These study results “provide insight into the natural history of [retroperitoneal sarcoma] beyond the first and second surgeries for [local recurrences].”
A study published in Cancer found that long-term survival in a select population of patients with retroperitoneal sarcoma (RPS) is possible following surgical resection of the second local recurrence.
Contrastingly, the study also found that patients who develop combined distant metastases and local recurrence have a poor prognosis.
“The results of the current study provide insight into the natural history of RPS beyond the first and second surgeries for [local recurrences],” the authors wrote.
In this study from the Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG), researchers assessed longitudinal outcomes from patients with a second recurrence of RPS following complete resection of a first local recurrence. Data was collected from patients who underwent resection of a first local recurrence from January 2002 to December 2011 at 22 sarcoma centers.
The primary end point for the study was overall survival (OS) after second recurrence.
Of 567 patients identified for the study, second recurrences occurred in 400 patients (70.5%) after an R0/R1 resection of a first locally recurrent RPS. Moreover, patterns of disease recurrence were local recurrence in 323 patients (80.75%), distant metastases in 55 patients (13.75%), and both local recurrence and distant metastases in 22 patients (5.5%). Notably, the main subtype observed among the local recurrence group was liposarcoma (77%), whereas distant metastases predominantly were leiomyosarcomas (43.6%). Among patients with a second local recurrence only, 200 patients (61.9%) underwent re-resection.
The 5-year OS rate varied significantly based on the pattern of failure (P < .001), with an OS rate of 45.6% observed for the local recurrence group, 25.5% for the distant metastases group, and 0% for the group with local recurrence and distant metastases. Further, on multivariable analysis, the only factors found to be correlated with an improvement in OS were both time between second surgery and the development of the second recurrence (32 months vs 8 months; HR, 0.44; P < .001) as well as surgery for second recurrence (yes vs no; HR, 3.25; P < .001). In patients not deemed suitable for surgical resection, the 5-year OS rate for patients undergoing surgery for a second local recurrence was 59% versus 18%.
“This difference in survival most likely is due to the relatively more favorable tumor biology and clinical parameters of the patients who survived the first recurrence and went on to develop a second recurrence,” the authors wrote. “Furthermore, patient comorbidities and tumor-related factors that were integral to patients being selected for the first surgery clearly were interrelated in decision making for the management of their second recurrence.”
Importantly, this study was limited by its retrospective nature combined with the selection bias associated with this type of study. However, the researchers suggested that, given the rarity of RPS, outcomes from participating centers provide a better appreciation of outcomes in this sort of rare patient population that are translatable to the global sarcoma community, which tend to be more challenging with single-institution cohorts.
Moving forward, the investigators indicated that the newly established, prospective REtroperitoneal SArcoma Registry (RESAR) database should address these biases and allow for more objective data to be produced to further understand the biology, treatment, and outcome of patients with RPS.
“Future studies using the new prospective RESAR database potentially will answer further questions regarding decision making and the role of multimodality therapy, and illuminate prognostic factors for long-term survival,” the authors concluded.
van Houdt WJ, Fiore M, Barretta F, et al. Patterns of Recurrence and Survival Probability After Second Recurrence of Retroperitoneal Sarcoma: A Study From TARPSWG. Cancer. doi: 10.1002/cncr.33139