CHICAGO, IL (May 29, 2013)—A new study by Fox Chase Cancer Center researchers—which will be presented at the 49th Annual Meeting of the American Society of Clinical Oncology on Monday, June 3—has identified a disconnect between clinical trials that look at new treatments for metastatic pancreatic cancer and the patient population most likely to be diagnosed with the disease. Clinical trials typically enroll, and base their findings on, patients in their 50's and 60's, but the median age at diagnosis is 72.
“We extrapolate our data from studies on younger patients to older patients, but they are different patients, and may have different biology of the disease,” says Namrata Vijayvergia, fellow in Department of Medical Oncology at Fox Chase. Vijayvergia and her colleagues recently found that older patients are less likely to undergo chemotherapy treatment, and have a shorter overall survival.
As a first step toward better understanding the geriatric form of the disease, the team analyzed medical records of 277 patients treated for metastatic pancreatic cancer at Fox Chase. Out of that group, 155 patients were 65 years old or younger; the other 122 were older than 65. The groups were balanced by sex, cancer stage and metastatic sites.
Younger patients were more likely to receive chemotherapy, and lived, on average, one month longer than older patients (6 months versus 5 months), the researchers reported. 92 percent of the younger patients received chemotherapy, compared with 79 percent of older patients. Only 34 percent of the older patients who underwent chemotherapy received treatment with more than one agent, compared with 52 percent of the younger patients. Among younger patients, those with lung metastases lived longer than average (10 months versus 6 months), and those with liver metastases had decreased survival.
Vijayvergia describes the study as a “stepping stone” toward knowing whether pancreatic cancer in older patients—those closer to the median diagnostic age of 72—has a different biology than the disease diagnosed in younger patients.
The primary investigator for the study was medical oncologist Steven J. Cohen, MD, medical director of Medical Oncology at Fox Chase Cancer Center Partners and principal investigator on the study.
“We started this study really to take a look at our own experience in terms of treating elderly patients with metastatic pancreatic cancer,” Cohen says.
In the past, Cohen says, knowing more about the older pancreatic cancer patient population wouldn't have made much of a difference, as chemotherapy treatment options were limited. The standard chemotherapy treatment was gemcitabine (sold as gemzar). But in recent years, he says, researchers have developed more aggressive chemotherapy regimens—many still including gemcitabine—that have improved outcomes. Cohen says the time has come to determine whether these more aggressive regiments will help an older patient population.
“We see that the elderly are not receiving as aggressive care as younger patients,” says Efrat Dotan, MD, a medical oncologist at Fox Chase who specializes in geriatric oncology and is working with Cohen and Vijayvergia on the study. “This raises an interesting question: Is this a function of the fact that the elderly can't tolerate treatment, or does this reflect a bias on the part of practitioners who do not want to treat elderly patients with aggressive chemotherapy?”
Dotan notes that future studies at our Center will incorporate not only the standard ways of assessing elderly patients, but also evaluation of novel biomarkers of aging such as telomere length. Telomeres, like plastic tips on shoelaces, are found at the ends of chromosomes. Telomeres shorten as a person gets older. Shorter telomeres have been linked to increased cancer incidence and risk of death. This biomarker is currently being evaluated as an assessment tool for older cancer patients with pancreatic and colorectal cancer at Fox Chase.
“In the past, when we did not have effective therapy for advanced pancreatic cancer, this questions was less relevant'” Dotan says. “Treatment for metastatic pancreatic cancer has gotten better and should be explored as a treatment option for the older patients as well as younger patient with metastatic pancreatic cancer.”
Other co-authors on the study include Karthik Devarajan at Fox Chase; Kamel Hatahet at Temple University; and medical student Farah Rahman at the Philadelphia College of Osteopathic Medicine.