Personalizing surgical margins in retroperitoneal sarcomas

Abstract

Retroperitoneal sarcomas are a group of diseases that behave differently from one another. Well-differentiated liposarcomas have an indolent biology but show a tendency to recur locally even years after primary resection. Dedifferentiated liposarcomas are characterized by a very high local recurrence risk, while the metastatic risk mainly depends on the histological characteristics of the dedifferentiated component. In leiomyosarcomas, hematogenous spread informs prognosis while local recurrences are far less common. Surgery is the cornerstone of treatment of all retroperitoneal sarcoma subtypes and its quality is the only treatment-related factor able to improve the oncological outcome. A frontline extended surgical approach is all the more critical in subtypes in which local control directly impacts prognosis.

Keywords:

• leiomyosarcoma
• liposarcoma
• outcome
• prognosis
• retroperitoneal sarcoma
• sarcoma
• solitary fibrous tumor
• surgery
• surgical margins

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• Retroperitoneal sarcomas (RPS) are rare. Four well-defined histotypes account for 80% of RPS patients: well-differentiated liposarcomas, dedifferentiated liposarcomas (DDLPS), leiomyosarcomas and solitary fibrous tumors. Each histotype shows specific biological characteristics, natural history and clinical behavior. Moreover, among the same histotype, the subdivision by tumor grade may identify subgroups with specific features.

• Studies from extremity soft tissue sarcomas have shown that margin status is a crucial determinant of the local recurrence (LR) risk and that surgical planning should be designed according to the tumor’s inherent biological aggressiveness, site and relationship with anatomical barriers.

• The only potentially curative treatment of RPS is macroscopically complete surgical resection at the first operation, avoiding tumor rupture. Most of the time, this implies the need for multivisceral resection. The kidney and colon are the most often resected organs.

• RPS lie in a highly complex space adjacent to vital organs. Anatomical constraints lead to a resection that is marginal by definition. Despite this, complete clearance of the ipsilateral retroperitoneal fat by conducting dissection beyond the anatomical barriers is possible through the use of a frontline extended surgical approach. This extended surgical policy has proven to be associated with a better LR rate and better overall survival in low-to-intermediate grade tumors in retrospective series.

• Well-differentiated liposarcomas are characterized by a favorable LR rate and overall survival compared to other histological subtypes. The distant metastasis potential is negligible. Since the outcome after LR is poor, every attempt should be made to maximize local control during primary surgery.

• G2 DDLPS show a strong tendency to recur locally with a relatively low metastatic potential. They are supposed to benefit most from a frontline extended surgical approach.

• G3 DDLPS and G3 leiomyosarcomas are characterized by a strong tendency to develop systemic metastasis. In these histotypes, the hematogenous spread of the disease informs prognosis. New effective drugs are greatly needed.

• Classic solitary fibrous tumors fare well after surgery and a more conservative surgical approach should be considered on an individualized basis.

Notes