Management of stage II colorectal cancer remains a considerable gray area where an individualized risk-based approach and more molecular research are needed, according to Axel Grothey, MD, of the Mayo Clinic in Rochester, Minnesota.
“Stage II is a little bit more complicated than stage III,” he commented. The initial step in his personal decision algorithm for managing stage II disease is to discern the patient’s risk for poor outcomes, first using clinical information.
Dr. Grothey’s viewpoint is that patients are at high risk if they have T4 tumors and/or had fewer than 12 lymph nodes examined at resection. “Those patients can be candidates for a stage III–like approach,” with adjuvant FOLFOX [leucovorin, fluorouracil, oxaliplatin] or XELOX [capecitabine (Xeloda), oxaliplatin], or an alternative regimen if they cannot receive oxaliplatin.
Further Risk Stratification
In the remaining stage II patients, oncologists can use a biologic marker, deficient mismatch repair phenotype (or microsatellite instability, MSI), to further risk-stratify.
“MSI-high tumors have excellent outcomes, with a very low rate of recurrence. These tumors are low risk, and they should not be treated,” Dr. Grothey maintained.
“For the intermediate-risk patients, this is exactly where we need molecular signatures—something like Oncotype DX, ColoPrint, or GCC [guanylyl cyclase C],” he concluded. “This is an area of active research right now to identify patients who might be candidates for chemotherapy or no treatment.” ■
Colorectal cancer studies reported at this year’s ASCO meeting offered little in the way of practice-changing information, according to Axel Grothey, MD, of the Mayo Clinic in Rochester, Minnesota. But they did confirm existing standards of care, he noted at the Best of ASCO® meeting in Seattle.