Metastasis-directed
treatment has emerged as a potential alternative for men with
“oligorecurrent” prostate
cancer – a state of disease with a limited number of metastatic lesions
after initial treatment. In the MDT approach, surgery or radiation therapy
(steretotactic 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 the growth of prostate cancer. Androgen deprivation therapy with or
without other systemic therapy is the standard treatment for metastatic
prostate cancer, but has numerous adverse effects that can decrease quality of
life – including sexual dysfunction, bone thinning, and loss of muscle
strength, among others. If MDT is effective in controlling limited recurrences,
it may avoid or delay the need for ADT.

For patients with solitary
metastases from prostate cancer, an approach called metastasis-directed therapy
(MDT) – focused treatment using surgery or radiation therapy, without androgen
deprivation therapy (ADT) – can slow the time to cancer progression, reports a
study in The Journal of Urology®, an Official Journal of the American
Urological Association (AUA). The journal is published in the Lippincott
portfolio by Wolters Kluwer.

“Metastasis-directed
therapy has been a controversial approach to management of solitary metastatic
recurrences of prostate cancer,” comments lead author Jack R. Andrews, MD,
of Mayo Clinic Arizona, Phoenix. “Our study is the first to show benefits
of both surgical and radiation therapy MDT without ADT in this group of
patients, potentially delaying the need for systemic treatment.”

MDT as potential
alternative targets area of cancer spread

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 patients with bone metastases. In both groups, average 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 reduction in
prostate-specific antigen (PSA) level. After surgery, PSA level decreased by
about half in 80.5% of patients after MDT. Most patients eventually needed ADT
or other systemic therapy for progressive cancer – median time 18.5 months.
However, at three years’ follow-up, 29% of patients were alive and free from
cancer progression.

In the radiation therapy
group, 40.3% of patients had a one-half reduction in PSA level. Median time to
systemic therapy was 17%, while three-year progression-free survival was 17%.
The researchers emphasize that their study was not designed to compare the
outcomes of surgery and radiation, as the two types of MDT were used in
patients with different kinds of cancer metastases (lymph node versus bone).

“The role of MDT in
prostate cancer remains highly controversial, with insufficient evidence for
recommendations in current guidelines,” Dr. Andrews and coauthors write.
They point out some key limitations of their study – including selection bias
related to the fact that patients opting for MDT were likely a “healthier,
most robust” group seeking a more aggressive treatment option.

“These results suggest
that MDT without ADT can delay 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 can
benefit the most from MDT.

Reference:

Jack R. Andrews et al, JOURNAL, The Journal of Urology, DOI: 10.1097/JU.0000000000002898

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