Primary Tumor Location Predicts Survival in Metastatic Colon Cancer, Impacts Choice of Targeted Therapy

May 19, 2016
Illustration of stage 4 colon cancer NCI

COLUMBUS, Ohio -- A retrospective analysis of phase 3 data from a large, multi-center clinical trial (CALGB/SWOG 80405) finds that primary tumor location (left versus right side) can help predict survival and guide optimal treatment choices for patients with metastatic colon cancer.

The study will be presented at the 2016 American Society of Clinical Oncology Annual meeting held in Chicago June 3-7, 2016. Richard Goldberg, MD, physician-in-chief at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC – James) is a co-author and local principal investigator of on the study, which was led nationally by Alan P. Venook of the University of California, San Francisco.

Researchers analyzed 1,100 patients as part of the study treated at hundreds of hospitals across the United States and Canada, including 30 patients treated at The OSUCCC – James.

Data showed that the patients with primary colon tumors originating on the left side (descending colon, sigmoid colon and rectum) survived on average significantly longer than patients whose tumors originated on the right side (the cecum and ascending colon). Patients with left-sided tumors had a longer median overall survival (33.3 months), compared to patients with right-side tumors (19.4 months).

“We now have definitive data showing us that right and left side colon cancers have very different characteristics – so much that they are almost like two different diseases that do better with different treatment paths, even though pathologically they look the same under a microscope,” says Goldberg.

Tumor Location and Targeted Therapy

The study results also revealed which chemotherapy drugs were most effective for left versus right-sided tumors, which researchers say could significantly change care choices for advanced colon cancer.

Among patients who received cetuximab (pronounced “seh-TUK-sih-mab”, marketed as Erbitux), patients with left-sided tumors lived 36 months, while those with right-sided tumors lived 16.7 months. Similar trends were observed among patients receiving another treatment, bevacizumab (pronounced “beh-vuh-SIH-zoo-mab”, marketed as Avastin): overall survival was 31.4 months and 24.2 months for patients with left- and right-sided tumors, respectively.

“This knowledge has very practical implications for clinical care because I now have definitive data that tells me I should consider whether my patients have left or right-sided colon cancers when determining the treatments that will provide the best possible outcomes,” adds Goldberg. “It also really drives home the message that colon cancers are not all the same. They are genetically programmed by different driving mutations, which will translate into more targeted therapies based on both location and a better understanding of these genetic drivers.”

While the original trial found no significant advantage in overall or progression-free survival in patients treated with bevacizumab or cetuximab when the data derived from all patients were pooled, this analysis suggests that the relative effectiveness of cetuximab and bevacizumab may differ depending on primary tumor location. Researchers are in the process of examining the molecular biology that underlies these findings.

Among patients with right-sided tumors, treatment with bevacizumab was associated with longer survival than that of cetuximab (24.2 months vs. 16.7 months). Conversely, among patients with left-side tumors, treatment with cetuximab was associated with longer overall survival than bevacizumab (36 months vs. 31.4 months).

Researchers stress that large, multi-center clinical trials like this one are important because they have the power to potentially uncover results that are not apparent in smaller studies.

This study received funding and support from BMS, Genentech, and Imclone in collaboration with the National Cancer Institute. Goldberg has been a past advisor to BMS and Genentech but not within the past five years.

Colon Cancer Incidence Rates, Importance of Screening

More than 136,000 people are diagnosed with colon and rectal cancer in the United States annually and it is the third most common cancer among both men and women. The disease has a 90 percent survival rate when caught in its earliest stages. African-Americans have the highest incidence and death rates in colon cancer compared with other racial groups.

Individuals age 50 or older of average risk should receive screening colonoscopy every 10 years. The American College of Gastroenterology recommends African Americans begin colonoscopy screening at age 45. Additionally, people with a personal history of inflammatory bowel disease, strong family history of colorectal cancer or polyps or a known family history of hereditary colorectal cancer syndrome should begin screening earlier.

“There is no question that screening colonoscopy saves lives. It is a shame for someone to die from a preventable disease like colon cancer so I encourage everyone to understand their personal risk for colorectal cancer then get screened accordingly and encourage their friends and loved ones to do the same,” says Goldberg.

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About the OSUCCC – James

The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute strives to create a cancer-free world by integrating scientific research with excellence in education and patient-centered care, a strategy that leads to better methods of prevention, detection and treatment. Ohio State is one of only 45 National Cancer Institute-designated Comprehensive Cancer Centers and one of only four centers funded by the NCI to conduct both phase I and phase II clinical trials on novel anticancer drugs. As the cancer program’s 306-bed adult patient-care component, The James is one of the top cancer hospitals in the nation as ranked by U.S. News & World Report and has achieved Magnet designation, the highest honor an organization can receive for quality patient care and professional nursing practice. At 21 floors with more than 1.1 million square feet, The James is a transformational facility that fosters collaboration and integration of cancer research and clinical cancer care.

Media Contact:
Amanda J. Harper
Director of Media Relations, OSUCCC – James
614-685-5420 or 513-659-6847 (cell)
Amanda.harper2@osumc.edu  

*News release adapted as originally written by Kelly Baldwin, ASCO Communications, 571-483-1365, kelly.baldwin@asco.org

Contact Media Staff

Amanda Harper

Director of Media Relations


614-685-5420 (direct)


614-293-3737 (main)


Amanda.Harper2@osumc.edu


Media staff are available by calling 614-293-3737 Monday through Friday between 8 a.m. and 5 p.m.

 

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