Retroperitoneal Surgical Resection Requires Multipronged Decision Making in Sarcoma

Retroperitoneal surgery for patients with sarcoma requires nuanced decision making that incorporates technical aspects of resection, as well as patient-related and tumor-related factors, according to a presentation given during the 2021 ESMO Congress.¹

Moreover, understanding the potential short- and long-term outcomes of retroperitoneal surgical resection in individual patients is critical before moving forward with surgery. Weighing these factors can inform whether resection, palliative surgery, or strategic delay is optimal.

“Resectability is not only a technical issue,” wrote presenter Dario Callegaro, MD, of Fondazione IRCCS Istituto Nazionale dei Tumori, in Milan, Italy. “If something is not resectable only because of a technical issue, ask for help. Sarcoma surgeons do not fly solo.”

Before considering patient- and tumor-related characteristics, guidelines regarding the resectability of sarcoma tumors should be consulted to determine whether a patient’s tumor is resectable, borderline resectable, or unresectable.

For example, guidelines from the pancreatic cancer space could be extrapolated to sarcoma in terms of defining borderline resectable disease.

In pancreatic ductal adenocarcinoma (PDAC), borderline resectability is determined at diagnosis by anatomical, biological, and conditional criteria.² In cases of borderline resectable PDAC, patients should be offered systemic chemotherapy as induction treatment, followed by chemoradiation in select cases.

The ongoing phase 3 STRASS2 trial (NCT04031677) is evaluating the role of surgery with or without neoadjuvant chemotherapy in patients with high-risk retroperitoneal sarcoma, including liposarcoma and leiomyosarcoma.³

The STRASS2 criteria for non-resectability are:

1. Involvement of the superior mesenteric artery, aorta, coeliac trunk and/or portal vein
2. Involvement of bone
3. Growth into the spinal canal
4. Progression of retrohepatic inferior vena cava leiomyosarcoma toward the right atrium
5. Infiltration of multiple major organs, such as the liver, pancreas, and/or major vessels

Patient-Based Factors

Preoperative risk assessments should be completed in all patients to predict short-term outcomes with retroperitoneal surgical resection. Notably, these assessments should incorporate the morbidity and mortality, age, body composition, frailty status, comorbidities, nutritional status, and psychological well-being of each patient.

“New instruments to better predict short-term outcomes are needed,” Callegaro wrote. “Multicenter prospective databases will be key.”

Tumor-Based Factors

Whether a patient presents with a primary or recurrent tumor should be taken into consideration when determining whether retroperitoneal surgical resection is optimal.

For example, findings from a multi-institutional Collaborative RPS Working Group study suggested that tumor size, histologic subtype, malignancy grade, multifocality, and completeness of resection were significant predictors of long-term outcomes in patients with retroperitoneal sarcoma.⁴

The median overall survival was 116 months in patients with primary tumors, 33 months in patients with locally recurrent tumors, 25 months in patients with distant metastatic tumors, and 12 months in patients with locally recurrent and distant metastatic tumors.^4,5

“Strategic delay is a useful option to select the proper treatment strategy in the recurrent setting in select patients,” Callegaro wrote.

Additionally, prognostic models, such as the Sarculator, for predicting long-term outcomes in the primary and recurrent settings are utilized.

Notably, in patients where it is known that retroperitoneal surgical resection would be incomplete, surgery may still have a role as palliative treatment.

In select patients with unresectable retroperitoneal liposarcoma, incomplete surgical resection was found to provide prolongation in survival with successful symptom palliation.6 Of 32 patients with preoperative symptoms, such as abdominal, flank, or pelvic pain, lower extremity pain, and dyspnea, 75% (n = 24) experienced successful symptom palliation with incomplete resection. Additionally, locally recurrent presentation vs primary disease was found to be associated with a negative prognosis (P = .009).

As such, young patients without relevant comorbidities, slow-growing disease, a long disease-free interval, symptoms related to mass effect, and no distant metastases, and for whom no other therapeutic potions are available could be considered candidates for palliative resection.

“Planned incomplete resection of a [retroperitoneal sarcoma] is exceptionally rare, but in very selected patients might be associated with improved survival and symptom palliation,” Callegaro concluded.

References

1. Callegaro D. Decision making in retroperitoneal sarcoma surgery: resectability, strategic delay and palliation. Presented at: 2021 ESMO Congress; September 16-21, 2021; virtual. Session: retroperitoneal sarcoma.
2. Perri G, Prakash L, Katz MHG. Defining and treating borderline resectable pancreatic cancer. Curr Treat Options Oncol. 2020;21(9):71. doi:10.1007/s11864-020-00769-1
3. Surgery without neoadjuvant chemotherapy in high risk retroperitoneal sarcoma (STRASS2). Clinicaltrials.gov. Updated July 20, 2021. Accessed October 4, 2021. https://clinicaltrials.gov/ct2/show/NCT04031677
4. Gronchi A, Strauss DC, Miceli R, et al. Variability in patterns of recurrence after resection of primary retroperitoneal sarcoma (RPS): a report on 1007 patients from the Multi-Institutional Collaborative RPS Working Group. Ann Surg. 2016;263(5):1002-1009. doi:10.1097/SLA.0000000000001447.
5. McNeill AJ, Miceli R, Strauss DC, et al. Post-relapse outcomes after primary extended resection of retroperitoneal sarcoma: a report from the Trans-Atlantic RPS Working Group. Cancer. 2017;123(11):1971-1978. doi:10.1002/cncr.30572
6. Shibata D, Lewis JJ, Leung DH, et al. Is there a role for incomplete resection in the management of retroperitoneal liposarcomas? J Am Coll Surg. 2001;193(4):373-379. doi:10.1016/s1072-7515(01)01024-9