For patients with solitary prostate cancer metastases, an approach called metastasis-directed therapy (MDT), a targeted treatment that uses surgery or radiation therapy, without androgen deprivation therapy (ADT) English), may delay time to cancer progression, reports study in The Journal of Urology®a Official Journal of the American Urological Association (AUA). The magazine is published in The Lippincott Portfolio by Wolters Kluwer.
Metastasis-directed therapy has been a controversial approach to the management of solitary metastatic recurrences of prostate cancer. Our study is the first to show the benefits of both surgical MDT and radiotherapy without ADT in this group of patients, which could delay the need for systemic treatment.”
Jack R. Andrews, MD, lead author, Mayo Clinic Arizona, Phoenix
MDT as a possible alternative target area for cancer spread
Metastasis-directed therapy has emerged as a possible alternative for men with “oligo-recurrent” prostate cancer, a disease state with a limited number of metastatic lesions after initial treatment. In the MDT approach, surgery or radiation therapy (stereotactic body radiation therapy, or SBRT) is used to specifically target the area of cancer spread.
That’s in contrast to ADT, systemic therapy to block testosterone and other male sex hormones, which promote prostate cancer growth. Androgen deprivation therapy with or without other systemic therapy is the standard treatment for metastatic prostate cancer, but it has numerous adverse effects that can decrease quality of life, including sexual dysfunction, bone thinning, and weight loss. muscle strength, among others. If MDT is effective in controlling limited recurrences, it may prevent or delay the need for ADT.
Dr. Andrews and colleagues evaluated their center’s experience with MDT, without ADT, in 124 patients with oligorecurrent prostate cancer between 2008 and 2018. Treatment consisted of surgery in 67 patients, most with lymph node metastases; and radiation in 57 patients, most with bone metastases. In both groups, the mean follow-up time was about four and a half years.
Promising results with MDT for oligorecurrent prostate cancer
Both forms of MDT were effective in terms of biochemical recurrence, reflected by the reduction in the level of prostate-specific antigen (PSA). After surgery, the PSA level decreased by approximately half in 80.5% of patients after MDT. Most patients eventually required ADT or other systemic therapy for progressive cancer, median time 18.5 months. However, at three years of follow-up, 29% of patients were alive and free of cancer progression.
In the radiation therapy group, 40.3% of patients had a halved reduction in PSA level. The median time to systemic therapy was 17%, while the three-year progression-free survival was 17%. The researchers emphasize that their study was not designed to compare the results of surgery and radiation, since the two types of MDT were used in patients with different types of cancer metastases (lymph node versus bone).
“The role of MDT in prostate cancer remains highly controversial, with insufficient evidence to make recommendations in current guidelines,” write Dr. Andrews and coauthors. They point to some key limitations of their study, including selection bias related to the fact that patients who opted for MDT were likely part of a “healthier, more robust” group seeking a more aggressive treatment option.
“These results suggest that MDT without ADT may delay the initiation of systemic therapy” in men with oligorecurrent prostate cancer, Dr. Andrews and colleagues conclude. They call for further studies to determine which patients with solitary metastases may benefit most from MDT.
Andrew, Jr. et al. (2022). Metastasis-directed therapy without androgen deprivation therapy in solitary oligorecurrent prostate cancer. Journal of Urology. doi.org/10.1097/JU.0000000000002898.