Presentation Authors: Humberto R Vigil*, Christopher Wallis, Toronto, Canada, Joseph LaBossiere, Edmonton, Canada, Sender Herschorn, Lesley Carr, Toronto, Canada
Introduction: Stress incontinence surgery is common and was revolutionized by the midurethral sling. In the wake of regulatory warnings, unsubstantiated claims regarding mesh have permeated public discourse. Despite no supporting evidence, concerns continue to exist regarding a link between mesh and malignancy. We sought to evaluate the association between stress incontinence surgery, including transvaginal mesh, and carcinogenesis in a large population-based cohort.
Methods: A retrospective cohort of adult women who underwent stress incontinence surgery from 1994-2016 in Ontario was captured from the Institute for Clinical Evaluation Sciences database. Women were identified using physician billing codes in Ontario for the different stress incontinence procedures. The primary outcome of interest was the diagnosis of pelvic cancers. These were defined using ICD-9 and ICD-10 billing codes. Pelvic cancers included urological and gynaecological malignancies. The standardized incidence rate (SIR) was calculated as the ratio of the observed number of pelvic cancer cases divided by the age-stratified expected number of pelvic cancer cases based on the Ontario population. Subgroup analyses were performed for individual malignancies and midurethral sling patients. Multivariable logistic regression modeling examined for risk factors of pelvic malignancy.
Results: A total of 120,999 women underwent a procedure for stress incontinence in the form of urethropexy, combined abdominal/vaginal sling, bulking agent or midurethral sling in Ontario during the study period. Midurethral sling accounted for 63% of procedures performed. Median follow up was 9.3 years (IQR 5.4-14.4). Expected cancer cases over a total exposure time of 1,221,668 person-years was 1,146. 935 pelvic cancers were observed with a frequency of 0.77%. The SIR for any cancer diagnosis compared to the general population of Ontario was 0.816, 95% CI 0.764-0.870. In patients who underwent a midurethral sling only, the expected number of cancer cases over an exposure time of 562,457 person-years was 576. 479 pelvic cancers were observed with an SIR of 0.831, 95% CI 0.758-0.909. On multivariable analysis, midurethral sling was not associated with an increased risk of pelvic cancer when compared to the other stress incontinence procedures.
Conclusions: Stress incontinence surgery including the transvaginal implantation of mesh was not associated with an increased risk of pelvic malignancy in a large population-based cohort.