Survival of patients with basal cell carcinoma, squamous cell carcinoma, and squamous cell carcinoma in situ: A whole population study.

BACKGROUND: Keratinocyte carcinoma (KC) is the commonest type of malignancy in humans; however, the impact of KC on survival is poorly understood. OBJECTIVES: This study characterizes the impact of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and squamous cell carcinoma in situ (SCCis) on the survival of Icelanders. METHODS: This whole population study evaluated relative survival of KC in Iceland by using a cancer registry containing records of all BCC, SCCis, and SCC cases recorded in Iceland between 1981 and 2015. RESULTS: Between 1981 and 2015, 8767 Icelanders were diagnosed with their first localized KC. A total of 6473 individuals with BCC, 1194 with SCCis, and 1100 with invasive SCC, respectively. BCC was not associated with decreased survival except for men diagnosed with BCC between 1981 and 1995 for whom decreased 10-year relative survival was observed (85.3, 95% CI [77.9-92.7]). SCC and SCCis were both associated with a decrease in relative survival for certain population subgroups such as individuals <50 years of age at time of diagnosis. CONCLUSION: Our whole population cohort survival study examining the Icelandic Cancer Registry supports prior studies demonstrating that BCC is not associated with a reduction in relative survival and that SCC and SCCis are associated with comparatively poor relative survival in certain population subgroups.

Declining invasive and rising in situ melanoma incidence trends in Iceland: A nationwide cohort study.

BACKGROUND: Melanoma is increasing worldwide, with incidence rates of invasive melanoma and melanoma in situ (MIS) varying by country. OBJECTIVE: To provide updated invasive melanoma and MIS incidence and mortality trends in Iceland and explore differences among sex and rurality. METHODS: In this whole-population study using the Icelandic Cancer Registry, patients diagnosed with invasive melanoma or MIS between 1957 and 2021 were included. Sex-specific world standardized incidence (WSR) and mortality rates were assessed by rurality. Joinpoint analysis was used to calculate trends using annual per cent change (APC). RESULTS: Invasive melanoma incidence rates increased from 0.66 to 7.0 (men) and 1.6 to 11.0 (women) per 100,000 person-years, and from 0.2 to 4.0 and 0.9 to 9.5 per 100,000 person-years for MIS in men and women, respectively, with a statistically significant linear trend (p = 0.001). WSR peaked in both men and women (10.7, 17.9 per 100,000 person-years) between 2002 and 2006 and has since been trending down. Between 1991 and 2005, the rise in invasive melanoma occurred more frequently in urban regions. Between 2003 and 2005, joinpoint analysis demonstrated a downtrend in invasive melanoma in men and women (-0.29, -0.73; p < 0.05). For MIS, the WSR peaked at 12.4 per 100,000 person-years in women between 1997 and 2001 before down-trending to 4.2. In recent years (2017-2021), the WSR has been steadily increasing in women with an APC of 1.43. Melanoma-specific mortality has decreased since 2012 (-0.07; p < 0.05). CONCLUSIONS: Declining invasive melanoma incidence and mortality rates in conjunction with the recent rise in MIS may reflect the impact of Iceland's sun safety and anti-sunbed educational campaigns, federal regulation of sunbeds and earlier melanoma detection in urban areas.

Universal tumor screening in a population with MSH6- and PMS2-associated Lynch syndrome.

PURPOSE: Universal screening for Lynch syndrome (LS) on resected colorectal carcinomas (CRCs) and endometrial carcinomas (ECs) was implemented in Iceland in 2017 using immunohistochemistry (IHC) for mismatch repair (MMR) proteins. We examined the efficacy of the universal screening algorithm to detect LS and the diagnostic accuracy of MMR IHC by comparing results with a population-based genotype database. METHODS: All patients diagnosed with CRC or EC per the Icelandic Cancer Registry from 2017 to 2019 who had tumor MMR IHC performed were included. Pathology reports and patient charts were reviewed. MMR IHC stains were crossmatched with genotyping results obtained from the deCODE database. RESULTS: IHC staining was done on 404 patients with CRC and 74 patients with EC. A total of 61 (15.1%) patients with CRC and 15 (20.3%) patients with EC were MMR-deficient. MMR IHC had 88.9% sensitivity in identifying patients with LS and a positive predictive value of 10.7%. Only 50% of individuals were appropriately referred for genetic testing, leading to underdiagnosis of LS. CONCLUSION: Universal screening for LS using MMR protein IHC in CRC and EC accurately identified patients appropriate for genetic testing in a population with MSH6 and PMS2 LS predominance. Because of lack of referral to genetic counseling, only 50% of patients with LS were identified through the screening algorithm.

[Liver surgeries in Iceland 2013-2017 - Comparison with Sweden in terms of quality registration].

INTRODUCTION: Cancers in the liver, bile duct system, gallbladder as well as metastases of the liver, have poor prognosis. Their treatment is comparable, with surgery being the most widespread, available curative treatment. Surgical treatment is anatomical or non-anatomical resection of the liver where the tumor and the adjacent liver tissue are removed. MATERIALS/METHODS: A list of patients diagnosed with cancer in the liver, bile duct system, gallbladder or metastases of the liver, during the time period 2013-2017, was obtained from the Icelandic Cancer Registry. Additional information was retrieved from medical records and entered into the electronic quality registration forms of Landspítalinn. A comparison was made between Sweden and Iceland. RESULTS: In total 108 patients were diagnosed with primary cancer of the liver, of which 24 (22%) underwent liver surgery. Of 264 diagnosed with liver metastases 38 (14%) underwent surgical treatment. A total of 63% of all reported cases were discussed at a multidisciplinary team meeting in Iceland but 93% in Sweden (p<0.0001). A sum of 29 patients (43%) developed complications within 30 days of surgery. Number of partial liver resections per 100.000 inhabitants were 2-8 in Iceland versus 4-13 in Sweden. The difference was even more apparent in patients with liver metastases. CONCLUSION: Liver surgeries performed in Iceland seem to be comparable to Sweden in terms of complications and post operative mortality. In Iceland, considerably fewer operations are performed per capita, especially on liver metastases which could be explained by the fact that fewer patients are discussed at multidisciplinary team meetings.

Metformin is associated with decreased risk of basal cell carcinoma: A whole-population case-control study from Iceland.

BACKGROUND: Metformin has anticarcinogenic properties and is also known to inhibit the sonic hedgehog pathway, but population-based studies analyzing the potential protective effect for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are needed. OBJECTIVES: To delineate the association between metformin use and invasive SCC, SCC in situ (SCCis), and BCC. METHODS: A population-based case-control study design was employed using all 6880 patients diagnosed in Iceland between 2003-2017 with first-time BCC, SCCis, or invasive SCC, and 69,620 population controls. Multivariate odds ratios (ORs) were calculated using conditional logistic regression. RESULTS: Metformin was associated with a lower risk of developing BCC (OR, 0.71; 95% confidence interval [CI], 0.61-0.83), even at low doses. No increased risk of developing SCC was observed. SCCis risk was mildly elevated in the 501-1500 daily dose unit category (OR, 1.40; 95% CI, 1.00-1.96). LIMITATIONS: This study was retrospective in nature with the inability to adjust for ultraviolet exposure, Fitzpatrick skin type, and comorbidities. CONCLUSION: Metformin is associated with decreased risk of BCC development, even at low doses. Metformin might have potential as a chemoprotective agent for patients at high risk of BCC, although this will need confirmation in future studies.

Association between hydrochlorothiazide and the risk of in situ and invasive squamous cell skin carcinoma and basal cell carcinoma: A population-based case-control study.

BACKGROUND: Population-based studies analyzing hydrochlorothiazide's (HCTZ's) effect on keratinocyte carcinoma, and particularly invasive squamous cell carcinoma (SCC), are lacking. OBJECTIVES: To characterize the association between HCTZ use and invasive SCC, SCC in situ (SCCis), and basal cell carcinoma (BCC). METHODS: This population-based case-control study included all 6880 patients diagnosed with first-time BCC, SCCis, and invasive SCC between 2003 and 2017 in Iceland and 69,620 population controls. Conditional logistic regression analyses were used to calculate multivariate odds ratios (ORs) for keratinocyte carcinoma associated with HCTZ use. RESULTS: A cumulative HCTZ dose above 37,500 mg was associated with increased risk of invasive SCC (OR, 1.69; 95% confidence interval [CI], 1.04-2.74). Users of HCTZ also had an increased risk of SCCis (OR, 1.24; 95% CI, 1.01-1.52) and BCC (OR, 1.14; 95% CI, 1.02-1.29). LIMITATIONS: Limitations include this study's retrospective nature with the resulting inability to adjust for ultraviolet exposure, Fitzpatrick skin type, and comorbidities. CONCLUSIONS: High cumulative exposure to HCTZ is associated with the development of keratinocyte carcinoma and, most importantly, invasive SCC. Sun protective behaviors alone may not eliminate the carcinogenic potential of HCTZ.

ECM1 secreted by HER2-overexpressing breast cancer cells promotes formation of a vascular niche accelerating cancer cell migration and invasion.

The tumor microenvironment is increasingly recognized as key player in cancer progression. Investigating heterotypic interactions between cancer cells and their microenvironment is important for understanding how specific cell types support cancer. Forming the vasculature, endothelial cells (ECs) are a prominent cell type in the microenvironment of both normal and neoplastic breast gland. Here, we sought out to analyze epithelial-endothelial cross talk in the breast using isogenic non-tumorigenic vs. tumorigenic breast epithelial cell lines and primary ECs. The cellular model used here consists of D492, a breast epithelial cell line with stem cell properties, and two isogenic D492-derived EMT cell lines, D492M and D492HER2. D492M was generated by endothelial-induced EMT and is non-tumorigenic while D492HER2 is tumorigenic, expressing the ErbB2/HER2 oncogene. To investigate cellular cross talk, we used both conditioned medium (CM) and 2D/3D co-culture systems. Secretome analysis of D492 cell lines was performed using mass spectrometry and candidate knockdown (KD), and overexpression (OE) was done using siRNA and CRISPRi/CRISPRa technology. D492HER2 directly enhances endothelial network formation and activates a molecular axis in ECs promoting D492HER2 migration and invasion, suggesting an endothelial feedback response. Secretome analysis identified extracellular matrix protein 1 (ECM1) as potential angiogenic inducer in D492HER2. Confirming its involvement, KD of ECM1 reduced the ability of D492HER2-CM to increase endothelial network formation and induce the endothelial feedback, while recombinant ECM1 (rECM1) increased both. Interestingly, NOTCH1 and NOTCH3 expression was upregulated in ECs upon treatment with D492HER2-CM or rECM1 but not by CM from D492HER2 with ECM1 KD. Blocking endothelial NOTCH signaling inhibited the increase in network formation and the ability of ECs to promote D492HER2 migration and invasion. In summary, our data demonstrate that cancer-secreted ECM1 induces a NOTCH-mediated endothelial feedback promoting cancer progression by enhancing migration and invasion. Targeting this interaction may provide a novel possibility to improve cancer treatment.

[Hepatitisvirus E: A discussion on two Icelandic cases].

Hepatitis E is a viral disease that is usually transmitted through contaminated drinking water and most often causes a self-limiting infection that does not require specific treatment. It is common in India and has caused outbreaks in Asia, Africa and Mexico but has very rarely been diagnosed in Iceland. We describe two cases of hepatitis E diagnosed in Iceland in the last year.

Gastroenteropancreatic neuroendocrine tumors in Iceland: a population-based study.

OBJECTIVE: To determine the incidence, distribution, and prognosis of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) over the last 30 years and analyze changes over time. METHODS: All patients diagnosed with GEP-NETs in Iceland from 1985 to 2014 were identified through the Icelandic Cancer Registry and pathology laboratory records. Relevant clinical information was obtained from medical records. In order to assess trends, the study period was divided into two periods, 1985-1999 and 2000-2014. RESULTS: A total of 364 patients with GEP-NETs were identified. Overall, 18 patients diagnosed at autopsy or with primary tumors of an unknown site were excluded, leaving 346 patients with 351 primary tumors for final analysis. The overall mean annual incidence 1985-2014 was 3.65/100,000, 3.39/100,000 during 1985-1999 and 3.85/100,000 during 2000-2014 (p = NS). The most common primary tumor site was the appendix (32%), followed by the jejunum/ileum (24%) and stomach (17%). In all, 18% of patients presented with distant metastases at the time of diagnosis, most noticeably patients with primary tumors of the colon (47%), pancreas (46%) and jejunum/ileum (39%). The most favorable 5-year survival was observed for tumors of the appendix (94%) and rectum (88%) and the least favorable for tumors of the pancreas (31%), colon (47%) and jejunum/ileum (66%). There were no statistically significant changes in incidence, staging or survival between the two time periods. CONCLUSIONS: In this population-based study, the incidence of GEP-NETs has not changed significantly over the last decades. The incidence of metastatic disease has remained stable and overall prognosis has not improved in recent years.

[Primary sclerosing cholangitis in Iceland 1992-2012].

BACKGROUND: Primary sclerosing cholangitis (PSC) is a chronic cholestatic disease affecting the intra- and/or extrahepatic biliary tree with inflammation and progressive stricture formation that can lead to cirrhosis, end stage liver failure and liver transplantation. Known risk factors include inflammatory bowel diseases (IBD), mainly ulcerative colitis (UC). Highest reported incidence in an adult population is 1.2-1.3/100.000 in Norway and Sweden, where 60-76% have IBD. The aim of this study was to investigate epidemiology of PSC in Iceland in the years 1992 to 2012 and the patients outcomes. METHODS: A search for the diagnosis "cholangitis" (ICD-10, K83.0) was performed in the database for hospital records in Landspítali (The National University Hospital of Iceland, LSH) and Akureyri Hospital from 1992 to 2012. We also looked through all ERCP and MRCP imaging done in LSH in the same period along with a text search in both the hospital records and the pathology database for liver biopsies. Data on these patients was collected until the end of 2016. RESULTS: A total of 42 patient got the diagnosis PSC within the period. Median age at diagnosis was 34 years, 67% were male and 90% adults (≥18 years old). Mean incidence per year was 0.69/100.000. Overall 88% of patients had IBD, thereof 89% UC. Seven patients have been diagnosed with cancer, four with cancer in the bile ducts and one in the gallbladder. Within the study period a total of five patients died (12%), 51 months (median) from diagnosis and three from cholangiocarcinoma, 51 months (median) from diagnosis. Three patients (7%) underwent liver transplantation, one required a transplant two times. CONCLUSIONS: The incidence of PSC in Iceland turned out to be lower than in our neighbouring countries in Scandinavia. It is unclear if this is due to underdiagnosis or, more likely, that PSC is simply more uncommon in Iceland. Overall 7% underwent liver transplantation and 12% died within the study period, main cause of mortality being cholangiocarcinoma.

The risk of developing a mismatch repair deficient colorectal cancer after undergoing cholecystectomy.

OBJECTIVES: Mismatch repair deficient (dMMR) colorectal cancer (CRC) is caused by inactivation of the MMR DNA repair system, most commonly via epigenetic inactivation of the MLH1 gene, and these tumors occur most frequently in the right colon. The objective was to determine whether cholecystectomy (CCY) increases the risk of a dMMR CRC by comparing CCY incidence in patients with dMMR CRC and proficient MMR (pMMR) CRC to unaffected controls. MATERIALS AND METHODS: All patients diagnosed with CRC in Iceland from 2000 to 2009 (n = 1171) were included. They had previously been screened for dMMR by immunohistochemistry (n = 129 were dMMR). Unaffected age- and sex-matched controls (n = 17,460) were obtained from large Icelandic cohort studies. Subjects were cross-referenced with all pathology databases in Iceland to establish who had undergone CCY. Odds ratios were calculated using unconditional logistic regression. RESULTS: Eighteen (13.7%) dMMR CRC cases and 90 (8.7%) pMMR CRC cases had undergone CCY compared to 1532 (8.8%) controls. CCY-related odds ratios (OR) were 1.06 (95% CI 0.90-1.26, p = .577) for all CRC, 1.16 (95% CI 0.66-2.05 p = .602) for dMMR CRCand 1.04 (95% CI 0.83-1.29, p = .744) for pMMR CRC. Furthermore, OR for dMMR CRC was 0.51 (95% CI 0.16-1.67, p = .266), 2.04 (95% CI 0.92-4.50, p = .080) and 1.08 (95% CI 0.40-2.89, p = .875) <10 years, 10-20 years and >20 years after a CCY, respectively. CONCLUSIONS: There was no evidence of increased risk of developing dMMR CRC after CCY although a borderline significantly increased 2-fold risk was observed 10-20 years after CCY. Larger studies are warranted to examine this further.

CpG promoter methylation of the ALKBH3 alkylation repair gene in breast cancer.

BACKGROUND: DNA repair of alkylation damage is defective in various cancers. This occurs through somatically acquired inactivation of the MGMT gene in various cancer types, including breast cancers. In addition to MGMT, the two E. coli AlkB homologs ALKBH2 and ALKBH3 have also been linked to direct reversal of alkylation damage. However, it is currently unknown whether ALKBH2 or ALKBH3 are found inactivated in cancer. METHODS: Methylome datasets (GSE52865, GSE20713, GSE69914), available through Omnibus, were used to determine whether ALKBH2 or ALKBH3 are found inactivated by CpG promoter methylation. TCGA dataset enabled us to then assess the impact of CpG promoter methylation on mRNA expression for both ALKBH2 and ALKBH3. DNA methylation analysis for the ALKBH3 promoter region was carried out by pyrosequencing (PyroMark Q24) in 265 primary breast tumours and 30 proximal normal breast tissue samples along with 8 breast-derived cell lines. ALKBH3 mRNA and protein expression were analysed in cell lines using RT-PCR and Western blotting, respectively. DNA alkylation damage assay was carried out in cell lines based on immunofluorescence and confocal imaging. Data on clinical parameters and survival outcomes in patients were obtained and assessed in relation to ALKBH3 promoter methylation. RESULTS: The ALKBH3 gene, but not ALKBH2, undergoes CpG promoter methylation and transcriptional silencing in breast cancer. We developed a quantitative alkylation DNA damage assay based on immunofluorescence and confocal imaging revealing higher levels of alkylation damage in association with epigenetic inactivation of the ALKBH3 gene (P = 0.029). In our cohort of 265 primary breast cancer, we found 72 cases showing aberrantly high CpG promoter methylation over the ALKBH3 promoter (27%; 72 out of 265). We further show that increasingly higher degree of ALKBH3 promoter methylation is associated with reduced breast-cancer specific survival times in patients. In this analysis, ALKBH3 promoter methylation at >20% CpG methylation was found to be statistically significantly associated with reduced survival (HR = 2.3; P = 0.012). By thresholding at the clinically relevant CpG methylation level (>20%), we find the incidence of ALKBH3 promoter methylation to be 5% (13 out of 265). CONCLUSIONS: ALKBH3 is a novel addition to the catalogue of DNA repair genes found inactivated in breast cancer. Our results underscore a link between defective alkylation repair and breast cancer which, additionally, is found in association with poor disease outcome.

Biliary tract malignancies: a population-based study on incidence, prognosis and management of patients.

BACKGROUND: Biliary tract malignancies are uncommon and few population-based studies are available. METHODS: This nationwide population-based study in Iceland included all patients diagnosed with intra- and extrahepatic cholangiocarcinoma, gallbladder and ampullary cancer from 1984 to 2012. Patients were identified through the Icelandic Cancer Registry. Clinical information was obtained from patient records. RESULTS: Overall 245 patients were identified: 38 had intrahepatic cholangiocarcinoma, 66 extrahepatic cholangiocarcinoma, 73 gallbladder cancer (GBC) and 68 ampullary cancer. Overall incidence for bile tract malignancies was 1-3 per 100,000 person-years and less than 1 by sub-type. The overall bile tract malignancies in males increased from 1.3 (95% CI 0.8-1.8) to 2.5 (1.9-3.1) per 100,000 inhabitants. The incidence of GBC among females decreased from 1.1 (0.7-1.5) to 0.5 (0.2-0.7). Surgery decreased for extrahepatic cholangiocarcinoma (56 to 23%, p = .027), ampullary cancer (80 to 48%, p = .03) and overall bile tract cancer (61 to 32%, p < .0001) but use of chemotherapy increased (4 to 32%, p < .0001). Five-year relative survival rates for men were 15% and 24% for women. No significant improvement was found in survival. CONCLUSIONS: Overall incidence of bile tract malignancies increased in males and GBC decreased in women. Long-term survival is poor and did not improve despite changes in treatment.

Etiology and management of esophageal food impaction: a population based study.

OBJECTIVE: Esophageal food impaction (FI) is a common clinical problem with limited information on incidence. Previous population based studies are lacking. The incidence, main etiological factors, recurrence and outcome of FI was determined in the present study in a population based setting. MATERIAL AND METHODS: This was a study of consecutive adult patients who presented with FI from 2008 to 2013 at the National University Hospital of Iceland. The mean crude incidence rate of FI was calculated. Retrospective analysis was undertaken on relevant clinical data such as type of bolus, management, complications, recurrence rate, risk factors for recurrence, and outcome. RESULTS: Overall 308 patients had endoscopically confirmed FI, males 199/308 (65%), median age 62 years. The mean crude incidence was 25 per 100,000 inhabitants per year. The types of FI was meat (68%), fish (12%), vegetable (4%) and other food/objects (16%). Causes for the FI included: esophageal strictures (45%), hiatal hernia (22%), eosinophilic esophagitis (EoE) (16%) and esophageal carcinoma (2%). Recurrence appeared in 21%, in which 24/48 (50%) had EoE vs. 40/260 (15%) in others (p = 0.0001). The removal of the foreign body was successful in 98% of the cases during the first endoscopy. Endoscopic associated complications included four (1.3%) aspirations, one (0.3%) esophageal perforation and one Boerhaave syndrome at presentation (both had EoE). CONCLUSIONS: The incidence of FI is the highest reported to date. EoE was strongly associated with recurrence of FI. In a population based setting endoscopy is a safe and effective procedure for removing FI.

The risk of colorectal cancer after an attack of uncomplicated diverticulitis.

OBJECTIVE: According to clinical guidelines, a colonoscopy is recommended after an attack of diverticulitis in order to exclude colorectal cancer (CRC). This is based on studies prior to the use of computerized tomography (CT) for confirmation of the diagnosis. We aimed to investigate the findings of a subsequent colonoscopy after an attack of uncomplicated diverticulitis. MATERIAL AND METHODS: The study cohort consisted of all patients with the diagnosis of uncomplicated diverticulitis, who underwent a subsequent colonoscopy 6-8 weeks later during a 6-years period in the National University Hospital of Iceland. The diagnosis of diverticulitis was based on clinical symptoms verified with a CT of the abdomen. Relevant clinical information was obtained from medical records and from the Icelandic Cancer Registry. RESULTS: A total of 282 patients had uncomplicated diverticulitis and 199 patients underwent endoscopy. Two patients had CRC (0.7%), diagnosed with diverticulitis but did not recover clinically. All other patients recovered clinically. Colonic polyps were found in 33 of 195 (17%) cases. In 19/33 (58%) cases the histology demonstrated hyperplastic polyps, and in 13/33 (39%) adenoma with mild dysplasia. Only 1/33 (3%) of the colonic polyps were >1 cm in size. CONCLUSIONS: Among patients experiencing an attack of uncomplicated diverticulitis the frequency of CRC was equal to what might be expected compared to the average risk in the population. In these patients a routine colonoscopy in the absence of other clinical signs of CRC seems hardly necessary, if the clinical course is uneventful and the patient recovers.

European genome-wide association study identifies SLC14A1 as a new urinary bladder cancer susceptibility gene.

Three genome-wide association studies in Europe and the USA have reported eight urinary bladder cancer (UBC) susceptibility loci. Using extended case and control series and 1000 Genomes imputations of 5 340 737 single-nucleotide polymorphisms (SNPs), we searched for additional loci in the European GWAS. The discovery sample set consisted of 1631 cases and 3822 controls from the Netherlands and 603 cases and 37 781 controls from Iceland. For follow-up, we used 3790 cases and 7507 controls from 13 sample sets of European and Iranian ancestry. Based on the discovery analysis, we followed up signals in the urea transporter (UT) gene SLC14A. The strongest signal at this locus was represented by a SNP in intron 3, rs17674580, that reached genome-wide significance in the overall analysis of the discovery and follow-up groups: odds ratio = 1.17, P = 7.6 × 10(-11). SLC14A1 codes for UTs that define the Kidd blood group and are crucial for the maintenance of a constant urea concentration gradient in the renal medulla and, through this, the kidney's ability to concentrate urine. It is speculated that rs17674580, or other sequence variants in LD with it, indirectly modifies UBC risk by affecting urine production. If confirmed, this would support the 'urogenous contact hypothesis' that urine production and voiding frequency modify the risk of UBC.