Changing Course in Pancreatic Cancer
The 66-year-old resident of Vero Beach, Fla., received her pancreatic cancer diagnosis almost seven years ago and underwent surgery to remove part of her pancreas and spleen. She then received an intense regimen of chemotherapy and radiation and was followed closely by her oncologist for the next five years without further treatment, as she appeared to be in remission.
Five years after receiving her diagnosis, she no longer needed imaging scans. However, in March, Smith began experiencing back pain. Scans and a biopsy revealed that her cancer had metastasized to her liver.
Her initial treatment with Abraxane had to be halted because it made her white blood cell count plummet. She restarted treatment with an altered schedule that included doses of granulocyte colony-stimulating factors (G-CSFs) to boost her white blood cells.
Early on, Smith struggled with other side effects, including rash, thrush, mouth sores and poor appetite. But as the treatment progressed, the side effects lessened. “Now I experience tiredness, lethargy and flu-like symptoms on the third and fourth day after chemo, but other than that I get along well,” she says.
About 45,000 new cases of pancreatic cancer are estimated to be diagnosed this year in the U.S. Patients with the disease face a tough challenge due to its aggressive nature and resistance to available treatments. Moreover, it can be difficult to diagnose in its early stages (less than 20 percent of tumors are confined to the pancreas at the time of diagnosis), so all too often, the disease has already spread to the point where surgical removal of the tumor is not possible. Thus, the one-year survival rate for all stages of the disease combined is about 20 percent. Unfortunately, disease recurrence is common, and the five-year survival rate for pancreatic cancer is 6 percent.
The best predictors of long-term survival following surgery (considered the only potentially curative treatment at this time) are small tumor size, no lymph node involvement and no cancer cells surrounding the tissue where the tumor was removed. There is also increasing evidence that the best outcomes after surgery for the disease are achieved at major medical centers that perform more than 20 pancreatic surgeries annually.
Inroads into effective treatments and better diagnostics have been slower than with many other cancers, but new approaches are emerging, especially as more is learned about the biologic makeup of the disease.
There are several types of pancreatic cancer, but they fall into two major categories: exocrine and endocrine. Approximately 95 percent of pancreatic cancers begin in the exocrine cells in the ducts of the pancreas and sometimes in the cells that make pancreatic enzymes that aid digestion. Within this category, there are a number of tumor types, but about 95 percent are adenocarcinomas. Endocrine tumors, also known as pancreatic neuroendocrine tumors (PNETs), are slower growing and develop in the islet cells, which produce hormones, such as insulin. These cancers are rare, accounting for less than 4 percent of pancreatic cancers. While treatment varies depending on the specific tumor type and stage, the prognosis for PNETs is usually better than for exocrine cancers.
Most cases of pancreatic cancer appear to be sporadic, in that they occur in patients who do not have an inherited predisposition. Smoking, by far, is the most common modifiable risk factor, accounting for about 20 percent of cases. Some studies have found that diet can play a role, in that high consumption of processed red meat and fats might increase pancreatic cancer risks, while fruits, vegetables and dietary fiber might have a protective effect, but more research is necessary to confirm those results. Being obese has also been linked with a higher risk.
Other risk factors include long-term inflammation of the pancreas (chronic pancreatitis) and certain inherited syndromes caused by genetic abnormalities. Diabetes can be a risk factor and a symptom of pancreatic cancer. “Diabetes or glucose intolerance often predates pancreatic cancer by several months,” says Diane M. Simeone, director of the Pancreatic Cancer Center at the University of Michigan in Ann Arbor. “We are trying to understand in more detail what the link is between diabetes and pancreatic cancer, and this could help us develop an early detection test.”
Of all people age 50 or older who have diabetes, one in 100 will receive a diagnosis of pancreatic cancer within three years of their diabetes diagnosis, according to Simeone. “We need to be able to take that information and better differentiate which individuals should get a further workup for pancreatic cancer.”