Erectile dysfunction develops in greater than 80% of patients treated for prostate cancer. External beam radiation has the same risk for erectile dysfunction as radical prostatectomy.

This study confirms that newer, more complex tools perform similarly to the simpler ADAM questionnaire. The lack of correlation between the clinical picture and the most commonly used biochemical confirmatory tests, again, clearly points to the paramount importance of the clinical evaluation. An emphasis and reliance on serum T alone hinders the clinician's ability to manage testosterone deficiency syndromes (TDS).

Previous studies of the relationship of gonadal function to impotence in men with diabetes mellitus have yielded conflicting results. Pituitary-testicular function was studied in 28 impotent diabetic men and 15 normal men. Impotence was documented by clinical history and subdivided into categories of primary organic (n = 16), primary psychogenic (n = 7), and unclassified (n = 5) on the basis of nocturnal penile tumescence (NPT) testing, psychological testing, and penile vascular studies. All NPT parameters were diminished (P less than or equal to 0.001) in the impotent diabetic men compared to values in the normal men. Endocrine studies revealed increased urinary LH (P less than or equal to 0.05) and diminished serum free testosterone levels in the diabetic men with primary organic impotence. These changes were not found in normal men or diabetic men with primary psychogenic impotence. Six months of treatment in a home blood glucose-monitoring program resulted in significant improvement in metabolic control but no improvement in pituitary-testicular function, NPT, or sexual performance in the primary organic impotent group. Eight patients with primary organic impotence and no evidence of penile vascular disease had significant improvement (P less than or equal to 0.01) in NPT results as well as subjective improvement in sexual function after 6 months of parenteral testosterone administration. These studies suggest that primary gonadal dysfunction may be related to organic impotence in diabetes, and improvement in selected patients can occur with androgen therapy.

The ability of the MMPI to discriminate between primary psychogenic impotence and primary organic impotence in males with diabetes mellitus was assessed. In order to provide the MMPI with the optimal situation to discriminate between the two groups, we attempted to form a homogeneous sample in terms of physical conditions. Thirty impotent diabetic males were classified as primary organic or primary psychogenic based on nocturnal penile tumescence data. Beutler et al.'s MMPI decision rules yielded a 63% misclassification of the two groups. Possible explanations for the lack of discriminative power of the MMPI with this sample of diabetic males were discussed in relation to previous findings. The power of nocturnal penile tumescence to classify men as having primary organic or primary psychogenic impotence was examined with reference to other vascular and endocrine variables.