October 7, 2008 � A surgical approach to treating peritoneal surface disease (PSD), or colorectal metastases to the peritoneum, deserves greater consideration from referring oncologists, according to the surgeon who is 1 of the authors of a new study that reviews successful outcomes of the treatment.
"Outcomes [morbidity, mortality, and overall survival] when patients have complete resection or removal of their cancer with this approach are similar to outcomes with successful surgical resection of colorectal hepatic metastases," said lead author of the study, Perry Shen, MD, associate professor of surgery at Wake Forest University School of Medicine, in Winston-Salem, North Carolina, in an interview with Medscape Oncology.
The surgical approach to colorectal metastases to the liver is "well accepted," whereas a surgical approach to colorectal metastases to the peritoneum is "not well accepted and is controversial," he explained. Currently, most patients with PSD are treated with chemotherapy alone, he added.
The surgical approach he uses consists of cytoreductive surgery and intraperitoneal hyperthermic chemotherapy for PSD, a technique that infuses the peritoneal cavity with heated chemotherapy during surgery, Dr. Shen explained. This approach is used in only a handful of centers in the United States, and Wake Forest is at the forefront. "We will do about 110 cases this year. We are 1 of the 3 busiest centers in the country. Our patients come from all over the world," he said.
Compares Well With Results of Surgery for Colorectal Hepatic Metastases
The new study was a review of colorectal cancer patients who underwent surgery for metastatic disease to either the peritoneum (n = 121) or the liver (n = 101), from 1992 to 2005, at Wake Forest, and was published online September 11 in the Annals of Surgical Oncology.
Dr. Shen emphasized that, in the study, "optimal" or complete resection of PSD was only achieved in 45% of patients treated with a combination of cytoreductive surgery and intraperitoneal hyperthermic chemotherapy. However, 95% of patients who underwent surgical resection of hepatic metastases (HM) had optimal resection, which is defined as negative margins on removed specimens.
Still, when complete resection was achieved, the overall survival was similar for the 2 groups (P = .32). Also similar was perioperative morbidity (42% with PSD vs 34% with HM; P = .38) and mortality (5.5% with PSD vs 4.2% with HM; P = .71).
Overall Survival After Complete Resection
| Overall Survival | 1 Year | 3 Years | 5 Years |
| Peritoneal surface disease | 91% | 48% | 26% |
| Hepatic metastases | 87% | 59% | 34% |
"The results of this study suggest that the peritoneum can be a target for a combined approach of radical tumor resection and [intraperitoneal hyperthermic chemotherapy] when metastatic disease is confined to its surface. The oncologic principle would be similar to that found with colorectal HM, resulting in a subset of patients achieving long-term survival," conclude the authors.
Obstacles to More Acceptance and Usage
Despite the success detailed in the study, Dr. Shen said that there are a number of major obstacles to cytoreduction surgery and that intraperitoneal hyperthermic chemotherapy is more widely accepted by oncologists, including the fact that only 45% of the PSD patients retrospectively reviewed in the study had optimal resection, compared with 95% of the HM patients.
Another obstacle to more referrals may be the patients themselves and their circumstances, said Amy Halverson, MD, assistant professor of surgical oncology at the Feinberg School of Medicine, and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, in Chicago, Illinois. "Patients may not have the motivation or resources to travel. To tell a patient, 'You have to go from Chicago to Nebraska [where the procedure is performed at Creighton University]' � that's not always easy," she said in an interview with Medscape Oncology.
Dr. Halverson also noted that the "limited data" to date on this surgical approach to PSD is also an obstacle to referral. "This study helps address that."
According to Dr. Halverson, she and her colleagues at Northwestern make referrals for cytoreduction surgery and intraperitoneal hyperthermic chemotherapy when the situation is appropriate. However, PSD that is treatable with this approach is not a common clinical presentation. "This has to do with volume. It's not that we don't see a role for this, we just see very few patients who are candidates," she said.
Dr. Shen also noted that PSD is not easily assessed with either computed tomography or magnetic resonance imaging scans, whereas HM is. "PSD doesn't show up well on scans. The tumor is more like a coating than a ball," he explained. Standard imaging often underestimates the extent of PSD and results in patients being taken into surgery who can then not undergo complete cytoreduction. The inability to define the extent of PSD before surgery leads surgeons to "open up the abdomen and see what's there," he added.
Also, cytoreductive surgery for PSD is "not necessarily technically demanding," but "formulating and executing an overall operative plan to treat diffuse PSD that may have altered anatomic relationships in a preoperative field can be challenging," write the authors.
The authors of the study also note that "most surgical trainees do not receive any experience or training with these types of patients [PSD], so lack of familiarity leads to a nihilistic view of their prognosis." Hepatic resection, on the other hand, is a standard procedure taught in most major surgical residency programs and is widely practiced.
The researchers have disclosed no relevant financial relationships.
Ann Surg Oncol. Published online September 11, 2008
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