The Weight of Obesity on Cancer Patients
Overweight and obese patients face worse side effects and survival odds than others with the same cancer. New efforts aim to help them get better care, become healthier and live longer.
By Melissa Weber
"God, help me. I don’t want to die fat,” Lela Satterfield prayed.
Adding Pounds Adds Risk
Adults and children carrying extra pounds face a higher risk of a cancer diagnosis.
Use these resources to lose weight and improve your health.
It was 2009, a year after the medically obese music teacher in Oceanside, California, had been diagnosed with stage I breast cancer. Satterfield had weighed about
235 pounds before a lumpectomy, chemotherapy and radiation therapy wiped out her tumor, but she came out of the treatment 30 pounds heavier. She soon changed her eating habits and lost 40 pounds—only to start gaining it back. “I panicked,” she says of regaining weight.
Satterfield is among an increasing number of cancer patients who are obese at diagnosis. Indeed, weight plays a role in greater cancer risk. (See "Adding Pounds Adds Risk."
) America’s obesity epidemic has become a crisis in cancer care, with the American Institute for Cancer Research, a cancer prevention nonprofit, estimating that more than 120,000 people in the U.S. each year develop one of a variety of cancers associated with excess body weight. Two decades worth of research have shown a litany of negative consequences for survivors of certain cancers who carry extra weight, such as worse survival rates, increased risk of cancer recurrence and more side effects.
The good news is that an unprecedented effort is underway to improve care and outcomes for overweight and obese cancer patients. More than 2,000 papers on obesity and cancer have appeared in scientific journals in recent decades, which is helping doctors better understand the obesity-cancer link. In May, the American Society of Clinical Oncology (ASCO) released a guide to help oncologists manage obesity-related challenges in patients.
More than a year after the American Medical Association recognized obesity as a disease in its own right, the verdict is still out on whether losing weight reduces the risk of recurrence or death from cancer for obese cancer patients. But now there is a better understanding about what obese cancer survivors and their doctors can do to improve survivors’ lives, says Jennifer Ligibel, a medical oncologist and researcher at Dana-Farber Cancer Institute in Boston.
“I tell my patients early on that there’s more to fighting cancer than medication,” she says.
Extra Weight Equals Extra Risks
In 1980, only about one in seven American adults were obese. Today, one in three are obese, meaning their body mass index, or BMI, is 30 or higher. (A normal-weight BMI is in the range of 18.5 to 24.9; 25 to 29.9 is considered overweight.) By these benchmarks, an obese person would include a 5-foot-5-inch woman who weighs at least 180 pounds or a 5-foot-11-inch man who tips the scales at 215 pounds or more.
Research suggests exercise can improve quality of life, lower the risk of lymphedema, lessen fatigue, improve body image, boost physical functioning and reduce depression.
There are nearly 14 million cancer survivors in the U.S., and for many cancers, studies indicate more than two-thirds of those diagnosed are overweight or obese. In addition, researchers from the American Cancer Society (ACS) came to an alarming conclusion in 2003: The condition of being overweight or obese may account for up to 14 percent of cancer deaths in men and 20 percent in women 50 or older.
Obesity correlates with some cancer types more than others. And the increased risk can be substantial: According to an analysis of more than 80 breast cancer studies reported in the Annals of Oncology online on April 27, 2014, obese women diagnosed with breast cancer are
35 percent more likely than normal-weight women to
die of their cancer and 41 percent more likely to die of any cause. Another study published in the Journal of the National Cancer Institute in 2006 found a 38 percent increased risk of cancer recurrence or a new cancer among very obese colon cancer survivors compared with normal-weight survivors. Very obese is defined as having a BMI
of 35 or higher.
“A lot of patients are not aware that obesity is a risk factor for recurrence,” Ligibel says. “Even oncologists haven’t paid much attention in the past to a patient’s weight, despite the association between obesity and worse cancer-related outcomes.”
Some of those worse outcomes extend beyond the cancer itself to the side effects of the disease or its treatment. Obese breast cancer survivors are at greater risk for lymphedema, a painful swelling that can occur after breast surgery. Incontinence is more likely and more severe in obese prostate cancer survivors. And obese patients with various cancers are at increased risk of blood clots during
chemotherapy, cancer-related fatigue, diminished quality of life and surgical complications such as infection.
Why Weight Adds Risk
As study after study showed that cancer recurs or progresses more often in obese patients, researchers started to ask why. What they’ve found is that excess body fat produces more estrogen and more growth factors, and people who are obese often have more insulin and more inflammation—all factors associated with cancer’s development and growth.
Having an obesity-related condition such as diabetes, heart disease or stroke also influences a patient’s survival odds, says Jeffrey Meyerhardt, a gastrointestinal oncologist and the clinical director of the Gastrointestinal Cancer Center at Dana-Farber. “Even if people are doing well from their cancer, you can’t neglect these other health issues,” he says.
But the most startling reason obese people with cancer may have lower survival rates than their normal-weight peers is that as many as 40 percent received too little chemotherapy. In the past, oncologists would often cap a chemo dose at a certain amount regardless of a patient’s weight out of fear that larger doses would be too toxic. Yet studies show obese patients treated with full doses based on their weight have no more side effects from chemotherapy than healthy-weight patients.
“Underdosing may in part explain why obese patients have a higher risk of recurrence and mortality,” says Gary Lyman, a medical oncologist at Fred Hutchinson Cancer Research Center in Seattle and a co-director of the Hutchinson Institute for Cancer Outcomes Research.
In 2012, ASCO released guidelines for oncologists that warned against dose-capping and advised them to use actual body weight to calculate chemo doses for obese patients. Lyman led the panel that wrote the guidelines and says many institutions that were dose-capping for obese patients have eliminated the practice. “There are legitimate reasons to cut back on chemotherapy strength, such as heart disease or kidney disease,” he says. “But obesity is not one of them.”
A year before the guidelines’ release, Tracy Smith from Durham, North Carolina, began chemotherapy for stage III breast cancer. She received full doses based on her weight, which at 310 pounds put her in the obese category.
Smith’s doctor told her she’d be getting a high dose of the toxic drugs. “It didn’t worry me,” she says, recalling bouts of mild nausea and shortness of breath but nothing severe. “She knew to base my chemo dose on my body weight, and I’m forever grateful for that.” Smith, 47, shows no signs of cancer and works as an aide for adults with intellectual disabilities.