Adjacent, Adherent, Invaded: A Spectrum of Biologic Aggressiveness Rather Than a Rationale for Selecting Organ Resection in Surgery of Primary Retroperitoneal Sarcomas

Abstract

Complete surgical resection of retroperitoneal sarcoma (RPS) remains the only potential curative treatment. The surgical strategy to achieve this optimal and most appropriate resection for each patient still creates some contention and controversy. Most contentious in this debate is the approach to the organs and structures neighboring a retroperitoneal sarcoma, with surgical strategy covering a spectrum from a conservative approach of organ-preserving and simple excision of the tumor alone to resection of the tumor and contiguous organs only when evidence of direct involvement exists to liberal multivisceral compartmental or extended resection of contiguous organs even if uninvolved. In the future, as more information is collected in a standardized and prospective fashion from specialist sarcoma units, this debate should evolve to define the most appropriate and personalized strategy, including extent of surgery, for each patient based on all available patient and prognostic factors.In this issue of Annals of Surgical Oncology, the group from Dana-Farber/Brigham and Women's Cancer Centre 1 report their experience of selective organ resection for primary retroperitoneal sarcomas, with the objective not to define the appropriate approach to surgical resection, but rather to examine the rate and rationale for organ resection and the rate of histopathologic organ infiltration (HOI) according to histologic subtype. In this elegant retrospective study, Fairweather et al. propose a six-tier system for classifying the rationale for organ resection.The rationale for organ resection was determined by reviewing the historic description of the procedure from the operative report. In this study, HOI is defined as infiltration of organ parenchyma or vessel wall by tumor cells. Organs that appeared to be inseparable from tumor were considered adherent. In 99 patients, at least one organ was resected, and the rationales for organ resection most often reported were tumor adherence, organ encasement, involved end-organ vasculature, and suspected invasion or tumor origin.This study has some limitations. First, the retrospective nature of the study makes it difficult to obtain a clear and accurate rationale from historic operative reports of organ resection. A patient selection bias existed regarding organ resection (e.g., influenced by age and comorbidities of the patient, surgical aggressiveness of the surgeon) and the degree of intraoperative subjectivity when a decision was made regarding the presence of a visible dissection plane or whether organs were adjacent or adherent to tumor. The study also does not include preoperative radiologic analysis, which should also contribute to the surgeon's decisionmaking process around the necessity for organ resection.The study lacked a standard for specimen processing, margin sampling, and characterization and definition of organ invasion. Consequently, the definition of HOI was not inclusive of tumors adherent to organs, which perhaps involved perivisceral/capsular invasion but not nece...

A systematic review of margin status in retroperitoneal liposarcomas: Does the R0 margin matter?

“…From our analysis, there were hardly any extractable data from the cohort studies concerning survival and LR data stratified by RPLPS subtypes (WDLPS/DDLPS), although the case series and reports suggest that the R0 margin benefits LR in WDLPS patients (R0, 24%; R1, 33%) but offers no additional benefit in DDLPS patients (R0, 40%; R1, 40%). At the same time, while a more aggressive multivisceral resection would increase the chance of attaining R0 margins ( 77 , 78 ), the final margin status attained potentially also depends on underlying tumor biology because more dedifferentiated RPLPS tends to be more locally invasive ( 6 ) and hence has a higher inherent tendency to invade the tumor capsule to increase the chance of margins being positive on final histopathology. It is therefore possible that despite a multivisceral resection, the margin status may end up as R1.…”

“…While adopted by most of Europe and the Trans-Atlantic group (TARPSWG) ( 5 ), differing opinions continue to exist regarding the utility of such an aggressive surgical approach in the management of retroperitoneal sarcomas (RPS). Few would argue for the preservation of involved or encased organs; as such, the debate lies mainly in the en bloc removal of adherent or adjacent organs in which the suspicion of histological invasion is low ( 6 , 7 ).…”

Who, how and what of pathology of soft tissue sarcoma

“…Once the diagnosis of sarcoma have been made, resectable locoregional disease may or may not undergo neoadjuvant therapy (11,22); in both cases resection specimen will arrive to the grossing room. For the pathologist or the pathologist's assistant, it is useful to examine the specimen together with the surgeon, that can highlight critical margins and re-build the in vivo configuration of the specimen (27). Standard gross description parameters are applied: specimen should be measured in three dimensions, as well as the closest distance of each margin from the edge of the tumor.…”

“…The pathologic report will basically differ for primary tumor, recurrence or relapse, and metastasis [grading in the last two should not be performed since it have not been proven useful, and can be confusing (11)], however the main difference in reporting is case of neoadjuvant therapies: histopathologic report for untreated primary tumor should include the histotype, the size, the mitotic rate, percentage of necrosis, FNCLCC grading, involved viscera or structures, distance from the nearest margins and the margin status. Margin positivity in trunk and extremities is often defined as presence of neoplastic cells ≤1 mm from the inked surface (29); margin status in retroperitoneal sarcoma is also relevant (30)(31)(32)(33), however a major limitation when reviewing the literature is that specialist sarcoma centers have different surgical approach and a lack of a common specimen processing, margin sampling, and characterization and definition of organ invasion (27). In contrast, reporting of post-treatment primary tumor should not include the grading, whereas should include assessment of tumor response (11,28).…”

Prognostic implications of histological organ involvement in retroperitoneal sarcoma

“…Mussi and colleagues 5 described two such patterns. The first is ‘pushing’, where an organ is embedded in a tumour without being invaded; this has also been referred to as ‘adherent’ in the literature 6 . The second is ‘infiltrative’, where clear evidence is noted of direct tumour infiltration into an organ 5 .…”