Incidence of impalpable carcinoma of the prostate and of non-malignant and precarcinomatous lesions in Greek male population: an autopsy study

Updated prevalence of latent prostate cancer in Chinese population and comparison of biopsy results: An autopsy-based study

Prostate cancer detected by autopsy is named latent prostate cancer. As the repertoire of clinical prostate cancer, latent cancer may better reflect the disease burden. Unlike clinical prostate specimens, which are obtained exclusively from biopsy-positive cases, prostate specimens obtained through autopsy provide information on biopsy-negative cases, helping calculate the true sensitivity of prostate biopsy. From 2014 to 2021, we collected autopsy specimens of the prostate from body donors in China and performed transperineal and transrectal biopsies on specimens before step-sectioning and pathological measurements. We found that the crude prevalence of latent prostate cancer in middle-aged and elderly men was 35.1% (81/231), which was higher than previous estimates for Chinese populations. The overall per-patient sensitivities of transperineal and transrectal biopsies were not significantly different (33.3% vs. 32.1%, p = 0.82), but the two approaches differed in preferential sampling area along the proximal-distal axis of the prostate. Transperineal biopsy had a higher sensitivity for detecting clinically significant lesions in the distal third (34.7% vs. 16.3%, p = 0.02) and distal half (30.6% vs. 18.1%, p = 0.04), while transrectal biopsy had a higher sensitivity for lesions in the proximal half (25.0% vs. 13.9%, p = 0.046). Both transperineal and transrectal methods of biopsy missed most small lesions (<0.1 mL) and 35.3% (6/17) of large lesions (>0.5 mL). In conclusion, the prevalence of latent prostate cancer in China has increased over the past 2 decades. Systematic transperineal and transrectal methods of biopsy had comparable sensitivities but had different preferential sampling areas. Both approaches miss one-third of large lesions.

A systematic review and meta-analysis of artificial intelligence diagnostic accuracy in prostate cancer histology identification and grading

BACKGROUND

Artificial intelligence (AI) is a promising tool in pathology, including cancer diagnosis, subtyping, grading, and prognostic prediction.

METHODS

The aim of the study is to assess AI application in prostate cancer (PCa) histology. We carried out a systematic literature search in 3 databases. Primary outcome was AI accuracy in differentiating between PCa and benign hyperplasia. Secondary outcomes were AI accuracy in determining Gleason grade and agreement among AI and pathologists.

RESULTS

Our final sample consists of 24 studies conducted from 2007 to 2021. They aggregate data from roughly 8000 cases of prostate biopsy and 458 cases of radical prostatectomy (RP). Sensitivity for PCa diagnostic exceeded 90% and ranged from 87% to 100%, and specificity varied from 68% to 99%. Overall accuracy ranged from 83.7% to 98.3% with AUC reaching 0.99. The meta-analysis using the Mantel-Haenszel method showed pooled sensitivity of 0.96 with I2 = 80.7% and pooled specificity of 0.95 with I2 = 86.1%. Pooled positive likehood ratio was 15.3 with I2 = 87.3% and negative - was 0.04 with I2 = 78.6%. SROC (symmetric receiver operating characteristics) curve represents AUC = 0.99. For grading the accuracy of AI was lower: sensitivity for Gleason grading ranged from 77% to 87%, and specificity from 82% to 90%.

CONCLUSIONS

The accuracy of AI for PCa identification and grading is comparable to expert pathologists. This is a promising approach which has several possible clinical applications resulting in expedite and optimize pathology reports. AI introduction into common practice may be limited by difficult and time-consuming convolutional neural network training and tuning.

Advances in Molecular Regulation of Prostate Cancer Cells by Top Natural Products of Malaysia

Prostate cancer (PCa) remains both a global health burden and a scientific challenge. We present a review of the molecular targets driving current drug discovery to fight this disease. Moreover, the preventable nature of most PCa cases represents an opportunity for phytochemicals as chemopreventive when adequately integrated into nutritional interventions. With a renovated interest in natural remedies as a commodity and their essential role in cancer drug discovery, Malaysia is looking towards capitalizing on its mega biodiversity, which includes the oldest rainforest in the world and an estimated 1200 medicinal plants. We here explore whether the list of top Malay plants prioritized by the Malaysian government may fulfill the potential of becoming newer, sustainable sources of prostate cancer chemotherapy. These include Andrographis paniculate, Centella asiatica, Clinacanthus nutans, Eurycoma longifolia, Ficus deltoidea, Hibiscus sabdariffa, Marantodes pumilum (syn. Labisia pumila), Morinda citrifolia, Orthosiphon aristatus, and Phyllanthus niruri. Our review highlights the importance of resistance factors such as Smac/DIABLO in cancer progression, the role of the CXCL12/CXCR4 axis in cancer metastasis, and the regulation of PCa cells by some promising terpenes (andrographolide, Asiatic acid, rosmarinic acid), flavonoids (isovitexin, gossypin, sinensetin), and alkylresorcinols (labisiaquinones) among others.

Overdiagnosis in urologic cancer : For World Journal of Urology Symposium on active surveillance in prostate and renal cancer

BACKGROUND

Cancer, which historically was diagnosed at late and incurable stages, has expanded to a heterogeneous group of conditions that vary from clinically insignificant to rapidly aggressive and lethal. This evolution is due to the widespread use of screening tests for early detection of cancer, both directed (i.e., PSA, mammography, colonoscopy) and undirected (abdominal imaging). The use of these tests has resulted in both benefits and harms. The benefits are a reduction in survival and mortality, due to significant cancers being diagnosed at a more curable stage. The harms are an increase, in some cases dramatic, in the diagnosis of clinically insignificant disease. These are called 'cancer' but not destined to affect the patient's life, even in the absence of treatment.

METHODS

Non-explicit summary of the literature on overdiagnosis of cancer.

RESULTS

The phenomenon of overdiagnosis requires two factors: the presence of a common reservoir of microfocal disease and a screening test to find it. These factors exist for breast, prostate, skin, renal, and thyroid cancers, and to a lesser degree for lung cancer. The problem of cancer overdiagnosis and overtreatment is complex, with numerous etiologies and many tradeoffs. It is a particular problem in prostate cancer but is a major issue in many other cancer sites. Screening for prostate cancer based on the best data from prospective randomized trials significantly reduces cancer mortality. However, reducing overtreatment in patients diagnosed with indolent disease is critical to the success of screening.

CONCLUSION

Active surveillance, the focus of this series of articles, is an important strategy to reduce overtreatment. This article reviews the pathological, clinical, social, and psychological aspects of overdiagnosis in cancer.

"More men die with prostate cancer than because of it" - an old adage that still holds true in the 21st century

BACKGROUND

Prostate cancer (PCa) incidence has risen due to PSA testing, making it the commonest male malignancy. Most PSA-detected cases are organ-confined. Whilst radical treatment has increased, there has been little change in PCa-specific mortality. Over-detection of clinically insignificant PCa and active surveillance are increasing. We compared studies from the 21st century versus earlier reports demonstrating how commonly PCa is incidentally detected at autopsy. We describe the ongoing increasing prevalence of PCa with age, along with features of autopsy-detected disease.

METHODS

A literature review of PubMed and Scopus was conducted using the search terms "prostate cancer or carcinoma", "latent" or "autopsy", to January 2019. Citations and references from all publications found in this search were manually reviewed to identify additional articles.

RESULTS

63 publications were identified between 1898 and 2017, reporting over 29,000 autopsies on subjects aged between 20 and ≥90 years. PCa prevalence was 21% across all ages, and we found no significant difference in 21st century studies versus earlier studies. Autopsy-detected incidental PCa cases were typically small (~0.5cubic cm), predominantly low grade, and only occasionally (10%) extra-prostatic. PCa prevalence increased with age, being detected in >50% in men aged ≥90 years. The frequency of high-grade PCa almost doubled with each increasing age category.

CONCLUSION

Most autopsy-detected PCa cases continue to be clinically insignificant. The prevalence of autopsy-detected PCa was 30-fold greater than PCa-specific mortality in each ten-year age category. This should be considered when counselling elderly men regarding PSA-testing, particularly in the context of competing co-morbidity.

Age and aggressiveness of prostate cancer: analysis of clinical and pathological characteristics after radical prostatectomy for men with localized prostate cancer

Introduction

The aim of this study was to describe age- related prostate cancer (PCa) characteristics in men after radical prostatectomy (RP).

Material and methods

There were 2,373 men who underwent RP for clinically localized PCa between 2002 and 2017 and had complete data that were included into the study. Among them, 315 (13.3%) men aged ≤55 years (GR-1), 1,098 (46.3%) men aged between 56 to 65 years (GR-2) and 960 (40.4%) men aged older than 65 years (GR-3) were identified. All preoperative and pathological parameters were compared between all three groups and between each group separately. High-risk prostate cancer (HRPCa) cases were analyzed separately. Regression analysis was used to evaluate the impact of age on cancer aggressiveness.

Result

Clinical stage (cT), biopsy Gleason score and D'Amico risk groups were different comparing age-related study groups (all p <0.01), respectively. Preoperatively cT1 and Gleason 6 were in the highest rate for GR-1 in comparison with GR-3: 35.9 vs. 27.1%, p = 0.003 and 65.1% vs. 56.7%, p = 0.008, respectively. Analyzing pathological parameters, only Gleason 9–10 was different between GR-1 and GR-3–3.8 vs. 7.6%, p = 0.02. There were 921 (38.8%) HRPCa cases identified. Age was a significant predictor for HRPCa (p = 0.019) in the regression analysis. The oldest men (GR-3) had up to 1.5 fold increased risk for HRPCa detection in comparison with the youngest one (p = 0.008, HR1.44. 95% CI 1.098–1.87).

Conclusions

Younger, ≤55-year-old men, are more likely to present with less aggressive clinical and pathological PCa features in comparison with the older ones. Increasing age has a significant influence on HRPCa detection after RP.

Prevalence and Associated Factors of Incidentally Diagnosed Prostatic Carcinoma among Patients Who Had Transurethral Prostatectomy in Tanzania: A Retrospective Study

Background

Prostatic carcinoma carries a high morbidity and mortality if it is not diagnosed early. In resource limited countries, patients are at increased risk of being diagnosed late as they are operated for presumed benign prostatic hyperplasia. The information on the magnitude and risk factors of this problem in our setting could assist in the overall optimization of care of patients at risk.

Methods

A retrospective study of patients who underwent prostatectomy for presumed benign prostatic enlargement was done at Bugando University Hspital in Tanzania. Patients' age, creatinine levels, urological Ultrasound, prostate specific antigen and Biopsy results were analyzed using STATA 11. The prevalence of incidental prostatic cancer was calculated and logistic regression was done for factors associated with incidental prostatic cancer.

Results

In total, 152 patients were included in this study. The median age was 69 (SD 9.4) years, 16 (10.53%,) and 49 (32.24%) participants had Hydronephrosis and elevated creatinine levels respectively. Eighty six (58.56%) patients had PSA >10 ng/mL and in total; 33 (21.71%) had incidental prostatic carcinoma. The incidental prostatic carcinoma was independently associated with age of 70– 80years (AOR=2.8, p = 0.013) and PSA levels >10ng/mL (AOR=3.2, p=0.014).

Conclusions

The prevalence of incidental prostatic carcinoma is high among patients undergoing transurethral prostatectomy for presumed benign prostatic hyperplasia in Tanzania with increased risk at age of 70–80 years and among those with PSA >10ng/mL. A national awareness campaign coupled with focused screening of patients above 60 years could increase the detection rate of prostatic carcinoma and reduce the magnitude of incidental diagnosis of this disease.

Active Surveillance for Papillary Thyroid Microcarcinoma: Challenges and Prospects

Active surveillance (AS) can be considered as an alternative to immediate surgery in low-risk papillary thyroid microcarcinoma (PTMC) without clinically apparent lymph nodes, gross extrathyroidal extension (ETE), and/or distant metastasis according to American Thyroid Association. However, in the past AS has been controversial, as evidence supporting AS in the management of PTMC was scarce. The most prominent of these controversies included, the limited accuracy and utility of ultrasound (US) in the detection of ETE, malignant lymph node involvement or the advent of novel lymph node malignancy during AS, and disease progression. We summarized publications and indicated: (1) US, performer-dependent, could not accurately diagnose gross ETE or malignant lymph node involvement in PTMC. However, the combination of computed tomography and US provided more accurate diagnostic performance, especially in terms of selection sensitivity. (2) Compared to immediate surgery patients, low-risk PTMC patients had a slightly higher rate of lymph node metastases (LNM), although the overall rate for both groups remained low. (3) Recent advances in the sensitivity and specificity of imaging and incorporation of diagnostic biomarkers have significantly improved confidence in the ability to differentiate indolent vs. aggressive PTMCs. Our paper reviewed current imagings and biomarkers with initial promise to help select AS candidates more safely and effectively. These challenges and prospects are important areas for future research to promote AS in PTMC.

Management and outcomes of Gleason six prostate cancer detected on needle biopsy: A single-surgeon experience over 6 years

Objective

To assess the management and oncological outcomes in men diagnosed with Gleason score (GS) 6 prostate cancer on needle biopsy in a regional centre, as compared with published international data.

Materials and methods

A retrospective analysis was conducted of patients who were diagnosed with GS 6 prostate cancer via transrectal ultrasound-guided or transperineal biopsy between June 2009 and September 2015 under the care of a single surgeon. Data were obtained from a prospectively collected database.

Results

A total of 166 patients were diagnosed with GS 6 prostate cancer. The mean age was 61 (range 46-79) years, with mean prostate-specific antigen of 6.7 (0.91-26.8) ng/mL at diagnosis. Of 166 patients, 117 (70.5%) patients were enrolled into the active surveillance program with 82 (70%) meeting Prostate Cancer Research International Active Surveillance (PRIAS) criteria, 44 patients underwent immediate definitive treatment (88.6% radical prostatectomy and 9.1% radiotherapy) and five watchful waiting. With a median follow-up of 1.8 years, 37 (31.6%) patients on AS had definitive treatment [30 cases (81%) were attributable to disease progression, 4 cases (10.8%) to an abnormal magnetic resonance imaging result and 3 cases (8.1%) for patient preference]. In the 35 patients who underwent radical prostatectomy immediately after diagnosis, the GS was ≥7 in 29 cases (82.9%), and the final pathology was pT3a in 16 (51.6%) and pT3b in one (2.9%). In patients who underwent radical prostatectomy after being on AS, the proportion of GS ≥7 prostate cancer was 29/32 (90.6%), with pT3a in six (18.8%) and pT3b in three (9.4%) cases. Overall, 23.5% of patients had a multiparametric magnetic resonance imaging scan.

Conclusion

This single-surgeon cohort of GS 6 prostate cancer patients demonstrates a high proportion of cases managed with active surveillance, with comparable rates to international literature. The majority of cases who underwent immediate definitive treatment had significant disease, indicating that patients are being appropriately selected for active surveillance.

Long-Term Oncological Outcomes for Young Men Undergoing Radical Prostatectomy for Localized Prostate Cancer

Aim. The aim of this study was to describe PCa characteristics and long-term outcomes in young men aged ≤55 years after radical prostatectomy (RP) and to compare them with older men cohort. Methods. Among 2,200 patients who underwent RP for clinically localized PCa at our centre between 2001 and 2015, 277 (10.3%) men aged ≤55 years were identified. All preoperative and pathological parameters were compared between groups. Biochemical progression free survival (BPFS) and disease progression free survival (DPFS) were assessed at 5 and 10 years. Results. Men aged ≤55 years had similar pathological tumor characteristics and biochemical recurrence rate (BCR) compared to their older counterparts. Disease progression rate 2.5% versus 0.4% was higher in older patients (p = 0.026). BPFS rate was not different in both study groups. Estimated 10-year DPFS was 98.8% in younger men compared to 89.2% in their older counterparts (p = 0.031). Multivariate Cox regression showed that Gleason score lymph-nodes and surgical margins status were significant predictors for disease progression. Conclusions. In our cohort, men aged ≤55 years had similar pathological PCa characteristics and BCR rate in comparison with older men. RP can be performed with excellent long-term DPFS results in men with localized PCa at ≤55 years of age.

Overtreatment in cancer - is it a problem?

The word "cancer" invokes fear even today in those diagnosed with it, largely due to the deep-rooted stigma associated with this emotive word, one associated with an incurable and fatal disease. This was true in years gone by, when cancer patients presented late with symptoms from advanced disease. Today, however, in the era of screening and an awareness of the value of early detection, it is no longer the case. The last half century has heralded an unparalleled rise in every aspect of cancer research, diagnostics and therapeutics, with a better understanding of basic science, pathological classifications, risk factors, prognosis and treatments. Screening programs have been adopted or suggested for many cancers. The pendulum is shifting. A new concept has emerged - that of cancer overdiagnosis, and together with this, cancer overtreatment. Medicine still remains a science of uncertainty and an art of assessing probability. Until personalized medicine evolves to a level that a person's lifetime risk of clinically significant cancer formation and expected outcome can be computed with a great degree of precision and confidence, clinicians and patients have to be cognizant of the problem of cancer overdiagnosis and overtreatment. In this editorial, we explore the current evidence and magnitude of this problem.

The Prevalence of Clinically Significant Prostate Cancer According to Commonly Used Histological Thresholds in Men Undergoing Template Prostate Mapping Biopsies

PURPOSE

Transrectal prostate biopsies are inaccurate and, thus, the prevalence of clinically significant prostate cancer in men undergoing biopsy is unknown. We determined the ability of different histological thresholds to denote clinically significant cancer in men undergoing a more accurate biopsy, that of transperineal template prostate mapping.

MATERIALS AND METHODS

In this multicenter, cross-sectional cohort of men who underwent template prostate mapping biopsies between May 2006 and January 2012, 4 different thresholds of significance combining tumor grade and burden were used to measure the consequent variation with respect to the prevalence of clinically significant disease.

RESULTS

Of 1,203 men 17% (199) had no previous biopsy, 38% (455) had a prior negative transrectal ultrasound biopsy, 24% (289) were on active surveillance and 21% (260) were seeking risk stratification. Mean patient age was 63.5 years (SD 7.6) and median prostate specific antigen was 7.4 ng/ml (IQR 5.3-10.5). Overall 35% of the patients (424) had no cancer detected. The prevalence of clinically significant cancer varied between 14% and 83% according to the histological threshold used, in particular between 30% and 51% among men who had no previous biopsy, between 14% and 27% among men who had a prior negative biopsy, between 36% and 74% among men on active surveillance, and between 47% and 83% among men seeking risk stratification.

CONCLUSIONS

According to template prostate mapping biopsy between 1 in 2 and 1 in 3 men have prostate cancer that is histologically defined as clinically significant. This suggests that the commonly used thresholds may be set too low.

Prevalence and management of prostate cancer among East Asian men: Current trends and future perspectives

OBJECTIVES

Previously East Asian men had been considered less likely to develop or die of prostate cancer. Emerging research and the onset of prostate-specific antigen screening in East Asian countries suggests that this may not be the case. We sought to analyze epidemiology and molecular genetic data and recent trends in the management of prostate cancer among East Asian men.

METHODS AND MATERIALS

We performed literature searches using PubMed, Embase, and Google Scholar to examine current literature on prostate cancer in East Asian men. Additionally, articles were searched for further references related to the topic.

RESULTS

Recent studies have reported increasing incidence of prostate cancer identified in East Asian men. Prostate cancer mortality has increased and is currently the fourth leading cause of death among men in Shanghai, China. Although prostate cancer was considered less aggressive among East Asian men, studies suggest that it is similarly aggressive to prostate cancer in Western populations. Molecular markers such as the TEMPRESS:ERG fusion gene and PTEN loss may provide novel methods of screening East Asian men for prostate cancer. National-level guidelines for prostate cancer screening and management are only available in Japan.

CONCLUSIONS

The prevalence of prostate cancer in East Asian men is likely similar to that in Western male populations. East Asian men present at higher stages of prostate cancer, likely because of a lack of standardized screening protocols. Urologists in Western countries should screen East Asian men for prostate cancer using the same standards as used for Western men.

Prostate MRI can reduce overdiagnosis and overtreatment of prostate cancer

The contemporary management of prostate cancer (PCa) has been criticized as fostering overdetection and overtreatment of indolent disease. In particular, the historical inability to identify those men with an elevated PSA who truly warrant biopsy, and, for those needing biopsy, to localize aggressive tumors within the prostate, has contributed to suboptimal diagnosis and treatment strategies. This article describes how modern multi-parametric MRI of the prostate addresses such challenges and reduces both overdiagnosis and overtreatment. The central role of diffusion-weighted imaging (DWI) in contributing to MRI's current impact is described. Prostate MRI incorporating DWI achieves higher sensitivity than standard systematic biopsy for intermediate-to-high risk tumor, while having lower sensitivity for low-grade tumors that are unlikely to impact longevity. Particular applications of prostate MRI that are explored include selection of a subset of men with clinical suspicion of PCa to undergo biopsy as well as reliable confirmation of only low-risk disease in active surveillance patients. Various challenges to redefining the standard of care to incorporate solely MRI-targeted cores, without concomitant standard systematic cores, are identified. These include needs for further technical optimization of current systems for performing MRI-targeted biopsies, enhanced education and expertise in prostate MRI among radiologists, greater standardization in prostate MRI reporting across centers, and recognition of the roles of pre-biopsy MRI and MRI-targeted biopsy by payers. Ultimately, it is hoped that the medical community in the United States will embrace prostate MRI and MRI-targeted biopsy, allowing all patients with known or suspected prostate cancer to benefit from this approach.

Baseline Prostate Atrophy is Associated with Reduced Risk of Prostate Cancer in Men Undergoing Repeat Prostate Biopsy

PURPOSE

We evaluated whether the presence and severity of baseline prostate atrophy in men with initial biopsy negative for prostate cancer was associated the risk of subsequent prostate cancer detection in a clinical trial with scheduled study mandated biopsies.

MATERIALS AND METHODS

We retrospectively analyzed the records of 3,084 men 50 to 75 years old with prostate specific antigen between 2.5 and 10 ng/ml, and a prior negative biopsy in the placebo arm of the REDUCE (Reduction by Dutasteride of Prostate Cancer Events) study who completed at least 1 per-protocol biopsy. Prostate cancer (defined as present or absent) and prostate atrophy (graded as absent, mild or moderate/marked) was assessed by central pathology review. The association of baseline atrophy with positive 2 and 4-year repeat biopsies was evaluated with logistic regression, controlling for baseline covariates.

RESULTS

Baseline prostate atrophy was detected in 2,143 men (70%) and graded as mild and moderate/marked in 1,843 (60%) and 300 (10%) baseline biopsies, respectively. Patients with atrophy were older and had a larger prostate, and more acute and chronic prostate inflammation. At 2-year biopsy the prostate cancer incidence was 17% (508 cases). Baseline atrophy was significantly associated with lower prostate cancer risk (univariable and multivariable OR 0.60, 95% CI 0.50-0.74 and OR 0.67, 95% CI 0.54-0.83, p <0.001, respectively) at the 2-year biopsy. These results were similar at the 4-year biopsy (univariable and multivariable OR 0.70, 95% CI 0.53-0.93 and OR 0.72, 95% CI 0.53-0.97, p = 0.03, respectively). Relative to no atrophy the prostate cancer risk at the 2-year repeat biopsy was lower for mild atrophy (OR 0.69, 95% CI 0.55-0.86) and moderate/marked atrophy (OR 0.51, 95% CI 0.34-0.76, each p <0.001).

CONCLUSIONS

Baseline prostate atrophy in men with a prostate biopsy negative for prostate cancer was independently associated with subsequent lower prostate cancer detection.

Prevalence of incidental prostate cancer: A systematic review of autopsy studies

Prostate cancer screening may detect nonprogressive cancers, leading to overdiagnosis and overtreatment. The potential for overdiagnosis can be assessed from the reservoir of prostate cancer in autopsy studies that report incidental prostate cancer rates in men who died of other causes. We aimed to estimate the age-specific incidental cancer prevalence from all published autopsy studies. We identified eligible studies by searches of Medline and Embase, forward and backward citation searches and contacting authors. We screened the titles and abstracts of all articles; checked the full-text articles for eligibility and extracted clinical and pathology data using standardized forms. We extracted mean cancer prevalence, age-specific cancer prevalence and validity measures and then pooled data from all studies using logistic regression models with random effects. The 29 studies included in the review dated from 1948 to 2013. Incidental cancer was detected in all populations, with no obvious time trends in prevalence. Prostate cancer prevalence increased with each decade of age, OR = 1.7 (1.6–1.8), and was higher in studies that used the Gleason score, OR = 2.0 (1.1–3.7). No other factors were significantly predictive. The estimated mean cancer prevalence increased in a nonlinear fashion from 5% (95% CI: 3–8%) at age <30 years to 59% (95% CI: 48–71%) by age >79 years. There was substantial variation between populations in estimated cancer prevalence. There is a substantial reservoir of incidental prostate cancer which increases with age. The high risk of overdiagnosis limits the usefulness of prostate cancer screening.

Lung cancer screening

Lung cancer is the leading cause of cancer death. Although smoking prevention and cessation programs have decreased lung cancer mortality, there remains a large at-risk population. Dismal long-term survival rates persist despite improvements in diagnosis, staging, and treatment. Early efforts to identify an effective screening test have been unsuccessful. Recent advances in multidetector computed tomography have allowed screening studies using low-dose computed tomography (LDCT) to be performed. This set the stage for the National Lung Screening Trial that found that annual LDCT screening benefits individuals at high risk for lung cancer. An understanding of the harmful effects of lung cancer screening is required to help maximize the benefits and decrease the risks of a lung cancer screening program. Although many questions remain regarding LDCT screening, a comprehensive lung cancer screening program of high-risk individuals will increase detection of preclinical and potentially curable disease, creating a new model of lung cancer surveillance and management.

Multiparametric MRI in prostate cancer management

Prostate cancer is the second most common cancer in men worldwide. The clinical behaviour of prostate cancer ranges from low-grade indolent tumours that never develop into clinically significant disease to aggressive, invasive tumours that may progress rapidly to metastatic disease and death. Therefore, there is an urgent clinical need to detect high-grade cancers and to differentiate them from the indolent, slow-growing tumours. Conventional methods of cancer detection-such as levels of prostate-specific antigen (PSA) in serum, digital rectal examination, and random biopsies-are limited in their sensitivity, specificity, or both. The combination of conventional anatomical MRI and functional magnet resonance sequences-known as multiparametric MRI (mp-MRI)-is emerging as an accurate tool for identifying clinically relevant tumours owing to its ability to localize them. In this Review, we discuss the value of mp-MRI in localized and metastatic prostate cancer, highlighting its role in the detection, staging, and treatment planning of prostate cancer.

Prostate cancer chemoprevention

Prostate cancer is a leading cause of morbidity and mortality in men and has significant treatment-associated complications. Prostate cancer chemoprevention has the potential to decrease the morbidity and mortality associated with this disease. Chemoprevention research to date has primarily focused on nutrients and 5 alpha-reductase inhibitors (5ARIs). A large randomized trial (SELECT) found no favorable effect of selenium or vitamin E on prostate cancer prevention. Two large randomized placebo controlled trials (the PCPT and REDUCE trials) have been published and have supported the role of 5ARIs in prostate cancer chemoprevention; however, these trials also have prompted concerns regarding the increase in high-grade disease seen with treatment and have not been approved by the US Food and Drug Administration (FDA) for chemoprevention. Conclusive evidence for the chemopreventive benefit of nutrients or vitamins is lacking, whereas the future role of 5ARIs remains to be clarified.

Overdiagnosis of prostate cancer

This chapter addresses issues relevant to prostate cancer overdiagnosis. Factors promoting the overdiagnosis of prostate cancer are reviewed. First is the existence of a relatively large, silent reservoir of this disease, as can be seen by evaluating autopsy studies and histologic step-sectioning results of prostates removed for other causes. The second main factor responsible for prostate cancer overdiagnosis is fairly widespread prostate-specific antigen and digital rectal examination-based screening, which has been fairly widely practiced in the United States for the past 20 years among heterogeneous groups of men. This has resulted in the identification of many men from this reservoir who otherwise may never have been diagnosed with symptomatic prostate cancer and is substantially responsible for the current annual incidence to mortality ratio for prostate cancer of approximately 6 to 1. Finally, the relatively indolent natural history and limited cancer-specific mortality as reported in a variety of contemporary randomized screening and treatment trials is reviewed. We attempt to quantitate the proportion of newly diagnosed prostate cancers that are overdiagnosed using various trial results and models. We explore the impact of prostate cancer overdiagnosis in terms of patient anxiety and the potential for overtreatment, with its attendant morbidity. We explore strategies to minimize overdiagnosis by targeting screening and biopsy only to men at high risk for aggressive prostate cancer and by considering the use of agents such as 5-alpha reductase inhibitors. Future prospects to prevent overtreatment, including better biopsy and molecular characterization of newly diagnosed cancer and the role of active surveillance, are discussed.

Prostate cancer overdiagnosis and overtreatment

PURPOSE OF REVIEW

To summarize the evidence, now extensive, that efforts to reduce prostate cancer mortality by screening and early detection result in overdiagnosis of disease that is clinically insignificant, and would never have been diagnosed in the patient's lifetime in the absence of screening. Overdiagnosis may result in overtreatment, which in the case of prostate cancer often carries significant, long-term quality-of-life effects. The review also addresses the solutions to the problem of overdiagnosis and overtreatment, and summarizes the outcomes of these approaches.

RECENT FINDINGS

Screening for prostate cancer has been demonstrated to reduce mortality, although with a high number needed to treat. One approach to this problem is to offer patients with favorable risk disease an initial conservative approach, with close monitoring and treatment for those patients who are reclassified as higher risk over time. Much preclinical data indicates that Gleason 6 prostate cancer does not carry the hallmarks of malignancy. However, a number of recent studies have demonstrated that in patients diagnosed with favorable risk prostate cancer (Gleason 6 or less, prostate-specific antigen <10), about 30% will harbor higher grade cancer and benefit from treatment. These patients are identifiable by a combination of repeat biopsy, serial prostate-specific antigen, and in borderline cases, multiparametric MRI.

SUMMARY

Active surveillance is a powerful solution to the problem of overdiagnosis and overtreatment associated with screening for prostate cancer. For the 40-50% of patients with favorable risk prostate cancer, it offers the benefit of personalized medicine, avoiding treatment and related quality-of-life effects altogether in the majority, and providing definitive management for the minority who are reclassified with higher risk disease over time.

Circulating MicroRNAs as Biomarkers of Prostate Cancer: The State of Play

MicroRNAs are key regulators of gene expression and play critical roles in both normal physiology and pathology. Recent research has demonstrated that these molecules are present in body fluids, such as serum, plasma, and urine, and can be readily measured using a variety of techniques. More importantly, emerging evidence suggests that circulating or urine miRNAs are useful indicators of disease. Here, we consider the potential utility of such miRNAs as noninvasive biomarkers of prostate cancer, a disease that would benefit substantially from novel diagnostic and prognostic tools. The studies aimed at identifying diagnostic, prognostic, and/or predictive miRNAs for prostate cancer are summarised and reviewed. Finally, practical considerations that will influence the translation of this recent research into clinical implementation are discussed.

Prostate cancer: is it time to expand the research focus to early-life exposures?

Although the contribution of lifestyle and environment (non-genetic factors) to prostate carcinogenesis is indicated by international variation in prostate cancer occurrence and migration studies, no conclusive modifiable risk factors have yet been identified. One possible reason for this may be the dearth of epidemiological research on exposures experienced early in life, when the immature prostate may be more susceptible to carcinogenic exposures. In this Opinion article, we summarize the rationale for studying early-life exposures, describe the small body of early-life research and its associated challenges, and point to solutions for future research.

Computed tomography screening for lung cancer: has it finally arrived? Implications of the national lung screening trial

The National Lung Screening Trial (NLST) has provided compelling evidence of the efficacy of lung cancer screening using low-dose helical computed tomography (LDCT) to reduce lung cancer mortality. The NLST randomized 53,454 older current or former heavy smokers to receive LDCT or chest radiography (CXR) for three annual screens. Participants were observed for a median of 6.5 years for outcomes. Vital status was available in more than 95% of participants. LDCT was positive in 24.2% of screens, compared with 6.9% of CXRs; more than 95% of all positive LDCT screens were not associated with lung cancer. LDCT detected more than twice the number of early-stage lung cancers and resulted in a stage shift from advanced to early-stage disease. Complications of LDCT screening were minimal. Lung cancer-specific mortality was reduced by 20% relative to CXR; all-cause mortality was reduced by 6.7%. The major harms of LDCT are radiation exposure, high false-positive rates, and the potential for overdiagnosis. This review discusses the risks and benefits of LDCT screening as well as an approach to LDCT implementation that incorporates systematic screening practice with smoking cessation programs and offers opportunities for better determination of appropriate risk cohorts for screening and for better diagnostic prediction of lung cancer in the setting of screen-detected nodules. The challenges of implementation are considered for screening programs, for primary care clinicians, and across socioeconomic strata. Considerations for future research to complement imaging-based screening to reduce the burden of lung cancer are discussed.

Precursors of prostate cancer

High-grade prostatic intraepithelial neoplasia (PIN) is the only accepted precursor of prostatic adenocarcinoma, according to numerous studies of animal models and man; other proposed precursors include atrophy and malignancy-associated changes (with no morphologic changes). PIN is characterized by progressive abnormalities of phenotype and genotype that are intermediate between benign prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. The only method of detection of PIN is biopsy because it does not significantly elevate serum prostate-specific antigen concentration and cannot be detected by ultrasonography. The mean incidence of PIN in biopsies is 9% (range, 4%-16%), representing about 115,000 new cases of isolated PIN diagnosed each year in the United States. The clinical importance of PIN is its high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent carcinoma, especially when multifocal or observed in association with atypical small acinar proliferation (ASAP). Carcinoma develops in most patients with PIN within 10 years. Androgen deprivation therapy and radiation therapy decrease the prevalence and extent of PIN, suggesting that these forms of treatment may play a role in prevention of subsequent cancer. Multiple clinical trials to date of men with PIN have had modest success in delaying or preventing subsequent cancer.

Inflammation and preneoplastic lesions in benign prostate as risk factors for prostate cancer

Benign changes ranging from atrophy and inflammation to high-grade prostatic intraepithelial neoplasia (HGPIN) are common findings on prostate core needle biopsies. Although atrophy and inflammation may be precursors of prostate cancer, only HGPIN is currently recommended to be included in surgical pathology reports. To determine whether these benign findings increase prostate cancer risk, we conducted a case-control study nested within a historical cohort of 6692 men with a benign prostate specimen collected between 1990 and 2002. The analytic sample included 574 case-control pairs comprised of cases diagnosed with prostate cancer a minimum of 1 year after cohort entry and controls matched to cases on date and age at cohort entry, race, and type of specimen. The initial benign specimen was reviewed for presence of HGPIN, atrophy (simple, lobular, and partial) and inflammation (glandular and/or stromal). HGPIN significantly increased risk for prostate cancer (odds ratio (OR)=2.00; 95% confidence interval (CI)=1.25-3.20). Inflammation within the stromal compartment was associated with decreased risk (OR=0.66; CI=0.52-0.84), and diffuse stromal inflammation of severe grade had the strongest inverse association with risk (OR=0.21; CI=0.07-0.62). In a model adjusted for prostate-specific antigen (PSA) level at cohort entry and inflammation, simple atrophy was associated with a 33% increased prostate cancer risk that was marginally significant (P=0.03). Clinicians should consider patterns and extent of inflammation when managing high-risk patients with negative biopsy results. Identifying benign inflammatory processes that underlie high PSA levels would help to reduce the number of unnecessary repeated prostate biopsies.

The multi-cancer marker, rs6983267, located at region 3 of chromosome 8q24, is associated with prostate cancer in Greek patients but does not contribute to the aggressiveness of the disease

BACKGROUND

Recently, several polymorphisms located on human chromosome 8q24 were found to be associated with prostate cancer risk with different frequency and incidence among the investigated populations. The authors conducted a prostate cancer case-control study in the Greek population to evaluate the association of the single nucleotide polymorphism (SNP) rs6983267, located at region 3 of chromosome 8q24, with this type of cancer.

METHODS

Samples of total blood from 86 patients with histologically confirmed prostate cancer and 99 healthy individuals were genotyped using real time polymerase chain reaction (PCR). Tumor-node-metastasis (TNM) stage, Gleason score and levels of prostate-specific antigen (PSA) at diagnosis were included in the analysis.

RESULTS

A highly significant association (odds ratio=2.84 and p-value=0.002) was found between rs6983267 and prostate cancer in the Greek population. The sensitivity, specificity, negative and positive predictive values of the presence of G allele for the discrimination between patients and controls were 81.40%, 39.4%, 53.9% and 70.9%, respectively. A lower proportion of homozygotes was found in patients with PSA level <4 ng/mL compared to those with PSA level more than 4 ng/mL (p=0.019). None of the other clinical factors nor the aggressiveness of the disease were found to be significantly associated with rs6983267 genotype.

CONCLUSIONS

The SNP rs6983267 is an established marker for a range of cancers. In prostate cancer, it indicates an enhanced risk for carriers to develop the disease in general. In our study it showed no association with aggressive forms or familial and early-onset prostate cancer families.

Overdiagnosis in cancer

This article summarizes the phenomenon of cancer overdiagnosis-the diagnosis of a "cancer" that would otherwise not go on to cause symptoms or death. We describe the two prerequisites for cancer overdiagnosis to occur: the existence of a silent disease reservoir and activities leading to its detection (particularly cancer screening). We estimated the magnitude of overdiagnosis from randomized trials: about 25% of mammographically detected breast cancers, 50% of chest x-ray and/or sputum-detected lung cancers, and 60% of prostate-specific antigen-detected prostate cancers. We also review data from observational studies and population-based cancer statistics suggesting overdiagnosis in computed tomography-detected lung cancer, neuroblastoma, thyroid cancer, melanoma, and kidney cancer. To address the problem, patients must be adequately informed of the nature and the magnitude of the trade-off involved with early cancer detection. Equally important, researchers need to work to develop better estimates of the magnitude of overdiagnosis and develop clinical strategies to help minimize it.

Prostate kallikrein markers in diagnosis, risk stratification and prognosis

The kallikrein, prostate-specific antigen (PSA), is one of the world's most frequently used disease biomarkers. After almost two decades of research and clinical experience, the diagnostic and monitoring limitations of PSA are beginning to be understood. Most physicians are aware of PSA's low specificity for cancer among older men with benign prostatic conditions; fewer are aware of recent data, which show that a prior negative biopsy or a prior PSA value below the threshold for biopsy might compromise the predictive accuracy of PSA even further. Furthermore, a subtle increase in serum PSA level during early middle age is strongly correlated with clinically important prostate cancer. We review current and past reports on the prostate kallikreins PSA and hK2 in relation to pathology and epidemiology.

Tumor-vascular interactions and tumor dormancy

Tumor progression is dependent on a number of sequential steps, including initial tumor-vascular interactions and recruitment of blood vessels (i.e., the angiogenic switch), as well as tumor cells interacting with the surrounding microenvironment and its different components. Failure of a microscopic tumor to complete one or more of these early stages may lead to delayed clinical manifestation of the cancer and a state of stable non-progressing disease (i.e., tumor dormancy). In this review, some of the clinical and experimental evidence is summarized, suggesting that microscopic human cancers, either primary, recurrent or metastatic, can remain in an asymptomatic, non-detectable, and occult state for a long period of time. We also review current experimental human tumor dormancy models which closely recapitulate clinically observed delay in tumor progress.