It’s no secret that penis size matters to men. Even though they don’t talk about it, men do pay attention to the commercials and ads for supplements, penis pumps and other items that claim they can remedy a shortened penis; and many men part with their money to find out if they will work.
The topic of penile length is really twofold. On the one hand, some men have or believe they have a short penis. Since each man’s idea of what constitutes a short penis is different, let’s set the standard by noting that the average penis length is 5 to 6 inches erect and 3.5 inches flaccid, according to WebMD. 
On the other hand, there are men who have undergone treatment for prostate cancer or Peyronie’s disease (curved or bent penis) and who then find their penis has shortened as a result of the treatment. This situation was the topic of a recent study, conducted by researchers from Dana-Farber/Brigham and Women’s Cancer Center, which involved men with prostate cancer who had been treated with radical prostatectomy or the use of hormone therapy along with radiation therapy. 
Prostate Cancer And A Shortened Penis
Basically, the study involved 948 men who were treated for prostate cancer and who experienced a recurrence of the disease. Twenty-five men (2.63 percent of the men) complained about a shortened penis after treatment and said that it affected their quality of life and their relationships and that they regretted having chosen their specific cancer treatment.
Complaints were more common among men who underwent radical prostatectomy than those who had hormone therapy plus radiation. None of the men who had radiation therapy alone said their penis had shortened.
According to Jim Hu, M.D., a surgeon at the University of California, Los Angeles Medical Center and one of the study’s co-authors, “previous studies have concluded that there is a shortened penis length following prostatectomy,” and it most often occurs in procedures in which the surgeon is unable to preserve the nerves (known as non-nerve sparing surgery).
More On Penis Shortening
How much can a man’s penis shrink after treatment for prostate cancer or Peyronie’s disease? According to one study published in the Journal of Urology, the average amount of penile shortening in a flaccid penis was .5 inch and about 1 inch when the penis was stretched. This study was conducted among men who had undergone radical prostatectomy. 
Peyronie’s disease is an inflammatory condition in which scar tissue in the penis can result in a painful, curved penis and/or erectile dysfunction. Surgical procedures to correct Peyronie’s disease also can result in a loss of penile length. Therefore, surgery that involves shortening the side of the penis opposite the scar tissue is usually reserved for men who have a long penis or those who have little or no erectile dysfunction.
Men who are considering treatment for prostate cancer that involves prostatectomy or hormone therapy and radiation therapy, or who are thinking about surgery for Peyronie’s disease, should ask their doctor about the possibility of penis shortening. Penis shortening is one side effect many doctors fail to discuss with their patients.
For more information on men’s health, see prostate.net.
 Reduced penile size and treatment regret in men with recurrent prostate cancer after surgery, radiotherapy plus androgen deprivation or radiotherapy alone. http://www.goldjournal.net/article/S0090-4295(12)01152-1/abstract
 American Urological Association. Peyronie’s disease. http://www.urologyhealth.org/urology/index.cfm?article=115