Although node-positive solid tumor malignancies frequently mandate adjuvant chemotherapy usage, the debate regarding Stage II (node negative) colon cancer continues to be ongoing relating to this issue. Medical oncologists have a variety of differing views as to whether additional chemotherapy should be offered after colectomy. While nodal status is an important indicator that is captured in our cancer registries, other markers may be equally or more significant as guides for applying additional therapy after colectomy. For instance, the presence of circulating tumor DNA (ctDNA) after surgery predicts very poor recurrence-free survival, whereas its absence predicts a low risk of recurrence. The benefit of adjuvant chemotherapy for ctDNA-positive patients is not well understood, but may play an important role in the future.

In the AJCC Cancer Staging Manual , Eighth Edition, the descriptor “cM0(i+)” was introduced to help capture the presence of both circulating cancer cells and ctDNA. While currently a minority of patients with colon cancer, as well as other malignancies are being evaluated for these occult findings, our registries must include these critical predictors if available. Our cancer registrars must be alert to these findings and their importance in cancer management. A ctDNA-guided approach to adjuvant treatment in cancer patients may give valuable additional information in the management of patients with Stage II colon cancer as well as other node-negative malignancies.