(P 214) EXPERIENCE OF MANAGEMENT FOR LOCALIZED PARATESTICULAR LIPOSARCOMA: A SINGLE INSTITUTION COHORT

Objective: Paratesticular liposarcoma is a rare soft tissue malignancy. The mainstay of treatment for these tumors is wide local excision to achieve negative margin status. Studies have suggested radiation therapy (RT) may improve local control, yet recurrence and overall survival benefit remains to be defined. The aim of this study was to update our prior experience including evaluation of patient characteristics, review of our institution’s approach to these patients, and analyze oncologic outcomes to elucidate optimal treatment management.

Methods: We identified all patients with liposarcoma of the spermatic cord, inguinal canal, and paratesticular regions treated at our sarcoma multi-disciplinary center between January 1, 1995 and December 31, 2020. Patient and tumor characteristics, treatment management, and oncologic outcomes were analyzed.

Results: 60 patients with localized disease were identified. Median follow up time was 48.5 months (interquartile range, 16.6-77.9 months). Median presenting age was 66.5 years old. 70% of patients (n=42) presented with a mass near the testicle, 17% (n=10) in the inguinal canal, and 13% (n=8) within the spermatic cord. Concern for malignancy on initial presentation was found in only 47% (n=28) of patients, 27% of patients had a presumed inguinal hernia (n=16), 18% unknown mass (n=11), 7% scrotal swelling (n=4), or 2% hydrocele (n=1). 32 patients (53%) underwent an initial surgery, including hernia repair, scrotal explorations, hydrocele evacuation, and excisional biopsy, excluding formal oncologic resection. 55 patients (92%) underwent oncologic curative intent surgery, defined as primary resection. Primary resection at our institution included orchiectomy, hemi-scrotal resection, and wide local excision. Median tumor size was 9.1cm (range 1.4-27.0cm). 37% (n=22) of patients had a well differentiated, 60% (n=36) dedifferentiated, 2% (n=1) pleomorphic, and 2% (n=1) myxoid liposarcoma. 20 patients (36%) achieved negative margins after primary resection. 6 patients received additional surgery after primary resection for positive margins. 16 patients received RT, 53% received preoperative and 47% postoperative RT in relation to primary resection. 25 patients (42%) patients developed either local (n=21) or distant (n=4) recurrence after primary resection. Median time to recurrence was 23.9 months (range 2.4-177.5 months). Of patients with recurrence, 28% received RT. 5-year recurrence free survival was 78% (95% CI 65.5-91.3) for well differentiated compared to 56% for dedifferentiated (95% CI 20.9-72.9) (p=0.22). There was no significant difference in 5-year overall survival for well differentiated (93%, 95% CI 61.3-99.1) versus dedifferentiated paratesticular liposarcoma (84%, 95% CI 61.7-93.6).

Conclusion: This study presents one of the largest single-institutional retrospective patient cohorts of paratesticular liposarcoma to date. Most cases were diagnosed incidentally. Given the complex anatomic location, negative microscopic margin with radical surgery remains challenging. Initial recurrence is more often local than distant. Radiation was used in a minority of cases, though the impact on overall disease control is not well defined. Even for patients with poorly differentiated liposarcoma, the overall survival at 5 years was 84%. A delineated strategy is needed to improve local disease control.

CTOS paratesticular liposarcoma Figure 1.pdf

CTOS paratesicular liposarcoma Table 1.pdf