Long-term survival following treatment of pseudomyxoma peritonei: an analysis of surgical therapy

Abstract

Summary background data: Pseudomyxoma peritonei (PMP) is a clinical syndrome with a poorly defined natural history. Relative contributions of tumor biology, patient selection, and the extent of treatment on ultimate outcome are not well characterized.

Methods: Patients treated at the Memorial Sloan-Kettering Cancer Center between 1980 and 2002 with a diagnosis of PMP were identified. Patient characteristics, pathologic features, and details of treatment were analyzed retrospectively.

Results: The 97 patients included in this study underwent a mean 2.2 +/- 0.1 operations (range, 1-6). Although complete cytoreduction was achieved in 55% (53/97), disease recurred in 91% (48/53) of patients. The median disease-free interval after complete cytoreduction was 24 months. The median overall survival was 9.8 years and was independently associated with low-grade pathologic subtype (P < 0.001) and the ability to achieve complete cytoreduction (P < 0.001). Ten-year survival was attained in 21% (20/97) of the patients, of which 90% (18/20) had low-grade pathologic features. At the time of death or completion of follow-up, only 12% (12/97) of the patients were disease free.

Conclusions: Outcome in patients with PMP is strongly associated with tumor biology. Although improved survival is associated with low-grade pathology and tumors amenable to complete cytoreduction, recurrence of PMP is common. Treatment may be beneficial, particularly in controlling symptoms, but absolute cure, defined as a prolonged disease-free state, is uncommon.

FIGURE 1. The extent of surgery score (ESS) is based on the number of abdominal regions involved in the operative procedure. Abdominal regions 0 to 8 are associated with specific anatomic structures located within the abdomen and pelvis. The small bowel is defined sequentially in a proximal to distal direction: region 9 is upper jejunum, region 10 is lower jejunum, region 11 is upper ileum, and region 12 is lower ileum.

FIGURE 2. The presence of documented symptoms associated with successive operations. The striped section of bar represents operations performed explicitly with palliative intent. * P < 0.05 documented symptoms versus prior operation. ^χ P < 0.05 palliative intent versus prior operation. ^α P < 0.05 versus durability of previous operation; d, durability; m, months.

FIGURE 3. Completeness of cytoreduction associated with successive operations. Complete cytoreduction was more common after the first and second operations (P < 0.001).

FIGURE 4. Completeness of cytoreduction associated with ESS score.

FIGURE 5. Long-term survival associated with pathologic designation (P < 0.001).

FIGURE 6. Comparison of long-term survival in patients with PMP from studies representing different treatment philosophies. The dotted line represents the overall survival of patients receiving aggressive surgical cytoreduction and intraperitoneal chemotherapy. To be selected for this therapy, patients, by definition, had favorable pathologic characteristics. The black line represents patients from the current study that had comparable favorable pathologic features. The curves were adjusted to reflect similar 10-year time intervals (years on the x axis).