Extended Surgery for Retroperitoneal Sarcoma: The Key to Maximizing the Potential for Cure and Survival

Surgery is the mainstay of treatment for localized soft-tissue sarcoma (STS). It consists primarily of resection of the tumor along with a cuff of surrounding healthy tissue. In limb and trunk wall sarcomas, this basically implies resection of the surrounding soft tissues, which are mainly muscles, subcutaneous fat, and skin.[1] In the retroperitoneum, this necessarily should imply resection of adjacent viscera, even when they are not overtly involved.[2] This is the only way to avoid/minimize the presence of tumor cells at the cut surface (ie, positive microscopic surgical margins). Positive microscopic surgical margins are associated with a higher risk of local failure, distant metastases, and death.[3-6] Moreover, for STS located at critical sites, such as retroperitoneal sarcoma (RPS), positive surgical margins may have a direct impact on survival, favoring the development of inoperable local recurrences.[7] Indeed, unlike with STS arising in the extremities and trunk wall, local control in RPS poses a significant challenge and remains the leading cause of death, particularly in patients with low- to intermediate-grade tumors-roughly 75% of all cases.[8-13] Extending the resection to adjacent uninvolved viscera for primary RPS is the only way to minimize the presence of microscopic surgical margins and hence maximize the chance of cure. In essence, this strategy should often include ipsilateral nephrectomy and colectomy; locoregional peritonectomy and myomectomy (partial/total) of the muscle of the lateral/posterior abdominal wall (usually the psoas) (see Figure); splenectomy and left pancreatectomy, for tumors located on the left upper side; occasionally pancreaticoduodenectomy or hepatectomy, for tumors located on the right side; and vascular and bone resection only if vessels/bone are overtly infiltrated.[2]

Retrospective comparisons of series collected through prospectively maintained databases have shown in the past years how this approach in primary RPS translates to far better local control (roughly 80% vs 50% at 5 years)[14,15] and significantly better overall survival (roughly 70% vs 50% at 5 years).[16] Data on short- to medium-term morbidity have been provided, showing how, if conducted in tertiary centers by a team dedicated to this disease, these operations are safe, even when several surrounding organs are resected en bloc with the tumor.[17]

FIGURE

Right-Side Well-Differentiated Liposarcoma

In line with these results, microscopic infiltration of surrounding macroscopically uninvolved resected organs has been reported to be greater than 50%.[18] Similarly, when extended resections were proposed as re-excisions after a primary simple resection (with a postoperative CT scan apparently negative), the rate of residual tumor was shown to be as high as 80%.[15]

Although a formal comparison between simple excision and extended resection for primary RPS never has been attempted and never will be, taken together the data described above clearly favor extended resection as the reference standard approach to management of primary RPS. On the other hand, when a local recurrence has developed, there is no evidence to pursue such an approach.

That said, RPS is not a single disease.[19] There are at least four major well-characterized histological subtypes of RPS: well-differentiated liposarcoma (see Figure), dedifferentiated liposarcoma, leiomyosarcoma, and solitary fibrous tumor. These have different natural histories and patterns of failures which should be factored into the decision-making process when planning the approach. Well-differentiated liposarcoma only recurs locally; leiomyosarcoma predominantly metastasizes hematogenously; dedifferentiated liposarcoma can either recur locally or metastasize; solitary fibrous tumor seldom recurs locally or metastasizes. Extended surgery is important for all RPS subtypes, but other complementary strategies are sorely needed to improve long-term results (especially for patients with dedifferentiated liposarcoma and leiomyosarcoma). Finally, well-differentiated liposarcoma at times is multifocal/bilateral. This multifocal/bilateral presentation currently cannot be anticipated and therefore cannot be considered an argument against the extended approach which benefits patients with all other forms of RPS.

At this time, complete surgical clearance of RPS at the first operation remains the best therapy. Every attempt should be made to refer such patients to tertiary centers with the needed surgical oncology expertise, and where the disparate biological behaviors of the various histological subtypes can be accommodated in the overall therapeutic approach.

Financial Disclosure:The author has no significant financial interest or other relationship with the manufacturers of any products or providers of any service mentioned in this article.

References:

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