The overall incidence of uterine cancer is decreasing because of the steady decreasing trend in the incidence of cancer of the cervix uteri, which accounts for the majority of uterine cancer. However, the incidence of cancer of the corpus uteri has been increasing during this period. Some explanations include the difficulty of ensuring uniformity in surgical practice, the lack of funding by the pharmaceutical industry, and the absence, until recently, of a surgically oriented cooperative clinical trials group. A unique feature of surgical trials is the intrinsic variability in surgical treatment due to human factors. The comparability of trial arms with different surgery will not be fully ensured.
Money is another problem in randomized trials involving surgery.
Trials of systemic treatment are pushed by industry with large financial support, whereas surgical trials are usually not supported by industry. One of these is a study to answer the question whether sentinel node biopsy in breast cancer is as effective as the more extensive standard axillary node dissection. Other important questions to be answered include the significance of secondary debulking surgery in stage III ovarian cancer patients with residual tumors larger than 1 cm, brachytherapy versus radical prostatectomy for prostate cancer and radical nephrectomy versus more limited surgery for renal cell cancer. The surgical factor is an underestimated variable in many solid tumor treatments. Even for the clinical trials testing adjuvant treatment, differences in the degree of local controls achieved through surgery may obscure the effect of systemic treatment.