Abstract 6075: Comprehensive genomic characterization of early-stage bladder cancer from 438 patients by whole genome- and exome sequencing

Background: The genomic landscape of cancer is complex and includes mutations and copy number alterations (CNAs) that affect several cancer related pathways and drive tumor evolution. Non-muscle-invasive bladder cancers (NMIBC) are largely orphan for integrative genomic studies. Large studies are needed to delineate the genomic complexity and heterogeneity of NMIBC.

Methods: A total of 438 patients with NMIBC were analyzed, 296 of which were part of the UROMOL cohort (PMID: 27321955). The median follow-up was 5 years. The progression rate was 13% (n= 56). Whole exome sequencing (WES) was performed on DNA from tumor (~150x) and matched germline samples to call somatic mutations. Additionally, shallow whole genome sequencing (sWGS; ~2x) was performed on DNA from 362 of the tumors to quantify CNAs. RNA-sequencing was available for 414 of the samples, and tumors were classified according to the UROMOL2021 transcriptomic classes. We identified significantly mutated genes by mutsigCV and significantly amplified or deleted regions by GISTIC2.

Results: The median tumor mutation burden (TMB) was 3.7/Mb. TMB was not associated with progression (p=0.28). A total of 61 genes were significantly mutated in the cohort, the most frequent being FGFR3 (61%), KDM6A (44%) and KMT2D (38%). Mutations in EP300 and RHOB were significantly associated with an increased risk of progression after adjusting for grade and stage (p=0.040 and 0.044, respectively). Several mutations showed a strong transcriptomic class dependent occurrence: mutations in RB1, TP53, ERCC2 and ERBB2 were enriched in the aggressive class 2a, FGFR3 and STAG2 in class 1 and class 3, and KMT2C and KMT2D in class 3.

Genome doubling was identified in 15% of the tumors. These tumors were enriched in the aggressive classes 2a and 2b and were associated with increased risk of progression (p=0.0049). In addition, we observed several significantly altered genomic regions, the most significant being deletions in 9p21.3 (CDKN2A & CDKN2B, 64%), 2q37.1 (GIGYF2 & EIF4E2, 28%) and amplification in 11q13.3 (CCND1, 9%). Class 2a tumors were enriched for genomic alterations in most of the significant regions. 9p21.3 was the only region with frequent homozygous losses (22%). High-level gains were prognostic of progression, independently of ploidy, stage and grade, for several regions, including 4p16.3 (FGFR3, p=0.00013), 17q23.2(TBX2, p=0.0004) and 8p11.23(ZNF703, p=0.011). In addition, we observed an enrichment of uniparental disomy in 4p16.3 (FGFR3, 8%).

Conclusion: Here we investigated the landscape of DNA alterations in NMIBC in a large patient cohort of NMIBC samples with paired transcriptomic data and detailed clinical follow-up. We identified several novel genomic alterations; specifically, we showed that 15% of the tumors had genome doublings, and we identified a complex underlying copy number landscape of the region containing FGFR3.

Citation Format: Frederik Prip, Philippe Lamy, Iver Nordentoft, Sia Viborg Lindskrog, Trine Strandgaard, Karin Birkenkamp-Demtröder, Gregers G. Hermann, Astrid C. Petersen, Veronika Bahlinger, Marc-Oliver Grimm, Marcus Horstmann, Karin Mogensen, Roman Nawroth, Ulrika Segersten, Danijel Sikic, Kim E. M van Kessel, Tobias Maurer, Tatjana Simic, Arndt Hartmann, Ellen C. C. Zwarthoff, Per-Uno Malmström, Torben Steiniche, Jørgen Bjerggaard Jensen, Núria Malats, Francisco X. Real, Lars Dyrskjøt. Comprehensive genomic characterization of early-stage bladder cancer from 438 patients by whole genome- and exome sequencing. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6075.

External Validation of the 2003 Leibovich Prognostic Score in Patients Randomly Assigned to SORCE, an International Phase III Trial of Adjuvant Sorafenib in Renal Cell Cancer

The 2003 Leibovich score guides prognostication and selection to adjuvant clinical trials for patients with locally advanced renal cell carcinoma (RCC) after nephrectomy. We provide a robust external validation of the 2003 Leibovich score using contemporary data from SORCE, an international, randomized trial of sorafenib after excision of primary RCC.

Read how we have shown that the 2003 Leibovich score demonstrates discriminative accuracy in contemporary clear-cell and non–clear-cell RCC patient cohorts, supporting its continued use to guide discussions on patient prognosis and risk-stratification in clinical trials.

Morpho-molecular signal correlation between optical coherence tomography and Raman spectroscopy for superior image interpretation and clinical diagnosis

The combination of manifold optical imaging modalities resulting in multimodal optical systems allows to discover a larger number of biomarkers than using a single modality. The goal of multimodal imaging systems is to increase the diagnostic performance through the combination of complementary modalities, e.g. optical coherence tomography (OCT) and Raman spectroscopy (RS). The physical signal origins of OCT and RS are distinctly different, i.e. in OCT it is elastic back scattering of photons, due to a change in refractive index, while in RS it is the inelastic scattering between photons and molecules. Despite those diverse characteristics both modalities are also linked via scattering properties and molecular composition of tissue. Here, we investigate for the first time the relation of co-registered OCT and RS signals of human bladder tissue, to demonstrate that the signals of these complementary modalities are inherently intertwined, enabling a direct but more importantly improved interpretation and better understanding of the other modality. This work demonstrates that the benefit for using two complementary imaging approaches is, not only the increased diagnostic value, but the increased information and better understanding of the signal origins of both modalities. This evaluation confirms the advantages for using multimodal imaging systems and also paves the way for significant further improved understanding and clinically interpretation of both modalities in the future.

An integrated multi-omics analysis identifies prognostic molecular subtypes of non-muscle-invasive bladder cancer

The molecular landscape in non-muscle-invasive bladder cancer (NMIBC) is characterized by large biological heterogeneity with variable clinical outcomes. Here, we perform an integrative multi-omics analysis of patients diagnosed with NMIBC (n = 834). Transcriptomic analysis identifies four classes (1, 2a, 2b and 3) reflecting tumor biology and disease aggressiveness. Both transcriptome-based subtyping and the level of chromosomal instability provide independent prognostic value beyond established prognostic clinicopathological parameters. High chromosomal instability, p53-pathway disruption and APOBEC-related mutations are significantly associated with transcriptomic class 2a and poor outcome. RNA-derived immune cell infiltration is associated with chromosomally unstable tumors and enriched in class 2b. Spatial proteomics analysis confirms the higher infiltration of class 2b tumors and demonstrates an association between higher immune cell infiltration and lower recurrence rates. Finally, the independent prognostic value of the transcriptomic classes is documented in 1228 validation samples using a single sample classification tool. The classifier provides a framework for biomarker discovery and for optimizing treatment and surveillance in next-generation clinical trials.

Morpho-molecular ex vivo detection and grading of non-muscle-invasive bladder cancer using forward imaging probe based multimodal optical coherence tomography and Raman spectroscopy

Non-muscle-invasive bladder cancer affects millions of people worldwide, resulting in significant discomfort to the patient and potential death. Today, cystoscopy is the gold standard for bladder cancer assessment, using white light endoscopy to detect tumor suspected lesion areas, followed by resection of these areas and subsequent histopathological evaluation. Not only does the pathological examination take days, but due to the invasive nature, the performed biopsy can result in significant harm to the patient. Nowadays, optical modalities, such as optical coherence tomography (OCT) and Raman spectroscopy (RS), have proven to detect cancer in real time and can provide more detailed clinical information of a lesion, e.g. its penetration depth (stage) and the differentiation of the cells (grade). In this paper, we present an ex vivo study performed with a combined piezoelectric tube-based OCT-probe and fiber optic RS-probe imaging system that allows large field-of-view imaging of bladder biopsies, using both modalities and co-registered visualization, detection and grading of cancerous bladder lesions. In the present study, 119 examined biopsies were characterized, showing that fiber-optic based OCT provides a sensitivity of 78% and a specificity of 69% for the detection of non-muscle-invasive bladder cancer, while RS, on the other hand, provides a sensitivity of 81% and a specificity of 61% for the grading of low- and high-grade tissues. Moreover, the study shows that a piezoelectric tube-based OCT probe can have significant endurance, suitable for future long-lasting in vivo applications. These results also indicate that combined OCT and RS fiber probe-based characterization offers an exciting possibility for label-free and morpho-chemical optical biopsies for bladder cancer diagnostics.

Adjuvant Sorafenib for Renal Cell Carcinoma at Intermediate or High Risk of Relapse: Results From the SORCE Randomized Phase III Intergroup Trial

PURPOSE

SORCE is an international, randomized, double-blind, three-arm trial of sorafenib after surgical excision of primary renal cell carcinoma (RCC) found to be at intermediate or high risk of recurrence.

PATIENTS AND METHODS

We randomly assigned participants (2:3:3) to 3 years of placebo (arm A), 1 year of sorafenib followed by 2 years of placebo (arm B), or 3 years of sorafenib (arm C). The initial sorafenib dose was 400 mg twice per day orally, amended to 400 mg daily. The primary outcome analysis, which was revised as a result of external results, was investigator-reported disease-free survival (DFS) comparing 3 years of sorafenib versus placebo.

RESULTS

Between July 2007 and April 2013, we randomly assigned 1,711 participants (430, 642, and 639 participants in arms A, B, and C, respectively). Median age was 58 years, 71% of patients were men, 84% had clear cell histology, 53% were at intermediate risk of recurrence, and 47% were at high risk of recurrence. We observed no differences in DFS or overall survival in all randomly assigned patients, patients with high risk of recurrence, or patients with clear cell RCC only. Median DFS was not reached for 3 years of sorafenib or for placebo (hazard ratio, 1.01; 95% CI, 0.83 to 1.23; P = .95). We observed nonproportional hazards; the restricted mean survival time (RMST) was 6.81 years for 3 years of sorafenib and 6.82 years for placebo (RMST difference, 0.01 year; 95% CI, -0.49 to 0.48 year; P = .99). Despite offering treatment adaptations, more than half of participants stopped treatment by 12 months. Grade 3 hand-foot skin reaction was reported in 24% of participants on sorafenib.

CONCLUSION

Sorafenib should not be used as adjuvant therapy for RCC. Active surveillance remains the standard of care for patients at intermediate or high risk of recurrence after nephrectomy and is the appropriate control of our current international adjuvant RCC trial, RAMPART.

Bladder tissue characterization using probe-based Raman spectroscopy: Evaluation of tissue heterogeneity and influence on the model prediction

Existing approaches for early-stage bladder tumor diagnosis largely depend on invasive and time-consuming procedures, resulting in hospitalization, bleeding, bladder perforation, infection and other health risks for the patient. The reduction of current risk factors, while maintaining or even improving the diagnostic precision, is an underlying factor in clinical instrumentation research. For example, for clinic surveillance of patients with a history of noninvasive bladder tumors real-time tumor diagnosis can enable immediate laser-based removal of tumors using flexible cystoscopes in the outpatient clinic. Therefore, novel diagnostic modalities are required that can provide real-time in vivo tumor diagnosis. Raman spectroscopy provides biochemical information of tissue samples ex vivo and in vivo and without the need for complicated sample preparation and staining procedures. For the past decade there has been a rise in applications to diagnose and characterize early cancer in different organs, such as in head and neck, colon and stomach, but also different pathologies, for example, inflammation and atherosclerotic plaques. Bladder pathology has also been studied but only with little attention to aspects that can influence the diagnosis, such as tissue heterogeneity, data preprocessing and model development. The present study presents a clinical investigative study on bladder biopsies to characterize the tumor grading ex vivo, using a compact fiber probe-based imaging Raman system, as a crucial step towards in vivo Raman endoscopy. Furthermore, this study presents an evaluation of the tissue heterogeneity of highly fluorescent bladder tissues, and the multivariate statistical analysis for discrimination between nontumor tissue, and low- and high-grade tumor.

Can routine outpatient follow-up of patients with bladder cancer be improved? A multicenter prospective observational assessment of blue light flexible cystoscopy and fulguration

BACKGROUND

The aim of this prospective cohort study was to determine the feasibility of incorporating blue light flexible cystoscopy (BLFC) and biopsy/fulguration into routine outpatient follow-up of non-muscle invasive bladder cancer patients.

METHODS

The study included patients with non-muscle-invasive bladder cancer (NMIBC) who were scheduled for routine follow-up. Hexaminolevulinate was instilled in the outpatient department, and the bladder was examined under white light and then with BLFC. Biopsies were taken from all suspicious lesions. Small tumors and suspicious lesions were fulgurated on site; patients with larger lesions were referred to the operating room for resection.

RESULTS

The study included 69 patients, with a mean age of 70 years (range 33-89 years) and a mean duration since NMIBC diagnosis of 8 years. Most patients had high-grade cancer at initial diagnosis (52/69) and were at high risk of recurrence (48/69). Two patients per hour could be assessed using outpatient BLFC. Preparation and instillation of hexaminolevulinate took less than 10 minutes per patient, and patients had an additional waiting time of 45-60 minutes following instillation, while the hexaminolevulinate solution was retained in the bladder before examination. Eleven patients had histologically confirmed tumors that were identified using both white light flexible cystoscopy and BLFC. An additional three patients had tumors that were identified by BLFC only: two with Ta tumors and one with carcinoma in situ. Of the 14 patients with confirmed tumors, 11 could be managed on site with fulguration, whereas three were referred to the operating room. No adverse events attributable to BLFC were reported.

CONCLUSION

Routine outpatient management of patients with NMIBC using BLFC and on-site biopsy/fulguration is feasible, despite the additional time required for hexaminolevulinate instillation, and appears to allow early detection of recurrent lesions, which can be fulgurated without the need for hospitalization.

Non-muscle-invasive bladder cancer: a vision for the future

The management of non-muscle-invasive bladder cancer (NMIBC) has evolved from the first reports on bladder endoscopy and transurethral resection to the introduction of adjuvant intravesical treatment. However, disease recurrence and progression remain an ongoing risk, placing a heavy burden on healthcare resources and on patients' quality of life. Deeper understanding of the molecular basis of the disease and developments in optics, lasers and computer science are already offering opportunities to revolutionize care and improve long-term prognosis. This article discusses developments likely to cause a paradigm shift towards the delivery of personalized care and reduced burden of disease in NMIBC.

Comprehensive Transcriptional Analysis of Early-Stage Urothelial Carcinoma

Non-muscle-invasive bladder cancer (NMIBC) is a heterogeneous disease with widely different outcomes. We performed a comprehensive transcriptional analysis of 460 early-stage urothelial carcinomas and showed that NMIBC can be subgrouped into three major classes with basal- and luminal-like characteristics and different clinical outcomes. Large differences in biological processes such as the cell cycle, epithelial-mesenchymal transition, and differentiation were observed. Analysis of transcript variants revealed frequent mutations in genes encoding proteins involved in chromatin organization and cytoskeletal functions. Furthermore, mutations in well-known cancer driver genes (e.g., TP53 and ERBB2) were primarily found in high-risk tumors, together with APOBEC-related mutational signatures. The identification of subclasses in NMIBC may offer better prognostication and treatment selection based on subclass assignment.

A five-factor biomarker profile obtained week 4-12 of treatment for improved prognostication in metastatic renal cell carcinoma: Results from DARENCA study 2

Background: Several biomarkers of treatment efficacy have been associated with a better prognosis in patients with metastatic renal cell carcinoma (mRCC). The prognostic significance of biomarkers in the early treatment phase is unclear.

Material and methods: In a complete national cohort of mRCC patients receiving first-line tyrosine kinase inhibitors (TKI) or interleukin-2 based immunotherapy (IT) from 2006 to 2010, overall survival (OS) was analysed for baseline International mRCC Database Consortium (IMDC) classification factors and on-treatment time-dependent biomarkers obtained day 1 each cycle week 4–12 after treatment initiation with multivariate analysis and bootstrap validation.

Results: A total of 735 patients received first-line TKI (59%) or IT (41%). Median OS was overall 14.0 months and 33.4, 18.5, and 5.8 months for baseline IMDC favourable, intermediate, and poor risk groups, respectively (p < 0.0001). Systolic blood pressure ≥140 mmHg, neutrophils < lower level of normal (LLN), platelets < LLN, sodium ≥ LLN, and LDH ≤1.5 times upper level of normal after treatment initiation were significantly associated with favourable OS independent of baseline IMDC risk group in multivariate analyses stratified for TKI and IT (p ≤ 0.04). Concordance (C)-index for IMDC classification alone was 0.625 (95% CI 0.59–0.66) and combined with the five-factor biomarker profile 0.683 (95% CI 0.64–0.72). For patients with good (3–5 factors) and poor (0–2 factors) biomarker profile median OS were 23.5 and 9.6 months, respectively (p < 0.0001). Adding the five-factor biomarker profile significantly improved prognostication in IMDC intermediate (25.7 vs. 12.0 months, p < 0.0001) and poor (12.8 vs. 6.4 months, p < 0.0001) risk groups. A trend was seen in IMDC favourable risk group (38.9 vs. 28.7 months, p = 0.112).

Conclusion: On-treatment hypertension, neutropenia, thrombocytopenia, LDH below 1.5 times upper level of normal, and normal sodium, obtained week 4–12 of treatment, are independent biomarkers of favourable outcome in mRCC, independent of treatment type.

Office-based transurethral devascularisation of low grade non-invasive urothelial cancer using diode laser. A feasibility study

BACKGROUND AND OBJECTIVE

Frequent recurrence of non-muscle invasive bladder tumours (NMIBC) requiring transurethral resection of bladder tumour (TUR-BT) and lifelong monitoring makes the lifetime cost per patient the highest of all cancers. A new method is proposed for the removal of low grade NMIBCs in an office-based setting, without the need for sedation and pain control and where the patient can leave immediately after treatment.

STUDY DESIGN/PATIENTS AND METHODS

An in vitro model was developed to examine the dose/response relationship between laser power, treatment time, and distance between laser fibre and target, using a 980 nm diode laser and chicken meat. The relationship between depth and extent of tissue destruction and the laser settings was measured using microscopy and non-parametric statistical analysis. A patient with low grade stage Ta tumour and multiple comorbidity, and therefore not fit for general anaesthesia, had a tumour devascularised using the laser at the tumour base, in the outpatient department. The tumour was left in the bladder.

RESULTS

In the in vitro model, depth of tissue destruction increased with laser illumination up to 30 seconds, where median depth was 4.1 mm. With longer illumination the tissue destruction levelled off. The width of tissue destruction was 2-3 mm independent of laser illumination time. The in vivo laser treatments devascularised the tumour, which was later shed from the mucosa and passed out with the urine in the days following treatment. Pain score was 0 on a visual log scale (0-10). The tumour had completely disappeared two weeks after treatment.

CONCLUSION

This diode laser technique may provide almost pain-free office-based treatment of low grade urothelial cancer using flexible cystoscopes in conscious patients. A prospective randomised study will be scheduled to compare the technique with standard TUR-BT in the operating theatre.

Overall survival after immunotherapy, tyrosine kinase inhibitors and surgery in treatment of metastatic renal cell cancer: outcome of 143 consecutive patients from a single centre

OBJECTIVE

The aim of this study was to evaluate overall survival (OS) after treatment of metastatic renal cell carcinoma (mRCC) following the introduction of tyrosine kinase inhibitors (TKIs) and mammalian target of rapamycin (mTOR) inhibitors.

MATERIAL AND METHODS

One-hundred and forty-three consecutive mRCC patients were given immunotherapy (n = 59), TKIs (n = 49) or sequential therapy (IMM → TKI group; n = 35). The TKI group included patients with higher age (p < 0.001), worse performance status (p = 0.005) and higher risk profile (p < 0.001) than the other two treatment groups. Number of metastases and sites and tumour histology did not differ between groups.

RESULTS

First line immunotherapy gave a median OS of 16.3 months and first line TKIs 10.9 months (p = 0.003). Survival longer than 5 years was limited to immunotherapy. Sarcomatoid component, metastatic sites, papillary histology, stage, performance status and white cell blood count were related to poor OS. Using multivariate analyses to adjust for risk predictors the difference in OS disappeared. Median OS before and after introduction of TKIs was 16 months and 14 months, respectively (p = 0.189). Memorial Sloan Kettering Cancer Center (MSKCC) risk groups were related to OS (p < 0.001). Heng's prognostic criteria appeared slightly more predictive than MSKCC (p = 0.12). Metastasectomy (n = 42) may improve OS [surgery: median OS 18.8 months, 95% confidence interval (CI) 12.3-48.5; no surgery: median OS 15 months, 95% CI 10.4-16.5; p = 0.07].

CONCLUSIONS

MSKCC and Heng's prognostic algorithms were valid for prognostication and can be used for individual planning of treatment and follow-up. Surgical removal of metastases may improve OS.

Exploration of two methods for quantitative Mitomycin C measurement in tumor tissue in vitro and in vivo

Two methods of quantifying Mitomycin C in tumor tissue are explored. A method of ultraviolet-visible absorption microscopy is developed and applied to measure the concentration of Mitomycin C in preserved mouse tumor tissue, as well as in gelatin samples. Concentrations as low as 60 μM can be resolved using this technique in samples that do not strongly scatter light. A novel method for monitoring the Mitomycin C concentrations inside a tumor is developed, based on microdialysis and ultraviolet-visible spectroscopy. A pump is used to perfuse a microdialysis probe with Ringer’s solution, which is fed to a flow cell to determine intratumor concentrations in real time to within a few μM. The success and limitations of these techniques are identified, and suggestions are made as to further development. To the authors’ knowledge these are the first attempts made to quantify Mitomycin C concentrations in tumor tissue.

Delayed healing at transurethral resection of bladder tumour sites after immediate postoperative mitomycin C instillation

The most common reactions to mitomycin C are dysuria and drug-related palmar and genital desquamation. This report describes two cases of delayed healing of the mucosa at resection sites after transurethral resection of bladder tumours, most likely due to immediate postoperative mitomycin C instillation of the bladder.

Diagnosis of bladder cancer recurrence based on urinary levels of EOMES, HOXA9, POU4F2, TWIST1, VIM, and ZNF154 hypermethylation

Background

Non muscle invasive bladder cancer (NMIBC) has the highest recurrence rate of any malignancy and as many as 70% of patients experience relapse. Aberrant DNA methylation is present in all bladder tumors and can be detected in urine specimens. Previous studies have identified DNA methylation markers that showed significant diagnostic value. We evaluated the significance of the biomarkers for early detection of tumor recurrence in urine.

Methodology/Principal Findings

The methylation levels of EOMES, HOXA9, POU4F2, TWIST1, VIM, and ZNF154 in urine specimens were measured by real-time PCR (MethyLight). We analyzed 390 urine sediments from 184 patients diagnosed with NMIBC. Urine from 35 age-matched control individuals was used to determine the methylation baseline levels. Recurrence was diagnosed by cystoscopy and verified by histology. Initially, we compared urine from bladder cancer patients and healthy individuals and detected significant hypermethylation of all six markers (P<0.0001) achieving sensitivity in the range 82%–89% and specificity in the range 94%–100%. Following, we validated the urinary hypermethylation for use in recurrence surveillance and found sensitivities of 88–94% and specificities of 43–67%. EOMES, POU4F2, VIM and ZNF154 were more frequently methylated in urine from patients with higher grade tumors (P≤0.08). Univariate Cox regression analysis showed that five markers were significantly associated with disease recurrence; HOXA9 (HR = 7.8, P = 0.006), POU4F2 (HR = 8.5, P = 0.001), TWIST1 (HR = 12.0, P = 0.015), VIM (HR = 8.0, P = 0.001), and ZNF154 (HR = 13.9, P<0.001). Interestingly, for one group of patients (n = 15) we found that hypermethylation was consistently present in the urine samples despite the lack of tumor recurrences, indicating the presence of a field defect.

Conclusion/Significance

Methylation levels of EOMES, HOXA9, POU4F2, TWIST1, VIM, and ZNF154 in urine specimens are promising diagnostic biomarkers for bladder cancer recurrence surveillance.

Electroporation enhances mitomycin C cytotoxicity on T24 bladder cancer cell line: a potential improvement of intravesical chemotherapy in bladder cancer

Intravesical mitomycin instillation combined with electric pulses is being used experimentally for the treatment of T1 bladder tumors, in patients unfit for surgery. Electroporation may enhance the uptake of chemotherapeutics by permeabilization of cell membranes. We investigated if electroporation improves the cytotoxicity of mitomycin. In two cell lines, T24 (bladder cancer cell line) and DC3F (Chinese hamster fibroblast), exposure to different concentrations of mitomycin (0.01-2000μM) was tested with and without electroporation (6 pulses of 1kV/cm, duration: 99μs, frequency: 1Hz). Cell viability was assessed by colorimetric assay (MTT). For both cell lines, mitomycin's IC_50 was approximately 1000μM in both pulsed and unpulsed cells. On T24 cells, electroporation and mitomycin caused (relative reduction) RR of survival of: 25%, 31% and 29%, by concentrations 0μM, 500μM and 1000μM respectively. For DC3F cells, the RRs of survival were: 28%, 29%, and 33%, by concentrations 0μM, 500μM and 1000μM respectively. In conclusion, electroporation and mitomycin together are about 30% more effective than mitomycin alone. The results help to elucidate the additive effect of mitomycin and electric pulses and support the use of this combination in the treatment of bladder cancer.

Low ANXA10 expression is associated with disease aggressiveness in bladder cancer

Background:

Markers for outcome prediction in bladder cancer are urgently needed. We have previously identified a molecular signature for predicting progression in non-muscle-invasive bladder cancer. ANXA10 was one of the markers included in the signature and we now validated the prognostic relevance of ANXA10 at the protein level.

Methods:

We investigated ANXA10 expression by immunohistochemistry using a tissue microarray with 249 Ta and T1 urothelial carcinomas. The expression of ANXA10 was also investigated in an additional set of 97 more advanced tumours. The functional role of ANXA10 in cell lines was investigated by siRNA-mediated ANXA10 knockdown using wound-healing assays, proliferation assays, and ingenuity pathway analysis.

Results:

Low expression of ANXA10 correlated with shorter progression-free survival in patients with stage Ta and T1 tumours (P<0.00001). Furthermore, patients with more advanced tumours and low ANXA10 expression had an unfavourable prognosis (P<0.00001). We found that ANXA10 siRNA transfected cells grew significantly faster compared with control siRNA transfected cells. Furthermore, a wound-healing assay showed that ANXA10 siRNA transfected cells spread along wound edges faster than control transfected cells.

Conclusion:

We conclude that ANXA10 may be a clinical relevant marker for predicting outcome in both early and advanced stages of bladder cancer.

Fluorescence-guided transurethral resection of bladder tumours reduces bladder tumour recurrence due to less residual tumour tissue in Ta/T1 patients: a randomized two-centre study

OBJECTIVES

•To compare the bladder tumour recurrence rate in stage Ta and T1 tumours after conventional transurethral resection of the bladder in white light (WL TURB) and after fluorescence-guided TURB (HAL TURB) using hexaminolaevulinate (HAL: Hexvix®, Photocure, Norway) for photodynamic diagnosis during 12 months of follow-up. •As secondary objectives, to relate the tumour recurrence rate to fluorescence-detected residual tumour after WL TURB and to assess the false positive rate.

PATIENTS AND METHODS

•This was a prospective, comparative, randomized, open-label study carried out in hospital outpatient urology clinics and the operating theatre. A total of 233 patients presenting with suspected superficial bladder tumour were recruited. Both patients with new tumours and patients with recurrent tumours were included. •The study duration was 2.5 years with follow-up cystoscopic investigations at 4, 8 and 12 months. •Patients were randomized to cystoscopy and WL TURB (118 patients) or WL TURB followed immediately by HAL TURB (115 patients). Cystoscopy/TURB and bladder biopsies were performed under general anaesthesia. No patients had intravesical chemotherapy immediately after TURB. •Recurrences were verified histologically.

RESULTS

•The two groups were similar regarding age and previous bladder cancer history. •In all, 90 patients from the HAL TURB group had bladder tumour. Fluorescence-guided cystoscopy after complete WL TURB identified residual tumour tissue in 44 of 90 patients (49%). In 37 of 83 (45%) residual Ta tumour was found; in three of seven residual T1 was found and in four cases carcinoma in situ. •True (and false) positive detection rate of photodynamic diagnosis was 64% (25%) and of white light 83% (16%). •In all, 145 patients were eligible for analysis of tumour recurrence. Twelve patients had their last follow-up after 4 months. The recurrence rate in patients followed for 12 months was 47.3% (35/74) after WL TURB and 30.5% (18/59) after HAL TURB (P= 0.05). •Kaplan-Meier analyses comprising data from all 145 patients showed that the recurrence-free period was significantly longer in the HAL TURB group than in the WL TURB group (P= 0.02).

CONCLUSION

•WL TURB often leaves residual tumour in the bladder. HAL TURB improves the detection of Ta/T1 tumours of the bladder resulting in more complete TURB procedures and thus a reduced recurrence rate.

The influence of the level of lamina propria invasion and the prevalence of p53 nuclear accumulation on survival in stage T1 transitional cell bladder cancer

PURPOSE

We assessed the influence of the level of lamina propria invasion and the prevalence of p53 nuclear immunoreactivity on the survival of patients with stage T1 transitional cell bladder cancer.

MATERIALS AND METHODS

All patients presenting with stage T1 bladder cancer were prospectively and routinely grouped according to the level of lamina propria invasion. Invasion of the tumor stalk was defined as stage T1a, invasion of the lamina propria proper superficial to the level of muscularis mucosa as stage T1b and into or deeper than the muscularis mucosa as stage T1c. The p53 nuclear immunoreactivity was determined with antibody PAB 1801.

RESULTS

The study comprised 143 patients including 31 (22%) with stage T1a disease, 60 (42%) with stage T1b and 52 (36%) with stage T1c. Mean patient age was 67 years (range 38 to 92) and mean followup was 4.7 years (range 2.4 to 9.7). Tumor grade related to the depth of lamina propria invasion (p < 0.05) and the prevalence of dysplasia in random mucosal biopsies was higher in stage T1b and T1c tumors than in stage T1a. Of all tumors 42% expressed p53 nuclear reactivity which correlated with tumor grade (p < 0.05). Also the prevalence of nuclear p53 was higher in stages T1b and T1c compared with T1a disease. Of the patients 115 were treated with transurethral resection alone and 28 underwent radical cystectomy. Overall survival was 60.1%. Age was the only independent predictor of survival in patients older than 75 years. For patients up to 75 years old survival related to age, level of lamina propria invasion and presence of p53 nuclear accumulation. For this subpopulation overall survival was 67%, and 79% for stage T1a, 70% for stage T1b and 57% for stage T1c (p < 0.05). Survival was higher in patients with p53 negative (73%) than in those with p53 positive (61%) tumors (p < 0.05). A multivariate analysis of the influence of lamina propria invasion and nuclear p53 status on survival histology was found to be the only independent predictor of survival.

CONCLUSIONS

Immediate radical cystectomy should be considered for patients with stage T1c tumors and for some patients with stage T1b disease, particularly those with tumors expressing p53 nuclear reactivity and with dysplasia in the random mucosal biopsies.

Transitional cell carcinoma express vitamin D receptors

Recently, vitamin D analogues have shown antineoplastic effect in several diseases. Vitamin D analogues exert its effect by interacting with the vitamin D receptor (VDR). Studies of VDR in transitional cell carcinoma (TCC) have not been reported. The purpose of the present study was therefore to examine whether human bladder tumor cells express VDR. Tumor biopsies were obtained from 26 patients with TCC. Expression of VDR was examined by immunohistochemical experiments. All tumors expressed VDR. Biopsies from advanced disease contained more VDR positive cells than low stage disease (p < 0.05). Similarly, also tumor grade appeared to be related to the number of cells expressing the receptor. Normal urothlium also expressed VDR but only with low intensity. Our study shows that TCC cells possess the VDR receptor which may make them capable to respond to stimulation with vitamin D, but functional studies of vitamin D's effect on TCC cells in vitro are necessary before the efficacy of treatment with vitamin D analogues in TCC can be evaluated in patients.

Transfection of glioma cells with the neural-cell adhesion molecule NCAM: effect on glioma-cell invasion and growth in vivo

The tumor growth and the invasive capacity of a rat glioma cell line (BT4Cn) were studied after transfection with the human transmembrane 140-kDa isoform of the neural-cell adhesion molecule, NCAM. After s.c. injection, the NCAM-transfected cells showed a slower growth rate than the parent cell line (BT4Cn). Upon intracerebral implantation with BT4Cn cells and different clones of NCAM-transfected cells, all animals developed neurological symptoms within 13-16 days. However, the tumors showed different growth characteristics. The NCAM-transfected BT4Cn cells were localized in the region of the injection site, with a sharply demarcated border between the tumor and brain tissue. In contrast, the parental cell line showed single-cell infiltration and more pronounced destruction of normal brain tissue. Using a 51Cr-release assay, spleen cells from rats transplanted with BT4Cn tumor cells generally showed a lower cytotoxic response than the spleen cells from rats transplanted with the transfected variants of BT4Cn cells, indicating that the transfection procedure in itself mediated an activation of the immune system. The present data suggest that NCAM may influence the malignant behavior of rat glioma cells in vivo.

The in vitro cytotoxicity of urine from patients with interstitial cystitis

Urine from patients with interstitial cystitis has been reported to be more cytotoxic than urine from healthy subjects when tested in vitro against cells from a normal urothelial cell line. The purpose of the present study was to develop a method to measure urinary cytotoxicity and so make it possible to estimate the toxicity of urine from interstitial cystitis patients. The study included 10 women with interstitial cystitis and 10 healthy controls. Urine specimens were obtained from both groups and urine cytotoxicity was measured by a modified 51Cr-release assay: A range of urine dilutions was added to suspensions of target cells with intracellular bound 51Cr, and cellular death was recorded by measuring the 51Cr-release from the target cells. The transitional cell bladder cell lines T24 and Hu609 and the erythroleukemia K562 cell line were used as target cells. There was no difference in urine cytotoxicity between interstitial cystitis patients and healthy controls. Urine cytotoxicity was increased by dilution in both groups.

Microsatellite instability in bladder cancer

Somatic instability at microsatellite repeats was detected in 6 of 200 transitional cell carcinomas of the bladder. Instabilities were apparent as changes in (GT)n repeat lengths on human chromosome 9 for four tumors and as alterations in a (CAG)n repeat in the androgen receptor gene on the X chromosome for three tumors. Single locus alterations were detected in three tumors, while three other tumors revealed changes in two or more loci. In one tumor we found microsatellite instability in all five loci analyzed on chromosome 9. The alterations detected were either minor 2-base pair changes or larger (> 2 base pairs) alterations in repeat length. All six tumors were low stage (Ta-T1), suggesting that these alterations can occur early in bladder tumorigenesis.

Distinct pattern of p53 mutations in bladder cancer: relationship to tobacco usage

A distinct mutational spectrum for the p53 tumor suppressor gene in bladder carcinomas was established in patients with known exposures to cigarette smoke. Single-strand conformational polymorphism analysis of exons 5 through 8 of the p53 gene showed inactivating mutations in 16 of 40 (40%) bladder tumors from smokers and 13 of 40 (33%) tumors from lifetime nonsmokers. Overall, 13 of the 50 (26%) total point mutations discovered in this and previous work were G:C-->C:G transversions, a relatively rare mutational type in human tumors. In six tumors, identical AGA (Arg)-->ACA (Thr) point mutations at codon 280 were observed, suggesting a mutational hotspot in these tumors. Comparison of the mutational spectra from smokers and nonsmokers revealed no obvious differences in the types or positions of inactivating mutations; however, 5 of 15 tumors containing point mutations from cigarette smokers had double mutations, four of which were tandem mutations on the same allele. No double mutations were found in tumors from nonsmoking patients. None of the mutations in smokers were G:C-->T:A transversions, which would be anticipated for exposure to the suspected cigarette smoke carcinogen 4-aminobiphenyl. The results suggest that, although cigarette smoke exposure may not significantly alter the kinds of mutations sustained in the p53 gene, it may act to increase the extent of DNA damage per mutagenic event.

Treatment of metastatic renal cell carcinoma by continuous intravenous infusion of recombinant interleukin-2: a single-center phase II study

PURPOSE

A single-center phase II study was performed to evaluate the efficacy of recombinant interleukin-2 (rIL-2) administered by continuous infusion to patients with metastatic renal cell carcinoma (RCC).

PATIENTS AND METHODS

Thirty-one patients with RCC were entered onto the study. rIL-2 (Proleukin; Eurocetus Corp, Amsterdam, The Netherlands) was administered intravenously in a dose of 18 x 10(6) IU/m2 per 24 hours. A maximum of two induction cycles and four maintenance cycles were given. Each induction cycle consisted of two rIL-2 infusion periods of 120 hours and 108 hours duration, respectively; these were separated by a 6-day rest period. Each maintenance cycle consisted of a 120 hours rIL-2 infusion period.

RESULTS

Six of 30 assessable patients (20%) responded; two (7%) with a complete response (CR) and four (13%) with a partial response (PR). The response duration for patients with CR was 209 and 715+ days, and for those with PR 161, 197, 245, and 353 days. Seven patients had stable disease (SD) with a median duration of 261 days (range, 127 to 381 days). The overall median survival was 261 days (range, 13 to 905+ days). The most frequent toxicities requiring dose reductions of rIL-2 were: hypotension in 87% of patients, dyspnea in 32%, CNS toxicity in 55%, and an increase in serum creatinine levels in 48%. Septicemia occurred in 16% of patients. Toxicities usually reversed on interruption of rIL-2 infusion. One patient (3%) died as a result of the treatment from initial CNS toxicity followed by multiorgan failure.

CONCLUSIONS

The study confirmed the antitumor efficacy of rIL-2 administered by continuous infusion in patients with metastatic RCC. The response rate was similar to that obtained by high-dose bolus injections of rIL-2. Toxicity was substantial but manageable in a specialized oncology ward without routine use of an intensive care unit.

In vitro production of TNF-alpha, IL-1 beta and IL-6 by mononuclear blood cells of patients with renal cell carcinoma undergoing rIL-2 treatment. Relation between clinical response and TNF-alpha production

The purpose of this study was to examine the production of IL-1 beta, IL-6 and TNF-alpha by peripheral blood mononuclear cells in patients with renal cell carcinoma treated with recombinant interleukin 2 (rIL-2). Peripheral blood mononuclear cells (PBMC) were purified from blood samples obtained six times during therapy and the production of IL-1 beta, IL-6 and TNF-alpha were determined after 18 h culture of the PBMC in culture medium or in medium containing 10 micrograms lipopolysaccharide (LPS)/ml, 10 ng LPS/ml or 1000 units rIL-2/ml. In vivo therapy with rIL-2 resulted in substantial changes in the production of the three cytokines. Only the production of TNF-alpha following in vitro stimulation with rIL-2 was related to the clinical response, being significant lower in responding patients than in non-responders (P less than 0.05). These findings suggest that the rIL-2-induced TNF-alpha production of PBMC in vitro is lower in renal cancer patients that respond to rIL-2 therapy than in non-responding patients.

Recombinant interleukin-2 and lymphokine-activated killer cell treatment of advanced bladder cancer: clinical results and immunological effects

The purpose of this study was to evaluate the efficacy of treatment with recombinant interleukin-2 (rIL-2) and lymphokine-activated killer cells in patients with advanced bladder cancer and to study the induced changes in the distribution of leukocyte subsets in blood and tumor. Nine patients with metastatic transitional cell cancer of the bladder were treated with a continuous infusion of rIL-2 combined with lymphocytes stimulated in vitro with rIL-2. None of the patients responded to the therapy despite substantial changes observed in the immunological cells, both in tumor and blood. The rIL-2 infusion induced migration of leukocytes to the tumors, which was related to increased expression of the adhesion molecule VLA-1 on both peripheral blood mononuclear cells and the endothelial cells of small tumor vessels. Only T-cells, predominately expressing IL-2 receptors, and macrophages infiltrated the tumors. Natural killer cells remained few or absent in the tumors, even though the natural killer cells in peripheral blood were activated by the treatment. This study shows that the present technique of rIL-2 and lymphokine-activated killer cell therapy is able to induce substantial changes in the immune system of patients with metastatic bladder cancer. However, this treatment did not induce tumor regression, which may be due to the advanced stage of disease.

LAK-cell-mediated cytotoxicity against tumor cell targets used to monitor the stimulatory effect of interleukin-2: cytotoxicity, target recognition and phenotype of effector cells lysing the Daudi, T24 and K562 tumor cell lines

The T24 transitional bladder carcinoma cell line, the Daudi Burkitt lymphoma cell line and the K562 erythroleukemia cell line have all been used as target cells in 51Cr release assays to measure the in vivo induced lymphokine-activated killer (LAK) cell cytotoxicity during interleukin-2 (IL-2) therapy of cancer patients. However, different relationships between the clinical response to IL-2 treatment and the LAK cytotoxicity have been reported using these three different target cells. The purpose of the present study was to evaluate whether the LAK cytotoxicities measured against these target cells represent similar effector-to-target-cell interactions, so similar conclusions may be drawn of 51Cr release assay results in which the cell lines are used as target cells. The cytotoxicity of peripheral blood mononuclear cells (PBMC) and PBMC depleted of different natural killer and T cell subsets was measured against the three targets. LAK cell recognition of targets was evaluated by cold target inhibition experiments, and the development of LAK-cell-mediated lysis with time was evaluated in 51Cr release assays of varying duration. This study shows that LAK-mediated lysis of T24 and Daudi cells was closely related and LAK cytotoxicity measured in 51Cr release assays against these two target cells may be measurement of similar effector-to-target cell interactions.

Intravesical BCG therapy in bladder carcinoma. Effect on cytotoxicity, IL-2 production and phenotype of peripheral blood mononuclear cells

The purpose of the study was to examine the effects of intravesical BCG treatment on the cytotoxicity, interleukin-2 (IL-2) production and distribution of the subsets of peripheral blood mononuclear cells (PBMC) in patients with carcinoma in situ of the bladder. Treatments were made in 6 patients during a conventional BCG treatment schedule. Four patients showed a complete response, one a partial response and one had a progressive disease after BCG treatment. Intravesical BCG did not induce significant changes in the cytotoxicity of PBMC. The distribution of NK-cells and T-cells also remained unchanged and so did the lectin induced production of IL-2. The results suggest that the effects of intravesical BCG on the immune system should be studied in lymphocytes isolated from the bladder.

Interleukin-2 dose, blood monocyte and CD25+ lymphocyte counts as predictors of clinical response to interleukin-2 therapy in patients with renal cell carcinoma

The purpose of this study was to determine immunological parameters in the peripheral blood that correlate with the clinical effect of interleukin-2 (IL-2) in patients with metastatic renal cell cancer. A group of 26 patients with metastatic renal cell cancer underwent IL-2 treatment using a 36-day schedule with continuous intravenous IL-2 infusion (3 x 10(6) units m-2 day-1) administered from days 1 to 5 and days 12 to 16. The white blood cell count and the absolute and relative number of neutrophils, lymphocytes, eosinophils and monocytes were recorded six times in peripheral blood during the treatment. Also the blood counts of T cell and NK cell subsets and cells expressing the T cell activation markers IL-2R alpha and VLA-1 were measured. The lymphokine-activated killer (LAK) cell cytotoxicity was measured either with or without additional in vitro stimulation by IL-2. Multivariate statistical analysis showed that the clinical responses were related to the administered dose of IL-2, to a low number of blood cells expressing IL-2 receptors and to a reduction in the blood monocyte count (P less than 0.05).

Reduced LAK cytotoxicity of peripheral blood mononuclear cells in patients with bladder cancer: decreased LAK cytotoxicity caused by a low incidence of CD56+ and CD57+ mononuclear blood cells

The cytotoxicity of unstimulated peripheral blood mononuclear cells (US-PBMC), phytohemagglutinin (PHA)-stimulated PBMC (PS-PBMC) and interleukin-2 (IL-2)-activated PBMC (LAK cells) was assessed in patients with noninvasive and invasive transitional-cell bladder cancer and compared with those determined in healthy controls. The differences in the cytotoxicities were correlated with specific changes in the subsets of peripheral blood mononuclear cells (PBMC). PBMC from 37 patients and 13 healthy controls were tested against the bladder cancer cell line T24 in 51Cr-release assays. The PBMC subsets were analyzed using monoclonal antibodies against T cells, natural killer (NK) -cells, monocytes, and activation markers. The cytotoxicities of US-PBMC, PS-PBMC, and LAK cells were all significantly lower in the cancer patients than in the controls (P less than 0.05). The percentages of PBMC positive for the NK-cell markers CD56 and CD57 were lowest in the patients and were correlated to the decrease in cytotoxicity. Depletion of CD56+ or CD57+ cells from PBMC prior to or after 2 days stimulation with IL-2 demonstrated that these cells are the major source of LAK-cell cytotoxicity and showed that the reduced ability of bladder cancer patient PBMC to develop LAK-cell cytotoxicity is a result of a low incidence of CD56+ and CD57+ cells in the blood. These findings indicate that IL-2 therapy alone might not be a sufficient therapy of bladder cancer patients.

Low dose intravesical heparin as prophylaxis against recurrent noninvasive (stage Ta) bladder cancer

A controlled randomized clinical trial was conducted to examine the efficacy of topical low dose heparin (0.125 gm./l., 25,000 units per l.) as prophylaxis against recurrent noninvasive (stage Ta) transitional cell bladder cancer. Transurethral tumor resection was done with irrigation fluid containing either 1.5% glycine with heparin or glycine solution alone. Tumor recurrence was determined by cystoscopy 4 to 6 months later. There were 70 patients evaluated: 38 in the heparin and 32 in the control group, respectively. The recurrence rate (heparin 74%, control 66%) and the median number of recurrences (heparin 3, range 1 to 15 and control 3, range 1 to 30) were similar (p greater than 0.05) in the 2 groups of patients. These observations show that low dose heparin administered in the irrigation fluid during transurethral resection does not decrease the recurrence rate of noninvasive (stage Ta) bladder cancer.

Voiding patterns and prevalence of incontinence in women. A questionnaire survey

A detailed questionnaire on the occurrence of irritative and obstructive voiding symptoms, incontinence and the number of childbirths was sent out to 600 women aged between 20 and 79 years, randomly selected from the National Register; 432 (72%) returned the questionnaire and 414 (69%) were evaluable. The frequency of obstructive symptoms such as hesitancy, intermittency and decreased stream was low. Diurnal frequency with voiding intervals less than 3 h were recorded by more than 50% of the women and about 10% voided more frequently than every second hour. Nocturia increased significantly with age; 54 (13.6%) voided at least twice per night. About 40% complained of incontinence but this was troublesome in only 6%; 15.3, 13.3 and 11.5% had stress, urge and mixed incontinence respectively. More than 8% wore nappies or sanitary towels every day to protect against urinary leakage. Although the tendency to wear nappies or sanitary towels increased with age, the increase was not statistically significant. There was a positive correlation between the occurrence of stress incontinence and childbirth in the group as a whole.

Voiding patterns in men evaluated by a questionnaire survey

A questionnaire on obstructive and irritative voiding symptoms was sent to 572 men aged between 20 and 79 years, selected at random from the National Register; 337 questionnaires were completed. None of the responders had consulted a doctor because of voiding symptoms. There was a significant increase in voiding symptoms and in the obstructive, irritative and total symptom scores between the sixth and seventh [corrected] decades, whereas the increases in the other decades were small. Only the prevalence of terminal dribbling was uniform. The prevalence of single obstructive and irritative voiding symptoms in men aged 60 to 79 years without subjective prostatism was the same as in patients admitted with prostatism, although most of the men had milder symptoms. Only nocturia and urge incontinence were more prevalent in patients admitted with prostatism. About 20% of men in the oldest decades had symptoms equal in severity to those found in men undergoing prostatectomy; 29% and 11% of men in the eighth decade [corrected] had nocturia twice and 3 times or more respectively; 19% complained of urge incontinence. More information on possible treatment is needed.

[Scientific articles in Ugeskrift for Laeger during a 25-year period. Types of articles and experimental design]

The purpose of this study was to examine possible trends in the research designs used in Ugeskrift for Laeger during 25 years. The scientific articles in 12 issues of the journal selected at random from each of the years 1959, 1964, 1969, 1974, 1979, and 1984 were reviewed. From each article, the following information was obtained: type of article (original paper, case report, or review), origin of the paper and number of authors. For the original papers, it was noted whether it was a longitudinal or a cross-sectional study, and whether it was a cohort or a trohoc study. Furthermore the number of subjects and the use of control group, randomization and blinding were registered. The number of articles and the number of authors per article increased during the period. Contrary to similar studies of some widely circulated English-language journals, we could not demonstrate any increase of the frequency of studies with weak research design. On the other hand, no striking improvement was observed either. Most studies had no control group and randomization and blinding were used in less than 10% of the original papers. The present study does not permit an evaluation of whether the research designs used i Ugeskrift for Laeger are satisfactory.

[Scientific articles in Ugeskrift for Laeger during a 25-year period. Analysis and interpretation of research results]

During a period of 25 years from 1959 to 1984, no essential alteration in the employment of descriptive statistics was observed in the original articles in the Ugeskrift whereas analytical statistics was employed to an increasing extent. In all of these volumes, defective, incorrect or less suitable employment of statistics could be demonstrated. Common problems were: analyses of materials in which some patients participated once while others participated on several occasions; debatable analyses of data on ranking scales; employment of 2-group tests on several groups; insufficient analysis of cross-over trials; lack of confidence intervals, and circular reasoning.

Early secondary suture versus healing by second intention of incisional abscesses

A controlled trial was set up to compare the treatment of wound abscesses, occurring after laparotomy, with either early secondary suture combined with cefuroxime and metronidazole given intravenously or by healing by second intention. The secondary suture was performed two days after wound drainage and resulted in a significant reduction (p less than 0.01) in healing time without complications. No reinfections occurred.