Polypropylene mesh: evidence for lack of carcinogenicity

Squamous-cell carcinoma due to mesh infection after umbilical hernia operation: third case of the literature

INTRODUCTION

Polypropylene (PP) meshes are safe synthetic products used for hernia repairs and associated with minimal complication. Chronic inflammation is thought to play a pathophysiological role in the development of cancer.Case presentation: We present a 67-year-old female case of squamous cell-cancer (SCC) that developed due to mesh after umbilical hernia operation. The mass in the anterior abdominal wall was totally resected. Pathology was reported as T2N0, moderately differentiated acantholytic type SCC. No recurrence or complication was detected in the fourth-month follow-up.

CONCLUSION

Cancer development after mesh is very rare and our case is the third case in the literature. Cancer development should be kept in mind in patients presenting with ulcerated masses if do not regress with infection treatment after mesh application.

Bladder cancer invasion along a tension-free vaginal mesh

INTRODUCTION

The effect of synthetic mesh after pelvic organ prolapse surgery on the progression of bladder cancer remains unclear.

CASE PRESENTATION

A 79-year-old woman who underwent a tension-free vaginal mesh procedure 8 years prior was diagnosed with carcinoma in situ of the bladder. Although intravesical Bacillus Calmette-Guérin therapy was started, the tumor rapidly became muscle invasive. Laparoscopic radical cystectomy was performed following radiochemotherapy; however, the tumor extended to the left internal obturator muscle along the mesh arm. Pathological findings showed desmoplastic high-grade urothelial carcinoma infiltrating around the mesh. Finally, cancer recurred rapidly in the left internal obturator muscle.

CONCLUSION

Synthetic mesh can become an abnormal anatomical pathway for tumor infiltration. Therefore, in high-risk bladder cancer patients who underwent a tension-free vaginal mesh procedure, radical cystectomy should be performed without delay before the tumor invades the perivesical tissue.

Cancer Risk After Midurethral Sling Surgery Using Polypropylene Mesh

OBJECTIVE

To assess whether there is any association between the implantation of synthetic polypropylene mesh slings for the treatment of stress urinary incontinence (SUI) and risk of cancer.

METHODS

We performed a nationwide cohort study based on the general female population in Sweden. All women entered the observational period as unexposed on January 1, 1997, and contributed person-time as unexposed unless they underwent a midurethral sling procedure for SUI, after which they contributed person-time as exposed until first occurrence of any cancer, death, emigration, or end of the observational period (December 31, 2009). Occurrence of primary cancer was ascertained from the Cancer Register. Hazard ratios (HRs) with 95% CIs were calculated by Cox proportional hazards regression.

RESULTS

The final study population included 5,385,186 women, including 20,905 exposed, encompassing a total of 44,012,936 person-years at risk. Other than an inverse association with rectal cancer (HR 0.5, 95% CI 0.3-0.8), there were no significant differences in risk between exposed and unexposed women for pelvic organ cancers including ovarian (HR 0.8, 95% CI 0.5-1.2), endometrial (HR 1.1, 95% CI 0.8-1.4), cervical (HR 0.4, 95% CI 0.2-1.0), bladder, and urethra (HR 0.7, 95% CI 0.4-1.2). No significant association was observed between exposed women and primary cancer in any organ system when compared with unexposed women. The relative risk for cancer after exposure showed little variation over time except for an inverse overall correlation within the first 4 years of surgery (HR 0.7, 95% CI 0.7-0.8). The incidence rates per 100,000 person-years (95% CIs) for exposed vs unexposed women were 20.5 (14.3-29.5) vs 21.0 (20.6-21.5) for rectal cancer, 25.5 (18.4-35.3) vs 19.8 (19.4-20.2) for ovarian cancer, 65.0 (53.0-79.8) vs 33.1 (32.6-33.7) for endometrial cancer, 5.7 (2.8-11.3) vs 11.9 (11.6-12.2) for cervical cancer, and 19.1 (13.1-27.8) vs 13.3 (13.0-13.7) for bladder and urethra cancer.

CONCLUSION

Our results suggest that midurethral polypropylene sling surgery for SUI is not associated with an increased cancer risk later in life.

Hernia and Cancer: The Points Where the Roads Intersect

Introduction: This review aimed to present common points, intersections, and potential interactions or mutual effects for hernia and cancer. Besides direct relationships, indirect connections, and possible involvements were searched. Materials and Methods: A literature search of PubMed database was performed in July 2018 as well as a search of relevant journals and reference lists. The total number of screened articles was 1,422. Some articles were found in multiple different searches. A last PubMed search was performed during manuscript writing in December 2018 to update the knowledge. Eventually 427 articles with full text were evaluated, and 264 included, in this review. Results: There is no real evidence for a possible common etiology for abdominal wall hernias and any cancer type. The two different diseases had been found to have some common points in the studies on genes, integrins, and biomarkers, however, to date no meaningful relationship has been identified between these points. There is also some, albeit rather conflicting, evidence for inguinal hernia being a possible risk factor for testicular cancer. Neoadjuvant or adjuvant therapeutic modalities like chemotherapy and radiotherapy may cause postoperative herniation with their adverse effects on tissue repair. Certain specific substances like bevacizumab may cause more serious complications and interfere with hernia repair. There are only two articles in PubMed directly related to the topic of "hernia and cancer." In one of these the authors claimed that there was no association between cancer development and hernia repair with mesh. The other article reported two cases of squamous-cell carcinoma developed secondary to longstanding mesh infections. Conclusion: As expected, the relationship between abdominal wall hernias and cancer is weak. Hernia repair with mesh does not cause cancer, there is only one case report on cancer development following a longstanding prosthetic material infections. However, there are some intersection points between these two disease groups which are worthy of research in the future.

Safety and efficacy of non-absorbable mesh in contemporary gynaecological surgery

Mesh-augmented pelvic floor surgery evolved to address the limitations of native tissue repair in reconstructive surgery. The development of the synthetic mid-urethral tape signalled a revolution in the treatment of stress urinary incontinence, whilst the use of mesh in abdominal apical prolapse repair may confer benefits over native tissue alternatives. However, these procedures can be associated with mesh-specific complications, underlining the need for shared decision-making between physicians and patients prior to mesh surgery.

Transvaginal non-absorbable mesh implants for pelvic organ prolapse are associated with a high risk of serious adverse events, leading to withdrawal or restricted use in many countries. Increased scrutiny has led to growing concerns about complications associated with all types of mesh-augmented reconstructive surgery, attracting widespread media attention.

National and international reports have been commissioned examining the safety and efficacy of mesh surgery in gynaecology. They have all highlighted systemic failures in the development, regulation and clinical adoption of medical devices. The widespread application of novel devices prior to the availability of reliable safety and efficacy data, and delayed recognition of adverse events, is of serious concern. Notwithstanding, the available data continue to support a role for mesh augmentation. This review outlines the evolution of gynaecological mesh, the safety and efficacy of pelvic floor surgery using non-absorbable mesh materials, and an overview of specific complications.

Outcomes after laparoscopic removal of retropubic midurethral slings for chronic pain

INTRODUCTION AND HYPOTHESIS

Midurethral slings (MUS) are an established treatment for stress urinary incontinence (SUI), with good objective outcomes and low rates of complications. However, large population-based registry studies highlighted long-term complications from polypropylene slings including erosion, dyspareunia and chronic pain. With recent highly negative media coverage, many women are presenting with chronic pain attributed to the mesh to request complete removal. The available literature provides limited evidence on safety, symptom resolution and incontinence following MUS removal.

METHODS

We identified all patients who underwent laparoscopic removal of MUS mesh at our hospital between 2011 and 2016. We extracted data from medical records to assess operative safety and contacted all patients by questionnaire that incorporated pain scales, symptom severity and satisfaction.

RESULTS

A total of 56 women were assessed. Removal occurred at a median of 44 months following sling insertion (range 3-192). Mean operative time was 74 min (range 44-132). Two patients were returned to theatre (one at 24 hours and one at 14 days) to evacuate a retropubic haematoma, but no visceral injuries occurred. The median inpatient stay was 2 days (range 1-7). Of the 46% of patients who returned the questionnaire (n = 26), 88% said they would recommend the procedure. There was a median 6-point decrease in pain scores (10-point numerical scale, p < 0.0001); 44.6% reported worsening SUI, more common with removal of the suburethral mesh [odds ratio (OR) 10.72 95% confidence interval (CI) 1.10-104].

CONCLUSIONS

Laparoscopic removal of MUS is feasible and effective but carries a risk of worsening SUI.

Challenging the Myth: Transvaginal Mesh is Not Associated with Carcinogenesis

PURPOSE

We sought to determine if there was a potential link between synthetic polypropylene mesh implantation for transvaginal pelvic organ prolapse and stress urinary incontinence, and carcinogenesis using statewide administrative data.

MATERIALS AND METHODS

Women who underwent transvaginal surgery for pelvic organ prolapse or stress urinary incontinence with mesh between January 2008 and December 2009 in New York State were identified using ICD-9-CM procedure codes and CPT-4 codes. Patients in the mesh cohort were individually matched to 2 control cohorts based on comorbidities and procedure date. Carcinogenesis was determined before and after matching at 1, 2 and 3 years, and during the entire followup time.

RESULTS

A total of 2,229 patients who underwent mesh based pelvic organ prolapse surgery and 10,401 who underwent sling surgery for stress urinary incontinence between January 2008 and December 2009 were included in the study. Mean followup was 6 years (range 5 to 7). Exact matching between the mesh and control cohorts resulted in 1,870 pairs for pelvic organ prolapse mesh and cholecystectomy (1:2), 1,278 pairs for pelvic organ prolapse mesh and hysterectomy (1:1), 7,986 pairs for sling and cholecystectomy (1:1) and 3,810 pairs for sling and hysterectomy (1:1). Transvaginal mesh implantation was not associated with an increased risk of a cancer diagnosis (pelvic/local cancers or any cancer) at 1 year and during the entire followup of up to 7 years.

CONCLUSIONS

Transvaginal surgery with implantation of mesh was not associated with the development of malignancy at a mean followup of 6 years.

Carcinogenic potential of polypropylene mid-urethral slings: what do we know so far?

INTRODUCTION AND HYPOTHESIS

Polypropylene (PP) mesh has come under increased scrutiny owing to previous FDA safety communications regarding the risks of mesh in trans-vaginal surgery and ensuing class action litigation for post-operative complications. Additional concerns have been raised regarding a possible link between implanted PP mesh and the long-term development of malignancy. Until recently, no research was specifically committed to the exploration of such a link. Our objective was to provide an overview of the recent literature focusing on any association between the use of PP mesh for midurethral sling procedures and the development of malignancy.

METHODS

Multiple online research databases were searched for information related to any possible carcinogenic potential of PP mesh.

RESULTS

There was no increased incidence in the development of malignancy after midurethral sling procedures using PP mesh in any of the studies.

CONCLUSION

Given the scarcity of evidence suggesting otherwise, the likelihood of PP mesh causing malignancy is exceptionally low. However, with few studies and an unknown latency period between exposure and diagnosis, more observational data would prove useful to exclude causality.

In vivo response to polypropylene following implantation in animal models: a review of biocompatibility

INTRODUCTION AND HYPOTHESIS

Polypropylene is a material that is commonly used to treat pelvic floor conditions such as pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Owing to the nature of complications experienced by some patients implanted with either incontinence or prolapse meshes, the biocompatibility of polypropylene has recently been questioned. This literature review considers the in vivo response to polypropylene following implantation in animal models. The specific areas explored in this review are material selection, impact of anatomical location, and the structure, weight and size of polypropylene mesh types.

METHODS

All relevant abstracts from original articles investigating the host response of mesh in vivo were reviewed. Papers were obtained and categorised into various mesh material types: polypropylene, polypropylene composites, and other synthetic and biologically derived mesh.

RESULTS

Polypropylene mesh fared well in comparison with other material types in terms of host response. It was found that a lightweight, large-pore mesh is the most appropriate structure.

CONCLUSION

The evidence reviewed shows that polypropylene evokes a less inflammatory or similar host response when compared with other materials used in mesh devices.

Polymeric Biomaterials for Medical Implants and Devices

In this review article, we focus on the various types of materials used in biomedical implantable devices, including the polymeric materials used as substrates and for the packaging of such devices. Polymeric materials are used because of the ease of fabrication, flexibility, and their biocompatible nature as well as their wide range of mechanical, electrical, chemical, and thermal behaviors when combined with different materials as composites. Biocompatible and biostable polymers are extensively used to package implanted devices, with the main criteria that include gas permeability and water permeability of the packaging polymer to protect the electronic circuit of the device from moisture and ions inside the human body. Polymeric materials must also have considerable tensile strength and should be able to contain the device over the envisioned lifetime of the implant. For substrates, structural properties and, at times, electrical properties would be of greater concern. Section 1 gives an introduction of some medical devices and implants along with the material requirements and properties needed. Different synthetic polymeric materials such as polyvinylidene fluoride, polyethylene, polypropylene, polydimethylsiloxane, parylene, polyamide, polytetrafluoroethylene, poly(methyl methacrylate), polyimide, and polyurethane have been examined, and liquid crystalline polymers and nanocomposites have been evaluated as biomaterials that are suitable for biomedical packaging (section 2). A summary and glimpse of the future trend in this area has also been given (section 3). Materials and information used in this manuscript are adapted from papers published between 2010 and 2015 representing the most updated information available on each material.