Cancer overdiagnosis: a challenge in the era of screening

Screening for Breast Cancer: Evidence Report and Systematic Review for the US Preventive Services Task Force

Importance

Breast cancer is a leading cause of cancer mortality for US women. Trials have established that screening mammography can reduce mortality risk, but optimal screening ages, intervals, and modalities for population screening guidelines remain unclear.

Objective

To review studies comparing different breast cancer screening strategies for the US Preventive Services Task Force.

Data Sources

MEDLINE, Cochrane Library through August 22, 2022; literature surveillance through March 2024.

Study Selection

English-language publications; randomized clinical trials and nonrandomized studies comparing screening strategies; expanded criteria for screening harms.

Data Extraction and Synthesis

Two reviewers independently assessed study eligibility and quality; data extracted from fair- and good-quality studies.

Main Outcomes and Measures

Mortality, morbidity, progression to advanced cancer, interval cancers, screening harms.

Results

Seven randomized clinical trials and 13 nonrandomized studies were included; 2 nonrandomized studies reported mortality outcomes. A nonrandomized trial emulation study estimated no mortality difference for screening beyond age 74 years (adjusted hazard ratio, 1.00 [95% CI, 0.83 to 1.19]). Advanced cancer detection did not differ following annual or biennial screening intervals in a nonrandomized study. Three trials compared digital breast tomosynthesis (DBT) mammography screening with digital mammography alone. With DBT, more invasive cancers were detected at the first screening round than with digital mammography, but there were no statistically significant differences in interval cancers (pooled relative risk, 0.87 [95% CI, 0.64-1.17]; 3 studies [n = 130 196]; I2 = 0%). Risk of advanced cancer (stage II or higher) at the subsequent screening round was not statistically significant for DBT vs digital mammography in the individual trials. Limited evidence from trials and nonrandomized studies suggested lower recall rates with DBT. An RCT randomizing individuals with dense breasts to invitations for supplemental screening with magnetic resonance imaging reported reduced interval cancer risk (relative risk, 0.47 [95% CI, 0.29-0.77]) and additional false-positive recalls and biopsy results with the intervention; no longer-term advanced breast cancer incidence or morbidity and mortality outcomes were available. One RCT and 1 nonrandomized study of supplemental ultrasound screening reported additional false-positives and no differences in interval cancers.

Conclusions and Relevance

Evidence comparing the effectiveness of different breast cancer screening strategies is inconclusive because key studies have not yet been completed and few studies have reported the stage shift or mortality outcomes necessary to assess relative benefits.

Ecological study estimating melanoma overdiagnosis in the USA using the lifetime risk method

OBJECTIVES

To quantify the proportion of melanoma diagnoses (invasive and in situ) in the USA that might be overdiagnosed.

DESIGN

In this ecological study, incidence and mortality data were collected from the Surveillance, Epidemiology and End Results 9 registries database. DevCan software was used to calculate the cumulative lifetime risk of being diagnosed with melanoma between 1975 and 2018, with adjustments made for changes in longevity and risk factors over the study period.

SETTING

USA.

PARTICIPANTS

White American men and women (1975-2018).

MAIN OUTCOME MEASURES

The primary outcome was excess lifetime risk of melanoma diagnosis between 1976 and 2018 (adjusted for year 2018 competing mortality and changes in risk factors), which was inferred as likely overdiagnosis. The secondary outcome was an excess lifetime risk of melanoma diagnosis in each year between 1976 and 2018 (adjusted and unadjusted).

RESULTS

Between 1975 and 2018 the adjusted lifetime risk of being diagnosed with melanoma (invasive and in situ) increased from 3.2% (1 in 31) to 6.4% (1 in 16) among white men, and from 1.6% (1 in 63) to 4.5% (1 in 22) among white women. Over the same period, the adjusted lifetime risk of being diagnosed with melanoma in situ increased from 0.17% (1 in 588) to 2.7% (1 in 37) in white men and 0.08% (1 in 1250) to 2.0% (1 in 50) in white women. An estimated 49.7% of melanomas diagnosed in white men and 64.6% in white women were overdiagnosed in 2018. Among people diagnosed with melanomas in situ, 89.4% of white men and 85.4% of white women were likely overdiagnosed in 2018.

CONCLUSIONS

Melanoma overdiagnosis among white Americans is significant and increasing over time with an estimated 44 000 overdiagnosed in men and 39 000 in women in 2018. A large proportion of overdiagnosed melanomas are in situ cancers, pointing to a potential focus for intervention.

Potential for Cure by Stage across the Cancer Spectrum in the United States

BACKGROUND

Cure fraction-the proportion of persons considered cured of cancer after long-term follow-up-reflects the total impact of cancer control strategies, including screening, without lead-time bias. Previous studies have not reported stage-stratified cure fraction across the spectrum of cancer types.

METHODS

Using a mixture cure model, we estimated cure fraction across stages for 21 cancer types and additional subtypes. Cause-specific survival for 2.4 million incident cancers came from 17 US Surveillance, Epidemiology, and End Results registries for adults 40 to 84 years at diagnosis in 2006 to 2015, followed through 2020.

RESULTS

Across cancer types, a substantial cure fraction was evident at early stages, followed by either a sharp drop from stages III to IV or a steady decline from stages I to IV. For example, estimated cure fractions for colorectal cancer at stages I, II, III, and IV were 62% (95% confidence interval: 59%-66%), 61% (58%-65%), 58% (57%-59%), and 7% (7%-7%), respectively. Corresponding estimates for gallbladder cancer were 50% (46%-54%), 24% (22%-27%), 22% (19%-25%), and 2% (2%-3%). Differences in 5-year cause-specific survival between early-stage and stage IV cancers were highly correlated with between-stage differences in cure fraction, indicating that survival gaps by stage are persistent and not due to lead-time bias.

CONCLUSIONS

A considerable fraction of cancer is amenable to cure at early stages, but not after metastasis.

IMPACT

These results emphasize the potential for early detection of numerous cancers, including those with no current screening modalities, to reduce cancer death.

Assessing the Predictive Power of the Hemoglobin/Red Cell Distribution Width Ratio in Cancer: A Systematic Review and Future Directions

Background and Objectives: The hemoglobin (Hb)/red cell distribution width (RDW) ratio has emerged as an accessible, repeatable, and inexpensive prognostic factor that may predict survival in cancer patients. The focus of this systematic review is to investigate the prognostic role of the Hb/RDW ratio in cancer and the implications for clinical practice. Materials and Methods: A literature search of PubMed, Scopus, and Web of Science databases was performed by an independent author between 18 March and 30 March 2023 to collect relevant literature that assessed the prognostic value of the Hb/RDW ratio in cancer. Overall survival (OS), progression-free survival (PFS), and the association of these with the Hb/RDW ratio were considered to be the main endpoints. Results: Thirteen retrospective studies, including 3818 cancer patients, were identified and involved in this review. It was observed that, when patients with a high vs. low Hb/RDW ratio were compared, those with a lower Hb/RDW ratio had significantly poorer outcomes (p < 0.05). In lung cancer patients, a one-unit increase in the Hb/RDW ratio reduces mortality by 1.6 times, whilst in esophageal squamous-cell carcinoma patients, a lower Hb/RDW ratio results in a 1.416-times greater risk of mortality. Conclusions: A low Hb/RDW ratio was associated with poor OS and disease progression in patients with cancer. This blood parameter should be considered a standard biomarker in clinical practice for predicting OS and PFS in cancer patients. Future searches will be necessary to determine and standardize the Hb/RDW cut-off value and to assess whether the Hb/RDW ratio is optimal as an independent prognostic factor or if it requires incorporation into risk assessment models for predicting outcomes in cancer patients.

Dominantly inherited micro-satellite instable cancer - the four Lynch syndromes - an EHTG, PLSD position statement

The recognition of dominantly inherited micro-satellite instable (MSI) cancers caused by pathogenic variants in one of the four mismatch repair (MMR) genes MSH2, MLH1, MSH6 and PMS2 has modified our understanding of carcinogenesis. Inherited loss of function variants in each of these MMR genes cause four dominantly inherited cancer syndromes with different penetrance and expressivities: the four Lynch syndromes. No person has an "average sex "or a pathogenic variant in an "average Lynch syndrome gene" and results that are not stratified by gene and sex will be valid for no one. Carcinogenesis may be a linear process from increased cellular division to localized cancer to metastasis. In addition, in the Lynch syndromes (LS) we now recognize a dynamic balance between two stochastic processes: MSI producing abnormal cells, and the host's adaptive immune system's ability to remove them. The latter may explain why colonoscopy surveillance does not reduce the incidence of colorectal cancer in LS, while it may improve the prognosis. Most early onset colon, endometrial and ovarian cancers in LS are now cured and most cancer related deaths are after subsequent cancers in other organs. Aspirin reduces the incidence of colorectal and other cancers in LS. Immunotherapy increases the host immune system's capability to destroy MSI cancers. Colonoscopy surveillance, aspirin prevention and immunotherapy represent major steps forward in personalized precision medicine to prevent and cure inherited MSI cancer.

Low-risk prostate lesions: An evidence review to inform discussion on losing the "cancer" label

BACKGROUND

Active surveillance (AS) mitigates harms from overtreatment of low-risk prostate lesions. Recalibration of diagnostic thresholds to redefine which prostate lesions are considered "cancer" and/or adopting alternative diagnostic labels could increase AS uptake and continuation.

METHODS

We searched PubMed and EMBASE to October 2021 for evidence on: (1) clinical outcomes of AS, (2) subclinical prostate cancer at autopsy, (3) reproducibility of histopathological diagnosis, and (4) diagnostic drift. Evidence is presented via narrative synthesis.

RESULTS

AS: one systematic review (13 studies) of men undergoing AS found that prostate cancer-specific mortality was 0%-6% at 15 years. There was eventual termination of AS and conversion to treatment in 45%-66% of men. Four additional cohort studies reported very low rates of metastasis (0%-2.1%) and prostate cancer-specific mortality (0%-0.1%) over follow-up to 15 years. Overall, AS was terminated without medical indication in 1%-9% of men. Subclinical reservoir: 1 systematic review (29 studies) estimated that the subclinical cancer prevalence was 5% at <30 years, and increased nonlinearly to 59% by >79 years. Four additional autopsy studies (mean age: 54-72 years) reported prevalences of 12%-43%. Reproducibility: 1 recent well-conducted study found high reproducibility for low-risk prostate cancer diagnosis, but this was more variable in 7 other studies. Diagnostic drift: 4 studies provided consistent evidence of diagnostic drift, with the most recent (published 2020) reporting that 66% of cases were upgraded and 3% were downgraded when using contemporary diagnostic criteria compared to original diagnoses (1985-1995).

CONCLUSIONS

Evidence collated may inform discussion of diagnostic changes for low-risk prostate lesions.

Advances in Early Detection of Melanoma and the Future of At-Home Testing

The past decade has seen numerous advancements in approaches to melanoma detection, each with the common goal to stem the growing incidence of melanoma and its mortality rate. These advancements, while well documented to increase early melanoma detection, have also garnered considerable criticism of their efficacy for improving survival rates. In this review, we discuss the current state of such early detection approaches that do not require direct dermatologist intervention. Our findings suggest that a number of at-home and non-specialist methods exist with high accuracy for detecting melanoma, albeit with a few notable concerns worth further investigation. Additionally, research continues to find new approaches using artificial intelligence which have promise for the future.

Overdiagnosis Due to Screening Mammography for Breast Cancer among Women Aged 40 Years and Over: A Systematic Review and Meta-Analysis

The current systematic review and meta-analysis was conducted to estimate the incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older. A PRISMA systematic search appraisal and meta-analysis were conducted. A systematic literature search of English publications in PubMed, Web of Science, EMBASE, Scopus, and Google Scholar was conducted without regard to the region or time period. Generic, methodological, and statistical data were extracted from the eligible studies. A meta-analysis was completed by utilizing comprehensive meta-analysis software. The effect size estimates were calculated using the fail-safe N test. The funnel plot and the Begg and Mazumdar rank correlation tests were employed to find any potential bias among the included articles. The strength of the association between two variables was assessed using Kendall’s tau. Heterogeneity was measured using the I-squared (I2) test. The literature search in the five databases yielded a total of 4214 studies. Of those, 30 articles were included in the final analysis, with sample sizes ranging from 451 to 1,429,890 women. The vast majority of the articles were retrospective cohort designs (24 articles). The age of the recruited women ranged between 40 and 89 years old. The incidence of overdiagnosis due to screening mammography for breast cancer among women aged 40 years and older was 12.6%. There was high heterogeneity among the study articles (I2 = 99.993), and the pooled event rate was 0.126 (95% CI: 15 0.101–0.156). Despite the random-effects meta-analysis showing a high degree of heterogeneity among the articles, the screening tests have to allow for a certain degree of overdiagnosis (12.6%) due to screening mammography for breast cancer among women aged 40 years and older. Furthermore, efforts should be directed toward controlling and minimizing the harmful consequences associated with breast cancer screening.

Estimativa de Incidência de Câncer no Brasil, 2023-2025

Introdução: O câncer é um problema de saúde pública mundial. Na última década, houve um aumento de 20% na incidência e espera-se que, para 2030, ocorram mais de 25 milhões de casos novos. Estimativas do número de casos novos de câncer são uma ferramenta poderosa para fundamentar políticas públicas e alocação racional de recursos para o combate ao câncer. A vigilância do câncer é um elemento crucial para planejamento, monitoramento e avaliação das ações de controle do câncer. Objetivo: Estimar e descrever a incidência de câncer no país, Regiões geográficas, Unidades da Federação, Distrito Federal e capitais, por sexo, para o triênio 2023-2025. Método: As informações foram extraídas do Sistema de Informação sobre Mortalidade e dos Registros de Câncer de Base Populacional. Foram estimados os casos novos e suas respectivas taxas de incidência pelos modelos de predição tempo-linear ou pela razão de incidência e mortalidade. Resultados: São esperados 704 mil casos novos de câncer para o triênio 2023-2025. Excetuando o câncer de pele não melanoma, ocorrerão 483 mil casos novos. O câncer de mama feminina e o de próstata foram os mais incidentes com 73 mil e 71 mil casos novos, respectivamente. Em seguida, o câncer de cólon e reto (45 mil), pulmão (32 mil), estômago (21 mil) e o câncer do colo do útero (17 mil). Conclusão: No Brasil, por suas dimensões continentais e heterogeneidade, em termos de território e população, o perfil da incidência reflete a diversidade das Regiões geográficas, coexistindo padrões semelhantes ao de países desenvolvidos e em desenvolvimento.

Identification of adenylate cyclase 2 methylation in bladder cancer with implications for prognosis and immunosuppressive microenvironment

Background

The incidence and mortality of bladder cancer (BCa) are increasing, while the existing diagnostic methods have limitations. Therefore, for early detection and response prediction, it is crucial to improve the prognosis and treatment strategies. However, with existing diagnostic methods, detecting BCa in the early stage is challenging. Hence, novel biomarkers are urgently needed to improve early diagnosis and treatment efficiency.

Methods

The gene expression profile and gene methylation profile dataset were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs), differentially methylated genes (DMGs), and methylation-regulated differentially expressed genes (MeDEGs) were gradually identified. A cancer genome map was obtained using online gene expression profile interaction analysis, and survival implications were produced using Kaplan-Meier survival analysis. GSEA was employed to predict the marker pathways where DEGs were significantly involved. The study used bisulfite PCR amplification combined with bisulfite amplicon sequencing (BSAS) to screen for methylation analysis of multiple candidate regions of the adenylate cyclase 2 (ADCY2) based on the sequence design of specific gene regions and CpG islands.

Results

In this study, DEGs and DMGs with significantly up- or down-regulated expression were selected. The intersection method was used to screen the MeDEGs. The interaction network group in STRING was then visualized using Cytoscape, and the PPI network was constructed to identify the key genes. The key genes were then analyzed using functional enrichment. To compare the relationship between key genes and the prognosis of BCa patients, we further investigated ADCY2 and found that ADCY2 can be a potential clinical biomarker in BCa prognosis and immunotherapy response prediction. In human BCa 5637 and MGH1 cells, we developed and verified the effectiveness of ADCY2 primers using BSAS technology. The findings revealed that the expression of ADCY2 is highly regulated by the methylation of the promoter regions.

Conclusion

This study revealed that increased expression of ADCY2 was significantly correlated with increased tumor heterogeneity, predicting worse survival and immunotherapy response in BCa patients.