Multiparametric Magnetic Resonance Imaging in Prostate Cancer Screening at the Age of 45 Years: Results from the First Screening Round of the PROBASE Trial

BACKGROUND

Magnetic resonance imaging (MRI) has been suggested as a tool for guiding biopsy recommendations in prostate cancer (PC) screening.

OBJECTIVE

To determine the performance of multiparametric MRI (mpMRI) in young men at age 45 yr who participated in a PC screening trial (PROBASE) on the basis of baseline prostate-specific antigen (PSA).

DESIGN, SETTING, AND PARTICIPANTS

Participants with confirmed PSA ≥3 ng/ml were offered mpMRI followed by MRI/transrectal ultrasound fusion biopsy (FBx) with targeted and systematic cores. mpMRI scans from the first screening round for men randomised to an immediate PSA test in PROBASE were evaluated by local readers and then by two reference radiologists (experience >10 000 prostate MRI examinations) blinded to the histopathology. The PROBASE trial is registered as ISRCTN37591328 OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The local and reference Prostate Imaging-Data and Reporting System (PI-RADS) scores were compared, and the sensitivity, negative predictive value (NPV), and accuracy were calculated for both readings for different cutoffs (PI-RADS 3 vs 4).

RESULTS AND LIMITATIONS

Of 186 participants, 114 underwent mpMRI and FBx. PC was detected in 47 (41%), of whom 33 (29%) had clinically significant PC (csPC; International Society of Urological Pathology grade group ≥2). Interobserver reliability between local and reference PI-RADS scores was moderate (k = 0.41). At a cutoff of PI-RADS 4, reference reading showed better performance for csPC detection (sensitivity 79%, NPV 91%, accuracy of 85%) than local reading (sensitivity 55%, NPV 80%, accuracy 68%). Reference reading did not miss any PC cases for a cutoff of PI-RADS <3. If PI-RADS ≥4 were to be used as a biopsy cutoff, mpMRI would reduce negative biopsies by 68% and avoid detection of nonsignificant PC in 71% of cases.

CONCLUSIONS

Prostate MRI in a young screening population is difficult to read. The MRI accuracy of for csPC detection is highly dependent on reader experience, and double reading might be advisable. More data are needed before MRI is included in PC screening for men at age 45 yr.

PATIENT SUMMARY

Measurement of prostate specific antigen (PSA) is an effective screening test for early detection of prostate cancer (PC) and can reduce PC-specific deaths, but it can also lead to unnecessary biopsies and treatment. Magnetic resonance imaging (MRI) after a positive PSA test has been proposed as a way to reduce the number of biopsies, with biopsy only recommended for men with suspicious MRI findings. Our results indicate that MRI accuracy is moderate for men aged 45 years but can be increased by a second reading of the images by expert radiologists. For broad application of MRI in routine screening, double reading may be advisable.

Digital Rectal Examination Is Not a Useful Screening Test for Prostate Cancer

BACKGROUND

Annual digital rectal examination (DRE) is recommended as a stand-alone screening test for prostate cancer (PCa) in Germany for 45+ yr olds. DRE diagnostic performance in men as young as 45 yr old has not been proved by a screening trial.

OBJECTIVE

To determine DRE diagnostic performance in a screening trial.

DESIGN, SETTING, AND PARTICIPANTS

This analysis was conducted within the multicentric, randomized PROBASE trial, which enrolled >46 000 men at age 45 to test risk-adapted prostate-specific antigen (PSA) screening for PCa.

INTERVENTION

(1) DRE was analyzed as a one-time, stand-alone screening offer at age 45 in 6537 men in one arm of the trial and (2) PCa detection by DRE was evaluated at the time of PSA-screen-driven biopsies (N = 578).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

(1) True-/false-positive detection rates of DRE as compared with PSA screening and (2) DRE outcome at the time of a prostate biopsy were evaluated.

RESULTS AND LIMITATIONS

(1) A prospective analysis of 57 men with suspicious DRE at age 45 revealed three PCa. Detection rate by DRE was 0.05% (three of 6537) as compared with a four-fold higher rate by PSA screening (48 of 23 301, 0.21%). The true-positive detection rate by DRE relative to screening by PSA was 0.22 (95% confidence interval [CI] = [0.07-0.72]) and the false-positive detection rate by DRE was 2.2 (95% CI = [1.50-3.17]). (2) Among PSA-screen-detected PCa cases, 86% had unsuspicious DRE (sensitivity relative to PSA was 14%), with the majority of these tumors (86%) located in the potentially accessible zones of the prostate as seen by magnetic resonance imaging.

CONCLUSIONS

The performance of stand-alone DRE to screen for PCa is poor. DRE should not be recommended as a PCa screening test in young men. Furthermore, DRE does not improve the detection of PSA-screen-detected PCa.

PATIENT SUMMARY

Our report demonstrated the poor diagnostic performance of digital rectal examination in the screening for prostate cancer in young men.

Adherence to a risk-adapted screening strategy for prostate cancer: First results of the PROBASE trial

PROBASE is a population-based, randomized trial of 46 495 German men recruited at age 45 to compare effects of risk-adapted prostate cancer (PCa) screening starting either immediately at age 45, or at a deferred age of 50 years. Based on prostate-specific antigen (PSA) levels, men are classified into risk groups with different screening intervals: low-risk (<1.5 ng/ml, 5-yearly screening), intermediate-risk (1.5-2.99 ng/ml, 2 yearly), and high risk (>3 ng/ml, recommendation for immediate biopsy). Over the first 6 years of study participation, attendance rates to scheduled screening visits varied from 70.5% to 79.4%, depending on the study arm and risk group allocation, in addition 11.2% to 25.4% of men reported self-initiated PSA tests outside the PROBASE protocol. 38.5% of participants had a history of digital rectal examination or PSA testing prior to recruitment to PROBASE, frequently associated with family history of PCa. These men showed higher rates (33% to 57%, depending on subgroups) of self-initiated PSA testing in-between PROBASE screening rounds. In the high-risk groups (both arms), the biopsy acceptance rate was 64% overall, but was higher among men with screening PSA ≥4 ng/ml (>71%) and with PIRADS ≥3 findings upon multiparameter magnetic resonance imaging (mpMRI) (>72%), compared with men with PSA ≥3 to 4 ng/ml (57%) or PIRADS score ≤ 2 (59%). Overall, PROBASE shows good acceptance of a risk-adapted PCa screening strategy in Germany. Implementation of such a strategy should be accompanied by a well-structured communication, to explain not only the benefits but also the harms of PSA screening.

Low positive predictive value of computed tomography screening for lung cancer irrespective of commonly employed definitions of target population

Screening for lung cancer (LC) by low-dose computed tomography (LDCT) has been demonstrated to reduce LC mortality in randomized clinical trials (RCTs), and its implementation is in preparation in many countries. However, definition of the target population, which was based on various combinations of age ranges and definitions of heavy smoking in the RCTs, is subject to ongoing debate. Using epidemiological data from Germany, we aimed to estimate prevalence of preclinical LC and positive predictive value (PPV) of LDCT in potential target populations defined by age and smoking history. Populations aged 50 to 69, 55 to 69, 50 to 74 and 55 to 79 years were considered in this analysis. Sex-specific prevalence of preclinical LC was estimated using LC incidence data within those age ranges and annual transition rates from preclinical to clinical LC obtained by meta-analysis. Prevalence of preclinical LC among heavy smokers (defined by various pack-year thresholds) within those age ranges was estimated by combining LC prevalence in the general population with proportions of heavy smokers and relative risks for LC among them derived from epidemiological studies. PPVs were calculated by combining these prevalences with sensitivity and specificity estimates of LDCT. Estimated prevalence of LC was 0.3% to 0.5% (men) and 0.2% to 0.3% (women) in the general population and 0.8% to 1.7% in target populations of heavy smokers. Estimates of PPV of LDCT were <20% for all definitions of target populations of heavy smokers. Refined preselection of target populations would be highly desirable to increase PPV and efficiency of LDCT screening and to reduce numbers of false-positive LDCT findings.

Screening for gastric cancer using exhaled breath samples

BACKGROUND

The aim was to derive a breath-based classifier for gastric cancer using a nanomaterial-based sensor array, and to validate it in a large screening population.

METHODS

A new training algorithm for the diagnosis of gastric cancer was derived from previous breath samples from patients with gastric cancer and healthy controls in a clinical setting, and validated in a blinded manner in a screening population.

RESULTS

The training algorithm was derived using breath samples from 99 patients with gastric cancer and 342 healthy controls, and validated in a population of 726 people. The calculated training set algorithm had 82 per cent sensitivity, 78 per cent specificity and 79 per cent accuracy. The algorithm correctly classified all three patients with gastric cancer and 570 of the 723 cancer-free controls in the screening population, yielding 100 per cent sensitivity, 79 per cent specificity and 79 per cent accuracy. Further analyses of lifestyle and confounding factors were not associated with the classifier.

CONCLUSION

This first validation of a nanomaterial sensor array-based algorithm for gastric cancer detection from breath samples in a large screening population supports the potential of this technology for the early detection of gastric cancer.

Systematic review: Gut microbiota in fecal samples and detection of colorectal neoplasms

Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality. Dysbiosis in the gut microbiota may be associated with CRC. This systematic review focuses on differences in gut microbial community between people diagnosed with CRC or adenoma and healthy individuals using fecal samples, emphasizing non-invasive fecal microbiome models for CRC early diagnosis. Nineteen studies were identified in a systematic literature search of Pubmed, Web of Science and ScienceDirect. Several bacteria were reported to differ in abundance between CRC and adenoma cases and healthy controls, with Fusobacterium the most common. Fecal multi-bacterial predictive models used to distinguish CRC patients from healthy controls had reported areas under the receiver operating curve (AUCs) in external validation populations of 0.68-0.77. Though advanced sequencing techniques could in the future complement current non-invasive methods for CRC early detection, more studies with high statistical power, comparable and reproducible methods and external validation of predictive models are needed.

International variation in the prevalence of preclinical colorectal cancer: Implications for predictive values of noninvasive screening tests and potential target populations for screening

Screening for colorectal cancer (CRC) is implemented in an increasing number of countries. We aimed to assess international variation in the prevalence of preclinical CRC and the resulting variation in positive and negative predictive values (PPVs, NPVs) of existing and potential CRC screening tests in various countries. Using age‐ and sex‐specific CRC incidence data and transition rates from preclinical to clinical CRC we estimated overall and age‐ and sex‐specific prevalence of preclinical CRC in the target population aged 50–74 years in different parts of the world. These prevalence estimates were used to derive PPVs and NPVs for existing and potential noninvasive screening tests with varying levels of sensitivity and specificity. Within all regions and countries, prevalence strongly increases with age and is higher in men than in women. In addition, major variation was seen between regions and countries, with overall prevalence varying between 1 and 0.1%. As a result, PPVs are expected to strongly vary between ∼10% for men in high incidence countries, such as Australia and Germany, and 1% for women in low incidence countries, whereas NPVs are expected to be consistently well above 99%. Variation in CRC prevalence profoundly affects expected PPVs of screening tests, and PPVs should be carefully considered when decisions on screening tests and strategies are made for specific populations and health care systems. Here, we provide estimates of preclinical CRC and expected PPVs and NPVs of noninvasive screening tests, which may enhance the empirical basis for planning of population‐based CRC screening strategies.

What's new?

Colorectal cancer (CRC) screening is implemented in an increasing number of countries, usually in a two‐step approach consisting in a noninvasive test followed by colonoscopy in case of a positive result. Prevalence of preclinical colorectal cancer strongly affects screening efficiency, but such data is scarce. Here, the authors provide detailed age‐ and sex‐specific preclinical CRC prevalence estimates for various countries and geographical regions and show their implications on expected positive and negative predictive values of existing and potential noninvasive screening tests. Knowledge of these predictive values should enhance the empirical basis for decisions on CRC screening tests and target populations.

Detection of cancer through exhaled breath: a systematic review

Background

Timely diagnosis of cancer represents a challenging task; in particular, there is a need for reliable non-invasive screening tools that could achieve high levels of adherence at virtually no risk in population-based screening. In this review, we summarize the current evidence of exhaled breath analysis for cancer detection using standard analysis techniques and electronic nose.

Methods

Relevant studies were identified searching Pubmed and Web of Science databases until April 30, 2015. Information on breath test performance, such as sensitivity and specificity, was extracted together with volatile compounds that were used to discriminate cancer patients from controls. Performance of different breath analysis techniques is provided for various cancers together with information on methodological issues, such as breath sampling protocol and validation of the results.

Results

Overall, 73 studies were included, where two-thirds of the studies were conducted on lung cancer. Good discrimination usually required a combination of multiple biomarkers, and area under the receiver operating characteristic curve or accuracy reached levels of 0.9 or higher in multiple studies. In 25% of the reported studies, classification models were built and validated on the same datasets. Huge variability was seen in different aspects among the studies.

Conclusions

Analyses of exhaled breath yielded promising results, although standardization of breath collection, sample storage and data handling remain critical issues. In order to foster breath analysis implementation into practice, larger studies should be implemented in true screening settings, paying particular attention to standardization in breath collection, consideration of covariates, and validation in independent population samples.

Comparison of prostate cancer survival in Germany and the USA: can differences be attributed to differences in stage distributions?

OBJECTIVES

To better understand the influence of prostate-specific antigen (PSA) screening and other health system determinants on prognosis of prostate cancer, up-to-date relative survival (RS), stage distributions, and trends in survival and incidence in Germany were evaluated and compared with the United States of America (USA).

PATIENTS AND METHODS

Incidence and mortality rates for Germany and the USA for the period 1999-2010 were obtained from the Centre for Cancer Registry Data at the Robert Koch Institute and the USA Surveillance Epidemiology and End Results (SEER) database. For analyses on stage and survival, data from 12 population-based cancer registries in Germany and from the SEER-13 database were analysed. Patients (aged ≥ 15 years) diagnosed with prostate cancer (1997-2010) and mortality follow-up to December 2010 were included. The 5- and 10-year RS and survival trends (2002-2010) were calculated using standard and model-based period analysis.

RESULTS

Between 1999 and 2010, prostate cancer incidence decreased in the USA but increased in Germany. Nevertheless, incidence remained higher in the USA throughout the study period (99.8 vs 76.0 per 100,000 in 2010). The proportion of localised disease significantly increased from 51.9% (1998-2000) to 69.6% (2007-2010) in Germany and from 80.5% (1998-2000) to 82.6% (2007-2010) in the USA. Mortality slightly decreased in both countries (1999-2010). Overall, 5- and 10-year RS was lower in Germany (93.3%; 90.7%) than in the USA (99.4%; 99.6%) but comparable after adjustment for stage. The same patterns were seen in age-specific analyses. Improvements seen in prostate cancer survival between 2002-2004 and 2008-2010 (5-year RS: 87.4% and 91.2%; +3.8% units) in Germany disappeared after adjustment for stage (P = 0.8).

CONCLUSION

The survival increase in Germany and the survival advantage in the USA might be explained by differences in incidence and stage distributions over time and across countries. Effects of early detection or a lead-time bias due to the more widespread utilisation and earlier introduction of PSA testing in the USA are likely to explain the observed patterns.

Basal cell skin cancer and the risk of second primary cancers: a cancer registry-based study in Lithuania

PURPOSE

The aim of this population-based cohort study was to determine the risk of second primary cancer in basal cell carcinoma (BCC) patients in Lithuania.

METHODS

This analysis was based on patients diagnosed with BCC in Lithuania between 1998 and 2007 and followed until 2011. Standardized incidence ratios for subsequent cancers as a ratio of observed number of cancer cases in people with previous BCC diagnosis to the expected number of cancer cases in the underlying general population were calculated.

RESULTS

After diagnosis of BCC, 1442 new cases of selected cancers were diagnosed. Compared with the general population, the incidence of all new primaries combined after BCC was very close to expected. Statistically meaningful increase in developing subsequent cancer was obtained for Hodgkin's lymphoma, prostate cancer, and leukemia in men, and for cancers of the lip, lung, and breast in women. Risk of melanoma and thyroid cancer was significantly elevated in both sexes. Relative risk of cancer of the eye was increased although not significant.

CONCLUSIONS

In our study, we found increased cancer risk for cancers related to sun exposure. In addition, increased risks were identified for Hodgkin's lymphoma, thyroid cancer, leukemia, prostate, and breast cancer in BCC patients.

Survival of patients with gastric lymphoma in Germany and in the United States

BACKGROUND AND AIM

This study aims to examine survival for gastric lymphomas and its main subtypes, mucosa-associated lymphoid tissue lymphoma (MALT), and diffuse large B-cell lymphoma (DLBCL), in Germany and in the United States.

METHODS

Data for patients diagnosed in 1997-2010 were used from 10 population-based German cancer registries and compared to the data from the US Surveillance, Epidemiology and End Results (SEER) 13 registries database. Patients age 15-74 diagnosed with gastric lymphomas were included in the analysis. Period analysis and modeled period analysis were used to estimate 5-year and 10-year relative survival (RS) in 2002-2010 and survival trends from 2002-2004 to 2008-2010.

RESULTS

Overall, the database included 1534 and 2688 patients diagnosed with gastric lymphoma in 1997-2010 in Germany and in the United States, respectively. Survival was substantially higher for MALT (5-year and 10-year RS: 89.0% and 80.9% in Germany, 93.8% and 86.8% in the United States) than for DLBCL (67.5% and 59.2% in Germany, and 65.3% and 54.7% in the United States) in 2002-2010. Survival was slightly higher among female patients and decreased by age for gastric lymphomas combined and its main subtypes. A slight, nonsignificant, increase in the 5-year RS for gastric lymphomas combined was observed in Germany and the United States, with increases in 5-year RS between 2002-2004 and 2008-2010 from 77.1% to 81.0% and from 77.3% to 82.0%, respectively. Five-year RS of MALT exceeded 90% in 2008-2010 in both countries.

CONCLUSIONS

Five-year RS of MALT meanwhile exceeds 90% in both Germany and the United States, but DLBCL has remained below 70% in both countries.

Cancer survival in Lithuania after the restoration of independence: rapid improvements, but persisting major gaps

BACKGROUND

Following restoration of political independence in 1990, Lithuania underwent rapid societal and economic changes. We aimed to assess trends in cancer survival in the first two decades following these changes.

MATERIAL AND METHODS

We used population-based data from the Lithuanian Cancer Registry and period analysis techniques to examine trends in one-, 2-5- and five-year relative survival between 1995-1999 and 2005-2009 for 24 common cancers in Lithuania.

RESULTS

Between 1995-1999 and 2005-2009, five-year relative survival increased significantly for 20 of 24 cancers, and for 10 cancers the increase exceeded 10% units. Five-year relative survival estimates reached 46%, 69% and 91% for colorectal, breast and prostate cancer in 2005-2009, respectively, while patients with testicular cancer, Hodgkin's or non-Hodgkin's lymphoma had a five-year relative survival of 77%, 75% and 50%, respectively.

CONCLUSION

We found a rapid increase in survival for most forms of common cancers in Lithuania between 1995 and 2009. Nevertheless, several cancers with effective therapies exhibit considerable gaps compared with Northern and Western European countries. Despite ongoing rises in survival, mortality declines are not yet manifesting for important common cancers such as breast and colorectal cancer. Rapid incidence rises suggest that increases in survival for prostate and thyroid cancers are massively influenced by early detection-related effects. Improving the availability of effective therapies, and carefully planned early detection programs may help to increase cancer survival in Lithuania in the future.