Staging of advanced bladder cancer. Current concepts and pitfalls.
Data presented in the preceding paragraphs should highlight to the reader several important features of clinical bladder cancer staging. Irrespective of the staging level being addressed, the available techniques uniformly have limitations, as well as advantages and disadvantages with respect to each other. A common shortcoming of both plain and cross-sectional techniques employing conventional X-rays is their lack of specificity. Every radiographic finding has an associated differential diagnosis in which neoplasia-related change is but one of many possibilities. Solitary abnormalities on bone scan or chest film serve as an excellent examples of this dilemma. The specificity of conventional imaging techniques is further compromised by attempts to increase sensitivity. As long as nonspecific anatomic changes are used as discriminating criteria, increases in test sensitivity will always occur at the price of specificity. It is hoped that advances in PET scanning and the use of isotope-labeled, tumor-selective monoclonal antibodies will overcome the limitations of currently available techniques. The significance of the limitations of a given test depends to some degree on whether the test is being used for clinical decision making or for patient stratification in a clinical trial. As an example, an aggressive transurethral resection of bladder tumors provides excellent information for clinical management but may introduce bias into multicenter studies in which this technique is not uniformly practiced. Similarly, the results of bimanual examination under anesthesia are important in the reference framework of the managing physician but are a poor quantifier of disease extent in multi-investigator clinical trials. Which staging studies are indicated and their optimal sequence for performance are influenced by pre-existing clinical information. Recognizing this, the staging algorithm in Figure 6 is intended to serve only as a guide to assist the clinician in the evaluation of patients with bladder neoplasms. As clarifications, several points concerning this algorithm merit mention. The literature suggests that as a single study, transurethral ultrasonography provides excellent local staging information. However, given that it is not widely available, the authors have chosen not to incorporate it into the staging schema. Optimally, it would be used immediately prior to transurethral resection of bladder tumors and bimanual examination. In addition, the algorithm lists MRI interchangeably with CT. While MRI appears to have slightly better sensitivity and specificity for both local and regional tumor stage relative to CT, its benefits are to some degree offset by its greater cost and the need to image the patient in multiple planes for lengthy intervals.(ABSTRACT TRUNCATED AT 400 WORDS)
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W A
WA
Department of Urology, University of Iowa, Iowa City.
Fuller
J R
JR
D000465:Algorithms; D001706:Biopsy; D001859:Bone Neoplasms / Q000556:secondary; D003952:Diagnostic Imaging; D006801:Humans; D008113:Liver Neoplasms / Q000556:secondary; D008175:Lung Neoplasms / Q000556:secondary; D009367:Neoplasm Staging / Q000379:methods; D001743:Urinary Bladder / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*