Investigators at the University of Texas MD Anderson Cancer Center, Houston, have reported on a new approach to treating previously inoperable complex pancreatic adenocarcinoma that has significantly increased long-term survival for some patients. Pancreatic adenocarcinoma is one of the most devastating forms of pancreatic cancer with survival rates of only 5 percent at five years. Surgical removal of these tumors offers a chance for cure, but it is estimated that only about 20 percent of patients can undergo this treatment. The tumor in the pancreas often grows into adjacent vital blood vessels, and this is the most common reason a surgeon will consider pancreatic cancer to be inoperable and incurable. However, the MD Anderson investigators have achieved an important milestone in the surgical treatment of the disease in terms of improving prognosis for patients who meet the criteria for a newly developed protocol.
In a study published in the July issue of the Journal of the American College of Surgeons, the investigators reported on 88 patients who had been told their tumors were inoperable after an initial surgical attempt at removal, 66 of whom completed a multidisciplinary treatment regimen with successful tumor removal. This approach has been refined at MD Anderson over the last 20 years and involves a more accurate and collaborative interpretation of CT scans of the tumor between surgeons and radiologists; chemotherapy and radiation treatment of the tumor; and finally an advanced approach to surgical resection with planned removal and reconstruction of involved vital blood vessels near the tumor.
“We’ve been able to achieve survival numbers for these patients that are comparable to those receiving surgery for clearly operable tumors,” reported lead study author Jason B. Fleming, MD, FACS. On average, patients in this study lived about 30 months after tumor removal, which is almost three times longer than the 11 months for patients who are never able to have their tumors surgically removed.
The study enrolled high-risk patients who had been originally diagnosed at outside institutions with operable, localized cancer. However, at their initial operations the intent to remove the tumor was aborted when the disease turned out to be more extensive than originally detected.
The study involved a cohort of patients referred to MD Anderson from 1990 to 2010, many of whom were ultimately able to undergo a successful operation to remove the tumors. While the results of small series and isolated cases in which this approach was used have been published, this is the largest study including only those patients who had a previous unsuccessful attempt to remove the tumor, according to Dr. Fleming.
The pancreas is located in the back of the abdomen, near vital arteries and veins that provide blood to the intestines and liver. If the tumor encroaches on these vessels, the operation to remove the tumor can also involve reconstructing these important blood vessels, raising the complexity of the procedure. Reconstructing these vessels in a way that restores appropriate blood flow is critical for the overall wellness and survivability of patients after the operation.
Inoperable Pancreatic Cancer
Inoperable pancreatic cancer is a cancer tumor that because of its location and/or stage rules out surgery as a treatment. Many pancreatic tumors are inoperable by the time they are discovered. This occurs because they have usually already advanced to a late stage. Early stages of pancreatic cancer do not display specific symptoms, so the tumors grow unnoticed until they are large enough or have spread to enough areas that they begin causing things such as abdominal pain, high blood sugar, and jaundice to name a few. In fact, only about 15 to 20 percent of tumors can still be surgically removed at the time of diagnosis. And only 30 percent of people who can undergo the surgery live longer than 5 years.
Most pancreatic cancer is deemed inoperable because it has invaded neighboring blood vessels, metastasized or spread to organs, or grown directly into surrounding structures. It is still technically possible to operate on the pancreas, but by this time surgery on the pancreas is almost pointless and carries far more risks than it does benefits.
The initial location of the pancreatic cancer tumor has an influence on whether or not surgery will be an option. A tumor can grow on the head, body, or tail of the pancreas. If it is occurs on the head, its symptoms appear early, thus doctors may catch it before it spreads. But if it is on the body or tail, it usually does not display symptoms. So by the time the tumor is found, it has spread to its neighbors.
Another sign of whether or not you have inoperable pancreatic cancer is where the cancer has spread. For instance, if it is only in the lymph nodes around the pancreas, the spread is considered locoregional and is operable, or resectable. But if the cancer is found in other areas, it is usually inoperable (unresectable), though surgeons must make the final decision.
The investigators stratified each patient’s risk for metastatic disease based on tumor involvement with local blood vessels, suspicious biopsy results and the nature of the tumor, and overall health status aside from pancreatic cancer. Patients who met these criteria underwent the protocol.
The key to screening patients for treatment and staging of their cancer is radiographic imaging, specifically in the interpretation of CT scans of the tumors before the operation, Dr. Fleming explained. “The interpretation needs to be performed in conjunction with the radiologist, but also with heavy involvement by the surgeon,” he said. “The goal should be to give the surgeon a clear idea of tumor location and vessel involvement before beginning the operation,” he said.
New Surgical Method for Inoperable Pancreatic Cancer?
In some cases, surgeons will not operate on patients with pancreatic cancer that has spread significantly in the local area, due to the many risks. A new surgical technique that uses many small pulses of electricity may change that.
This surgical technique known as irreversible electroporation (IRE) was pioneered in cancers of the liver - it’s an advanced form of the more commonly used electric knife technology.
The technique is being modified for possible use with pancreatic cancer.
Pancreatic cancers are difficult to detect until the tumor has grown large enough to change nearby organs. Treatment is difficult due to the delicate tissue of the pancreas, as well as several major blood vessels located next to it.
The high precision of the irreversible electroporation provides new options for all pancreatic cancer patients, including those with advanced disease.
Guided by imaging systems, a team of surgeons and radiologists can destroy or remove the tumor without damaging nearby structures.
“We think in another 12 to 15 months we will have a lot more evidence to support the use of IRE for inoperable pancreatic cancer patients,” said Govindarajan Narayanan, M.D., chief of vascular and interventional radiology at the University of Miami.
The MD Anderson protocol also uses a scoring system along with structured documentation for the radiologist to more accurately assess the extent of tumor-vessel involvement, according to Dr. Fleming. “With good imaging and good interpretation you have a high likelihood of being able to predict involvement of the vessels before surgical treatment, not after,” he said. About 46 percent of the patients in this study required some type of vascular resection, according to Dr. Fleming.