Quality of surgical margins and local recurrence in primary extremity soft tissue sarcoma (STS).

Abstract

10068 Background: In previous studies, quality of margins after resection of primary STS of extremity was only defined by their size. Methods: We analyzed all patients (pts) with primary limbs STS addressed for surgery in our institution from 1997 to 2008 in a prospective data base. All histological specimens were reviewed and quality of margins prospectively evaluated. The minimum margin (in mm) and the type of surrounding tissue (muscle, aponevrosis, fat, periosteum) were registered on fixed specimen. The endpoints were mortality, local recurrence (LR) and distant metastasis analyzed by Cox multivariate models. Results: There were 450 pts: 50% were operated at first after pre-operative biopsy (Group A) and 50% had a second extended resection after unplanned surgery (Group B). 81% were deep. Mean tumor size was 12cm in group A and 7cm in group B (p<.0001). Grades were: 1 (21%), 2 (33%), 3 (47%). 99% had limb sparing surgery with 14% flap reconstruction. Margins (mm) were 0 in 14%, [0 – 1]: 28%, [1 – 5]: 37%, [5 – 10]: 11%, >10: 10%. Clear median minimum margin was 2mm (0.5 – 35). Tissue type varied according to width, with higher proportion of aponevrosis and periosteum below 2mm (61%) than above (29%) (p<.0001). In group B, residual tumor was found in 61% of pts. 36% of pts received chemotherapy (neo-adjuvant 88%, adjuvant 12%), 18% had neo-adjuvant isolated limb perfusion. 74% of pts received radiotherapy (post op 93%, pre op 6%) with a median dose of 50Gy (30 to 70Gy). Among pts who had neo adjuvant ILP/CT/RX, the mean% of viable cells was 36, 44 and 46 respectively. With a median follow up of 4.2 yrs, the 5-yr OS, LR and metastatic rates were 79%, 8% and 22% respectively. In the multivariate analysis, high grade (p<.0001) and large tumor size (p<.002) were the only predictive factors for shorter OS. Absence of clear margins (0mm) was significantly predictive of LR (p<.001). Conclusions: In this high risk series, a very low rate of local recurrence was observed despite a small median minimum margin. This suggests that the quality of margins should integrate the quality of the tissue involved. A planned extended surgery associated with combined treatments guarantees a very low risk of amputation or re intervention. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Novartis, Pfizer, PharmaMar Novartis, Pfizer, PharmaMar