Methadone, which has unique mechanism of long-acting mu receptor agonism paired with N-Methyl-D-Aspartate（NMDA）antagonism, is thought to have potential to control pain no longer responsive to other opioids. Fatal adverse effects of methadone are respiratory suppression and QT interval prolongation, which leads to ventricular tachycardia. Here we report a case of a patient who benefited from starting on methadone in hospital and increasing methadone safely in a home-based care setting. A 79-year-old Japanese woman, who developed local recurrence after resection for primary retroperitoneal leiomyosarcoma, presented with frequent burning pain in right groin area. After receiving palliative radiation therapy, she took oxycodone and adjuvant analgesics but without relief, and began experiencing somnolence. She underwent opioid switching from oxycodone to methadone with her breakthrough pain remarkably improved. When her breakthrough pain recurred after discharge, escalating dosages of methadone was performed successfully with no serious adverse effects even in a home-based care setting, by forming multidisciplinary collaboration for the management of prescribing methadone among healthcare providers near her home.