The majority of patients with stage II colon cancer are cured with surgery alone. For some patients, adjuvant chemotherapy yields a significant but small absolute survival benefit; however, it is unclear which patients will benefit. While the benefit of adjuvant chemotherapy has been demonstrated in stage III disease, it remains controversial for stage II patients.

Gene profiling tests, such as OncotypeDX and Coloprint, can be used as a decision making tool, when patients are uncertain whether to receive adjuvant therapy or not, notes Alan Venook, MD. Data from the community setting shows that gene profiling results can change the pre-planned treatment in as many as 40% of cases, adds Axel Grothey, MD. In many situations, profiling results are more likely to result in forgoing adjuvant therapy rather than administering it.

These tests do not indicate whether the patient will benefit from adjuvant chemotherapy, only whether the cancer is likely to relapse. Importantly, there are gradations of patients with stage II colon cancer that are all lumped together, since they have different risks of recurrence. A patient with stage II T4bN0 disease may have a higher recurrence risk than a patient with stage IIIa, for example.

Factors other than tumor stage are important to consider when establishing recurrence risk. However, isolating one concept from another in terms of what really constitutes high-risk stage II colon cancer can be challenging, explains Venook. Adding to this, an algorithm for determining risk does not exist, leaving many to rely on common sense, prognostic factors, and patient factors, such as comorbidities and preferences, emphasizes Herbert Hurwitz, MD.