Martijn Busstra

Prospective validation of a risk calculator which calculates the probability of a positive prostate biopsy in a contemporary clinical cohort

BACKGROUND Prediction models need validation to assess their value outside the development setting. OBJECTIVE To assess the external validity of the European Randomised study of Screening for Prostate Cancer (ERSPC) Risk Calculator (RC) in a contemporary clinical cohort. METHODS The RC calculates the probability of a positive sextant prostate biopsy (P(posb)) using serum prostate-specific antigen (PSA), results of digital rectal examination, transrectal ultrasound (TRUS) and ultrasound assessed prostate volume. We prospectively validated the RC in 320 biopsied men (55-75 years), with no previous prostate biopsy, included in five Dutch hospitals in 2008-2011. If the P(posb) was ≥ 20% a biopsy was recommended. The performance of the RC was tested by comparing the observed outcomes to predicted probabilities, using the area under the curve (AUC) and decision curves analyses. RESULTS Compared to the screening cohort, men in the clinical cohort differed. They had higher PSA levels (median 6.8 versus 4.3 ng/ml, p<0.01), less TRUS-lesions (27% versus 34%, p = 0.01) and more prostate cancer (PCa) at biopsy (43% versus 25%, p<0.01). Mainly eight biopsy cores were taken. Despite the differences between these cohorts, the mean observed probability agreed with the mean predicted probability (43% versus 40%). The RC predicted P(posb) better than a model with PSA and digital rectal examination, AUC 0.77 (95% confidence interval (CI) 0.72-0.83) and 0.71 (95%CI 0.65-0.76, p<0.01), respectively. This was confirmed by the decision curves analysis. Under the 20% threshold, 17% (11/63) of the biopsied men were diagnosed with PCa. Two of 11 men had an important cancer (Gleason 3+4). CONCLUSIONS The ERSPC RC performs well in a Dutch clinical cohort in men with previous PSA tests and contemporary biopsy schemes, and outperforms a PSA and DRE-based approach in the decision to perform a biopsy.

Optimization of Nonmuscle Invasive Bladder Cancer Recurrence Detection Using a Urine Based FGFR3 Mutation Assay

PURPOSE FGFR3 mutations occur in 70% of nonmuscle invasive bladder tumors. Although urine based FGFR3 mutation analysis can detect recurrence, its sensitivity may be limited if samples have few or no tumor cells. We determined whether test sensitivity depends on tumor size and the time point of urine collection, and how to increase sensitivity. MATERIALS AND METHODS A total of 440 urine samples from 18 patients with a suspicious bladder lesion at cystoscopy were collected during 6 days before surgery. Eight patients (300 samples) had an FGFR3 mutant tumor, including 4 each with a tumor greater than 3 and less than 1.5 cm. Polymerase chain reaction based FGFR3 analysis was done on all tumors and urine samples. RESULTS FGFR3 mutations were detected in 257 of the 300 urine samples (86%) from patients with an FGFR3 mutant tumor. Assay sensitivity was 100% for tumors greater than 3 cm and 75% for tumors less than 1.5 cm. It increased to 100% in patients with a less than 1.5 cm tumor when samples were pooled during 24 hours. Sensitivity was not influenced by the time of urine collection. All urine samples from patients with an FGFR3 wild-type tumor were negative for FGFR3 mutation. CONCLUSIONS The sensitivity of tumor detection increased with tumor size. FGFR3 assay sensitivity depends on the number of shed tumor cells and improves by increasing urine volume. These findings suggest that there is an upper limit to the sensitivity of the FGFR3 assay when 1 urine sample is analyzed. This may also apply to other DNA or RNA based assays.

A phase II study of temozolomide in hormone-refractory prostate cancer.

Introduction: Hormone-refractory disseminated prostate cancer is a major oncological problem. Preclinical studies with temozolomide, an oral alkylating agent, in prostate cancer have shown encouraging results. In phase I studies the safety of temozolomide in non-prostate cancer patients has been demonstrated. Based on these results, a phase II study of temozolomide in patients with metastatic disease who had developed progressive symptomatic disease while on antiandrogen therapy, was initiated. Methods: A group of 18 patients started a 5-day temozolomide regimen, with a 28-day treatment cycle. Response parameters (prostate-specific antigen, bone scan, quality of life questionnaire) and toxicity (common toxicity criteria for international studies) were recorded at regular intervals. Results: Of the 18 patients, 16 were evaluable by completing two or three cycles. All patients developed progressive disease within two cycles, except one who had progressive disease at the end of cycle 3. Of the 16 evaluable patients, 11 developed new bone metastases (bone scan), 1 developed lung metastases, 4 had progressive disease as reflected by a 25% increase in serum PSA together with subjective progression, and 7 and 5 had progressive disease as reflected by decreased quality of life and increased pain score, respectively. Toxicity was limited to nausea and vomiting, which was effectively treated with antiemetic medication, and anemia and thrombocytopenia, which returned to normal values within 1 week. Discussion: Treatment with temozolomide was generally well tolerated, with occasionally moderate toxicity. As all patients developed progressive disease the results are rather discouraging. Temozolomide is ineffective for the treatment of patients with symptomatic progressive hormone-refractory prostate cancer.

Compliance with biopsy recommendations of a prostate cancer risk calculator

Study Type – Diagnostic (cohort)

Selecting men diagnosed with prostate cancer for active surveillance using a risk calculator: a prospective impact study

Study Type – Prognosis (cohort series)

In-depth investigation of the molecular pathogenesis of bladder cancer in a unique 26-year old patient with extensive multifocal disease: a case report.

BackgroundThe molecular characteristics and the clinical disease course of bladder cancer (BC) in young patients remain largely unresolved. All patients are monitored according to an intensive surveillance protocol and we aim to gain more insight into the molecular pathways of bladder tumors in young patients that could ultimately contribute to patient stratification, improve patient quality of life and reduce associated costs. We also determined whether a biomarker-based surveillance could be feasible.Case PresentationWe report a unique case of a 26-year-old Caucasian male with recurrent non-muscle invasive bladder tumors occurring at a high frequency and analyzed multiple tumors (maximal pTaG2) and urine samples of this patient. Analysis included FGFR3 mutation detection, FGFR3 and TP53 immunohistochemistry, mircosatellite analysis of markers on chromosomes 8, 9, 10, 11 and 17 and a genome wide single nucleotide polymorphism-array (SNP). All analyzed tumors contained a mutation in FGFR3 and were associated with FGFR3 overexpression. None of the tumors showed overexpression of TP53. We found a deletion on chromosome 9 in the primary tumor and this was confirmed by the SNP-array that showed regions of loss on chromosome 9. Detection of all recurrences was possible by urinary FGFR3 mutation analysis.ConclusionsOur findings would suggest that the BC disease course is determined by not only a patients age, but also by the molecular characteristics of a tumor. This young patient contained typical genetic changes found in tumors of older patients and implies a clinical disease course comparable to older patients. We demonstrate that FGFR3 mutation analysis on voided urine is a simple non-invasive method and could serve as a feasible follow-up approach for this young patient presenting with an FGFR3 mutant tumor.

Selecting men diagnosed with prostate cancer for active surveillance using a risk calculator

Study Type – Prognosis (cohort series)

Selecting men diagnosed with prostate cancer for active surveillance using a risk calculator: a prospective impact study: SELECTING MEN FOR ACTIVE SURVEILLANCE WITH RISK CALCULATOR

Study Type – Prognosis (cohort series)