Endocrine Abstracts

Background: Prostate cancer is the most commonly diagnosed male malignancy. Androgen Deprivation Therapy (ADT) with GnRH agonist is commonly used intreating localized prostate cancer. Side effect of ADT is a loss of bone density resulting inosteopenia or osteoporosis. Research concerningpossible molecular and cellular mechanisms of ADT-induced bone changes are still incomplete. Matrix Gla Protein (MGP) is a vitamin-K-dependent protein which is synthesized in a variety of tissues, including bone tissue. MGP overexpression seems to promote the osteoblast proliferation but its function in ADT-induced osteoporosis is unknown.

Objectives: Aim of the study is to analyze the bone and metabolic changes in men treated with ADT for localized prostate cancer.

Methods: This is a prospective, pilot study of two groups of 10 men with localized prostate cancer. The studygroup received ADT while the control group was clinically observed or treated with radiotherapy. We performed dual-energy X-ray densitometry and blood sampling (hormone, metabolic profile, and bone metabolism parameters) in each patient. In addition, we measured the MGP level. The 1stmeasurement was undertaken at the time of the diagnosis, while the 2nd measurement was done 3 months later.

Results: At baseline, no differences were found in all analyzed parameters between the two groups (densitometry, blood count, sedimentation rate, glucose, creatinine, calcium, phosphorous, PTH, alkaline phosphatase, vitamin D, total testosterone, SHBG, lipide profile, P1NP, CTX, MGP). In the follow-up, we only observedstatistically significant change in the total testosterone level between the study and the control group (0.31 nmol/l vs. 17.99 nmol/l, P < 0.05). We found no statistically significant difference in the level of MGP between the study and the control group in the follow-up period (648.5 pmol/l vs. 801.2 pmol/l, P = 0.24).

Conclusions: Most of the analyzed hormone, metabolic, and bone parameters in these two groups did not significantly change over 3 months, except for the level of total testosterone which is due to expectedADT effect. However, we find this period too short to result in a significant bone and metabolicchanges. Longer observation of these patients is mandatory to come to the final conclusion.