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.

Segmented regression, a versatile tool to analyze mRNA levels in relation to DNA copy number aberrations

DNA copy number aberrations (CNA) and subsequent altered gene expression profiles (mRNA levels) are characteristic features of cancerous cells. Integrative genomic analysis aims to identify recurrent CNA that may have a potential role in cancer development, assuming that gene amplification is accompanied by overexpression, while deletions give rise to downregulation of gene expression. We propose a segmented regression-based approach to identify CNA-driven alteration of gene expression profiles. Segmented regression allows to fit piecewise linear models in different domains of CNA joined by a change-point, where the mRNA-CNA relationship undergoes structural changes. Here, we illustrate the implementation and applicability of the proposed model using 1,161 chromosome fragments detected as DNA CNA in primary tumors from 97 breast cancer patients. We identified significant CNA-driven changes in gene expression levels for 341 chromosome fragments, of which 72 showed a nonlinear relationship to CNA. For 59 of 72 chromosome fragments (82%), we observed an initial increase in mRNA levels due to changes in CNA. After the change-point was passed, the mRNA levels reached a plateau, and a further increase in DNA copy numbers did not induce further elevation in mRNA levels. In contrast, for 13 chromosome fragments, the change-point marked the point where mRNA production accelerated. We conclude that segmented regression modeling may provide valuable insights into the impact CNA have on gene expression in cancer cells.

Tobacco smoking and long-lasting symptoms from the bowel and the anal-sphincter region after radiotherapy for prostate cancer

BACKGROUND AND PURPOSE

Tobacco smoking can cause vascular injury, tissue hypoxia and fibrosis as can ionizing radiation. However, we do not know if tobacco smoking increases the risk of long-term side effects after radiotherapy for prostate cancer.

METHODS

We identified 985 men treated with radiotherapy for prostate cancer between 1993 and 2006. In 2008, long-lasting symptoms appearing after radiotherapy for prostate cancer were assessed through a study-specific questionnaire as were smoking habits and demographic factors of all these men. In the questionnaire the prostate-cancer survivors were asked to report symptom occurrence the previous six months.

RESULTS

We obtained information on tobacco smoking from 836 of the 985 prostate-cancer survivors with a median time to follow-up of six years (range 2-14 years). The prevalence ratio of defecation urgency among current smokers compared to never smokers was 1.6 (95% CI 1.2-2.2). Corresponding prevalence ratio for diarrhea was 2.8 (95% CI 1.2-6.5), the sensation of bowel not completely emptied after defecation 2.1 (95% CI 1.3-3.3) and for sudden emptying of all stools into clothing without forewarning 4.7 (95% CI 2.3-9.7).

CONCLUSION

Tobacco smoking among prostate-cancer survivors treated with radiotherapy increases the risk of certain long-lasting symptoms from the bowel and anal-sphincter region.

Orgasm-associated urinary incontinence and sexual life after radical prostatectomy

INTRODUCTION

Involuntary release of urine during sexual climax, orgasm-associated urinary incontinence, occurs frequently after radical prostatectomy. We know little about its prevalence and its effect on sexual satisfaction.

AIM

To determine the prevalence of orgasm-associated incontinence after radical prostatectomy and its effect on sexual satisfaction.

METHODS

Consecutive series, follow-up at one point in calendar time of men having undergone radical prostatectomy (open surgery or robot-assisted laparoscopic surgery) at Karolinska University Hospital, Stockholm, Sweden, 2002-2006. Of the 1,411 eligible men, 1,288 (91%) men completed a study-specific questionnaire.

MAIN OUTCOME MEASURE

Prevalence rate of orgasm-associated incontinence.

RESULTS

Of the 1,288 men providing information, 691 were sexually active. Altogether, 268 men reported orgasm-associated urinary incontinence, of whom 230 (86%) were otherwise continent. When comparing them with the 422 not reporting the symptom but being sexually active, we found a prevalence ratio (with 95% confidence interval) of 1.5 (1.2-1.8) for not being able to satisfy the partner, 2.1 (1.1-3.5) for avoiding sexual activity because of fear of failing, 1.5 (1.1-2.1) for low orgasmic satisfaction, and 1.4 (1.2-1.7) for having sexual intercourse infrequently. Prevalence ratios increase in prostate-cancer survivors with a higher frequency of orgasm-associated urinary incontinence.

CONCLUSION

We found orgasm-associated urinary incontinence to occur among a fifth of prostate cancer survivors having undergone radical prostatectomy, most of whom are continent when not engaged in sexual activity. The symptom was associated with several aspects of sexual life.

Insulin glargine use and short-term incidence of malignancies - a three-year population-based observation

AIMS/HYPOTHESIS

To further investigate the association of cancer occurrence with the use of insulin glargine.

METHODS

We followed 114 838 individuals using insulin between 1 July and 31 December 2005. From 1 January 2006 to 31 December 2008, we noted the occurrence of malignancies (cohort I). Insulin users between 1 July and 31 December 2006 were followed for the occurrence of malignancies in 2007 and 2008 (cohort II). Users of insulin during three consecutive six-month periods from 1 July 2005 to 31 December 2006 were followed for the occurrence of malignancies in 2007 and 2008 (cohort III). The Prescribed Drug Register, the Cancer Register, and the Causes of Death Register were used to obtain information on targeted person-time and outcome. We retrieved variables reflecting potential confounding factors from the Swedish National Diabetes Register, the Prescribed Drug Register, the Patient Register, the Medical Birth Register and the National Education Register. With Poisson regression we evaluated the association between insulin use and malignancy outcome with adjustment for confounders.

RESULTS

The adjusted incidence rate ratio (and 95% confidence interval) for women who used insulin glargine alone compared with those who used other types of insulin, was 1.60 (1.10-2.32) for breast cancer but included 1.0 for malignancy outcomes other than breast cancer for men and women when analyzing cohort I with follow-up in 2006-2008. For cohort II and III the corresponding incidence rate ratios were 1.38 (0.87-2.18), and 0.87 (0.41-1.85), respectively.

CONCLUSION/INTERPRETATION

We do not see an increased risk during 2008 for breast cancer in the insulin glargine group. We need data for additional years before we can state with reasonable certainty that the increase in breast cancer incidence that we observed in Sweden in 2006 and 2007 was due to a random fluctuation or whether there is an association with the use of insulin glargine.

Radical prostatectomy versus watchful waiting in early prostate cancer

BACKGROUND

In 2008, we reported that radical prostatectomy, as compared with watchful waiting, reduces the rate of death from prostate cancer. After an additional 3 years of follow-up, we now report estimated 15-year results.

METHODS

From October 1989 through February 1999, we randomly assigned 695 men with early prostate cancer to watchful waiting or radical prostatectomy. Follow-up was complete through December 2009, with histopathological review of biopsy and radical-prostatectomy specimens and blinded evaluation of causes of death. Relative risks, with 95% confidence intervals, were estimated with the use of a Cox proportional-hazards model.

RESULTS

During a median of 12.8 years, 166 of the 347 men in the radical-prostatectomy group and 201 of the 348 in the watchful-waiting group died (P=0.007). In the case of 55 men assigned to surgery and 81 men assigned to watchful waiting, death was due to prostate cancer. This yielded a cumulative incidence of death from prostate cancer at 15 years of 14.6% and 20.7%, respectively (a difference of 6.1 percentage points; 95% confidence interval [CI], 0.2 to 12.0), and a relative risk with surgery of 0.62 (95% CI, 0.44 to 0.87; P=0.01). The survival benefit was similar before and after 9 years of follow-up, was observed also among men with low-risk prostate cancer, and was confined to men younger than 65 years of age. The number needed to treat to avert one death was 15 overall and 7 for men younger than 65 years of age. Among men who underwent radical prostatectomy, those with extracapsular tumor growth had a risk of death from prostate cancer that was 7 times that of men without extracapsular tumor growth (relative risk, 6.9; 95% CI, 2.6 to 18.4).

CONCLUSIONS

Radical prostatectomy was associated with a reduction in the rate of death from prostate cancer. Men with extracapsular tumor growth may benefit from adjuvant local or systemic treatment. (Funded by the Swedish Cancer Society and the National Institutes of Health.).

Pilot testing of methods for evaluation of acupuncture for emesis during radiotherapy: a randomised single subject experimental design

BACKGROUND

Many acupuncture studies are of weak methodological quality, possibly due to lack of pilot testing. This pilot study tested design features, including test of feasibility, compliance to treatment and data collection, level of blinding success and the patients' potential perceived effects of the treatment, in preparation for an efficacy study.

METHOD

A modified single subject experimental design was conducted. 10 cancer patients were randomised to verum penetrating acupuncture or non-penetrating sham needles for 30 min 2-3 times/week during radiotherapy over abdomen/pelvis. They answered test-retested emesis questions (r=0.527-1.0) covering nausea, vomiting, use of antiemetics, wellbeing and activities of daily living.

RESULTS

Overall, the patients completed 98% of the 345 emesis-questionnaire days and 101 of the 115 offered treatments. All patients believed they received verum acupuncture. 10 patients experienced antiemetic effects, seven relaxation, five pain-reduction and five experienced sleep improvement. Two types of nausea questions showed absolute concordance (r=1.0) (n of observations=456). Nausea was experienced by one of five verum acupuncture treated patients (duration median 0% of the radiotherapy-days) and four of five sham acupuncture treated patients (duration median 24% of the radiotherapy-days). Patients experiencing nausea rated decreased wellbeing and performance of daily activities compared to patients free from nausea.

CONCLUSIONS

All patients were blinded, complied with verum/sham treatments and data-collection, and believed they had effects of the received treatment. The methods for verum/sham treatment and data collection may thus be used in an adequately powered randomised controlled study of the effect of acupuncture for radiotherapy-induced emesis.

Getting the grip on nonspecific treatment effects: emesis in patients randomized to acupuncture or sham compared to patients receiving standard care

Background

It is not known whether or not delivering acupuncture triggers mechanisms cited as placebo and if acupuncture or sham reduces radiotherapy-induced emesis more than standard care.

Methodology/Principal Findings

Cancer patients receiving radiotherapy over abdominal/pelvic regions were randomized to verum (penetrating) acupuncture (n = 109; 99 provided data) in the alleged antiemetic acupuncture point PC6 or sham acupuncture (n = 106; 101 provided data) performed with a telescopic non-penetrating needle at a sham point 2–3 times/week during the whole radiotherapy period. The acupuncture cohort was compared to a reference cohort receiving standard care (n = 62; 62 provided data). The occurrence of emesis in each group was compared after a mean dose of 27 Gray. Nausea and vomiting were experienced during the preceding week by 37 and 8% in the verum acupuncture group, 38 and 7% in the sham acupuncture group and 63 and 15% in the standard care group, respectively. The lower occurrence of nausea in the acupuncture cohort (verum and sham) compared to patients receiving standard care (37% versus 63%, relative risk (RR) 0.6, 95 % confidence interval (CI) 0.5–0.8) was also true after adjustment for potential confounding factors for nausea (RR 0.8, CI 0.6 to 0.9). Nausea intensity was lower in the acupuncture cohort (78% no nausea, 13% a little, 8% moderate, 1% much) compared to the standard care cohort (52% no nausea, 32% a little, 15% moderate, 2% much) (p = 0.002). The acupuncture cohort expected antiemetic effects from their treatment (95%). Patients who expected nausea had increased risk for nausea compared to patients who expected low risk for nausea (RR 1.6; Cl 1.2–2.4).

Conclusions/Significance

Patients treated with verum or sham acupuncture experienced less nausea and vomiting compared to patients receiving standard care, possibly through a general care effect or due to the high level of patient expectancy.

Trial Registration

ClinicalTrials.gov NCT00621660

Loose stools lead to fecal incontinence among gynecological cancer survivors

BACKGROUND

Many patients treated with radiotherapy to the pelvic region report a change in bowel habits. Loose stools, urgency and fecal incontinence may have a significant impact on daily life and social functioning.

MATERIAL AND METHODS

We attempted to follow up 789 women, treated with pelvic radiotherapy for a gynecological cancer during 1991 to 2003 at two departments of gynecological oncology in Sweden. A control group of 478 women from the Swedish Population Registry was also included. As a preparatory study, we made in-depth interviews with 26 women previously treated for gynecological cancer. Based on their narratives, we constructed a study-specific questionnaire including 351 questions and validated it face-to-face. The questionnaire covered questions of physical symptoms originating in the pelvis, demographics, psychological and quality of life factors. In relation to bowel symptoms, 60 questions were asked.

RESULTS

Six-hundred and sixteen (78%) gynecological cancer survivors and 344 (72%) control women participated. Two-hundred and twenty-six (37%) cancer survivors reported loose stools at least once a week. Eighty-three percent of the survivors with loose stools every day reported defecation urgency with fecal leakage, compared to 20% of cancer survivors without loose stools. Cancer survivors with loose stools at least once a week were 7.7 times more likely to suffer from defecation urgency with fecal leakage (95% CI 4.4-13.3) compared to those who had loose stools once a month or less. In order to avoid loose stools affected survivors with loose stools often skipped meals (13%), made an active choice of food (47%) and preferentially used prescribed medication (36%).

DISCUSSION

There is a relation between loose stools and defecation urgency with fecal leakage among long-term gynecological cancer survivors treated with pelvic radiotherapy. Targeting loose stools can possibly help survivors to decrease frequency of fecal leakage.

Genotypes, haplotypes and diplotypes of three XPC polymorphisms in urinary-bladder cancer patients

PURPOSE

The XPC gene is involved in DNA damage recognition in the nucleotide excision repair pathway (NER). We investigated the additive effects of single nucleotide polymorphisms (SNPs) in bladder-cancer patients and population controls for three XPC polymorphisms: A499V (C>T), K939Q (A>C), and poly AT (PAT, -/+).

EXPERIMENTAL DESIGN

311 bladder-cancer patients from a population-based cohort and 337 population controls were genotyped using the PCR-restriction fragment length polymorphism (RFLP) technique.

RESULTS

We found complete linkage between the K939Q (A>C) and PAT (-/+) polymorphisms and therefore only the K939Q (A>C) polymorphism was included in analyses. The over all estimated odds ratio was 1.7 (95% CI 1.3-2.4) for A499V (C>T) and 1.4 (95% CI 1.0-2.0) for K939Q (A>C). The associated odds ratio increase with the variant allele homozygotes was six-fold for the A499V (C>T) and three-fold for the K939Q (A>C) polymorphism (OR=5.7, 95% CI 3.4-9.5 and OR=2.6, 95% CI 1.3-5.6, respectively). The variant allele haplotype of the two polymorphisms (T₄₉₉C₉₃₉) was associated with a nearly four fold increased odds ratio compared to the common allele haplotype (C₄₉₉A₉₃₉) (OR=3.6, 95% CI:1.9-6.9). Combined genotype analysis showed an increased disease association with increasing number of variant alleles (p<0.0001), with a dominant effect of the A499V polymorphism. In addition we observed association of the disease with increasing number of variant alleles for the A499V polymorphism and an early age at diagnosis (p=0.004).

CONCLUSIONS

Our results suggest an association between the XPC genotypes of the A499V, K939Q and PAT polymorphisms and urinary-bladder cancer. We propose a poly-allelic effect of these polymorphisms where the cumulative effect on disease becomes higher than the individual allelic effects.

Model selection in medical research: a simulation study comparing Bayesian model averaging and stepwise regression

Background

Automatic variable selection methods are usually discouraged in medical research although we believe they might be valuable for studies where subject matter knowledge is limited. Bayesian model averaging may be useful for model selection but only limited attempts to compare it to stepwise regression have been published. We therefore performed a simulation study to compare stepwise regression with Bayesian model averaging.

Methods

We simulated data corresponding to five different data generating processes and thirty different values of the effect size (the parameter estimate divided by its standard error). Each data generating process contained twenty explanatory variables in total and had between zero and two true predictors. Three data generating processes were built of uncorrelated predictor variables while two had a mixture of correlated and uncorrelated variables. We fitted linear regression models to the simulated data. We used Bayesian model averaging and stepwise regression respectively as model selection procedures and compared the estimated selection probabilities.

Results

The estimated probability of not selecting a redundant variable was between 0.99 and 1 for Bayesian model averaging while approximately 0.95 for stepwise regression when the redundant variable was not correlated with a true predictor. These probabilities did not depend on the effect size of the true predictor. In the case of correlation between a redundant variable and a true predictor, the probability of not selecting a redundant variable was 0.95 to 1 for Bayesian model averaging while for stepwise regression it was between 0.7 and 0.9, depending on the effect size of the true predictor. The probability of selecting a true predictor increased as the effect size of the true predictor increased and leveled out at between 0.9 and 1 for stepwise regression, while it leveled out at 1 for Bayesian model averaging.

Conclusions

Our simulation study showed that under the given conditions, Bayesian model averaging had a higher probability of not selecting a redundant variable than stepwise regression and had a similar probability of selecting a true predictor. Medical researchers building regression models with limited subject matter knowledge could thus benefit from using Bayesian model averaging.

Defecation disturbances after cystectomy for urinary bladder cancer

OBJECTIVE

• To describe and compare long-term defecation disturbances in patients who had undergone a cystectomy due to urinary bladder cancer with non-continent urostomies, continent reservoirs and orthotopic neobladder urinary diversions.

PATIENTS AND METHODS

• During their follow-up we attempted to contact all men and women aged 30-80 years who had undergone cystectomy and urinary diversion at seven Swedish hospitals. • During a qualitative phase we identified defecation disturbances as a distressful symptom and included this item in a study-specific questionnaire together with free-hand comments. The patients completed the questionnaire at home. • Outcome variables were dichotomized and the results are presented as relative risks with 95% confidence interval.

RESULTS

• The questionnaire was returned from 452 (92%) of 491 identified patients. Up to 30% reported problems with the physiological emptying process of stool (bowel movement, sensory rectal function, awareness of need for defecation, motoric rectal and anal function, straining ability). • A sense of decreased straining capacity was reported by 20% of the men and women with non-continent urostomy and 14% and 8% of those with continent reservoirs and orthotopic neobladders, respectively.

CONCLUSIONS

• Of the cystectomized individuals 30% reported problems with the physiological emptying process of stool (bowel movement, sensory rectal function, awareness of need for defecation, motoric rectal and anal function, straining ability). • Those wanting to improve the situation for bladder cancer survivors may consider communicating before surgery the possibility of stool-emptying problems, and asking about them after surgery.

Symptoms 10-17 years after breast cancer radiotherapy data from the randomised SWEBCG91-RT trial

BACKGROUND

Postoperative radiotherapy decreases the risk for local recurrence and improves overall survival in women with breast cancer. We have limited information on radiotherapy-induced symptoms 10-17 years after therapy.

MATERIAL AND METHODS

Between 1991 and 1997, women with lymph node-negative breast cancer were randomised in a Swedish multi-institutional trial to breast conserving surgery with or without postoperative radiotherapy. In 2007, 10-17 years after randomisation, the group included 422 recurrence-free women. We collected data with a study-specific questionnaire on eight pre-selected symptom groups.

RESULTS

For six symptom groups (oedema in breast or arm, erysipelas, heart symptoms, lung symptoms, rib fractures, and decreased shoulder mobility) we found similar occurrence in both groups. Excess occurrence after radiotherapy was observed for pain in the breast or in the skin, reported to occur "occasionally" by 38.1% of survivors having undergone radiotherapy and surgery versus 24.0% of those with surgery alone (absolute difference 14.1%; p=0.004) and at least once a week by 10.3% of the radiotherapy group versus 1.7% (absolute difference 8.6%; p=0.001). Daily life and analgesic use did not differ between the groups.

CONCLUSIONS

Ten to 17 years after postoperative radiotherapy 1 in 12 women had weekly pain that could be attributed to radiotherapy. The symptoms did not significantly affect daily life and thus the reduced risk for local recurrence seems to outweigh the risk for long-term symptoms for most women.

Regional differences in local recurrence rates after rectal cancer surgery

AIM

To analyse a substantial regional difference in local failure rate after rectal cancer surgery focusing on management.

METHOD

National, population-based, prospective registry data were used, including comprehensive 5-year follow up of 3783 patients operated on in the period 1998-2000. Local recurrence rates were compared using crude rate, Kaplan-Meier estimates and competing risk methodology. Resected patients (651 regional and 3132 national) were analysed and subgroup comparisons of management were performed.

RESULTS

The crude local recurrence rate was 13.7% in the regional cohort and 7.1% in the national cohort. The absolute difference of 6.6% may partly be explained by systematic errors of underreporting (≤ 1.4%), differences in patient populations and indications for surgery. A significant difference in the use of neoadjuvant radiotherapy (explaining ≤ 1.0%) and some aspects of surgical strategy were also observed.

CONCLUSIONS

We conclude that some of the difference in the registered incidence of local recurrence between the regional and the national cohorts remains unexplained and may depend on surgical technique in terms of lack of radicality in removing tumour tissue.

The (CCTTT)n microsatellite polymorphism in the nitric oxide synthase 2 gene may influence bladder cancer pathogenesis

PURPOSE

We analyzed whether the NOS2 promoter microsatellite (CCTTT)n polymorphism influences bladder cancer pathogenesis.

MATERIALS AND METHODS

We genotyped 359 patients with bladder cancer in a population based cohort and 164 population controls by DNA fragment analysis and sequencing. Genotypes were combined with information on tumor stage, grade and stage, grade progression and cancer specific death. Clinical followup was 5 years.

RESULTS

We divided (CCTTT)n alleles into short-10 or fewer, intermediate-11 or 12 and long-13 or greater repeats. Patients homozygous for 13 or longer (CCTTT)n repeats were at decreased odds ratio for bladder cancer (p = 0.010). However, after illness developed they were at 3-fold increased hazard ratio for stage progression (p = 0.062) and 4-fold increased hazard ratio for death from bladder cancer (p = 0.056). We discovered what is to our knowledge a previously undescribed polymorphism at position 23105343 (C/T). There was no difference in frequency between bladder cancer cases and population controls for this polymorphism. No associations were found between tumor stage, grade or stage and grade progression. However, patients with bladder cancer with the heterozygous CT genotype were at 3-fold increased hazard ratio of death from cancer (p = 0.011).

CONCLUSIONS

Nitric oxide can induce proliferation or apoptosis depending on the cellular context. Results suggest that the (CCTTT)n NOS2 microsatellite may influence bladder cancer risk and aggressiveness. This polymorphism may have an impact on disease pathogenesis, possibly by affecting intracellular nitric oxide levels.