Testing the Combination of Belinostat and SGI-110 (Guadecitabine) or ASTX727 for the Treatment of Unresectable and Metastatic Conventional Chondrosarcoma

Inclusion Criteria: * Patients must have biopsy-proven conventional chondrosarcoma (CS) which is: * Either metastatic or locally advanced and unresectable, and * Measurable at study entry according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria, and * Amenable to biopsy with imaging guidance at no or acceptable risk to the patient as defined by institutional guidelines for research-related biopsies or the treating investigator's assessment * In addition, the following criteria must be met: * Patients must have at least one lesion measurable by RECIST version 1.1 criteria which has not been previously irradiated * Patients who have histologic evidence of grade 1 chondrosarcoma only must either be symptomatic from their disease in the opinion of the treating investigator or demonstrate radiographic evidence of disease progression in the 3 months prior to initiation of study treatment * Note: Pathology review and confirmation of diagnosis will occur at the site enrolling the patient on this study * Patients may have been treated with any number of prior systemic therapies. Because there are no Food and Drug Administration (FDA)-approved treatments for this disease, patients who have received no prior systemic therapy are also eligible. However, disease must be deemed surgically unresectable * Age \>= 18 years. Chondrosarcoma is rarely encountered in children and adolescents * Eastern Cooperative Oncology Group (ECOG) performanc…