Resectable Well-Differentiated versus Dedifferentiated Liposarcomas: Two Different Diseases Possibly Requiring Different Treatment Approaches
Division of retroperitoneal liposarcoma (RPLS) into well-differentiated (WD) and dedifferentiated (DD) subtypes is established; however, WD and DD are usually treated similarly. We hypothesized that WD and DD have distinct biological behaviors mandating different treatments.
A prospective sarcoma database identified all primary/recurrent RPLS treated between 1996 and 2007: 77 DD (52%) and 58 WD (39.2%) patients were analyzed for recurrence rate, recurrence free survival (RFS), and overall survival (OS).
At presentation, WD were mostly primary whereas DD were mostly recurrent (75.9% versus 58.4%; p = 0.04). A significant proportion of DD (37.7%) received chemotherapy compared to WD (1.7%; p < 0.0001). Multivisceral resection was more common in DD versus WD (45.5% versus 31%; p = 0.01). Gross total resection rates were equivalent (WD: 86.2%; DD: 85.7%). Overall and local recurrence were higher in DD versus WD (82.2% versus 50% and 71.2% versus 46.3%; p < 0.0001). Only 3.7% WD recurred as high grade metastatic disease. Median time to recurrence was 55.5 months in WD versus 13.5 months in DD (p < 0.0001). RFS and OS (1, 2, and 5 year) were higher in WD than DD (80.3% versus 55.9%; 65.1% versus 34.1%; 41.9% versus 7.8%; p < 0.0001) and (98% versus 88.1%; 95.6% versus 71.9%; 92.1% versus 36.5%; p < 0.0001) respectively.
WD and DD have distinct biological behaviors. Gross total resection is achievable in most WD; unlike DD, high-grade recurrence is uncommon. Treatment should therefore reflect these biologic differences by maximizing survivorship while avoiding unnecessarily extensive multivisceral resection.
The biological behaviors of well-differentiated and dedifferentiated liposarcomas differ significantly. This article presents outcomes of two different surgical approaches that were implemented at the UTMDACC, treating these tumors as different disease entities.
KeywordsRetroperitoneal liposarcoma Atypical lipomatous tumor Well differentiation Dedifferentiation
- 4.Enzinger FM, Weiss SW. Liposarcoma: soft tissue tumors, 3rd ed. St. Louis: CV Mosby, 2001Google Scholar
- 5.Fletcher CDM, Unni K, Mertens F. Pathology and genetics of tumours of soft tissue and bone. Lyon, France: International Agency for Research on Cancer (IARC), 2002Google Scholar
- 10.LinehanDC, Lewis JJ, Leung D, et al. Influence of biologic factors and anatomic site in completely resected liposarcoma. J Clin Oncol 2000;18:1637–43Google Scholar
- 13.Mantel N. Evaluation of survival data and two new rank order statistics arising in its consideration. Cancer Chemotherapy Rep 1966; 60:163–70Google Scholar
- 14.Cox DR. Regression models and life tables (with discussion). J R Stat Soc B 1972; 34:187–220Google Scholar
- 15.Venables WN, Ripley BD. Modern applied statistics with Splus, 3rd ed. New York, Springer, 1999Google Scholar