The penis is the
male sex organ through which runs the urethra that is
connected to the bladder and ultimately the testicles.
The penis is made up spongy tissue that is arranged
in three columns called the corpora cavernosa and corpus
spongiosum. During arousal, the caverns are filled with
blood that causes erection. Prostate cancer treatment
can cause the closure of small veins that contribute
to erectile process. The result may be the inability
to have erections satisfactory for sexual penetration.
Some prostate cancer treatments such as the prostatectomy
or radiation therapy may cause shrinkage of the penis
either by shortening the urethra or arteriosclerosis.
Drugs such as the oral sildenafil or penile suppositories
and injections or the vacuum erection device may increase
the flow of blood into the penis.