Distinguishing Between Well-Differentiated and Dedifferentiated Retroperitoneal Liposarcomas in the Preoperative Setting: A Work in Progress in the Era of Precision Medicine

Abstract

This issue of Annals of Surgical Oncology includes a retrospective study evaluating the predictive value of preoperative biopsy for patients affected by retroperitoneal liposarcoma. This study aimed to investigate the contribution of preoperative histologic diagnosis to multimodal treatment planning. The authors hypothesized that neoadjuvant treatment may be underused for patients affected by dedifferentiated (DD) liposarcoma due to the lack of preoperative biopsy accuracy. They accordingly reviewed 256 patients affected by well-differentiated (WD) liposarcoma and DD liposarcoma of the retroperitoneum who underwent surgery at the MD Anderson Cancer Center during a 20-year span. Of the patients in this series, 120 (46.8 %) had undergone preoperative biopsy and were retrospectively analyzed. Compared with the final pathologic diagnosis, the preoperative biopsy was able to identify WD liposarcoma with 85 % accuracy, which was significantly higher than the accuracy for identifying DD liposarcoma (37 %). The authors claim that these different accuracy rates lead to significant undertreatment of DD liposarcoma. The report by Ikoma et al. also gives an interesting insight into the multimodal treatment strategy for retroperitoneal soft tissue sarcomas and the appropriateness of adjuvant treatment. To date, standard treatment for primary retroperitoneal sarcoma is surgery with complete en bloc tumor resection. Whether this should be different for the two liposarcoma entities still is debated. Some authors advocate an extended systematic approach for both, whereas others, including the authors of the current report, are in favor of a more conservative resection for WD liposarcoma. In this perspective, correct preoperative diagnosis is essential for making the proper decision because the two entities cannot be distinguished intraoperatively. The role of neoadjuvant treatment still is debated because, to date, no randomized trials of preoperative treatment for retroperitoneal sarcoma have been concluded and reported. The National Comprehensive Cancer Network (NCCN) guidelines offer the option of preoperative radiation therapy, chemotherapy, or both based on lowerlevel evidence without a uniform consensus. The European Society for Medical Oncology (ESMO) guidelines, on the other hand, consider adjuvant/neoadjuvant chemotherapy as an individualized (or investigational) indication and preoperative radiation therapy as only investigational for retroperitoneal sarcomas. One randomized trial currently is recruiting patients in Europe and North America. It explores the impact of preoperative radiation therapy in primary retroperitoneal sarcoma and includes both WD and DD liposarcomas (EORTC-62092-22092, STRASS, NCT01344018). Outside of the investigational setting, therefore, the use of neoadjuvant therapies must be decided by a multidisciplinary sarcoma board in the context of high-risk disease or a locally advanced (and/or nearly unresectable) presentation. The main prognostic factors to be considered in decision making for local recurrence and distant metastasis of retroperitoneal sarcomas are histology subtype and tumor grade. Dedifferentiated liposarcomas are known to exist in at least two variants: intermediate and high grade. The former has a predominant risk of local recurrence, whereas the latter carries a risk reaching 40 % for distant metastasis. For this reason, patients affected by high-grade DD retroperitoneal liposarcoma may be considered for neoadjuvant Society of Surgical Oncology 2014