Sampling Modality: Influence on Predicting Outcome in Adult Soft Tissue Sarcomas of the Extremities
Hatim Khoja, Brendan C Dickson, Jay S Wunder, Peter C Ferguson, Anthony Griffin, Jesse Babwah, David Howarth, Rita A Kandel. Mount Sinai Hospital, Toronto, ON, Canada
Background: At present, histologic grade is one of the best predictors of outcome in adult soft tissue sarcomas. Core needle biopsies (CNB) have become increasingly popular in the diagnosis and management of these tumours. The objective of this study was to determine if grading of CNB could predict patient outcome.
Design: Seventy-six core biopsies and 65 open biopsies (OB) of spindle cell sarcomas of the extremities were retrieved retrospectively from the archives of our institution. All patients had at least 3 years follow-up. No patient had pre-operative radiation, metastases at the time of presentation, or a diagnosis of liposarcoma of any type. Patient age; tumor type, size, and depth were recorded. All tumours were reviewed histologically and graded using the FNCLCC system and correlated with outcome.
Results: The mean patient age and average tumour size (>5cm) were similar in both groups. However more tumours (50%) were superficial in the OB than the CNB (20%). The range of diagnoses was similar; although more cases of sarcoma NOS were present in the CNB group. The percentages of grades 1, 2 and 3 tumours were similar in both CNB and OB groups. Grade as determined on CNB was not predictive of disease free (Chi2= 0.747, p=0.688) or overall survival (Chi2=0.749, p=0.688) by Kaplan Meier analysis. In contrast OB were predictive of disease free survival (Chi2=8.98, p=0.011) and showed a trend to predicting overall survival (Chi2=5.37, p=0.068). Interestingly in contrast to OB, grade 3 tumours diagnosed on CNB were not predictive of outcome.
Conclusions: The data suggest that OB is recommended if grading is to be used as a prognostic factor in spindle cell soft tissue sarcomas of the extremities. CNB are likely inadequate for predicting prognosis because of the limited sampling that prevents accurate grading of grade 1 and 2 tumours. It is not clear why tumours classified as grade 3 on CNB have limited ability to predict prognosis. It is possible that our sample number is too small for accurate prediction although this is considered less likely as there was a similar percentage of grade 3 tumours in the OB and the CNB groups. This requires further investigation.
Category: Bone & Soft Tissue
Monday, March 19, 2012 1:00 PM
Poster Session II # 19, Monday Afternoon