was 16.8% (95% CI = 12.1%–21.5%). Among 271 high-risk patients (mrMRF+ and/or cT4), 5-year rates were 5.9% (95% CI = 3.0%–8.8%) for locoregional recurrence and 34.5% (95% CI = 28.6%–40.4%) for distant metastasis.
The investigators concluded, “The findings support the avoidance of neoadjuvant chemoradiotherapy in low-risk patients and suggest that in high-risk patients, neoadjuvant therapy should be intensified to improve prognosis.”
Theodor Junginger, MD, of the Department of General and Abdominal Surgery, University Medical Center Mainz, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.