Their finding is drawn from patients in the previously reported Canadian MRC CR07/NCIC CTG C016 trial. In that study, men and women with operable rectal cancer had a three-year local recurrence rate of 4.4% if they had short-course preoperative radiotherapy, compared to 10.6% if they had surgery first.
A secondary aim of the trial was to examine disease-related symptoms and adverse effects of treatment, to try to balance the advantages against any negative impact on quality of life.
In a June 28 online report in the Journal of Clinical Oncology, Lindsay C. Thompson of the Medical Research Council in London, U.K., and colleagues note that 1,208 patients in the trial (89% of the total cohort) completed the Medical Outcomes Study Short-Form 36-item (MOS SF-36) and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal 38-item (EORTC QLQ-CR38) questionnaires.
There was a significant increase in male sexual dysfunction following surgery (p < 0.001) no matter the treatment arm. Starting at six months, however, men who had preoperative radiation therapy reported significantly greater dysfunction (p = 0.004), with the difference maintained for at least two years.
Very few women completed the sexual dysfunction questions, and so the researchers could not draw any firm conclusions about sexual dysfunction for that gender.
Patients in both treatment arms had similar decreases in physical function at three months. After that point, physical function returned to baseline in both groups. Treatment assignment seemed to have no major effect on general health or bowel function, but in an exploratory analysis more pre-op radiation patients had fecal incontinence at two years (53.2% versus 37.3%; p = 0.007).
The researchers hope their findings will help clinicians balance the benefits of preoperative radiation with its "detrimental toxicity" in their discussions with patients. They emphasize that preoperative radiation yielded fewer recurrences and that any modification of treatment shouldn't risk an increase.
"The challenges for the future are to further improve surgical techniques and to reliably identify low-risk patients who do not need preoperative radiotherapy," they conclude.
J Clin Oncol 2010.
Last Updated: 2010-07-22 13:01:09 -0400 (Reuters Health)
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