Certain patients who underwent surgery for lymph-node positive colon cancer (stage 3) may require only three months of chemotherapy after surgery instead of the standard six months, according to an analysis of six clinical trials with more than 12,800 patients.
The study, “Prospective pooled analysis of six phase III trials investigating duration of adjuvant (adjuv) oxaliplatin-based therapy (3 vs 6 months) for patients (pts) with stage III colon cancer (CC): The IDEA (International Duration Evaluation of Adjuvant chemotherapy) collaboration,” was recently presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting June 2-6 in Chicago.
After surgery, colon cancer patients undergo rounds of chemotherapy to lower the chance of their cancer returning (cancer recurrence). Currently, a combination of chemotherapies — FOLFOX or CAPOX — is administered over six months, but researchers aimed to assess whether it could be reduced to just three months.
Researchers pooled data from six different clinical trials from North America, Europe, and Asia to understand the impact of cancer recurrence when comparing three vs. six months of chemotherapy.
The randomized Phase 3 trials included the SCOT (NCT00749450), TOSCA (NCT00646607), Alliance/SWOG 80702, IDEA France (GERCOR/PRODIGE), ACHIEVE, and HORG. The initiative to analyze the six clinical trial was established more than 10 years ago and was named IDEA (International Duration Evaluation of Adjuvant chemotherapy).
The study’s primary endpoints were disease-free survival (DFS), defined as time from enrollment to relapse, second colon cancer, and all-cause mortality.
The non-inferiority of three months of chemotherapy compared to six months was not statistically established for the overall cohort. However, researchers found that patients who underwent the three-month course had a 74.6 percent chance of being colon cancer-free at three years, compared to 75.5 percent in the six-month course — a difference of less than 1 percent.
Looking specifically at patients with a low risk of cancer recurrence, which accounted for 60 percent of all patients, the difference between the three- and six-month treatment period was only 0.2 percent — 83.1 percent in patients receiving the three-month chemo course compared to 83.3 percent in patients who underwent the six-month course.
“Our findings could apply to about 400,000 colon cancer patients worldwide every year. For 60 percent of these patients, who have lower risk for cancer recurrence, three months of chemotherapy will likely become the new standard of care,” the study’s lead author, Axel Grothey, MD, an oncologist at the Mayo Clinic Cancer Center in Rochester, Minnesota, said in a press release.
“Patients with higher risk colon cancer, however, should discuss these results with their doctor to see if a shorter course of therapy would be right for them, taking into account their preference, age, and ability to tolerate chemotherapy,” he added.
Chemotherapy has many adverse side effects. Nerve damage is a lifelong severe adverse effect associated with Elotaxin (oxaliplatin), one of the chemotherapy drugs used for colon cancer.
“Many side effects of chemotherapy, such as hair loss, go away over time, but nerve damage is a side effect some patients have to deal with for the rest of their lives,” Grothey said.
In the group treated for three months of chemotherapy, nerve damage, which manifests as numbness or tingling of the hands and feet, was markedly less common.
The researchers believe that this work may affect the lives of many patients in the near future, allowing for a more tailored approach to colon cancer. They urge federal financial support for studies addressing the question “can we give less treatment?” as pharmaceutical companies are unlikely to be interested in such studies.