The information and links on this page are no longer being updated and are provided for reference purposes only.
Special Issue: Cancer and Obesity Research
The Right Balance: Helping Cancer Survivors Achieve a Healthy Weight
The number of long-term cancer survivors in the United States is rising, as is the number of people who are overweight or obese, raising the specter that excess pounds could diminish length and quality of life for many who have survived cancer.
Obesity has been linked with increased risks of recurrence and death in several cancers, including common cancers such as breast, colorectal, and prostate. For example, recent findings from the California Teachers Study, which enrolled 4,000 breast cancer survivors, showed that being obese at the time of study entry was associated with a substantial increase in the risk of dying from breast cancer in several subgroups, including women who had been treated for estrogen receptor-positive breast cancer.
The data supporting obesity's potentially deleterious impact on some cancer survivors is strong enough that clinical trials have been launched to help survivors control their weight.
The goal is not only to reduce the risk of cancer recurrence and death, according to Dr. Catherine Alfano of NCI's Office of Cancer Survivorship. "We know that cancer survivors face a multitude of chronic and late effects of cancer treatment that limit their ability to participate fully in their life roles and decrease their quality of life," Dr. Alfano said. Interventions that help survivors maintain a healthy weight, she continued, may also decrease the risk of obesity-related health problems like diabetes and heart disease.
Targeting At-Risk Survivor Populations
NCI-funded researchers are testing diet and physical activity interventions in overweight and obese African American breast cancer survivors in an effort to reduce recurrences and improve quality of life.
Studies have shown that some cancer survivors are more likely than others to be overweight or obese. One such group is survivors of pediatric acute lymphoblastic leukemia (ALL). In a large study that involved participants in the NCI-supported Childhood Cancer Survivor Study (CCSS), adult survivors of pediatric ALL were substantially more likely than their siblings to be obese. Girls diagnosed with ALL before the age of 4 were nearly four times more likely than their siblings to become obese.
Steroids used to treat ALL can produce substantial weight gain. But other factors also affect weight gain and health over the longer term, noted Dr. Kevin Oeffinger of Memorial Sloan-Kettering Cancer Center in New York, the study's lead investigator. Obesity rates in ALL survivors in the CCSS study, he explained, were significantly higher in those who had been treated with high-dose radiation to the brain.
The radiation treatments "affect so many pathways that affect patients' muscle strength and development," Dr. Oeffinger said. Although roughly 80 percent of children diagnosed with ALL are cured, these types of long-term effects of treatment can greatly limit survivors' ability to be active, he said.
Primary Care-Based Programs Help Obese Patients Lose Weight
Obese patients lost an average of 10 to 11 pounds over 2 years with support and counseling programs managed by their primary care physicians, according to the results of two NIH-funded clinical trials published online this week in the New England Journal of Medicine.
In each trial—one conducted at practices affiliated with the Johns Hopkins University and the other at practices affiliated with the University of Pennsylvania—approximately 400 obese patients with at least one additional cardiovascular risk factor were randomly assigned to weight-loss interventions that offered different levels of support or usual care. In both trials, participants who received counseling support (delivered in-person, over the phone, or both) over 24 months had substantially greater weight loss and were more likely to lose at least 5 percent of their initial body weight than patients who received minimal support or usual care.
Treatments for ALL can also have long-lasting cardiac effects, such as cardiomyopathy (a disease of the heart muscle), "and we know that obesity increases cardiovascular disease risk," Dr. Oeffinger continued. Future research is needed to more closely examine whether, and the extent to which, obesity can aggravate this underlying treatment-related cardiovascular risk, he said.
Obesity rates are also particularly elevated in endometrial cancer survivors, and as researchers have feared, those excess pounds are indeed detrimental to health. In one small study of overweight and obese endometrial cancer survivors, 43 percent had hypertension, 33 percent had metabolic syndrome, and 21 percent had type 2 diabetes. Fewer than half of participants reported engaging in even moderate exercise.
Trials Aim to Take Off the Weight
A number of trials to help overweight and obese cancer survivors shed weight are now under way. Most of the trials are in survivors of breast cancer and leukemia, but a small NCI-supported trial is also enrolling endometrial cancer survivors.
Researchers at the University of California, San Diego, Moores Cancer Center are enrolling overweight and obese survivors of childhood ALL in a small NCI-funded clinical trial. The trial aims to reduce participants' body mass index, explained the trial's co-principal investigator, Dr. Jeannie Huang. The weight loss intervention, which relies heavily on Internet and text messaging tools, is tailored to the needs of young cancer survivors, whose families are also involved in the process.
There is clearly a need for greater awareness of weight problems in ALL survivors and for effective interventions, Dr. Huang believes. "We're talking about a child or teenager who had a life-threatening illness, and you go from getting through that terror to what are perceived as more 'minor' health concerns, like putting on weight," she said. "The families are often simply happy that their son or daughter is alive and thriving, and don't recognize that weight gain puts them at risk for other health problems, as well as a secondary cancer."
One participant in the Moores trial, Ana Otanez, and her family are well aware of the need to maintain a healthy weight. Ana, who was diagnosed with ALL 10 years ago at the age of 6, said she has been seeing a nutritionist for "as long as I can remember." She learned about the trial during a visit with her physician, and she and her family agreed that it was worth pursuing.
Every morning, she receives text messages on her phone with guidance on physical activity and losing weight. "Things like 'don't eat seconds' and 'avoid junk food,'" she said. She also gets recipes for healthy meals via the trial's participant website. The recipes often end up as part of family meals.
"It really is a family thing," Otanez said. "My family really helps me and supports me." Her goal, she continued, is to lose at least 10 pounds during the trial's 4-month intervention period.
A similar NCI-funded trial being conducted at Georgetown Lombardi Comprehensive Cancer Center is enrolling overweight and obese African American breast cancer survivors. (Learn more about the trial in the accompanying video.) African American women with breast cancer are more likely to die from the disease than their white counterparts and are also more likely to have more aggressive types of breast cancer.
"They're also more likely to be obese and have more comorbid conditions than Caucasian women," said Dr. Vanessa Sheppard, who, along with Dr. Lucile Adams-Campbell, is leading the trial.
Over a 3-month period, women in the trial receive nutrition counseling, have scheduled visits with trainers, participate in support groups, and receive weekly phone calls from a coach—a fellow breast cancer survivor—to check on their progress and to provide motivation and guidance. Like the ALL survivor trial, the Georgetown trial aims to lower BMI, change dietary and physical activity behaviors, and improve quality of life.
Help with weight management is clearly an unmet need for these women, Dr. Sheppard stressed. Before enrolling, only one of the women in the trial "had been referred to any type of nutritionist or had a referral for exercise by their oncologist," she continued. "So they can really benefit from this type of intervention."
Researchers from the University of California, San Diego are leading the largest trial to date of weight loss in cancer survivors. Dubbed the ENERGY trial and funded by a $5.4 million grant from NCI, the 4-year, multisite trial will eventually enroll 800 overweight or obese breast cancer survivors.
Unlike some of the smaller trials in similar populations, the ENERGY trial's intervention component lasts 2 years. Participants are randomly assigned to an intensive-care arm or a usual-care arm.
The trial takes an aggressive, long-term approach toward weight loss in the intervention arm, including getting participants to build up to at least 1 hour a day of moderate to vigorous exercise. Participants attend weekly group counseling sessions for the first 4 months after enrollment. The group sessions are an important part of cognitive behavioral therapy, said the trial's lead investigator, Dr. Cheryl Rock. Many women have tried and failed to lose weight, Dr. Rock explained, so the therapy helps teach participants about the many aspects of behavioral and thinking patterns that are necessary to shed weight and keep it off.
"Social support is really important for people trying to lose weight, and also for cancer survivors," she continued. "Survivors have a lot of commonalties around what they have gone through, including fears that linger about recurrences, so that support is important."
Participants in the usual-care arm will receive individual counseling, educational support, and guidance on weight loss.
The trial's initial goal is to help participants achieve and maintain weight loss and improve their quality of life. But the hope, Dr. Rock stressed, is to eventually expand the trial to enroll approximately 2,500 women and follow them long enough to measure whether the intervention has an impact on breast cancer recurrence. "But even if we only show that survivors' quality of life is improved, that will be very important," Dr. Rock said.