Large, Prospective Study Finds Long-Term Obesity Is Associated with Poorer Pancreatic Cancer Survival

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In this News Digest:

- Summary of a study being published online October 21, 2013 in the Journal of Clinical Oncology, reporting that patients with pancreatic cancer who were overweight or obese years before their diagnosis tend to have more advanced disease at diagnosis and shorter survival.

- The findings add to increasing evidence linking obesity with cancer, suggesting that maintaining a healthy body weight not only reduces the risk of developing certain cancers, but may also improve outcomes after a cancer diagnosis.

- Quote for attribution to Smitha Krishnamurthi, MD, American Society of Clinical Oncology Cancer Communications Committee member and gastrointestinal cancers expert

Newswise — New results from a prospective study published in the Journal of Clinical Oncology show that patients with a body mass index (BMI) in the obese range live on average two to three months less after a pancreatic cancer diagnosis, compared with healthy weight patients, even after adjusting for factors that are known to predict survival for patients with this disease, such as age and disease stage. This association was statistically strongest for people who were overweight two decades before their diagnosis.

Pancreatic cancer is the fourth leading cause of cancer-related death in the United States. Most patients with pancreatic adenocarcinoma, which accounts for more than 90% of new cases, survive less than a year after their diagnosis.

Obesity is a major public health problem in the United States and many other countries around the world. While it is well known that obesity is a risk factor for heart disease and diabetes, it is becoming increasingly clear that it is also associated with cancer risk and outcomes. In fact, scientists predict that obesity will become the leading preventable cause of cancer in the near future.

Several prior studies have shown that elevated BMI increases the risk of developing pancreatic cancer, but thus far there has been little research on whether BMI affects the aggressiveness of the disease or survival after diagnosis.

“This study adds to mounting evidence for the role of weight control in improving outcomes for patients with cancer. It also reinforces the importance of maintaining a healthy weight throughout your life, which may lead to better outcomes after diagnosis and help prevent pancreatic cancer from developing,” said senior study author Brian M. Wolpin, MD, MPH, an assistant professor of medicine at Dana-Farber Cancer Institute and Harvard Medical School in Boston, MA. “While our findings will not affect the way we treat patients today, they provide new leads for investigating the molecular pathways that may be responsible for the survival difference between obese and healthy-weight patients. Hopefully, in the future, that research will bring new approaches for treatment of pancreatic cancer.”

Researchers evaluated the association between patients’ BMI in 1986 and survival after diagnosis of pancreatic cancer among participants from two large prospective cohort studies – the Nurses’ Health Study and the Health Professionals Follow-Up Study. Participants of those studies were surveyed on medical history, health behaviors, and lifestyle choices. The present study assessed 902 cases of pancreatic adenocarcinoma that were diagnosed during a 24-year period.

Overall, the median length of survival after diagnosis for those patients was five months. According to Dr. Wolpin, on average, healthy weight patients (BMI less than 25 kg/m2) lived 2 to 3 months longer than obese patients (BMI greater than or equal to 35 kg/m2). The association between higher prediagnostic BMI and shorter survival persisted after adjusting for differences in age, gender, race/ethnicity, smoking status, and disease stage. Obese patients were also more likely to be diagnosed with advanced disease – 72% of obese patients had metastatic disease at diagnosis compared to 59% of healthy-weight patients.

The association between BMI and survival was even stronger among the 202 patients with high BMI assessed 18-20 years before diagnosis. Assuming that most people remain overweight once they gain weight, according to Dr. Wolpin, this finding suggests that being overweight for a prolonged period of time leads to worse outcomes. This study also suggests further avenues of research on the link between obesity and cancer. For example, it is not yet clear if the same changes that promote tumor development in obese people also affect the aggressiveness of the tumor. Several ongoing studies are already exploring metabolic (energy and nutrient processing) pathways and genomic changes in relation to obesity and cancer. This work might reveal whether tumors that develop in obese people are susceptible to different treatments than tumors that develop in healthy-weight people.

This research was funded in part by a 2009 Conquer Cancer Foundation of ASCO Career Development Award to Brian Wolpin.

ASCO Perspective:
Smitha Krishnamurthi, MD, ASCO Cancer Communications Committee member and gastrointestinal cancers expert
“While previous retrospective studies suggested a link between obesity and pancreatic cancer survival, the prospective nature of this study makes the findings more reliable. An interesting aspect of this study is that it suggests that obesity, particularly chronic obesity, increases the risk of death from pancreatic cancer. This study, however, could not distinguish if the increased risk of death was due to metabolic and inflammatory changes that accompany obesity or due to other health complications of obesity.”

The full study can be found online at the Journal of Clinical Oncology.

About the Journal of Clinical Oncology:
Journal of Clinical Oncology, the flagship journal of the American Society of Clinical Oncology, is a leader in reach, readership, impact, and influence. With a focus on significant clinical oncology research, Journal of Clinical Oncology publishes over 1,000 articles in 36 issues a year.

About ASCO:
Founded in 1964, the American Society of Clinical Oncology (ASCO) is the world's leading professional organization representing physicians who care for people with cancer. With more than 30,000 members, ASCO is committed to improving cancer care through scientific meetings, educational programs and peer-reviewed journals. ASCO is supported by its affiliate organization, the Conquer Cancer Foundation, which funds ground-breaking research and programs that make a tangible difference in the lives of people with cancer. For ASCO information and resources, visit www.asco.org. Patient-oriented cancer information is available at www.cancer.net.

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Study Finds Racial and Social Disparities in Kidney Allocation Among Young Transplant Recipients

 

• Among kidney transplant recipients younger than 40 years of age, African Americans and individuals with less education were more likely to receive lower-quality organs than Caucasians and those with college degrees.
• African Americans with higher education levels were not more likely to receive a lower-quality kidney than Caucasians with college degrees.

Newswise — Washington, — Among younger kidney transplant recipients, a disproportionate number of African Americans and individuals with less education receive organs that are of lower quality or are considered marginal, according to a study appearing in an upcoming issue of the Clinical Journal of the American Society of Nephrology (CJASN). The findings suggest that there are racial and social disparities in the allocation of transplanted organs that need to be addressed.

Older kidney disease patients who have a high risk of dying while on dialysis may benefit from accepting a so-called extended criteria donor (ECD) kidney—which is more likely to fail than a standard criteria donor kidney—rather than remaining on a transplant wait list. But younger patients and those with short wait times are usually better off holding out for a standard criteria donor kidney. Despite this, some young patients still end up receiving ECD kidneys.

Rajesh Mohandas MD, MPH, Mark Segal MD, PhD (University of Florida), and their colleagues looked to see if demographic factors play a role in whether younger patients accept ECD kidneys. They analyzed all first single-kidney transplants documented in the United States from 2000 to 2009 in patients 18 to 40 years of age and waitlisted less than three years.

Among the major findings:
• Of 13,615 ECD transplants, 591 (4.3%) kidneys went to recipients between 18 and 40 years of age who were waitlisted less than three years.
• African Americans were 1.7 times more likely to receive an ECD kidney than Caucasians.
• Individuals with less education were 2.3 times more likely to receive an ECD kidney than those with a college degree; however, African Americans with higher education levels were not more likely to receive such a lower-quality kidney than Caucasians with college degrees.

“To our knowledge, this is the first report showing that there are racial and social disparities in the quality of allocated transplanted organs. Understanding that such disparities exist is the essential first step to addressing inequalities in health care and to attempt to improve patient outcomes,” said Dr. Mohandas. He added that it is important to ensure that kidney transplant candidates are not just informed, but also educated about their choices.

Study co-authors include Michael Casey, MD, Robert Cook, MD, MPH, Kenneth Lamb, PhD, and Xuerong Wen, MS.

Disclosures: The authors reported no financial disclosures.

The article, entitled “Racial and Socioeconomic Disparities in the Allocation of Extended Criteria Donor Kidneys,” will appear online at http://cjasn.asnjournals.org/ on October 10, 2013, doi: 10.2215/CJN01430213.

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Founded in 1966, and with more than 14,000 members, the American Society of Nephrology (ASN) leads the fight against kidney disease by educating health professionals, sharing new knowledge, advancing research, and advocating the highest quality care for patients.