Predicting Colorectal Cancer Recurrence

In a recent study, a test called ColoPrint accurately identified risk of recurrence in stage 2 colon cancer patients. The test, which examines the expression of 18 genes, could help patients and their medical teams decide on whether chemotherapy is needed after surgery.

Most stage 2 patients are cured by surgery alone, but about 20 to 30 percent eventually develop distant metastases. Although stage 1 patients generally just undergo surgery and stage 3 patients may have surgery and adjuvant therapy, the benefits of treatment of stage 2 patients are more uncertain.

Currently, risk of recurrence for these patients is determined by certain characteristics of the patient and tumor, such as age, gender, tumor size, biomarkers and whether the cancer has spread to the lymph nodes, but it’s often not enough to make a reliable prognosis.

The ColoPrint study included 233 patients with stage 2 or stage 3 disease. The data, released at the Gastrointestinal Cancers Symposium in late January, showed stage 2 patients who were deemed to be at high risk (approximately 27 percent of the 135 patients with stage 2 disease in the study) had an 80.5 percent chance of distant metastases at five years compared with 95 percent of patients at low risk. Of the 27 percent who were identified at high risk, 20 percent had a recurrence. Five percent of patients who were identified as low risk had a recurrence.

The importance of these findings is that patients who are identified as low risk for recurrence could be spared chemotherapy. However, the test does not identify which high-risk patients would ultimately benefit from chemotherapy.

During a press conference at the meeting, lead author of the study, Robert Rosenberg, MD, PhD, surgeon and assistant professor at the University Hospital at Technical University in Munich, Germany, said, “What is immediately clear […] is that none of the clinical factors are significantly correlated with the development of distant metastases in our study, while ColoPrint does show compelling statistical significance.”

The maker of the ColoPrint gene signature test also developed MammaPrint, the molecular diagnostic test that predicts distant recurrence risk of certain types of breast cancer. ColoPrint is the second such gene test to look at recurrence risk in colon cancer. Another gene signature assay, Oncotype DX Colon Cancer Assay became available early last year, but does not require fresh tissue—one potential drawback to the ColoPrint test, experts say.

Two other ColoPrint clinical trials are in the works. One, an evaluation called PARSC (Prospective study for the Assessment of Recurrence risk in Stage II CC patients using ColoPrint), is aiming to complete enrollment of 600 stage 2 patients and expects interim results later this year, while another study examines ColoPrint in stage 3 patients.