Shorter Chemo Duration for Colon Cancer May Spare Patients Toxicity

Axel Grothey, MD

CHICAGO-Patients may be able to simplify their course of chemotherapy after surgery for stage III lymph node–positive colon cancer, according to a new analysis of six clinical trials (abstract LBA1). The data, presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting, held June 2–6, suggest that some patients may only need half of the longstanding standard course of chemotherapy.

The researchers examined data on 12,834 patients and found that 3 months of chemotherapy was nearly as effective as 6 months in patients with relatively lower recurrence risk. The findings suggest that this new schedule results in fewer side effects, particularly nerve damage.

“The side effects were dramatically lower and so this will change the standard of care,” said senior study author Axel Grothey, MD, an oncologist at the Mayo Clinic Cancer Center in Rochester, Minnesota.

Since 2004, the standard adjuvant therapy after surgery has been a combination of chemotherapies (FOLFOX or XELOX) given over a period of 6 months. The goal of this study, which pooled data from 6 studies conducted in North America, Europe, and Asia, was to determine if 3 months of chemotherapy was as effective as 6 months.

The analysis showed that a 3-month course of chemotherapy was associated with a lower chance of being colon cancer free at 3 years compared with the standard 6-month course (74.6% vs 75.5%). In patients considered low risk for cancer recurrence (60% of patients in the study), the difference was even smaller (83.1% in patients receiving a 3-month course vs 83.3% in patients receiving a 6-month course).

“It is very good news. It will decrease long-term side effects that would affect quality of life,” said Grothey. He noted that patients with higher-risk colon cancer should discuss these results with their clinicians to tailor a course of therapy optimal for them, taking into account their preference, age, and ability to tolerate chemotherapy.

Nerve damage was substantially less common in patients receiving a 3-month course of chemotherapy compared with a 6-month course (15% vs 45% with FOLFOX and 17% vs 48% with XELOX). For all patients combined, the rate of disease-free survival at 3 years was slightly lower with 3 months of chemotherapy vs 6 months of chemotherapy (74.6% vs 75.5%). The type of chemotherapy regimen selected affected the difference in 3-year disease-free survival between the 3-month and 6-month treatment durations (75.9% vs 74.8% with XELOX and 73.6% vs 76.0% with FOLFOX). Patients were followed for a median time of 39 months.