Adjuvant radiotherapy for extremity and trunk wall atypical lipomatous tumor/well-differentiated LPS (ALT/WD-LPS): a French Sarcoma Group (GSF-GETO) study.

ABSTRACT

BACKGROUND: The role of adjuvant radiotherapy (RT) in the management of atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WD-LPS) remains controversial. METHODS: Two hundred eighty-three patients with operable ALT/WD-LPS, no history of previous cancer, chemotherapy (CT) or RT, treated between 1984 and 2011 registered in the Conticabase database were included and described. Overall (OS), progression-free survival (PFS) and time to local relapse (TTLR) were evaluated from the time of first treatment. RESULTS: Three of 20 centers enrolled 58% of the patients. Median age at diagnosis was 61 (range 25-94) years, 147 patients (52%) were males, 222 (78%) patients had their primary tumor located in an extremity while 36 (13%) and 25 (9%) had tumors involving the girdle and the trunk wall, respectively. The median size of primary tumors was 17 cm (range 2-48 cm). Adjuvant RT was given to 132 patients (47%). Patients who received adjuvant RT had larger tumors (P = 0.005), involving more often the distal limbs (P < 0.001). Use of adjuvant RT varied across centers and along the study period. Other characteristics were balanced between the two groups. Median follow-up was 61.7 months. None of the patients developed metastasis during follow-up. The 5-year local relapse-free survival rates were 98.3% versus 80.3% with and without adjuvant RT, respectively (P < 0.001). Once stratified on time period (before/after 2003), adjuvant RT, tumor site and margin status (R0 versus other) were independently associated with TTLR. No OS difference was observed (P = 0.105). CONCLUSION: In this study, adjuvant RT following resection of ALT/WD-LPS was associated with a reduction of LR risk.