{'fraction_non_alphanumeric': 0.025474525474525476, 'fraction_numerical': 0.008491508491508492, 'mean_word_length': 4.979104477611941, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Ovarian cancer screening.

BACKGROUND
Despite advances in evaluation and treatment, ovarian cancer mortality has decreased minimally during the past two decades. Most patients have advanced-stage disease at diagnosis, and the prognosis is poor. As a result, there has been increasing interest in the development of methods for the early detection of ovarian cancer. To benefit from screening, a disease should (1) be a significant cause of mortality, (2) have a high prevalence in the screened population, (3) have a preclinical phase that can be detected by screening, and (4) be amenable to therapy, such that the survival rate of patients with early-stage disease is significantly higher than that of patients with advanced-stage disease. Ovarian cancer fulfils all of these criteria.


METHODS
An optimal screening method should be safe, easy to do, time efficient, and acceptable to the patients being screened. Most importantly, it should have a high sensitivity and specificity.


RESULTS
Currently, the most effective screening methods for ovarian cancer are serum CA 125 levels and transvaginal sonography (TVS). In screening studies, the serum CA 125 level has had a reasonably high specificity but a low sensitivity. Currently, approximately 8000 asymptomatic women have been screened with TVS. Ten primary ovarian cancers were detected, and all were Stage I lesions. Patients whose tumors were detected by TVS all have been cured by conventional treatment. TVS screening has resulted in a significant reduction in stage at detection and in the case-specific death rate from ovarian cancer. In these studies, TVS has had a high sensitivity but only a moderate specificity. CA 125 level, Doppler flow sonography, and the use of a morphology index are being evaluated as methods to increase the specificity of TVS.


CONCLUSIONS
A large multiinstitutional study is indicated to determine if annual TVS screening will cause a significant decrease in site-specific mortality from ovarian cancer.