The odds of surviving cancer of the pancreas increase dramatically for patients whose tumors are smallest, according to a new study by researchers at Saint Louis University and the M.D. Anderson Cancer Center in Houston - the first study to specifically evaluate the link between tumor size and survival rates for one of the most common and deadly cancers.
The findings - in the current edition of Pancreas (www.pancreasjournal.com) - vividly underscore the importance of early diagnosis of pancreatic cancer, the researchers said.
"Even though it seems intuitive and was supported by preliminary observations from earlier studies, for the first time we now have evidence that a progressive decrease in the size of a pancreatic tumor at the time of diagnosis improves patient outcomes rather dramatically," said Banke Agarwal, M.D., Associate Professor of gastroenterology at the Saint Louis University School of Medicine and lead author of the study.
"These data emphasize the benefit and the need of finding and diagnosing tumors in the pancreas as early as possible," Agarwal added. "In order to make progress against pancreatic cancer, we have to redouble our efforts to identify symptoms that are associated with the early stages of the disease."
Pancreatic cancer is the fourth most common cancer in the United States and one of the most deadly, responsible for more than 33,000 deaths a year, according to the National Institutes of Health.
Despite many advances in the fight against other cancers in recent years, the prognosis for patients diagnosed with the pancreatic cancer has remained extremely poor. That's largely because the cancer is frequently not suspected and is difficult to diagnose in its early stages, when most people are asymptomatic or have non-specific symptoms that are easily ignored or attributed to other diseases.
The study looked at 65 patients who were diagnosed with pancreatic cancer at the M.D. Anderson Cancer in Houston between December 2000 and December 2001. Their average age was 67 years old; 38 were men.
Researchers found a striking correlation between a patient's prognosis and the size of their tumor at the time of diagnosis.
Of the 12 patients whose tumors were 20 millimeters or smaller, their median survival after diagnosis was 17.2 months. For those with tumors 21-25 mm, median survival was 12.3 months. For those with tumors 26-30 mm, median survival was 8.5 months. And for those with tumors larger than 30 mm, median survival was 7.6 months. Of those patients whose tumors were 20 mm or smaller, two were still alive after 48 months; none of the patients with tumors larger than 30 mm were alive after 36 months.
Unfortunately, while the patients with the smallest tumors had the highest rates of survival, they were relatively small in number. Only 12 patients - or 18 percent - had tumors 20 mm or smaller. By contrast, the largest group of patients - 27, or 42 percent - had tumors larger than 30 mm.
In addition, the average tumor size of patients in the study was 32.9 mm - well above the threshold at which survival rates are lowest. That figure is roughly comparable to an average tumor size of about 30 mm among pancreatic cancer patients in general, according to the study.
"These numbers illustrate why we've made so little progress in improving outcomes for people who are diagnosed with pancreatic cancer - we're not finding their tumors until they're too big and it's too late," Agarwal said. "We know we have a much better chance of helping someone survive pancreatic cancer if it's caught early and their tumor is small."
Major advances in imaging technology in recent years have greatly improved physicians' ability to diagnose progressively smaller pancreatic tumors. This hasn't led to earlier diagnosis, however, because patients generally don't get to the doctor until symptoms appear - and by then it's too late.
Agarwal said researchers will need to focus on finding ways to identify people who should be screened early for pancreatic cancer. Screening of the general population for the disease hasn't proven effective - but screening of people with a family history of pancreatic cancer is under active investigation, he said.
In addition, preliminary data from other studies have shown that elderly people who've been recently diagnosed with diabetes or depression have a higher likelihood of pancreatic cancer - providing another avenue for researchers to explore, Agarwal said.
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first medical degree west of the Mississippi River. The school educates physicians and biomedical scientists, conducts medical research, and provides health care on a local, national and international level. Research at the school seeks new cures and treatments in five key areas: cancer, liver disease, heart/lung disease, aging and brain disease, and infectious disease.