Hot flushes is a cotmnon phenomenon in women during the menopausal transition. In men treated with castration because of prostate cancer, hot flushes are probably the most cotmnon and distressing side-effect and are as common in these men as in menopausal women but the course of the flushes is unknown. Flushes also occur in healthy aging men, but the prevalence is unknown. The mechanisms behind hot flushes are not fully understood. They are probably caused by instability in the thermoregulatory centre due to a decrease in sex hotmone concentrations. Calcitonin Gene-Related Peptide (CGRP) and perhaps also Neuropeptide Y (NPY) are probably involved in menopausal hot flushes in women and could also be involved in men following therapeutic castration.
The aims of this thesis were to compare different methods of castration as regards the occunence and course of hot flushes, and to investigate the prevalence of hot flushes in an unselected population of elderly men. A further aim was to see if CGRP and NPY are involved in hot flushes in men, in the same way as has previously been suggested in women.
In this thesis two different modalities of castration therapy were compared: 1. castration by means of estrogens (Polyestradiol phosphate) and 2. total androgen blockade (a. bilateral orchiectomy or b. GnRH-analogue combined with oral anti-androgen). A much lower incidence of hot flushes were seen in the first group (1). Flushes induced by castration with estrogen were also milder and tended to disappear with time.
The prevalence of hot flushes in a male population 55 years of age and above was investigated by means of a questionnaire. Thirty per cent of the men repotted flushes and half of these found the flushes distressing, i.e. every sixth man in the study. There was an association between flushes and a number of symptoms that are often related to low testosterone concentrations in the blood.
The 24-hour urinaty excretion of CGRP was investigated in 17 men with prostate cancer before and after castration. Thirteen of the 17 men developed hot flushes after castration, but the urinary excretion of CGRP was not significantly altered.
Blood-samples were taken during hot flushes in 10 men for analysis of CGRP- and NPY-plasma concentrations. CGRP increased in 6 men (we failed to obtain CGRP measurements in the other men due to technical problems). NPY concentrations were below the detection limit for the analysis in all samples.
In conclusion vasomotor symptoms are common in men subjected to castration therapy. Different castration modalities result in different prevalence of hot flushes, something that should be considered when choosing the method of castration for men with prostate cancer. Hot flushes also occur in normal, aging men. The mechanisms behind hot flushes in men and women may be similar. CGRP may be involved in hot flushes in castrated men.
In order to be able to develop new treatment regimens for these vasomotor symptoms fmther studies on the mechanisms behind hot flushes should be undertaken, in both castrated and in otherwise healthy elderly men.
Linköping: Linköpings universitet , 2002. , 78 p.