Shorter duration chemo for low-risk stage III colon cancer

Volume 6, Issue 3, 2017

Summary

Reducing the length of adjuvant therapy with oxaliplatin is effective and reduces toxicity.

Photograph of Axel Grothey, M.D.

Axel Grothey, M.D.

Photograph of Qian Shi, Ph.D.

Qian Shi, Ph.D.

For patients with low-risk stage III colon cancer, a shortened course of oxaliplatin-based chemotherapy after surgery was associated with reduced side effects compared with the traditional course of chemotherapy and was just as effective, according to the International Duration Evaluation of Adjuvant Chemotherapy (IDEA collaboration) study, which included six clinical trials of nearly 13,000 patients from 12 countries.

In the study, patients underwent a three-month course of chemotherapy instead of the standard six-month course of chemotherapy and experienced fewer and less severe side effects, such as nerve damage.

As a result of these findings, Mayo Clinic researchers and other scientists involved in the study say shorter duration chemotherapy may become the standard of care for patients with low-risk stage III colon cancer. Low-risk stage III colon cancer is defined as colon cancer that has not spread to the peritoneal surface or to other organs and that doesn't involve more than three lymph nodes.

Results of the IDEA collaboration study were presented at the 2017 annual meeting of the American Society of Clinical Oncology in Chicago by Mayo Clinic researchers who are also members of the Alliance for Clinical Trials in Oncology.

"Chemotherapy after surgery, also known as adjuvant therapy, is a standard treatment to increase the cure rate of patients with colon cancer who have undergone surgery and had cancer spread to lymph nodes," said Axel Grothey, M.D., a Mayo Clinic oncologist in Rochester, Minnesota, and senior author of the research paper detailing findings from the IDEA colon cancer study. "The current standard adjuvant therapy, which was established more than a decade ago, is a combination of two or three drugs — one of which is called oxaliplatin — given for about six months."

The key side effect of oxaliplatin (Eloxatin) is nerve damage that may result in permanent numbness, tingling and pain in the hands and feet, even after chemotherapy is discontinued. The likelihood of developing neurotoxicity and its severity is closely related to the duration of therapy and total dose of oxaliplatin received over time, Dr. Grothey said.

"The goal of our study was to investigate if a shorter, three-month duration of oxaliplatin-based therapy is as effective in reducing the risk of cancer recurrence as the standard six-month duration," said co-author Qian Shi, Ph.D., a Mayo Clinic biostatistician in Rochester.

According to Dr. Grothey, a shorter duration of chemotherapy could spare patients potentially unnecessary toxicity and lead to substantial savings in health care costs. Shorter duration chemotherapy could also become the new standard of care in the postoperative management of patients with low-risk stage III colon cancer.

Researchers in the study did observe a slight decrease in disease-free survival, which is defined as being alive without recurrence of cancer, for patients receiving the shorter duration of chemotherapy for overall stage III colon cancer. However, for low-risk stage III colon cancer, three months of treatment was shown to be as effective as six months of treatment.

The study findings also could lead to a more individualized treatment duration based on a patient's individual preference, age, tolerance of therapy and risk of recurrence, Dr. Grothey said.