Sarcopenia, or loss of muscle mass, is one of the best documented adverse effects of long term use of ADT. Sarcopenia can be assessed with various imaging techniques that can measure the size of a muscle.
This new study used MRI to measure the volume of a muscle that is rarely studied by muscle physiologists, but is crucial for many bodily functions. That muscle is the levator ani, which forms the pelvic floor. In this longitudinal study, the authors document loss of volume of the levator ani based on MRI measurements from 34 men who were on ADT versus 29 age-match control patients who were not on ADT. The measurements were taken before men started ADT, as well as at 6 and 12 months after ADT.
The authors speculate that sarcopenia in the levator ani may in some way contribute to problems in sexual function or urinary control. Although this is true, we suspect there may be far more interesting and significant clinical implications to garner from their findings.
Several researchers have previously found that ADT use increases the risk of respiratory infections (e.g., pneumonia) in prostate cancer patients (Hicks et al., 2017; Schmid et al., 2016). What prevents most of us from getting pneumonia more often than we do is our ability to cough, to clear infectious microbiota from our lungs. To cough forcefully, we rapidly compress our abdominal cavity while opening our airway. That compression is accomplished by a strong, rapid and abrupt contraction of our body wall muscles and the muscle of our pelvic floor. A weaker levator ani would potentially lead to a weaker cough, and compromised coughing may subsequently put patients at risk of pneumonia. Thus, the finding of ADT-induced sarcopenia in the levator ani may have far more clinical relevance than the authors discuss in their paper.
To read the study abstract, please see:
Cheung AS, Cunningham C, Ko DD, Ly V, Gray H, Hoermann R, Strauss BJG, Hassan EB, Duque G, Ebeling P, Pandy MG, Zajac JD, Grossmann M. (2018). Selective loss of levator ani and leg muscle volumes in men undergoing androgen deprivation therapy. J Clin Endocrinol Metab. [Epub ahead of print]. doi: 10.1210/jc.2018-01954.