Global study sets new risk-based standard to personalize chemotherapy for colon cancer

June 5, 2017

After surgery for lymph-node positive colon cancer (stage III), some patients may only need half of the long-standing standard course of chemotherapy. In an analysis of six clinical trials with over 12,800 patients, 3 months of chemotherapy was nearly as effective as 6 months in patients with relatively lower recurrence risk and caused fewer side effects, particularly nerve damage.

These data will be presented in ASCO's Plenary Session, which features four abstracts deemed to have the greatest potential to impact patient care, out of the more than 5,000 abstracts featured as part of the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting.

Chemotherapy lowers the chance of after surgery. Since 2004, the standard (adjuvant) treatment after surgery has been a combination of chemotherapies (FOLFOX or CAPOX), given over a period of six 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 was as effective as 6 months. While the primary endpoint was not proven statistically, a shorter, 3-month course of chemotherapy was associated with a less than 1% lower chance of being colon cancer free at 3 years compared to the standard 6-month course (74.6% vs. 75.5%). In considered at low risk of 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).

"Our findings could apply to about 400,000 colon cancer patients worldwide every year. For 60% of these patients, who have lower risk for cancer recurrence, 3 months of chemotherapy will likely become the new standard of care," said senior study author Axel Grothey, MD, an oncologist at the Mayo Clinic Cancer Center in Rochester, Minn. "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."

A key side effect of one of the chemotherapies in the regimen - oxaliplatin - is nerve damage, which can result in permanent numbness, tingling, and pain. The longer a patient receives oxaliplatin, the greater the chance for severe and long-lasting nerve damage. Nerve damage (numbness/tingling of the hands and feet) was substantially less common in patients receiving a 3-month course of chemotherapy vs. a 6-month month course (15% vs. 45% with FOLFOX and 17% vs. 48% with CAPOX).

"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," said Dr. Grothey.

About the Study

This study is a prospective, pre-planned analysis of pooled data from six concurrent, phase III conducted in 12 countries. It was established more than 10 years ago as so-called IDEA collaboration (International Duration Evaluation of Adjuvant therapy). A steering committee oversaw the study design, and an independent statistical center reviewed the results from all six clinical trials (findings from three of which are being presented at the ASCO Annual Meeting). The study received public funding only.

"We needed this large number of patients to answer the study question, but at the time this study began in 2007 it was not possible to run one study of that size anywhere in the world," said Dr. Grothey. "With more than 12,834 patients, this is the largest collaboration of its kind in oncology."

Key Findings

Patients were followed for a median time of 39 months. For all patients combined, the rate of disease-free survival at 3 years was slightly lower with 3 months of chemotherapy than with 6 months of chemotherapy (74.6% vs. 75.5%). The type of selected affected the difference in 3-year disease-free survival between the 3-month and 6-month treatment duration (75.9% vs. 74.8% with CAPOX and 73.6% vs 76.0% with FOLFOX), although the difference was relatively small in both cases.

In the subset of patients with lower risk colon cancer (defined as cancer spread to 1-3 lymph nodes and not completely through the bowel wall), the disease-free survival rate at 3 years was almost identical for those who received 3 (83.1%) and 6 months of chemotherapy (83.3%).

The rate of clinically meaningful (grade 2 or greater) nerve damage differed depending on the type of chemotherapy regimen received, but was consistently higher for people who received 6 months versus 3 of chemotherapy (45% vs. 15% with FOLFOX and 48% vs. 17% with CAPOX).

"Aside from , longer chemotherapy also means more diarrhea and fatigue, more doctor appointments, blood draws, and time away from work and social interactions," said Dr. Grothey.

"This is extremely important work that will affect the lives of many of my patients hopefully tomorrow, and will allow us to provide a more personalized approach to our patients with colon . Although addressing the question, 'can we give less treatment?' is of major importance to patients and their doctors, it is rare to see this type of study. Given that these questions are unlikely to be of interest to the pharmaceutical industry, federal support for these trials is critical," said Dr. Baxter.

Explore further: targeted therapy can delay recurrence of intermediate-stage lung cancer

More information: abstracts.asco.org/199/AbstView_199_188616.html

Related Stories

targeted therapy can delay recurrence of intermediate-stage lung cancer

May 18, 2017
The targeted therapy gefitinib appears more effective in preventing recurrence after lung cancer surgery than the standard of care, chemotherapy. In a phase III clinical trial, patients with epidermal growth factor receptor ...

Olaparib slows growth of BRCA-related metastatic breast cancer

June 5, 2017
Findings from a phase III clinical trial of about 300 women may introduce PARP inhibitors as a new type of treatment for breast cancer. Compared to standard chemotherapy, the oral targeted medicine olaparib (Lynparza) reduced ...

Certain nuts may help ward off return of colon cancer: study

May 18, 2017
Eating certain kinds of tree nuts, such as almonds, pecans, walnuts, hazelnuts and cashews, has been linked to a dramatically lower risk of colon cancer recurrence, researchers said Wednesday.

Chemotherapy effectiveness and initiation time after lung cancer surgery

January 5, 2017
A new study suggests patients who recover slowly from non-small-cell lung cancer (NSCLC) surgery may still benefit from delayed chemotherapy started up to four months after surgery, according to a new study published online ...

Adjuvant chemotherapy in early-stage colon cancer may improve survival

July 15, 2016
Researchers and physicians have grappled with the role of "adjuvant," or post-surgery, chemotherapy for patients with early-stage colon cancer, even for cancers considered high risk. Now researchers from the University of ...

Findings suggest overuse of chemotherapy among younger patients with colon cancer

January 25, 2017
Young and middle-aged patients with colon cancer are nearly 2 to 8 times more likely to receive postoperative chemotherapy than older patients, yet study results suggest no added survival benefit for these patients, according ...

Recommended for you

Researchers unravel novel mechanism by which tumors grow resistant to radiotherapy

November 23, 2017
A Ludwig Cancer Research study has uncovered a key mechanism by which tumors develop resistance to radiation therapy and shown how such resistance might be overcome with drugs that are currently under development. The discovery ...

African Americans face highest risk for multiple myeloma yet underrepresented in research

November 23, 2017
Though African-American men are three times more likely to be diagnosed with multiple myeloma, a type of blood cancer, most scientific research on the disease has been based on people of European descent, according to a study ...

Encouraging oxygen's assault on iron may offer new way to kill lung cancer cells

November 22, 2017
Blocking the action of a key protein frees oxygen to damage iron-dependent proteins in lung and breast cancer cells, slowing their growth and making them easier to kill. This is the implication of a study led by researchers ...

One-size treatment for blood cancer probably doesn't fit all, researchers say

November 22, 2017
Though African-American men are three times more likely to be diagnosed with a blood cancer called multiple myeloma, most scientific research on the disease has been based on people of European descent, according to a study ...

One in four U.S. seniors with cancer has had it before

November 22, 2017
(HealthDay)—For a quarter of American seniors, a cancer diagnosis signals the return of an old foe, new research shows.

Combination immunotherapy targets cancer resistance

November 22, 2017
Cancer immunotherapy drugs have had notable but limited success because in many cases, tumors develop resistance to treatment. But researchers at Yale and Stanford have identified an experimental antibody that overcomes this ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.