SUNRISE Study Proves Predictive Ability of 12-Gene Colon Cancer Recurrence Assay

The American Cancer Society lists colon and rectal cancers as the second leading cause of cancer-related deaths in the United States—however, the death rate has seen a steady decline over the years. Earlier screening strategies and better genetic tests have been the backbone of the efforts to detect the disease earlier, and a new 12-gene test could prove a significant addition to the armamentarium especially in patients who have developed an advanced stage of colon cancer.

A collaborative study between research groups in the United States and in Japan assessed the capability of a 12-gene Recurrence Score test to reveal the natural course of recurrence in Asian patients with stage II and III colon cancer who have undergone surgery but not received any adjuvant chemotherapy. The objective of the SUNRISE study was to evaluate the Oncotype DX Colon Recurrence Score assay for its ability to stratify patients and identify those who would most benefit from adjuvant chemotherapy.

The trial enrolled 630 patients between 20 and 80 years of age with stage II or stage III colon cancer who had surgical resection between 2000 and 2005. None of the patients had received preoperative chemotherapy, immunotherapy, or radiation therapy or surgery with postoperative chemotherapy within 3 months of resection. The ratio of recurrence to nonrecurrence was 1:2. The test was performed on paraffin-embedded primary tumor tissue to identify the association of the Recurrence Score result with recurrence-free interval (RFI).

The analysis found that of the 597 patients who could be analyzed, 247 has stage II and 350 had stage III colon cancer. The analysis found that the continuous Recurrence Score was significantly associated with RFI, following adjustment of disease stage (HR for a 25-unit increase in Recurrence Score, 2.05; 95% CI, 1.47 to 2.86; P < .001). The authors had classified the patients into low (< 30), intermediate (30 to 40), and high (≥ 41) Recurrence Score risk groups; the trial found that:

• Patients with stage II disease in the high-risk group had a 5-year risk of recurrence similar to patients with stage IIIA to IIIB disease in the low-risk group (19% vs 20%)
• Patients with stage IIIA to IIIB disease in the high-risk group had a recurrence risk similar to that of patients with stage IIIC disease in the low-risk group (approximately 38%)

Based on their findings, the authors conclude that the SUNRISE study confirmed the Recurrence Score as a prognostic marker in resectable stage II and III colon cancer treated with surgery alone. The trial “established its clinical validity in Asian patients,” they write, and the score can be used by oncologists to establish which patients would benefit from adjuvant chemotherapy.

The test, Onctotype DX Colon Recurrence Score assay, is manufactured by Genomic Health Inc.

Reference

Yamanaka T, Oki E, Yamazaki K, et al. 12-Gene Recurrence Score assay stratifies the recurrence risk in stage II/III colon cancer with surgery alone: the SUNRISE study [published online June 20, 2016]. J Clin Oncol. doi:10.1200/JCO.2016.67.0414.