Patterns of disease relapse in primary extremity soft tissue sarcoma
Session type: Oral
Theme: Diagnosis and therapy
Extremity soft tissue sarcomas comprise a range of distinct histological subtypes. This study aimed to characterise the patterns of disease relapse in patients undergoing resection of primary extremity soft tissue sarcoma.
All patients undergoing resection of primary extremity soft tissue sarcoma at the Royal Marsden Hospital between January 2004 and January 2014 were identified from an institutional database.
In the period examined, 556 patients underwent resection. The median age was 63 years with a M:F ratio of 1.3. The most common histological subtypes were undifferentiated pleomorphic sarcoma (169 patients, 30.4 per cent), well-differentiated liposarcoma (63 patients, 11.3 per cent), myxoid liposarcoma (62 patients, 11.2 per cent), myxofibrosarcoma (54 patients, 9.7 per cent) and leiomyosarcoma (39 patients, 7.0 per cent). The median maximum tumour diameter was 9 cm, with the majority of tumours being of intermediate or high grade (65.1%). The most common site was the thigh, accounting for 50.4% of cases.
Local recurrence free survival (LRFS) did not differ significantly between histological subtypes (p=0.222). Distant metastases free survival and disease specific survival did differ significantly between subtypes (DMFS, p<0.001; DSS p<0.001), with the worst outcomes seen in undifferentiated pleomorphic sarcoma 56% (95 % CI 52.5 to 61.1) and 60.1% (95% CI 55.6 to 64.6), respectively. However, on multivariable analysis, histological subtype was not found to be independently prognostic of LRFS, DMFS or DSS. Metastatic disease developed in 149 patients with the most common site of first metastasis being the lungs (120 patients, 80.5 per cent). The site of first metastasis differed between subtypes with extrapulmonary metastases predominant in myxoid liposarcoma (11 of 13 patients, 84.6 per cent, p<0.001).
Although histological subtype was not found to be an independent prognostic factor for oncological outcomes, the site of first metastasis differs significantly between subtypes.