US for postmenopausal bleeding: consensus development and patient-centered outcomes.

Abstract

Radiologists are relatively new in their involvement in evaluation of patients with postmenopausal bleeding (PMB). Most patients who present with this perplexing symptom have a benign cause, yet expenditures on costly examinations and indirect costs related to concern about endometrial cancer takes a substantial toll. Until recently, patients with PMB would undergo gynecologic testing, including endometrial biopsy, dilatation and curettage, or hysteroscopy to evaluate for the cause of bleeding. In the gynecologic literature, investigators in most studies (1) have pointed out the relative infrequency of cancer (10%) and the relative frequency of endometrial atrophy (40%–50%) as causes of PMB. More recently, radiologists and gynecologists performing transvaginal ultrasonography (US) and saline-infusion hysterosonography have discovered large numbers of polyps and leiomyomas in these patients, which suggests that the previous techniques were not able to accurately depict the exact cause of PMB (2–6). In this issue of Radiology, Medverd and Dubinsky (7) model cost minimization by using US techniques versus endometrial sampling in patients with abnormal bleeding after menopause. In choosing to study this vexing clinical problem with decision modeling techniques, the authors have raised many questions addressed by an important consensus conference held in October 2000 and sponsored by the Society of Radiologists in Ultrasound, or SRU (8). At that conference, participants used consensus-building techniques to attempt to answer some important questions about PMB. Important consensus statements were: 1. Transvaginal US is the imaging procedure of choice to evaluate patients with PMB. Transabdominal US alone is not adequate to evaluate the endometrium. 2. Transvaginal US must be performed with meticulous technique to be considered adequate for evaluation. 3. By using the meta-analytic summary of Smith-Bindman et al (9), it was determined that with an endometrial thickness of 5 mm or less, the chance of a patient having endometrial cancer is about 1%. The conferees also noted that there is no acceptable upper limit of normal for endometrial thickness for any patient, and further evaluation is warranted when there are symptoms and the endometrium is more than 5 mm thick. 4. The conferees also agreed to standard terminology for two of the important US examinations, namely, transvaginal US and saline-infusion sonohysterography. In their analysis, Medverd and Dubinsky (7) discuss the accuracy of the standard evaluative techniques for PMB. It is notable that efforts to ascertain the sensitivity and specificity of the competing technologies have been fraught with difficulties attributable to the inaccuracy of the reference standards with which the newer technologies have been compared. At the consensus conference, it was pointed out that endometrial biopsy has a high rate of inadequacy of sampling, necessitating performance of other examinations such as saline-infusion hysterosonography, hysteroscopy, or dilation and curettage. On the other hand, when separating endometrial cancer from nonmalignant causes of PMB, endometrial biopsy performs well (10). Because of a paucity of literature on the subject, the consensus conference was not able to develop consensus about the relative cost-effectiveness of US versus biopsy techniques. This analysis was left as a question to be placed on a research agenda. Medverd and Dubinsky (7) nicely point out the lower cost of US techniques with all scenarios. As they suggest, however, the analysis does not include consideration of any clinically relevant outcomes such as the number of cancers or polyps detected or the number of life-years saved, making it a cost minimization analysis only. Cost minimization analysis, as the investigators have conducted, is used to compare the net cost of interventions (broadly defined to include diagnostic testing) that achieve the same net cost, assuming that the two interventions achieve the same outcome, for example, cancer detection or additional life expectancy. Cost-effectiveness analysis incorporates the costs and outcomes (effects) of an intervention and at least one