12-gene assay predicted risk for rectal cancer recurrence

The Oncotype DX Recurrence Score more accurately predicted risk for local recurrence, distant recurrence and rectal cancer-specific survival in patients with stage II disease, according to study results presented at the European Cancer Congress.

Researchers evaluated data from 297 patients enrolled in the Dutch Total Mesorectal Excision trial. Of them, 130 had stage II rectal cancer, 110 had stage IIIA or IIIB disease, and 57 had stage III C disease.

Each patient underwent total mesorectal excision without neoadjuvant or adjuvant treatment. Investigators used the 12-gene Oncotype DX Recurrence Score assay to evaluate RNA from the paraffin-embedded primary rectal tumor tissue.

Median follow-up was 11 years.

Overall, the assay predicted risks for 5-year recurrence (P=.011), distant recurrence (P=.03) and rectal cancer-specific survival (P=.007).

Researchers found the assay more accurately predicted survival and recurrence in patients with stage II rectal cancer. In this cohort, 48% of patients had a low recurrence score, with a 12% (95% CI, 6-24) risk for recurrence and 5% (95% CI, 2-16) risk for rectal cancer mortality.

Researchers reported 23% of patients had a high recurrence score. In this group, the risk for recurrence was 53% (95% CI, 35-73) and the risk for rectal cancer-specific mortality was 37% (95% CI, 21-59).

“The 12-gene [Recurrence Score assay] is a predictor of recurrence risk in rectal cancer patients treated with surgery alone, indicating a similar underlying biology in colon and rectal cancer,” the researchers wrote. “[The assay] may be clinically useful in stage II rectal cancer patients, where [it] can help identify high-risk patients who could benefit from — and low-risk patients who may forego — adjuvant chemotherapy.”

For more information:

Reimers MS. Abstract #1. Presented at: The European Cancer Congress 2013. Sept. 27 – Oct. 2, 2013; Amsterdam.

Disclosure: See the study for a full list of the researchers’ relevant financial disclosures.