Rapid Eradication of Extensive Spinal Metastases in a Prostate-Cancer Patient Taking Androgen-deprivation Therapy, Chemotherapy, and Oral Recombinant Methioninase on a Low-Methionine Diet.

BACKGROUND/AIM: Bone metastasis of prostate cancer is a recalcitrant disease treated by androgen-deprivation therapy (ADT), chemotherapy, and radiation. We have previously shown that methionine restriction with oral recombinant methioninase (o-rMETase) alone or in combination with chemotherapeutic agents was apparently effective for prostate-cancer patients, including a patient with extensive bone metastases. In the present study, we described a patient with spinal metastases of prostate cancer treated with ADT, chemotherapy with docetaxel, and methionine restriction with o-rMETase and a low-methionine diet.

CASE REPORT: The present report is on a 62-year-old male prostate-cancer patient with a history of prostatectomy who was subsequently diagnosed by prostate specific membrane antigen (PSMA)-PET imaging to have extensive spinal metastases. The patient then received combination therapy with ADT (relugolix and darolutamide), docetaxel chemotherapy, o-rMETase (twice a day 250 units, 5 mg), and a low-methionine diet. Six months later, a second PSMA-PET demonstrated marked regression of metastases, with only residual uptake in the cervical spine. At nine months, [11C]methionine-PET confirmed complete disappearance of the residual lesion, and no distant metastases were detected. The present findings suggest remission of spinal metastases from prostate cancer.

CONCLUSION

The patient achieved an apparent complete response of prostate-cancer spinal metastases after treatment with ADT, chemotherapy, and methionine restriction. Further studies, including controlled clinical trials are necessary to validate this new paradigm of treatment for prostate-cancer bone metastases.