A liquid biopsy test may enable physicians to determine whether a patient with stage II colon cancer needs chemotherapy after surgery, according to a recent study published in The New England Journal of Medicine on June 4.
Chemotherapy is an ordeal not only for a patient’s physical but financial health. And unlike stage III colon cancer for which chemotherapy is routinely recommended after primary surgery, adjuvant chemotherapy may not be necessary for some patients with stage II colon cancer. Another unresolved question is exactly what kind of chemotherapy should be used.
The new study suggests that a post-surgery liquid biopsy test capable of detecting circulating tumor DNA (ctDNA) that cancer cells shed into the blood could eliminate the need for adjuvant chemotherapy for at least some patients. Presence of ctDNA from the cancer after surgery would indicate that the patient is at higher risk of recurrence. The question would then be whether the benefits the individual patient would derive would outweigh the risks and costs of adjuvant chemotherapy.
Very few patients with cancers that have grown through the colon wall but not reached the lymph nodes will actually benefit from adjuvant chemotherapy, noted study leader Dr. Jeanne Tie of the Peter MacCallum Cancer Centre in Melbourne, Australia. And utilization of liquid biopsies may enable patients to do what they most want to do after surgery—make a confident and medically sound decision to skip chemotherapy.