Tumor volume as a prognostic factor for sarcomatosis

BACKGROUND. The appropriate therapeutic interventions for sarcomatosis, or sarcoma characterized by intraabdominal dissemination, remain unclear. The authors performed a retrospective analysis of their recent experience with patients diagnosed with sarcomatosis to determine the overall survival and the effects of clinicopathologic features on survival rates at two and four years. METHODS. A query of the authors' prospective soft tissue sarcoma database identified 51 patients with a diagnosis of sarcomatosis who were evaluated at the authors' institution between June 1996 and June 1999. Clinical and pathologic factors were evaluated, and survival was calculated using a Kaplan-Meier survival analysis. Disease was categorized as low or high volume based on findings at surgical exploration or computed tomography scan evaluation. Disease was classified as low/intermediate grade or high grade based upon histologic examination. RESULTS. Twenty five patients were male and 26 were female. The median time from the initial diagnosis of sarcoma to the development of sarcomatosis was 0.9 years (range, 0-26 years). Thirty nine patients were treated with surgery, whereas 32 received primarily nonsurgical treatment. Histology revealed gastrointestinal stromal tumor (GIST) in 33 patients and other histologies in 18 patients. The two year overall survival rate of patients with GIST was similar to that of patients with other types of sarcoma (38% versus 42%, respectively, P = 0.77). Patients with low volume disease had an overall two year survival rate of 82%, compared with only 24% for patients with high volume disease (P = 0.008). There was no difference in the overall survival rates of patients with low grade (n = 18) versus high grade tumors (n = 33, P = 0.29). With a median followup of 2.7 years (range, 0.5-26.4 years), the median time from sarcomatosis to death was 13 months (range, 4-42 months). CONCLUSIONS. Evaluating volume of disease at the time of diagnosis permits stratification of patients into prognosis based subsets. We found no significant difference in two or four year survival rates in patients with GIST and those with non-GIST sarcomatosis.