Most episodes of HPV infection and many CIN1 and CIN2 cases are transient and will not develop into CIN3 or cancer.28 (link)–30 (link) The potential harms associated with detecting these transient lesions include the anxiety associated with a “positive” cancer screening test, potential stigmatization from the diagnosis of a sexually transmitted infection, discomfort from additional diagnostic and treatment procedures, bleeding from treatment, and, longer term, an increased risk of pregnancy complications such as preterm delivery due to treatment31 (link). Having a positive test at any point in one’s life may contribute to a perception of an increased risk of cancer, and a subsequent desire for more testing, further increasing the likelihood of another positive test.32 (link) Although any false positive test has the potential for inducing anxiety or other psychological distress, quality-of-life instruments are rarely included in controlled clinical trials of screening. Because of this, we used the number of colposcopies, both alone and relative to CIN3+ and cancer detected, as the primary measure of harm, since colposcopies themselves are associated with physical discomfort, and are a necessary pre-requisite to more invasive treatments with greater short- and long-term risks of harms. Since the number of subjects undergoing colposcopy is usually reported in controlled studies, and more screening leads to more screen positives and therefore more colposcopy, it provides a surrogate for potential harm of screening analogous to the use of the detection of CIN3 as a surrogate for cervical cancer for potential benefits of screening.
Our basic tenets regarding risk and risk-based interventions were as follows:
We recognize that the women at different ages may have different tradeoffs in benefits and harms from screening. These differences are addressed through the development of age-specific screening recommendations.