A Tough Cancer to Treat
Pancreatic cancer is often detected late because symptoms do not seem serious
By Ashley Welch
Last week, pancreatic cancer took the life of Apple co-founder Steve Jobs. Several days earlier, Dr. Ralph Steinman, winner of the 2011 Nobel Prize for medicine, died from the same cancer, just days before the award was announced.
The National Cancer Institute estimates that there will be 44,030 new cases and 37,660 deaths resulting from pancreatic cancer in the United States this year. The American Cancer Society says pancreatic cancer patients have only a 20 percent chance to live at least one year after diagnosis, and fewer than 4 percent will be alive after five years.
Many doctors agree that the reason for such daunting numbers is that pancreatic cancer is one of the most difficult cancers to treat. Why is this and what is it about its nature that makes it so deadly?
Pancreatic cancer begins in the tissues of the pancreas, a six-inch-long organ located horizontally behind the stomach in the abdomen. It secretes enzymes that aid in digestion and produces hormones that help regulate the metabolism of sugars. Cancer occurs when cells begin dividing uncontrollably and form lumps of tissue, which become tumors and interfere with the main functions of the pancreas.
The first reason pancreatic cancer is difficult to treat is that it is often goes undetected until it's in its advanced stages. This is because the early signs of pancreatic cancer are varied and are common with many other, less serious health conditions.
"Most of the time, pancreatic cancer presents very nonspecific symptoms that do not necessarily give any indication of a serious disease," said Dr. Chandan Guha, a professor and vice chair of radiation oncology at Albert Einstein College of Medicine and Montefiore Medical Center.
These early symptoms include bloating, nausea, indigestion and abdominal pain, things Guha said people may often ignore because they are minor ailments that they expect to experience in their day-to-day lives.
By the time more serious symptoms, such as severe weight loss and jaundice (the yellowing of the eyes and skin), occur, the cancer has often reached advanced stages and has most likely spread outside the pancreas.
At this stage, the cancer is almost impossible to remove because it often spreads to vital blood vessels that are in close proximity to the pancreas.
"The pancreas lives in a very protected location," said Dr. Steven Standiford, a surgical oncologist and chief of staff at Cancer Treatment Centers of America in Philadelphia. "A small tumor in the pancreas can involve the portal vein, the major vein that drains the intestine into the liver, the hepatic artery, the artery to the liver, or the mesenteric artery, which is the main artery to the intestine, making the cancer inoperable at that point."
Doctors must then turn to radiation and chemotherapy for treatment. Yet, according to Standiford, although some progress has been made in treating pancreatic cancer with these methods, they do not yield the same dramatic results as for other types of cancer, such as breast cancer and Hodgkin's disease. The reason for pancreatic cancer's weak response to these methods, he said, is not known.
"It could be that we haven't found the right drugs," he said, "or is it that the tumor is just that resistant, that it's much harder to find the right drugs."
Such limited treatment options, coupled with late detection, are the main reasons for the low life expectancy and high mortality rate associated with pancreatic cancer.
So what hope is there for the future treatment of this deadly disease?
Scientists are working all over the country on different ways to extend the lifespan of pancreatic cancer patients and possibly find a cure.
Some methods under development include trying new chemotherapy drugs and improving the delivery of the drugs to the cancer site. Others are experimenting with "targeted therapy" drugs, which would attack the unique aspects of cancer cells while causing little harm to healthy cells. Still other doctors, including Guha at Einstein Medical College, are working on vaccines for pancreatic cancer.
Though vaccines are typically thought of as a means to prevent a disease, this type of vaccine would help treat an existing cancer by strengthening the body's natural defenses against it.
Guha said this is essentially done by "trying to educate the body's own immune system to consider the tumor as dangerous and to fight it."
He is studying whether a vaccine, coupled with chemotherapy, would improve overall survival and induce strong tumor-specific immunity in patients with inoperable pancreatic cancer.
Though this vaccine is still in experimental trials, Guha said he has hope that such treatments will soon make for more positive outcomes for pancreatic cancer patients.
Apple co-founder Steve Jobs died last week from pancreatic cancer, which continues to have one of the lowest cancer survival rates, 4 percent after five years.
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