Factors, treatments, and outcomes associated with primary soft tissue malignancies of the forearm: A series of 31 cases

Abstract

Background: Primary soft tissue malignancies of the forearm constitute up to 24% of soft tissue extremity malignancies and present a difficult problem when attempting to preserve both life and forearm function. As described by Enneking, recurrence and metastasis are the two largest contributors to morbidity and mortality and therefore, the primary consideration must be to excise the entire tumor. However, since limb salvage is the preferred treatment over amputation in 95% of cases, many physicians elect to perform marginal resections over wide resections in the attempt to increase functional outcomes. Our study aimed to compare recurrence rates and forearm functional outcomes between these groups to better guide clinical decision making.

Questions/purposes: (1) What is the difference in recurrence rates between wide resection of the tumor and marginal resection? (2) Between wide and marginal resection groups, what is the functional difference as measured by MSTS functional outcome scores? The purpose of our study was to answer these two questions and better understand if marginal resection yielded better results compared to wide resection.

Patients and methods: Following IRB approval, we conducted a retrospective case series between 1999 and 2019. Included in the study were patients with a primary malignancy in the predetermined borders of the forearm with a minimum of two-year follow up post-operatively. All patients in the study were operated on by physicians in the Southern California Kaiser Permanente system. Thirty-one patients met criteria for the study. Recurrence rates and metastatic disease was determined through serial history and physical examination, with patients undergoing magnetic resonance (MRI) imaging of the affected area and computed tomography (CT) of the chest every 6 months for the first 2 years, and every 12 months for the following 3 years. MSTS scores were obtained in subsequent follow-ups following the guidelines set by the MSTS scoring system.

Results: Of the 31 patients evaluated, 4 (12.9%) had recurrence and 2 (6.5%) had signs of metastasis. Between the marginal excision and wide excision groups, all 4 recurrences happened in the marginal excision group and none occurred in the wide excision group. In addition, in the pathology report, excisions with 0.1 cm margins or less on any side had 3 instances of recurrence (31%) whereas there was only 1 recurrence (4.8%) outside of this group. MSTS scores for both wide excision and marginal excision were within 1 point with average scores being 26 and 26.9, respectively.

Conclusions: Consistent with the literature, our study found that closer surgical margins lead to higher rates of recurrence due to the increased likelihood of aberrant tumor. However, when looking at functional outcome scores, we found minimal benefit in marginal resections compared to wide resections. The lack of MSTS score difference between both groups highlighted that the perceived benefit of choosing a marginal resection over wide excision may be nominal at best. Therefore, we recommend performing an additional intraoperative resection on narrow margins to reduce the chance of recurrence. Of note, clinical discernment in the form of preserving valuable neurovascular structures such as the median nerve should still be an important consideration.

Keywords: Distal radius; Giant cell tumor; MSTS score; Recurrence; Sarcoma.