A new Mayo Clinic study reviewed CT scans of pancreatic cancer patients done before their cancer diagnosis and found that the cancer rapidly progresses from early to advanced stage in the six months prior to traditional clinical diagnosis. The study also found that in one-half of the diabetic patients, their new-onset diabetes predated clinical diagnosis of cancer by more than six months, giving researchers one more clue for earlier detection of pancreatic cancer. “Past studies have shown an association between recent diagnoses of diabetes and pancreatic cancer,” says Suresh Chari, M.D., a Mayo Clinic gastroenterologist and lead author of this study. “Our goal with this study was to establish a timeline for the progression of pancreatic cancer, especially in relation to the development of new-onset diabetes.”
Pancreatic cancer, the fourth leading cause of cancer death in the United States, claims nearly 32,000 lives each year. Patients with this type of cancer seldom exhibit disease-specific symptoms until the cancer is at an advanced stage and surgery is no longer an option, therefore, fewer than 5 percent of pancreatic cancer patients survive five years after diagnosis. This study population consisted of 23 patients who underwent at least one CT scan for unrelated reasons before the diagnosis of pancreatic cancer. Dr. Chari’s team found that while 70 percent of patients had advanced cancer at diagnosis, all scans done six months or more prior to diagnosis showed no evidence of the cancer.
Fourteen patients in the study had data on diabetes and its date of onset could be established. On average, the cancer was diagnosed five months after the diabetes first developed, and in 50 percent of patients, the diabetes occurred six months or more before the diagnosis of cancer. All scans done prior to the onset of diabetes were normal; however, by the time the cancer was diagnosed, 80 percent of the patients were already in advanced stages of pancreatic cancer and could not be treated with surgery.
“This research is encouraging because it shows that when patients with pancreatic cancer first exhibit high blood sugar, there’s still time to diagnose the cancer early enough to be treated by surgery,” says Dr. Chari. However, type 2 diabetes is far more common than pancreatic cancer-induced diabetes. According to Dr. Chari, only one in 100 to 200 patients with new-onset diabetes will be diagnosed with pancreatic cancer. “We are, therefore, not recommending that all new-onset diabetics undergo screening,” he says. The question Dr. Chari’s team now faces is identifying another clue to determine who among the group of patients with new-onset diabetes have a high likelihood of developing pancreatic cancer.
“Because of the connection with diabetes, we know there’s a clue in the blood of these patients,” says Dr. Chari. “Our next step is to determine whether the pancreatic cancer is actually producing something that is causing a unique form of diabetes. If that’s the case, we want to identify that ‘something’ to differentiate between pancreatic cancer-induced diabetes and regular type 2 diabetes.” The eventual goal of this research is to identify another layer of screening (in addition to tests for high blood sugar) to identify individuals who are more likely to have pancreatic cancer — allowing for earlier detection and increased opportunity for surgical treatment.
June 20, 2006
Original web page at Mayo Clinic