RecruitingProspective Study Evaluating the Treatment Outcomes for Localised Recurrent, Resectable Retroperitoneal LiposarcomaThe aim of the study is to collect prospective data on the treatment outcomes in patients with first localized, resectable recurrent retroperitoneal well-differentiated and/or dedifferentiated liposarcoma undergoing curative intent treatment. Patients enrolled in this study will form a validation cohort of the TARPSWG recurrent RPS nomogram. The treatment decision (surgery alone, or preoperative RT +/- chemotherapy followed by surgery) is per the institutional multidisciplinary team recommendation.