In Indonesia, the challenge of osteosarcoma progression is further worsened by patients' dependence on traditional massage therapy, low socio-economy, and educational status. This study aims to analyze the differences in the characteristics, laboratory findings, surgery techniques, degree of histopathological necrosis, and metastasis between osteosarcoma patients with and without prior massage manipulation therapy. This research is an analytical observational study with a prospective and retrospective cohort design. Patients were treated and followed for one year to evaluate the occurrence of metastasis. Prospective data was collected through interviews, and secondary data was collected from the patient's medical record. Of 84 subjects analyzed, 69% had a history of massage. There was an increase in LDH and ALP in patients with massage manipulation (p = 0.026). The median time to metastasis from baseline in the massage group (4 months) was statistically significant compared to the non-manipulation group (12 months) (p