Colon Cancer: How Much Adjuvant Chemotherapy is Enough?

Atrium Health Levine Cancer has guided hundreds of patients with Stage III colon cancer through adjuvant chemotherapy, and we’ve seen how it can trigger neuropathy and other side effects that significantly impact quality of life.

The International Duration Evaluation of Adjuvant Chemotherapy (IDEA) study, a prospective, preplanned analysis of pooled data from six concurrent, Phase III clinical trials conducted in 20 countries, found it’s appropriate to use three months of adjuvant chemotherapy in a subgroup of patients in contrast to what used to be the traditional, six-month standard for all patients with Stage III colon cancer. This research marks important progress, but it comes with complicated caveats and distinctions – including new definitions of low-risk and high-risk Stage III colon cancer.

Which Duration is Right for Your Patients?

IDEA found that three months of oxaliplatin-based adjuvant therapy reduced neurotoxicity by at least 50 percent, with a less than 1 percent difference in disease-free survival compared to a six-month regimen. Further analysis showed that the shorter duration is an acceptable approach for patients who have a low risk of recurrence.

This is reflected in the latest National Comprehensive Cancer Network guidelines, which concluded that three months of CapeOX is noninferior to six months for low-risk patients defined as (T1–3; N1). However, six months of adjuvant chemotherapy is needed for high-risk patients defined as T4 and/or N2.

Still, not all Stage III colon cancer patients can be created equal. “Different patients have different risk of relapse, and many patients can’t complete six months of adjuvant therapy without significant neuropathy,” says Mohamed Salem, MD, Levine Cancer gastrointestinal oncologist. “Sometimes the punishment doesn't fit the crime. You have to weigh the potential benefit versus its impact on quality of life.”

When to Stop Adjuvant Chemotherapy

Neuropathy can get so severe that it makes it hard to perform routine tasks like using a computer or putting on jewelry. This is especially problematic for the growing number of younger patients with colon cancer – their careers and lifestyles can depend on their strength and dexterity.

Many younger patients also worry about chemotherapy’s effect on their ability to have children. Dr. Salem goes out of his way to ask each patient about any goals that might be jeopardized by chemotherapy. Then, during adjuvant therapy, he constantly monitors patients’ neuropathy and assesses their quality of life. In high-risk patients, he will stop adjuvant chemotherapy well before six months if the neuropathy poses a significant threat.

“The lost benefit of not finishing all 12 cycles can be trivial compared to adjuvant therapy’s potentially life-changing consequences,” Dr. Salem says.

How Levine Cancer Can Help

Levine Cancer’s first-hand knowledge of the IDEA study – combined with our high volumes of colon cancer patients – gives us unique expertise in understanding how different patients react to adjuvant chemotherapy. As the guidelines evolve, our experts are eager to trade ideas with outside oncologists and offer input on which approach is best.

“We’re all in this together,” Dr. Salem says. “Whether it’s a phone call, an email or an appointment to give a second opinion, we’re happy to share our perspective and learn from each other for the greater goal. This is one step forward in a long journey of the fight against cancer.”

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