Radiation therapy given before surgery to remove rectal cancer can reduce the risk that the cancer will return at the site of the original tumor. In some cases it can shrink tumors significantly allowing for surgery that spares the sphincter muscle closing the anus and avoiding a permanent colostomy.
However, research in the [October 2005 *Annals of Surgery*](http://www.annalsofsurgery.com/pt/re/annos/toc.00000658-200510000-00000.htm;jsessionid=DLXGyCyb1Tc8BDtrfGDR254EBG0zJn5b48F6zJPWzjOts8wwT9il!586698740!-949856144!9001!-1) found that radiotherapy results in more sexual problems in men than surgery alone.
Surgeons studied the difference between surgery alone and surgery with pre-operative radiotherapy in 201 men being treated for rectal cancer. They assessed the ability to achieve and maintain an erection, have an orgasm, and be sexually active at 7 time points, beginning before surgery and ending 4 years later.
The most severe dysfunction was found 8 months after surgery when there was a 7.4% difference in achieving an erection, 12.6% difference in maintaining one, and a 16.2% difference in having orgasm between the radiotherapy and surgery only groups. In addition, men who had radiotherapy were 13.7% less likely to be sexually active. Recovery of sexual functioning after the 8 month point was slow, but never returned completely.
The effect increased with age.
The researchers were able to build and validate a model to help patients and doctors predict how much radiotherapy might effect the sexuality of an individual man.
The research and the predictive model were reported in the *Annals of Surgery* (240-4:502-511, October 2005). The lead author was Alexander G. Heriot. The team concluded:
Conclusions: Radiotherapy has an adverse effect on sexual function, the effect being maximal at 8 months after surgery. The risk of sexual dysfunction can be quantified preoperatively using the proposed index and can assist patients in making better informed choices on the type of treatment they receive.
In [a Dutch study in the March 20, 2005 edition of the *Journal of Clinical Oncology*](http://www.jco.org/cgi/content/abstract/23/25/6199), 900 men and women, who were part of a randomized trial surgery alone or surgery and radiotherapy, also showed poorer sexual functioning in males. Females also had sexual problems after pre-surgical radiotherapy.
In addition, radiation-treated patients recovered normal bowel movements more slowly and were less active 3 months after surgery than those who had surgery alone.
However, the patients reported no significant differences in health-related quality of life on questionnaires answered before treatment and at 3, 6, 12, 18, and 23 months after treatment.
Since there is a way of predicting the risk of sexual problems after radiation treatment for rectal cancer developed by Dr. Heriot’s team, patients should be encouraged to discuss risks and benefits of radiation prior to surgery.
[Read the abstract of the Heriot study in the *Annals of Surgery*.](http://www.annalsofsurgery.com/pt/re/annos/abstract.00000658-200510000-00005.htm;jsessionid=DLXGyCyb1Tc8BDtrfGDR254EBG0zJn5b48F6zJPWzjOts8wwT9il!586698740!-949856144!9001!-1)
[Read the Marijnen study abstract in the *Journal of Clinical Oncology.*](http://www.jco.org/cgi/content/abstract/23/9/1847)