Big Plans: ASCO Targets Obesity-Cancer Link

But No Evidence Weight Loss Improves Survival

Nick Mulcahy

October 01, 2014

The American Society of Clinical Oncology (ASCO) wants to be a leader in "reducing the impact of obesity on cancer," and has issued a position statement that outlines ideas on how it will do so.

Obesity is "quickly overtaking tobacco as the leading preventable cause of cancer," write the authors of the statement, led by Jennifer Ligibel, MD, from the Dana-Farber Cancer Institute in Boston.

The position statement, which is the first of its kind related to obesity from ASCO, was published online today in the Journal of Clinical Oncology.

"Everybody knows that obesity in not good for the heart. But the same message is not out there about obesity being a risk factor for cancer," Dr. Ligibel told Medscape Medical News in an interview.

Thus, ASCO addresses the issue of public education in the position statement, and much more.

The statement also outlines policies in research, clinical guidance, and advocacy (including proposed efforts to get reimbursement for obesity-related services for cancer patients).

But there is a problem with the evidence base of the initiative — there is no proof that weight loss improves survival in cancer patients. Nor is there evidence that weight loss prevents the development of cancer.

There have never been randomized controlled trials undertaken to test either of these fundamental concepts, acknowledged Dr. Ligibel.

"If weight loss was a drug, the studies would have been done a long time ago," she said.

However, there are many studies of various lifestyle interventions, including weight loss, that show better outcomes and "concrete benefits" in cancer patients, Dr. Ligibel reported.

The statement lists some of these demonstrated benefits, which include less fatigue, better quality of life, better body image, lower incidence of comorbidity, and favorable changes in biomarkers linked to cancer risk and prognosis.

Importantly, observational studies have shown that obesity is linked to an elevated risk for cancer, cancer recurrence, and cancer-related mortality in a number of cancers, the authors point out.

An expert not involved with the position statement is "thrilled" to see it.

"As clinicians, we are aware of the devastating effects obesity can have on cancer outcomes, and even how weight gain during cancer treatment can be a negative prognostic factor," said Nicole Simone, MD, from the Sidney Kimmel Medical College at Thomas Jefferson University in Philadelphia, in an email to Medscape Medical News. She is a radiation oncologist who is conducting a single-group study of calorie restriction during breast cancer radiotherapy.

Because most of America is overweight, the proposed ASCO policies and initiatives address big needs, explained the immediate past president of the organization.

"With nearly 3 in 4 Americans obese or overweight, obesity has become a tremendous public health challenge that also impacts cancer care and prevention today," said Clifford A. Hudis, MD, from the Memorial Sloan Kettering Cancer Center in New York City, in a press statement.

Obesity is potentially a many-headed monster in the world of cancer, he suggested.

"We can't allow obesity to undo decades of progress in prevention, early diagnosis, and treatment of cancer," Dr. Hudis said.

By 2030, it is estimated that almost half a million Americans will be diagnosed with obesity-related cancers annually, according to the ASCO press statement.

That means that oncologists will be seeing a lot of obese cancer patients.

The position of ASCO is that oncologists — or nurses, counselors, or other staff — should help those patients lose weight.

"The oncology care team — the providers with whom a patient has the closest relationships in the critical period after a cancer diagnosis — is in a unique position to help patients lose weight and make other healthy lifestyle changes," Dr. Ligibel and colleagues write.

Time to Get Organized; Summit in November

More clinical research on obesity and lifestyle interventions in cancer patients is also needed. And ASCO wants to help get research organized, according to Dr. Ligibel.

"There is a lot of money going into this area of research, but it is not coordinated," she said.

To address that, ASCO will host a summit on November 4 in Washington, DC, to bring together investigators from various disciplines, including medical oncology, nutrition, physical activity, and behavior medicine.

The aim of the meeting will be to help prioritize research, ensure major questions are being addressed, and explore possible funding sources.

"A multidisciplinary summit is a fabulous idea," said Dr. Simone. "For success, ASCO and other groups must help the National Cancer Institute see the need for more funding opportunities in this area," she noted.

By holding the summit, ASCO will be putting some of its money where its mouth is with regard to research.

It has also spent funds on the clinical guidance portion of the position statement. ASCO developed guides for oncology providers and for patients on the effects of obesity on cancer risk and cancer-related mortality, as reported earlier this year by Medscape Medical News.

But ASCO wants to see money flow into oncology and other medical practices that care for overweight and obese patients.

The position statement calls for a number of policy changes to increase access to obesity screening, diagnosis, and treatment.

It highlights the need to close gaps in private and public insurance coverage for weight management services for both the general public and cancer patients.

ASCO also calls on the Centers for Medicare & Medicaid Services to add obesity to the list of chronic diseases eligible for the proposed complex chronic care management services payments.

The statement also encourages the Department of Health and Human Services to clearly define access to obesity treatment services in the new state healthcare exchange plans under the Affordable Care Act.

In addition, ASCO wants to work with other groups who are more expert in weight loss, nutrition, exercise, and other subjects, said Dr. Ligibel.

"We want to partner with organizations that have been thinking about obesity for a much longer time," she said.

The authors have disclosed no relevant financial relationships.

J Clin Oncol.Published online October 1, 2014. Abstract

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