Characterizing prostate cancer risk through multi-ancestry genome-wide discovery of 187 novel risk variants

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.

Evaluating approaches for constructing polygenic risk scores for prostate cancer in men of African and European ancestry

Genome-wide polygenic risk scores (GW-PRSs) have been reported to have better predictive ability than PRSs based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer-risk variants from multi-ancestry GWASs and fine-mapping studies (PRS269). GW-PRS models were trained with a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls that we previously used to develop the multi-ancestry PRS269. Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI = 0.635-0.677) in African and 0.844 (95% CI = 0.840-0.848) in European ancestry men and corresponding prostate cancer ORs of 1.83 (95% CI = 1.67-2.00) and 2.19 (95% CI = 2.14-2.25), respectively, for each SD unit increase in the GW-PRS. Compared to the GW-PRS, in African and European ancestry men, the PRS269 had larger or similar AUCs (AUC = 0.679, 95% CI = 0.659-0.700 and AUC = 0.845, 95% CI = 0.841-0.849, respectively) and comparable prostate cancer ORs (OR = 2.05, 95% CI = 1.87-2.26 and OR = 2.21, 95% CI = 2.16-2.26, respectively). Findings were similar in the validation studies. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the PRS269 developed from multi-ancestry GWASs and fine-mapping.

Evaluating Approaches for Constructing Polygenic Risk Scores for Prostate Cancer in Men of African and European Ancestry

Genome-wide polygenic risk scores (GW-PRS) have been reported to have better predictive ability than PRS based on genome-wide significance thresholds across numerous traits. We compared the predictive ability of several GW-PRS approaches to a recently developed PRS of 269 established prostate cancer risk variants from multi-ancestry GWAS and fine-mapping studies (PRS 269 ). GW-PRS models were trained using a large and diverse prostate cancer GWAS of 107,247 cases and 127,006 controls used to develop the multi-ancestry PRS 269 . Resulting models were independently tested in 1,586 cases and 1,047 controls of African ancestry from the California/Uganda Study and 8,046 cases and 191,825 controls of European ancestry from the UK Biobank and further validated in 13,643 cases and 210,214 controls of European ancestry and 6,353 cases and 53,362 controls of African ancestry from the Million Veteran Program. In the testing data, the best performing GW-PRS approach had AUCs of 0.656 (95% CI=0.635-0.677) in African and 0.844 (95% CI=0.840-0.848) in European ancestry men and corresponding prostate cancer OR of 1.83 (95% CI=1.67-2.00) and 2.19 (95% CI=2.14-2.25), respectively, for each SD unit increase in the GW-PRS. However, compared to the GW-PRS, in African and European ancestry men, the PRS 269 had larger or similar AUCs (AUC=0.679, 95% CI=0.659-0.700 and AUC=0.845, 95% CI=0.841-0.849, respectively) and comparable prostate cancer OR (OR=2.05, 95% CI=1.87-2.26 and OR=2.21, 95% CI=2.16-2.26, respectively). Findings were similar in the validation data. This investigation suggests that current GW-PRS approaches may not improve the ability to predict prostate cancer risk compared to the multi-ancestry PRS 269 constructed with fine-mapping.

Prostate cancer risk stratification improvement across multiple ancestries with new polygenic hazard score

BACKGROUND

Prostate cancer risk stratification using single-nucleotide polymorphisms (SNPs) demonstrates considerable promise in men of European, Asian, and African genetic ancestries, but there is still need for increased accuracy. We evaluated whether including additional SNPs in a prostate cancer polygenic hazard score (PHS) would improve associations with clinically significant prostate cancer in multi-ancestry datasets.

METHODS

In total, 299 SNPs previously associated with prostate cancer were evaluated for inclusion in a new PHS, using a LASSO-regularized Cox proportional hazards model in a training dataset of 72,181 men from the PRACTICAL Consortium. The PHS model was evaluated in four testing datasets: African ancestry, Asian ancestry, and two of European Ancestry-the Cohort of Swedish Men (COSM) and the ProtecT study. Hazard ratios (HRs) were estimated to compare men with high versus low PHS for association with clinically significant, with any, and with fatal prostate cancer. The impact of genetic risk stratification on the positive predictive value (PPV) of PSA testing for clinically significant prostate cancer was also measured.

RESULTS

The final model (PHS290) had 290 SNPs with non-zero coefficients. Comparing, for example, the highest and lowest quintiles of PHS290, the hazard ratios (HRs) for clinically significant prostate cancer were 13.73 [95% CI: 12.43-15.16] in ProtecT, 7.07 [6.58-7.60] in African ancestry, 10.31 [9.58-11.11] in Asian ancestry, and 11.18 [10.34-12.09] in COSM. Similar results were seen for association with any and fatal prostate cancer. Without PHS stratification, the PPV of PSA testing for clinically significant prostate cancer in ProtecT was 0.12 (0.11-0.14). For the top 20% and top 5% of PHS290, the PPV of PSA testing was 0.19 (0.15-0.22) and 0.26 (0.19-0.33), respectively.

CONCLUSIONS

We demonstrate better genetic risk stratification for clinically significant prostate cancer than prior versions of PHS in multi-ancestry datasets. This is promising for implementing precision-medicine approaches to prostate cancer screening decisions in diverse populations.

Marital status and prostate cancer incidence: a pooled analysis of 12 case-control studies from the PRACTICAL consortium

While being in a committed relationship is associated with a better prostate cancer prognosis, little is known about how marital status relates to its incidence. Social support provided by marriage/relationship could promote a healthy lifestyle and an increased healthcare seeking behavior. We investigated the association between marital status and prostate cancer risk using data from the PRACTICAL Consortium. Pooled analyses were conducted combining 12 case-control studies based on histologically-confirmed incident prostate cancers and controls with information on marital status prior to diagnosis/interview. Marital status was categorized as married/partner, separated/divorced, single, or widowed. Tumours with Gleason scores ≥ 8 defined high-grade cancers, and low-grade otherwise. NCI-SEER's summary stages (local, regional, distant) indicated the extent of the cancer. Logistic regression was used to derive odds ratios (ORs) and 95% confidence intervals (CI) for the association between marital status and prostate cancer risk, adjusting for potential confounders. Overall, 14,760 cases and 12,019 controls contributed to analyses. Compared to men who were married/with a partner, widowed men had an OR of 1.19 (95% CI 1.03-1.35) of prostate cancer, with little difference between low- and high-grade tumours. Risk estimates among widowers were 1.14 (95% CI 0.97-1.34) for local, 1.53 (95% CI 1.22-1.92) for regional, and 1.56 (95% CI 1.05-2.32) for distant stage tumours. Single men had elevated risks of high-grade cancers. Our findings highlight elevated risks of incident prostate cancer among widowers, more often characterized by tumours that had spread beyond the prostate at the time of diagnosis. Social support interventions and closer medical follow-up in this sub-population are warranted.

Additional SNPs improve risk stratification of a polygenic hazard score for prostate cancer

BACKGROUND

Polygenic hazard scores (PHS) can identify individuals with increased risk of prostate cancer. We estimated the benefit of additional SNPs on performance of a previously validated PHS (PHS46).

MATERIALS AND METHOD

180 SNPs, shown to be previously associated with prostate cancer, were used to develop a PHS model in men with European ancestry. A machine-learning approach, LASSO-regularized Cox regression, was used to select SNPs and to estimate their coefficients in the training set (75,596 men). Performance of the resulting model was evaluated in the testing/validation set (6,411 men) with two metrics: (1) hazard ratios (HRs) and (2) positive predictive value (PPV) of prostate-specific antigen (PSA) testing. HRs were estimated between individuals with PHS in the top 5% to those in the middle 40% (HR95/50), top 20% to bottom 20% (HR80/20), and bottom 20% to middle 40% (HR20/50). PPV was calculated for the top 20% (PPV80) and top 5% (PPV95) of PHS as the fraction of individuals with elevated PSA that were diagnosed with clinically significant prostate cancer on biopsy.

RESULTS

166 SNPs had non-zero coefficients in the Cox model (PHS166). All HR metrics showed significant improvements for PHS166 compared to PHS46: HR95/50 increased from 3.72 to 5.09, HR80/20 increased from 6.12 to 9.45, and HR20/50 decreased from 0.41 to 0.34. By contrast, no significant differences were observed in PPV of PSA testing for clinically significant prostate cancer.

CONCLUSIONS

Incorporating 120 additional SNPs (PHS166 vs PHS46) significantly improved HRs for prostate cancer, while PPV of PSA testing remained the same.

Polygenic hazard score is associated with prostate cancer in multi-ethnic populations

Genetic models for cancer have been evaluated using almost exclusively European data, which could exacerbate health disparities. A polygenic hazard score (PHS1) is associated with age at prostate cancer diagnosis and improves screening accuracy in Europeans. Here, we evaluate performance of PHS2 (PHS1, adapted for OncoArray) in a multi-ethnic dataset of 80,491 men (49,916 cases, 30,575 controls). PHS2 is associated with age at diagnosis of any and aggressive (Gleason score ≥ 7, stage T3-T4, PSA ≥ 10 ng/mL, or nodal/distant metastasis) cancer and prostate-cancer-specific death. Associations with cancer are significant within European (n = 71,856), Asian (n = 2,382), and African (n = 6,253) genetic ancestries (p < 10-180). Comparing the 80th/20th PHS2 percentiles, hazard ratios for prostate cancer, aggressive cancer, and prostate-cancer-specific death are 5.32, 5.88, and 5.68, respectively. Within European, Asian, and African ancestries, hazard ratios for prostate cancer are: 5.54, 4.49, and 2.54, respectively. PHS2 risk-stratifies men for any, aggressive, and fatal prostate cancer in a multi-ethnic dataset.

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction.

The CHEK2 Variant C.349A>G Is Associated with Prostate Cancer Risk and Carriers Share a Common Ancestor

The identification of recurrent founder variants in cancer predisposing genes may have important implications for implementing cost-effective targeted genetic screening strategies. In this study, we evaluated the prevalence and relative risk of the CHEK2 recurrent variant c.349A>G in a series of 462 Portuguese patients with early-onset and/or familial/hereditary prostate cancer (PrCa), as well as in the large multicentre PRACTICAL case-control study comprising 55,162 prostate cancer cases and 36,147 controls. Additionally, we investigated the potential shared ancestry of the carriers by performing identity-by-descent, haplotype and age estimation analyses using high-density SNP data from 70 variant carriers belonging to 11 different populations included in the PRACTICAL consortium. The CHEK2 missense variant c.349A>G was found significantly associated with an increased risk for PrCa (OR 1.9; 95% CI: 1.1-3.2). A shared haplotype flanking the variant in all carriers was identified, strongly suggesting a common founder of European origin. Additionally, using two independent statistical algorithms, implemented by DMLE+2.3 and ESTIAGE, we were able to estimate the age of the variant between 2300 and 3125 years. By extending the haplotype analysis to 14 additional carrier families, a shared core haplotype was revealed among all carriers matching the conserved region previously identified in the high-density SNP analysis. These findings are consistent with CHEK2 c.349A>G being a founder variant associated with increased PrCa risk, suggesting its potential usefulness for cost-effective targeted genetic screening in PrCa families.

Polymorphisms in the androgen receptor CAG repeat sequence are related to tumour stage but not to ERG or androgen receptor expression in Malaysian men with prostate cancer

INTRODUCTION

Polymorphic expression of a CAG repeat sequence in the androgen receptor (AR) gene may influence the activity of the AR and the occurrence of prostate cancer and the TMPRSS2-ERG fusion event. Furthermore, this polymorphism may be responsible for the ethnic variation observed in prostate cancer occurrence and expression of the ERG oncogene. We investigate the expression of AR and ERG in the biopsies of Malaysian men with prostate cancer and in the same patients relate this to the length of the CAG repeat sequence in their AR gene.

MATERIALS AND METHODS

From a PSA screening initiative, 161 men were shown to have elevated PSA levels in their blood and underwent prostatic tissue biopsy. DNA was extracted from the blood, and exon 1 of the AR gene amplified by PCR and sequenced. The number of CAG repeat sequences were counted and compared to the immunohistochemical expression of ERG and AR in the matched tumour biopsies.

RESULTS

Of men with elevated PSA, 89 were diagnosed with prostate cancer, and 72 with benign prostatic hyperplasia (BPH). There was no significant difference in the length of the CAG repeat in men with prostate cancer and BPH. The CAG repeat length was not associated with; age, PSA or tumour grade, though a longer CAG repeat was associated with tumour stage. ERG and AR were expressed in 36% and 86% of the cancers, respectively. There was no significant association between CAG repeat length and ERG or AR expression. However, there was a significant inverse relationship between ERG and AR expression. In addition, a significantly great proportion of Indian men had ERG positive tumours, compared to men of Malay or Chinese descent.

CONCLUSIONS

CAG repeat length is not associated with prostate cancer or expression of ERG or AR. However, ERG appears to be more common in the prostate cancers of Malaysian Indian men than in the prostate cancers of other Malaysian ethnicities and its expression in this study was inversely related to AR expression.

Management of advanced prostate cancer in a middle-income country: real-world consideration of the Advanced Prostate Cancer Consensus Conference 2017

OBJECTIVE

To examine the results of the Malaysian Advanced Prostate Cancer Consensus Conference (MyAPCCC) 2018, held for assessing the generalizability of consensus reached at the Advanced Prostate Cancer Consensus Conference (APCCC 2017) to Malaysia, a middle-income country.

METHODS

Six key sections were chosen: (1) high-risk localized and locally advanced prostate cancer, (2) oligometastatic prostate cancer, (3) castration-naïve prostate cancer, (4) castrate resistant prostate cancer, (5) use of osteoclast-targeted therapy and (6) global access to prostate cancer drugs. There were 101 consensus questions, consisting of 91 questions from APCCC 2017 and 10 new questions from MyAPCCC 2018, selected and modified by the steering committee; of which, 23 questions were assessed in both ideal world and real-world settings. A panel of 22 experts, comprising of 11 urologists and 11 oncologists, voted on 101 predefined questions anonymously. Final voting results were compared with the APCCC 2017 outcomes.

RESULTS

Most voting results from the MyAPCCC 2018 were consistent with the APCCC 2017 outcomes. No consensus was achieved for controversial topics with little level I evidence, such as management of oligometastatic disease. No consensus was reached on using high-cost drugs in castration-naïve or castration-resistant metastatic prostate cancer in real-world settings. All panellists recommended using generic drugs when available.

CONCLUSIONS

The MyAPCCC 2018 voting results reflect the management of advanced prostate cancer in a middle-income country in a real-world setting. These results may serve as a guide for local clinical practices and highlight the financial challenges in modern healthcare.

Author Correction: Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

In the version of this article initially published, the name of author Manuela Gago-Dominguez was misspelled as Manuela Gago Dominguez. The error has been corrected in the HTML and PDF version of the article.

Author Correction: Germline variation at 8q24 and prostate cancer risk in men of European ancestry

The original version of this Article contained an error in the spelling of the author Manuela Gago-Dominguez, which was incorrectly given as Manuela G. Dominguez. This has now been corrected in both the PDF and HTML versions of the Article.

Circulating Metabolic Biomarkers of Screen-Detected Prostate Cancer in the ProtecT Study

BACKGROUND

Whether associations between circulating metabolites and prostate cancer are causal is unknown. We report on the largest study of metabolites and prostate cancer (2,291 cases and 2,661 controls) and appraise causality for a subset of the prostate cancer-metabolite associations using two-sample Mendelian randomization (MR).

METHODS

The case-control portion of the study was conducted in nine UK centers with men ages 50-69 years who underwent prostate-specific antigen screening for prostate cancer within the Prostate Testing for Cancer and Treatment (ProtecT) trial. Two data sources were used to appraise causality: a genome-wide association study (GWAS) of metabolites in 24,925 participants and a GWAS of prostate cancer in 44,825 cases and 27,904 controls within the Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) consortium.

RESULTS

Thirty-five metabolites were strongly associated with prostate cancer (P < 0.0014, multiple-testing threshold). These fell into four classes: (i) lipids and lipoprotein subclass characteristics (total cholesterol and ratios, cholesterol esters and ratios, free cholesterol and ratios, phospholipids and ratios, and triglyceride ratios); (ii) fatty acids and ratios; (iii) amino acids; (iv) and fluid balance. Fourteen top metabolites were proxied by genetic variables, but MR indicated these were not causal.

CONCLUSIONS

We identified 35 circulating metabolites associated with prostate cancer presence, but found no evidence of causality for those 14 testable with MR. Thus, the 14 MR-tested metabolites are unlikely to be mechanistically important in prostate cancer risk.

IMPACT

The metabolome provides a promising set of biomarkers that may aid prostate cancer classification.

Germline variation at 8q24 and prostate cancer risk in men of European ancestry

Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10-15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62-4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification.

Heterogenous expression of ERG oncoprotein in Malaysian men with adenocarcinoma of the prostate

INTRODUCTION

Prostate cancer is a heterogenous disease and the mechanisms that drive it to behave differently are not well understood. Tumour expression of the ERG oncogene occurs in the majority of patients with prostate cancer in Western studies. This is considered to be oncogenic as ERG acts as a transcription factor to regulate genes involved in tumour proliferation and invasion. In this study we investigated expression of ERG in Malaysian men with prostate cancer.

METHODS

Tissues were collected from 80 patients with clinically detected prostate cancer and treated with radical prostatectomy. Cases were tested for ERG by immunohistochemistry using the mouse monoclonal antibody EP111. All blocks on 48 cases were tested in order to determine the extent of heterogeneity of ERG expression within individual cases. ERG expression was analysed in relation to patient age, ethnicity and tumour stage and grade.

RESULTS

Forty-six percent of cases were ERG positive. There was no significant association between ERG and tumour grade or stage. Sixty-nine percent of Indian patients had ERG positive tumours; this was significantly higher (p=0.031) than for Chinese (40%) and Malay (44%) patients. Heterogeneity of ERG expression, in which both positive and negative clones were present, was seen in 35% of evaluated cases. Evaluation by tumour foci showed younger patients had more ERG positive tumour foci than older patients (p=0.01). Indian patients were more likely to have the majority of tumour foci with ERG staining positively, compared to either Chinese or Malay patients (P <0.01).

CONCLUSION

In this study, tumour expression of ERG was more likely to occur in patients of Indian ethnicity.

Association analyses of more than 140,000 men identify 63 new prostate cancer susceptibility loci

Genome-wide association studies (GWAS) and fine-mapping efforts to date have identified more than 100 prostate cancer (PrCa)-susceptibility loci. We meta-analyzed genotype data from a custom high-density array of 46,939 PrCa cases and 27,910 controls of European ancestry with previously genotyped data of 32,255 PrCa cases and 33,202 controls of European ancestry. Our analysis identified 62 novel loci associated (P < 5.0 × 10-8) with PrCa and one locus significantly associated with early-onset PrCa (≤55 years). Our findings include missense variants rs1800057 (odds ratio (OR) = 1.16; P = 8.2 × 10-9; G>C, p.Pro1054Arg) in ATM and rs2066827 (OR = 1.06; P = 2.3 × 10-9; T>G, p.Val109Gly) in CDKN1B. The combination of all loci captured 28.4% of the PrCa familial relative risk, and a polygenic risk score conferred an elevated PrCa risk for men in the ninetieth to ninety-ninth percentiles (relative risk = 2.69; 95% confidence interval (CI): 2.55-2.82) and first percentile (relative risk = 5.71; 95% CI: 5.04-6.48) risk stratum compared with the population average. These findings improve risk prediction, enhance fine-mapping, and provide insight into the underlying biology of PrCa1.

Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants

Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling.

Spontaneous gastro-pancreatic fistula - a hitherto unknown natural history of IPMN?

Intraductal papillary mucinous neoplasm (IPMN) is a distinct group of benign pancreatic neoplasms often discovered incidentally on imaging. Apart from their malignant potential, little is known about their natural history as most are surgically resected. We report an unusual presentation and possible natural history of IPMN in a patient who refused surgery and hence was on regular follow up.

Safety and efficacy of self-expanding removable metal esophageal stents during neoadjuvant chemotherapy for resectable esophageal cancer

Patients with esophageal cancer may present with dysphagia and weight loss. Resectable lesions require consideration of neoadjuvant chemotherapy, which improves survival but have side effects, which compound already poor intake. Prevention of malnutrition has historically required interventions such as surgical jejunostomy or percutaneous endoscopic gastrostomy, which carry associated morbidity. With established roles in palliation, self-expanding removable metal stents (SERMS) may provide an alternative intervention in resectable disease. We sought to evaluate outcomes from our unit's introduction of SERMS in dysphagic patients prior to esophagectomy. All dysphagic patients presenting with esophageal cancer and considered for curative surgery between April 2006 and November 2008 were offered preoperative treatment of dysphagia with SERMS during neoadjuvant chemotherapy. Baseline and preoperative outcomes assessed included dysphagia score and nutritional markers. Sixteen patients underwent esophageal stenting during neoadjuvant therapy of whom 7/16 (44%) were female with mean age 63 (53-76). In 12/16 (75%), tumors were located in the lower one third of the esophagus. There was a significant fall in mean dysphagia score from 2.5 (range 1-4) to 1.1 (range 0-3) immediately preoperatively. There was no significant change in serum albumin, weight, or body mass index. Stent-related morbidity occurred in 4/16 (25%) patients and stomach migration occurred in 7/16 (43.8%). All were resolved endoscopically and there was no stent-related mortality. Of 10/16 (62.5%) patients ultimately progressing to esophagectomy, 30-day mortality was 6.3%. Anastomotic leak occurred in one patient (10%) and R1 resection rate was 20%. SERMS are a safe and effective intervention in dysphagic patients undergoing neoadjuvant chemotherapy for esophageal cancer. Complications are minor and readily treatable with endoscopy. Objective parameters suggest nutritional status is maintained and symptoms are improved. SERMS do not appear to compromise resection.

PleurX drain use in the management of malignant ascites: safety, complications, long-term patency and factors predictive of success

OBJECTIVES

The aim of this article was to assess the success, safety, complication profile and factors associated with long-term patency of tunnelled peritoneal drains (PleurX) in the treatment of refractory malignant ascites.

METHODS

Over a 4-year period, 28 consecutive patients (32 drain insertions) with refractory malignant ascites were treated with a PleurX drain. The study group comprised 7 males and 21 females (mean age, 61 years). A combination of fluoroscopic and ultrasound guidance was used to insert 4 drains; the remaining 28 drains were inserted under ultrasound guidance alone. Patient history, biochemical profiles, pathological and procedural records and clinical follow-up until death were reviewed. Statistical analysis included multivariate logistic regression analysis and Kaplan-Meier curves (p<0.05 was considered significant).

RESULTS

There was a 100% technical success rate for the insertion of the drain; there were no procedure-related deaths and no major complications. Only minor complications were reported: three (10%) immediate; three (10%) early; and two (7%) late. Factors significantly associated with these complications included current chemotherapy, low haemoglobin levels, low albumin levels, high white cell count and high c-reactive protein levels. The length of time the drains remained in situ, and therefore patent, ranged from 5 to 365 days (mean, 113 days). Out of the original 28 tunnelled drains, 24 (86%) remained in situ and functioning until the patients' death. Four (14%) drains dislodged and a subsequent PleurX drain was inserted on the opposite side of the abdominal wall. These new drains remained patent until the patient's death. The annual event rate was 0.45 events per year. A comorbid diagnosis of renal disease or chemotherapy was significantly related to a decreased length of patency.

CONCLUSION

The use of tunnelled peritoneal drains is safe and effective and we would advocate their use as a first-line approach in patients with refractory malignant ascites. Care and regular follow-up is indicated following insertion of the drain in all patients, especially those on chemotherapy and those with a pre-procedure diagnosis of renal disease.

Peritoneal implantation of ureter in a cadaveric kidney transplant recipient

We report here a case of a kidney transplant recipient in whom the ureter was initially implanted into the peritoneum. Excessive ultrafiltration volume and reversal of serum vs dialysate creatinine ratio when the patient was recommenced on continuous ambulatory peritoneal dialysis first suggested the diagnosis which was subsequently confirmed by a plain abdominal x-ray demonstrating placement of ureteric stent in the peritoneum. This rare complication was successfully corrected with surgical re-implantation of ureter into the bladder and 5 years later, the patient remains well with good graft function.

P53 protein expression in transitional cell carcinoma of the bladder - experience of the University of Malaya Medical Centre

OBJECTIVES

To study the incidence of p53 oncoprotein overexpression and its relationship to tumour grade, stage and clinical prognosis in a cohort of local Malaysian patients.

METHODS

All cases of transitional cell carcinoma (TCC) of the bladder diagnosed and treated at the University of Malaya Medical Centre from January 1995 to December 2000 were retrieved from the hospital records. Sections from paraffin-embedded tissues were retrieved and stained for p53 oncoprotein using immunohistochemistry techniques. P53 oncoprotein results were analyzed in relation to tumour grade, stage and clinical prognosis. Fisher's exact test was used to evaluate the relationship between categorical variables and the Kaplan-Meier procedure was used to assess survival outcomes. The Cox regression model was used for multivariate analysis.

RESULTS

A total of 64 cases were studied. The mean follow-up period was 23.7 months. The number of p53 positive cases was significantly higher in high-grade (G3) (p = 0.006) and muscle-invasive tumours ( summation operator T2, p = 0.035). The status of p53 expression had no significant association with recurrence-free (p = 0.594) or overall survival (p = 0.955). In multivariate analysis, a multiplicity of tumours at presentation (p = 0.004) and a history of cigarette smoking (p = 0.016) were independent predictors of recurrence. Tumour stage (p = 0.024) was the single independent predictor for poor overall survival.

CONCLUSIONS

Overexpression of p53 is associated with TCC of higher grade and tumour stage. It had no significant impact on prognosis in this cohort of TCC cases.

A prospective, randomized, double-blind study comparing lignocaine gel and plain lubricating gel in relieving pain during flexible cystoscopy

OBJECTIVE

To determine the optimum duration for the retention of 2% lignocaine gel intraurethrally as an anaesthetic for flexible cystoscopy in men.

PATIENTS AND METHODS

A prospective, randomized, double-blind, placebo-controlled trial was conducted in two parts. Initially, the importance of duration was determined, i.e. whether pain relief was significantly improved when lignocaine gel was instilled for longer than is currently practised. As pain relief was improved by retaining the lignocaine gel for longer, the optimum time was determined in a second trial. Initially, 90 patients were divided into four groups receiving 20 mL of 2% lignocaine gel or plain lubricating gel for 5 or 25 min. Subsequently, 60 men were divided into two groups receiving 20 ml of 2% lignocaine gel for 15 or 25 min. The patients' discomfort was recorded using a 4-point descriptive pain scale and a 100 mm non-graphical visual analogue scale.

RESULTS

In the first study, those patients receiving lignocaine gel for 25 min experienced significantly less pain than the other three groups. In the second, lignocaine gel in the urethra for 15 min provided the same level of pain relief as lignocaine for 25 min.

CONCLUSION

Pain during flexible cystoscopy can be significantly reduced when 20 mL of 2% lignocaine gel is left in the urethra for 15 min; lignocaine gel would be more effective when left for longer than is currently practised.

Heatstroke: its clinical and pathological presentation, with particular attention to the liver

Heatstroke is a potentially fatal disorder caused by an extreme elevation of body temperature. It is the most severe of the illnesses produced as a result of a high ambient temperature; however, it also may occur sporadically among individuals working or exercising in more favorable weather conditions, particularly early in their training before acclimatization occurs. The liver is a common site of tissue injury in cases of heatstroke and can be the site of fatal tissue injury in cases that survive the initial neurologic injury. Prompt early recognition of heatstroke as the entity responsible for a given patient's problems and effective early cooling with attention to expected complications can result in complete recovery in most cases. In a minority (< 10%) in whom neurologic injury has not resulted in an early death occurring within the first 2-3 days, the hepatic injury due to heatstroke can result in death that occurs a week or more after the onset of the heat stress, unless the liver is replaced. Recently, two such cases have been referred to the University of Pittsburgh for transplantation. On the basis of these two referrals and a review of the literature, we believe that this problem occurs more often than is currently appreciated, principally because of a lack of knowledge about the problem. In an attempt to correct this information deficit, this review was prepared.