Cancer Stage Compared With Mortality as End Points in Randomized Clinical Trials of Cancer Screening: A Systematic Review and Meta-Analysis

Importance

Randomized clinical trials of cancer screening typically use cancer-specific mortality as the primary end point. The incidence of stage III-IV cancer is a potential alternative end point that may accelerate completion of randomized clinical trials of cancer screening.

Objective

To compare cancer-specific mortality with stage III-IV cancer as end points in randomized clinical trials of cancer screening.

Design, Setting, and Participants

This meta-analysis included 41 randomized clinical trials of cancer screening conducted in Europe, North America, and Asia published through February 19, 2024. Data extracted included numbers of participants, cancer diagnoses, and cancer deaths in the intervention and comparison groups. For each clinical trial, the effect of screening was calculated as the percentage reduction between the intervention and comparison groups in the incidence of participants with cancer-specific mortality and stage III-IV cancer.

Exposures

Randomization to a cancer screening test or to a comparison group in a clinical trial of cancer screening.

Main Outcomes and Measures

End points of cancer-specific mortality and incidence of stage III-IV cancer were compared using Pearson correlation coefficients with 95% CIs, linear regression, and fixed-effects meta-analysis.

Results

The included randomized clinical trials tested benefits of screening for breast (n = 6), colorectal (n = 11), lung (n = 12), ovarian (n = 4), prostate (n = 4), and other cancers (n = 4). Correlation between reductions in cancer-specific mortality and stage III-IV cancer varied by cancer type (I2 = 65%; P = .02). Correlation was highest for trials that screened for ovarian (Pearson ρ = 0.99 [95% CI, 0.51-1.00]) and lung (Pearson ρ = 0.92 [95% CI, 0.72-0.98]) cancers, moderate for breast cancer (Pearson ρ = 0.70 [95% CI, -0.26 to 0.96]), and weak for colorectal (Pearson ρ = 0.39 [95% CI, -0.27 to 0.80]) and prostate (Pearson ρ = -0.69 [95% CI, -0.99 to 0.81]) cancers. Slopes from linear regression were estimated as 1.15 for ovarian cancer, 0.75 for lung cancer, 0.40 for colorectal cancer, 0.28 for breast cancer, and -3.58 for prostate cancer, suggesting that a given magnitude of reduction in incidence of stage III-IV cancer produced different magnitudes of change in incidence of cancer-specific mortality (P for heterogeneity = .004).

Conclusions and Relevance

In randomized clinical trials of cancer screening, incidence of late-stage cancer may be a suitable alternative end point to cancer-specific mortality for some cancer types, but is not suitable for others. These results have implications for clinical trials of multicancer screening tests.

Projecting the impact of multi-cancer early detection on late-stage incidence using multi-state disease modeling

BACKGROUND

Downstaging- reduction in late-stage incidence-has been proposed as an endpoint in randomized trials of multi-cancer early detection (MCED) tests. How downstaging depends on test performance and follow-up has been studied for some cancers but is understudied for cancers without existing screening and for MCED tests that include these cancer types.

METHODS

We develop a model for cancer natural history that can be fit to registry incidence patterns under minimal inputs and can be estimated for solid cancers without existing screening. Fitted models are combined to project downstaging in MCED trials given sensitivity for early- and late-stage cancers. We fit models for 12 cancers using incidence data from the Surveillance, Epidemiology, and End Results program and project downstaging in a simulated trial under variable preclinical latencies and test sensitivities.

RESULTS

A proof-of-principle lung cancer model approximated downstaging in the National Lung Screening Trial. Given published stage-specific sensitivities for 12 cancers, we projected downstaging ranging 21%-43% across plausible preclinical latencies in a hypothetical 3-screen MCED trial. Late-stage incidence reductions manifest soon after screening begins. Downstaging increases with longer early-stage latency or higher early-stage test sensitivity.

CONCLUSION

Even short-term MCED trials could produce substantial downstaging given adequate early-stage test sensitivity.

IMPACT

Modeling the natural histories of cancers without existing screening facilitates analysis of novel MCED products and trial designs. The framework informs expectations of MCED impact on disease stage at diagnosis and could serve as a building block for designing trials with late-stage incidence as the primary endpoint.

Isolating the Drivers of Racial Inequities in Prostate Cancer Treatment

BACKGROUND

Black individuals in the United States are less likely than White individuals to receive curative therapies despite a 2-fold higher risk of prostate cancer death. While research has described treatment inequities, few studies have investigated underlying causes.

METHODS

We analyzed a cohort of 40,137 Medicare beneficiaries (66 and older) linked to the Surveillance Epidemiology and End Results (SEER) cancer registry who had clinically significant, non-metastatic (cT1-4N0M0, grade group 2-5) prostate cancer (diagnosed 2010-2015). Using the Kitagawa-Oaxaca-Blinder decomposition, we assessed the contributions of patient health and health care delivery on the racial difference in localized prostate cancer treatments (radical prostatectomy or radiation). Patient health consisted of comorbid diagnoses, tumor characteristics, SEER site, diagnosis year, and age. Health care delivery was captured as a prediction model with these health variables as predictors of treatment, reflecting current treatment patterns.

RESULTS

A total of 72.1% and 78.6% of Black and White patients received definitive treatment, respectively, a difference of 6.5 percentage points. An estimated 15% [95% confidence interval (CI): 6-24] of this treatment difference was explained by measured differences in patient health, leaving the remaining estimated 85% (95% CI: 74-94) attributable to a potentially broad range of health care delivery factors. Limitations included insufficient data to explore how specific health care delivery factors, including structural racism and social determinants, impact differential treatment.

CONCLUSIONS

Our results show the inadequacy of patient health differences as an explanation of the treatment inequity.

IMPACT

Investing in studies and interventions that support equitable health care delivery for Black individuals with prostate cancer will contribute to improved outcomes.

Prediagnostic evaluation of multicancer detection tests: Design and analysis considerations

There is growing interest in multicancer detection (MCD) tests, which identify molecular signals in the blood indicating a potential preclinical cancer. A key stage in evaluating MCD tests is a prediagnostic performance study, in which investigators store specimens from asymptomatic persons and later test stored specimens from cancer cases and a random sample of controls to determine predictive performance. Performance metrics include cancer-specific true and false positive rates and a cancer-specific positive predictive value, with the latter compared to a decision-analytic threshold. The sample size tradeoff method, which trades imprecise targeting of the true positive rate for precise targeting of a zero false positive rate can substantially reduce sample size while increasing the lower bound of positive predictive value. For a 1-year follow-up, with ovarian cancer as the rarest cancer considered, the sample size tradeoff method yields a sample size of 163,000 compared with a sample size of 720,000 based on standard calculations. These design and analysis recommendations should be considered in planning a specimen repository and in the prediagnostic evaluation of MCD tests.

Benefits and harms of prostate specific antigen testing according to Australian guidelines

Guidelines for prostate specific antigen (PSA) testing in Australia recommend that men at average risk of prostate cancer who have been informed of the benefits and harms, and who decide to undergo regular testing, should be offered testing every 2 years from 50 to 69 years. This study aimed to estimate the benefits and harms of regular testing in this context. We constructed Policy1-Prostate, a discrete event microsimulation platform of the natural history of prostate cancer and prostate cancer survival, and PSA testing patterns and subsequent management in Australia. The model was calibrated to pre-PSA (before 1985) prostate cancer incidence and mortality and validated against incidence and mortality trends from 1985 to 2011 and international trials. The model predictions were concordant with trials and Australian observed incidence and mortality data from 1985 to 2011. Out of 1000 men who choose to test according to the guidelines, 36 [21-41] men will die from prostate cancer and 126 [119-133] men will be diagnosed with prostate cancer, compared with 50 [47-54] and 94 [90-98] men who do not test, respectively. During the 20 years of active PSA testing, 32.3% [25.6%-38.8%] of all PSA-test detected cancers are overdiagnosed cases that is, 30 [21-42] out of 94 [83-107] PSA-test detected cancers. Australian men choosing to test with PSA every two years from 50 to 69 will reduce their risk of ever dying from prostate cancer and incur a risk of overdiagnosis: for every man who avoids dying from prostate cancer, two will be overdiagnosed with prostate cancer between 50 and 69 years of age. Australian men, with health professionals, can use these results to inform decision-making about PSA testing.

Revisiting the standard blueprint for biomarker development to address emerging cancer early detection technologies

Novel liquid biopsy technologies are creating a watershed moment in cancer early detection. Evidence supporting population screening is nascent, but a rush to market the new tests is prompting cancer early detection researchers to revisit the standard blueprint that the Early Detection Research Network established to evaluate novel screening biomarkers. In this commentary, we review the Early Detection Research Network's Phases of Biomarker Development (PBD) for rigorous evaluation of novel early detection biomarkers and discuss both hazards and opportunities involved in expedited evaluation. According to the PBD, for a biomarker-based test to be considered for population screening, 1) test sensitivity in a prospective screening setting must be adequate, 2) the shift to early curable stages must be meaningful, and 3) any stage shift must translate into clinically significant mortality benefit. In the past, determining mortality benefit has required lengthy randomized screening trials, but interest is growing in expedited trial designs with shorter-term endpoints. Whether and how best to use such endpoints in a manner that retains the rigor of the PBD remains to be determined. We discuss how computational disease modeling can be harnessed to learn about screening impact and meet the needs of the moment.

Implementation outcomes of the integrated district evidence to action (IDEAs) program to reduce neonatal mortality in central Mozambique: an application of the RE-AIM evaluation framework

BACKGROUND

Scarce evidence exists on audit and feedback implementation processes in low-resource health systems. The Integrated District Evidence to Action (IDEAs) is a multi-component audit and feedback strategy designed to improve the implementation of maternal and child guidelines in Mozambique. We report IDEAs implementation outcomes.

METHODS

IDEAs was implemented in 154 health facilities across 12 districts in Manica and Sofala provinces between 2016 and 2020 and evaluated using a quasi-experimental design guided by the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework. Reach is the proportion of pregnant women attending IDEAs facilities. Adoption is the proportion of facilities initiating audit and feedback meetings. Implementation is the fidelity to the strategy components, including readiness assessments, meetings (frequency, participation, action plan development), and targeted financial support and supervision. Maintenance is the sustainment at 12, 24, and 54 months.

RESULTS

Across both provinces, 56% of facilities were exposed to IDEAs (target 57%). Sixty-nine and 73% of pregnant women attended those facilities' first and fourth antenatal consultations (target 70%). All facilities adopted the intervention. 99% of the expected meetings occurred with an average interval of 5.9 out of 6 months. Participation of maternal and child managers was high, with 3076 attending meetings, of which 64% were from the facility, 29% from the district, and 7% from the province level. 97% of expected action plans were created, and 41 specific problems were identified. "Weak diagnosis or management of obstetric complications" was identified as the main problem, and "actions to reinforce norms and protocols" was the dominant subcategory of micro-interventions selected. Fidelity to semiannual readiness assessments was low (52% of expected facilities), and in completing micro-interventions (17% were completed). Ninety-six and 95% of facilities sustained the intervention at 12 and 24 months, respectively, and 71% had completed nine cycles at 54 months.

CONCLUSION

Maternal and child managers can lead audit and feedback processes in primary health care in Mozambique with high reach, adoption, and maintenance. The IDEAs strategy should be adapted to promote higher fidelity around implementing action plans and conducting readiness assessments. Adding effectiveness to these findings will help to inform strategy scale-up.

Prostate cancer screening in African American men: a review of the evidence

BACKGROUND

Prostate cancer is the most diagnosed cancer in African American men, yet prostate cancer screening regimens in this group are poorly guided by existing evidence, given underrepresentation of African American men in prostate cancer screening trials. It is critical to optimize prostate cancer screening and early detection in this high-risk group because underdiagnosis may lead to later-stage cancers at diagnosis and higher mortality while overdiagnosis may lead to unnecessary treatment.

METHODS

We performed a review of the literature related to prostate cancer screening and early detection specific to African American men to summarize the existing evidence available to guide health-care practice.

RESULTS

Limited evidence from observational and modeling studies suggests that African American men should be screened for prostate cancer. Consideration should be given to initiating screening of African American men at younger ages (eg, 45-50 years) and at more frequent intervals relative to other racial groups in the United States. Screening intervals can be optimized by using a baseline prostate-specific antigen measurement in midlife. Finally, no evidence has indicated that African American men would benefit from screening beyond 75 years of age; in fact, this group may experience higher rates of overdiagnosis at older ages.

CONCLUSIONS

The evidence base for prostate cancer screening in African American men is limited by the lack of large, randomized studies. Our literature search supported the need for African American men to be screened for prostate cancer, for initiating screening at younger ages (45-50 years), and perhaps screening at more frequent intervals relative to men of other racial groups in the United States.

Multicancer Early Detection Tests: An Overview of Early Results From Prospective Clinical Studies and Opportunities for Oncologists

A multitude of blood-based multicancer early detection (MCED) tests assessing cancer-related alterations in circulating genomic analytes and other associated signatures are currently being developed with the potential to disrupt current single-organ screening paradigms. Pathways for clinical implementation of these novel MCED tests have not been delineated, particularly for the patients with signal positive results requiring additional confirmatory testing. In this overview, we highlight early results from prospective clinical studies testing the efficacy of genomic MCED tests in cohorts of patients without known cancer diagnoses. Additionally, we discuss a proposed professional expansion of the oncology practice relating to the diagnostic workup of individuals found to have an MCED signal positive for cancer. As MCED blood tests have the potential to dramatically upend current cancer screening paradigms and downstream cancer therapy, it is imperative for oncologists to be aware of important clinical studies and the multitude of unanswered questions. The current gaps in the clinical implication of these tests may serve as a meaningful and rewarding expansion of oncology practice.

Risk of cancer versus risk of cancer diagnosis? Accounting for diagnostic bias in predictions of breast cancer risk by race and ethnicity

OBJECTIVES

Cancer risk prediction may be subject to detection bias if utilization of screening is related to cancer risk factors. We examine detection bias when predicting breast cancer risk by race/ethnicity.

METHODS

We used screening and diagnosis histories from the Breast Cancer Surveillance Consortium to estimate risk of breast cancer onset and calculated relative risk of onset and diagnosis for each racial/ethnic group compared with non-Hispanic White women.

RESULTS

Of 104,073 women aged 40-54 receiving their first screening mammogram at a Breast Cancer Surveillance Consortium facility between 2000 and 2018, 10.2% (n = 10,634) identified as Asian, 10.9% (n = 11,292) as Hispanic, and 8.4% (n = 8719) as non-Hispanic Black. Hispanic and non-Hispanic Black women had slightly lower screening frequencies but biopsy rates following a positive mammogram were similar across groups. Risk of cancer diagnosis was similar for non-Hispanic Black and White women (relative risk vs non-Hispanic White = 0.90, 95% CI 0.65 to 1.14) but was lower for Asian (relative risk = 0.70, 95% CI 0.56 to 0.97) and Hispanic women (relative risk = 0.82, 95% CI 0.62 to 1.08). Relative risks of disease onset were 0.78 (95% CI 0.68 to 0.88), 0.70 (95% CI 0.59 to 0.83), and 0.95 (95% CI 0.84 to 1.09) for Asian, Hispanic, and non-Hispanic Black women, respectively.

CONCLUSIONS

Racial/ethnic differences in mammography and biopsy utilization did not induce substantial detection bias; relative risks of disease onset were similar to or modestly different than relative risks of diagnosis. Asian and Hispanic women have lower risks of developing breast cancer than non-Hispanic Black and White women, who have similar risks.

Temporal effect of imatinib adherence on time to remission in chronic myeloid leukemia patients

INTRODUCTION

Adherence to imatinib in chronic myeloid leukemia (CML) patients is estimated to be as low as 70% despite its clinical benefit, and our understanding of the impact of nonadherence in this population is limited. This study presents a novel application of the Alternating Conditional Estimation (ACE) algorithm in newly diagnosed CML patients to map the full dose-response curve (DRC) and determine how the strength of this curve varies over time.

METHODS

We applied the ACE algorithm alongside a backward elimination procedure to detect the presence of time dependence and nonlinearity in the relationship between imatinib adherence and time-to-remission. An extended Cox model allowing for the flexible modeling of identified effects via unpenalized B-splines was subsequently fit and assessed.

RESULTS

The substantial improvement in model fit associated with the extended Cox approach suggests that traditional Cox proportional hazards model assumptions do not hold in this setting. Results indicate that the DRC for imatinib is non-linearly increasing, with an attenuated effect above a 74% adherence rate. The strength of this effect on remission varied over time and was strongest in the initial months of treatment, reaching a peak around 90 days post-initiation (log hazard ratio: 2.12, 95% confidence interval: 1.47 to 2.66).

CONCLUSION

Most patients that achieved remission did so by 4 months (120 days) with consistently high adherence, suggesting that this could be a critical time and duration for realizing treatment benefit and patient monitoring. Findings regarding the relationship between adherence and remission can additionally help guide the design of future studies.

Racial disparities in prostate cancer mortality: a model-based decomposition of contributing factors

To investigate the relative contributions of natural history and clinical interventions to racial disparities in prostate cancer mortality in the United States, we extended a model that was previously calibrated to Surveillance, Epidemiology, and End Results (SEER) incidence rates for the general population and for Black men. The extended model integrated SEER data on curative treatment frequencies and cancer-specific survival. Starting with the model for all men, we replaced up to 9 components with corresponding components for Black men, projecting age-standardized mortality rates for ages 40-84 years at each step. Based on projections in 2019, the increased frequency of developing disease, more aggressive tumor features, and worse cancer-specific survival in Black men diagnosed at local-regional and distant stages explained 38%, 34%, 22%, and 8% of the modeled disparity in mortality. Our results point to intensified screening and improved care in Black men as priority areas to achieve greater equity.

Melanoma literacy among the general population of three western US states

Melanoma is a significant cause of cancer death, despite being detectable without specialized or invasive technologies. Understanding barriers to preventive behaviors such as skin self-examination (SSE) could help to define interventions for increasing the frequency of early detection. To determine melanoma knowledge and beliefs across three high-incidence US states, 15,000 surveys were sent to a population-representative sample. We aimed to assess (1) melanoma literacy (i.e., knowledge about melanoma risks, attitudes, and preventive behaviors) and (2) self-reported SSE and its association with melanoma literacy, self-efficacy, and belief in the benefits of SSE. Of 2326 respondents, only 21.2% provided responses indicating high knowledge of melanoma, and 62.8% reported performing an SSE at any time in their lives. Only 38.3% and 7.3% reported being "fairly" or "very" confident about doing SSE, respectively. SSE performance among respondents was most strongly associated with higher melanoma knowledge, higher self-efficacy, and personal history of melanoma. Melanoma literacy among survey respondents was modest, with greater literacy associated with a higher likelihood of reported preventive behavior. This assessment establishes a baseline and provides guidance for public health campaigns designed to increase prevention and early detection of this lethal cancer.

Early Detection of Prostate Cancer: AUA/SUO Guideline Part II: Considerations for a Prostate Biopsy

PURPOSE

The summary presented herein covers recommendations on the early detection of prostate cancer and provides a framework to facilitate clinical decision-making in the implementation of prostate cancer screening, biopsy, and follow-up. This is Part II of a two-part series focusing on initial and repeat biopsies, and biopsy technique. Please refer to Part I for discussion of initial prostate cancer screening recommendations.

MATERIALS AND METHODS

The systematic review utilized to inform this guideline was conducted by an independent methodological consultant. The systematic review was based on searches in Ovid MEDLINE and Embase and Cochrane Database of Systematic Reviews (January 1, 2000-November 21, 2022). Searches were supplemented by reviewing reference lists of relevant articles.

RESULTS

The Early Detection of Prostate Cancer Panel developed evidence- and consensus-based guideline statements to provide guidance in prostate cancer screening, initial and repeat biopsies, and biopsy technique.

CONCLUSIONS

The evaluation of prostate cancer risk should be focused on the detection of clinically significant prostate cancer (Grade Group 2 or higher [GG2+]). The use of laboratory biomarkers, prostate MRI, and biopsy techniques described herein may improve detection and safety when a prostate biopsy is deemed necessary following prostate cancer screening.

Early Detection of Prostate Cancer: AUA/SUO Guideline Part I: Prostate Cancer Screening

PURPOSE

The summary presented herein covers recommendations on the early detection of prostate cancer and provides a framework to facilitate clinical decision-making in the implementation of prostate cancer screening, biopsy, and follow-up. This is Part I of a two-part series that focuses on prostate cancer screening. Please refer to Part II for discussion of initial and repeat biopsies as well as biopsy technique.

MATERIALS AND METHODS

The systematic review utilized to inform this guideline was conducted by an independent methodological consultant. The systematic review was based on searches in Ovid MEDLINE and Embase and Cochrane Database of Systematic Reviews (January 1, 2000-November 21, 2022). Searches were supplemented by reviewing reference lists of relevant articles.

RESULTS

The Early Detection of Prostate Cancer Panel developed evidence- and consensus-based guideline statements to provide guidance in prostate cancer screening, initial and repeat biopsy, and biopsy technique.

CONCLUSIONS

Prostate-specific antigen (PSA)-based prostate cancer screening in combination with shared decision-making (SDM) is recommended. Current data regarding risk from population-based cohorts provide a basis for longer screening intervals and tailored screening, and the use of available online risk calculators is encouraged.

Test sensitivity in a prospective cancer screening program: A critique of a common proxy measure

The true sensitivity of a cancer screening test, defined as the frequency with which the test returns a positive result if the cancer is present, is a key indicator of diagnostic performance. Given the challenges of directly assessing test sensitivity in a prospective screening program, proxy measures for true sensitivity are frequently reported. We call one such proxy empirical sensitivity, as it is given by the observed ratio of screen-detected cancers to the sum of screen-detected and interval cancers. In the setting of the canonical three-state Markov model for progression from preclinical onset to clinical diagnosis, we formulate a mathematical relationship for how empirical sensitivity varies with the screening interval and the mean preclinical sojourn time and identify conditions under which empirical sensitivity exceeds or falls short of true sensitivity. In particular, when the inter-screening interval is short relative to the mean sojourn time, empirical sensitivity tends to exceed true sensitivity, unless true sensitivity is high. The Breast Cancer Surveillance Consortium (BCSC) has reported an estimate of 0.87 for the empirical sensitivity of digital mammography. We show that this corresponds to a true sensitivity of 0.82 under a mean sojourn time of 3.6 years estimated based on breast cancer screening trials. However, the BCSC estimate of empirical sensitivity corresponds to even lower true sensitivity under more contemporary, longer estimates of mean sojourn time. Consistently applied nomenclature that distinguishes empirical sensitivity from true sensitivity is needed to ensure that published estimates of sensitivity from prospective screening studies are properly interpreted.

Short-term Endpoints for Cancer Screening Trials: Does Tumor Subtype Matter?

Multicancer early detection tests are precipitating a reexamination of potential short-term endpoints for cancer screening trials. A reduction in advanced stage incidence is a prime candidate, and stage-shift models that substitute early-stage for late-stage survival have been used to predict mortality reduction due to screening. However, standard stage-shift models often ignore prognostic subtypes, effectively implying that cancers detected early also have an associated subtype shift. To illustrate the differences between mortality predictions from stage-shift models that ignore versus preserve prognostic subtype, we use ovarian cancer partitioned by histologic subtype and prostate cancer partitioned by grade. We infer general conditions under which stage-shift models that preserve prognostic subtype are likely to predict mortality reductions that differ from those that ignore subtype and examine the implications for short-term endpoints based on stage in cancer screening trials.

Estimating the Number of Men Living with Metastatic Prostate Cancer in the United States

BACKGROUND

Metastatic prostate cancer (MPC) includes metastases detected at diagnosis (de novo) and those occurring after diagnosis with early-stage disease (recurrent). Cancer registries collect data only on de novo MPC, providing a partial picture of the burden of MPC. We use cancer registry data to estimate the number of men living with MPC in the United States including both de novo and recurrent cases.

METHODS

We apply a back-calculation method to estimate MPC incidence and prevalence from U.S. prostate cancer mortality and de novo MPC relative survival for cases diagnosed between 2000 and 2017 in 18 Surveillance, Epidemiology, and End Results registries. We hold overall prostate cancer mortality and MPC survival constant for future prevalence projections.

RESULTS

On January 1, 2018, we estimated 120,400 U.S. men living with MPC (45% de novo, 55% recurrent). The age-adjusted prevalence in 2018 for Black men was over double that of White men (137.1 vs. 62.2 per 100,000 men). By 2030, 192,500 men are expected to be living with MPC, with the increase being driven by population growth projections.

CONCLUSIONS

The number of men living with MPC in the United States exceeds 100,000 and represents a small fraction of the >3 million men living with a prior diagnosis of prostate cancer.

IMPACT

Relatively similar fractions of de novo and recurrent MPC among prevalent cases highlight opportunities for management of localized disease in reducing the MPC burden. Changes in diagnostic technologies could lead to greater growth in MPC cases in the United States than projected. See related commentary by Stopsack et al., p. 585.

Abstract P4-03-03: Elevated Risk of Breast Cancer Diagnosis in Women with Dense Breasts reflects a similarly Elevated Risk of Breast Cancer Onset that is Robust to the Effect of Density on Mammography Sensitivity

Dense breasts are associated with a higher risk of breast cancer diagnosis, which has impacted risk prediction tools and patient notification policies. However, given that mammography is less sensitive for women with dense breasts and these women may be subject to different confirmation testing pathways, the true association between breast density and cancer risk is unknown. We investigated the relationship between breast density and onset using a natural history model that accounts for differential sensitivity and rates of exams by breast density. Data consisted of Breast Cancer Surveillance Consortium mammogram and cancer outcomes among women aged 40-54 with a first digital mammogram between 2000-2018 (N=33,542). Of these, 15,092 had non-dense (almost entirely fatty or scattered fibroglandular densities) and18,450 had dense (heterogeneously dense or extremely dense) breasts. We estimated the empirical sensitivity of mammograms in dense and non-dense breasts (fraction of diagnosed cancers that were screen detected) and examined rates of mammograms by density. We estimated the relative risk of breast cancer diagnosis five years after the first exam using Kaplan Meier methods and the relative risk of breast cancer onset from a natural history model, assuming density-specific sensitivity was equal to the empirical sensitivity. Empirical sensitivity was .88 in women with non-dense and .78 in women with dense breasts. Mammogram utilization was somewhat higher in women with dense breasts (HR for subsequent mammograms 1.10 (95% CI [1.07, 1.12]). The relative risk of diagnosis for dense versus non-dense breasts was 1.80 (95% CI [1.46,2.57]); based on the natural history model the relative risk of onset was 1.73 [1.43,2.25]. The estimated relative risk of onset ranged from 1.67 to 2.03 under assumptions that the relative sensitivity of the screening episode for dense versus non-dense breasts was 1.0 to 0.4. In conclusion, the association of risk of breast cancer onset with breast density is robust to assumptions about the relative sensitivity in dense and non-dense breasts.

Citation Format: Jane M. Lange, Charlotte Gard, Ellen O’meara, Ruth Etzioni. Elevated Risk of Breast Cancer Diagnosis in Women with Dense Breasts reflects a similarly Elevated Risk of Breast Cancer Onset that is Robust to the Effect of Density on Mammography Sensitivity [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-03.

Estimating stage-specific sensitivity for cancer screening tests

OBJECTIVES

When evaluating potential new cancer screening modalities, estimating sensitivity, especially for early-stage cases, is critical. There are methods to approximate stage-specific sensitivity in asymptomatic populations, both in the prospective (active screening) and retrospective (stored specimens) scenarios. We explored their validity via a simulation study.

METHODS

We fit natural history models to lung and ovarian cancer screening data that permitted estimation of stage-specific (early/late) true sensitivity, defined as the probability subjects screened in the given stage had positive tests. We then ran simulations, using the fitted models, of the prospective and retrospective scenarios. Prospective sensitivity by stage was estimated as screen-detected divided by screen-plus interval-detected cancers, where stage is defined as stage at detection. Retrospective sensitivity by stage was estimated based on cancers detected within specified windows before clinical diagnosis with stage defined as stage at clinical diagnosis.

RESULTS

Stage-specific true sensitivities estimated by the lung cancer natural history model were 47% (early) and 63% (late). Simulation results for the prospective setting gave estimated sensitivities of 81% (early) versus 62% (late). In the retrospective scenario, early/late sensitivity estimates were 35%/57% (1-year window) and 27%/49% (2-year window). In the prospective scenario, most subjects with negative early-stage screens presented as other than early-stage interval cases. Results were similar for ovarian cancer, with estimated prospective sensitivity much greater than true sensitivity for early stage, 84% versus 25%.

CONCLUSIONS

Existing methods for approximating stage-specific sensitivity in both prospective and retrospective scenarios are unsatisfactory; improvements are needed before they can be considered to be reliable.

Modeling the impact of novel systemic treatments on lung cancer screening benefits

BACKGROUND

Since low-dose computed tomography (LDCT) screening was shown to be effective in the National Lung Screening Trial (NLST), novel targeted therapies and immunotherapies for advanced lung cancer have become available. This study investigated the impact of these treatment advances on the expected benefits of LDCT screening.

METHODS

A microsimulation model of LDCT screening for high-risk individuals under standard systemic treatments (chemotherapy and radiation therapy) and novel treatments (immunotherapy and targeted therapy) was used. The model assumed a reduction in advanced-stage disease consistent with the NLST, and given the stage at diagnosis, it projected survival. The disease-specific relative mortality reduction (MR) due to LDCT screening was projected in the trial setting and in a population eligible for LDCT screening under the current US Preventive Services Task Force (USPSTF) recommendations.

RESULTS

The availability of novel treatments reduced the MR in the LDCT arm of the NLST from 15% to 13.5% and the number of lung cancer deaths prevented from 310 to 224 per 100,000 persons screened. Over 10 years, population LDCT screening based on USPSTF recommendations prevented 374 lung cancer deaths per 100,000 under standard treatments (13.3% MR) and 236 per 100,000 under fully adopted novel treatments (10.6% MR). The number needed to screen to avert one death over 10 years was 270 under standard treatments and 440 under novel treatments.

CONCLUSIONS

The transition from standard systemic treatments to novel treatments is expected to reduce the relative and absolute mortality benefits of LDCT screening. Benefit-harm tradeoffs of LDCT screening are likely to change as novel treatments become widespread.

Abstract IA018: Opportunity for interception as a driver of benefit in cancer early detection: implications for multi-cancer early detection testing

Early detection cannot succeed unless there is adequate opportunity for cancer to be diagnosed and intercepted within its early preclinical phase. An understanding of opportunity for early detection and interception is therefore critical in predicting potential mortality reduction due to screening. Opportunity is not directly observable but may be learned using data from prospectively screened cohorts and populations. In this presentation I will share a history of methods for learning about early detection opportunity and will present examples of how we have built on this work to study opportunity for early detection in prostate and breast cancer. I will describe a generic model of how opportunity and sensitivity combine to produce stage shift and mortality reduction and will briefly explore whether a lack of opportunity may have been behind the results of the UCKCTOCS trial. I will use this learning to motivate why I believe a prospective study to investigate opportunity for multi-cancer detection and interception is warranted before or alongside ongoing and planned screening trials. This work in in collaboration with Roman Gulat i and Lukas Owens (Fred Hutch), Jane Lange (OHSU) and Marc Ryser (Duke University). We acknowledge funding from the National Cancer Institute and collaboration with and data from the Breast Cancer Surveillance Consortium

Citation Format: Ruth Etzioni, Roman Gulati, Lukas Owens, Jane Lange, Marc D. Ryser. Opportunity for interception as a driver of benefit in cancer early detection: implications for multi-cancer early detection testing. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr IA018.

Deconstructing, Addressing, and Eliminating Racial and Ethnic Inequities in Prostate Cancer Care

CONTEXT

Men of African ancestry have demonstrated markedly higher rates of prostate cancer mortality than men of other races and ethnicities around the world. In fact, the highest rates of prostate cancer mortality worldwide are found in the Caribbean and Sub-Saharan West Africa, and among men of African descent in the USA. Addressing this inequity in prostate cancer care and outcomes requires a focused research approach that creates durable solutions to address the structural, social, environmental, and health factors that create racial disparities in care and outcomes.

OBJECTIVE

To introduce a conceptual model for evaluating racial inequities in prostate cancer care to facilitate the development of translational research studies and interventions.

EVIDENCE ACQUISITION

A collaborative review of literature relevant to racial inequities in prostate cancer care and outcomes was performed. Existing literature was used to highlight various components of the conceptual model to inform future research and interventions toward equitable care and outcomes.

EVIDENCE SYNTHESIS

Racial inequities in prostate cancer outcomes are driven by a series of structural and social determinants of health that impact exposures, mediators, and outcomes. Social determinants of equity, such as laws/policies, economic systems, and structural racism, affect the inequitable access to environmental and neighborhood exposures, in addition to health care access. Although the incidence disparity remains problematic, various studies have demonstrated parity in outcomes when social and health factors, such as access to equitable care, are normalized. Few studies have tested interventions to reduce inequities in prostate cancer among Black men.

CONCLUSIONS

Worldwide, men of African ancestry demonstrate worse outcomes in prostate cancer, a phenomenon driven largely by social factors that inform biologic, environmental, and health care risks. A conceptual model was presented that organizes the many factors that influence prostate cancer incidence and mortality. Within that framework, we must understand the current state of inequities in clinical prostate cancer practice, the optimal state of what equitable practice would be, and how achieving equity in prostate cancer care balances costs, benefits, and harms. More robust characterization of the sources of prostate cancer inequities should inform testing of ambitious and innovative interventions as we work toward equity in care and outcomes.

PATIENT SUMMARY

Men of African ancestry demonstrate the highest rates of prostate cancer mortality, which may be reduced through social interventions. We present a framework for formalizing the identification of the drivers of prostate cancer inequities to facilitate the development of interventions and trials to eradicate them.

Stage Shift as an Endpoint in Cancer Screening Trials: Implications for Evaluating Multicancer Early Detection Tests

BACKGROUND

Disease-specific mortality is a consensus endpoint in cancer screening trials. New liquid biopsy-based screening tests, including multi-cancer early detection (MCED) tests, are creating a need to reduce the typically lengthy screening trial process. Endpoints based on the reduction in late-stage disease (stage shift) have been proposed but it is unclear how well they predict the impact of screening on disease-specific mortality across a variety of cancers potentially detectable by MCED tests.

METHODS

We develop a mathematical formulation relating the reduction in late-stage cancer to the expected reduction in disease-specific mortality if cases diagnosed early via screening receive a corresponding shift in mortality. We investigate the similarity between the expected mortality reduction and the observed mortality reduction in published trials of screening for breast, lung, ovarian, and prostate cancer.

RESULTS

The expected mortality reduction for a given stage shift varies significantly depending on cancer- and stage-specific survival distributions, with some cancer types showing little possibility for mortality improvement even under substantial stage shift. The expected mortality reduction fails to consistently match the mortality outcomes of published trials.

CONCLUSIONS

In MCED, any mortality benefit is likely to vary substantially across target cancers. Stage shift does not appear to be a reliable basis for inference about mortality reduction across cancers potentially detectable by MCED tests.

IMPACT

Stage shift may be an appealing endpoint for evaluation of cancer screening tests but it appears to be an unreliable predictor of mortality benefit; furthermore, the same stage shift can mean different things for different cancers.

Abstract 23: Will novel systemic treatments alter the benefit of lung cancer screening?: A microsimulation study

Background: The U.S. Preventive Services Task Force has recently updated its 2013 lung cancer screening guidelines with low-dose computed tomography. In the last decade, population level mortality for advanced non-small cell lung cancer fell significantly due to the novel targeted and immunotherapy-based treatments. Moreover, with detection of new molecular targets, these therapies are expected to become the ultimate curative options. However, how these treatments might impact the benefits of lung cancer screening is unknown.

Methods: We utilize a computer microsimulation modeling framework to screen the U.S. population aged 50 to 80 who had a 20 pack-year smoking history and currently smoked or had quit within the past 15 years under both standard treatments (chemotherapy and radiotherapy) and novel treatments (immunotherapy and targeted therapy) settings. The corresponding mortality reductions associated with the stage shift via low-dose computed screening are projected for each setting.

Results: Over 25 years, risk-targeted screening saves 243 lives per 20,000 under standard therapies (12% mortality reduction) and 99 per 20,000 under fully adopted novel therapies (6% mortality reduction). Under standard treatment, 1.28 cancers are over-diagnosed per life saved; under fully adopted novel therapies, this increases to 3.46. Over 25 years the number needed to screen to avert one death is 82 under standard treatment and 202 under fully adopted novel therapies.

Conclusions: Ongoing transition from chemotherapy and radiotherapy to novel immunotherapies and targeted therapies may reduce the expected lives saved by low-dose computed tomography screening. Screening recommendations might need to be reconsidered as novel treatments become widespread.

Citation Format: Kemal Caglar Gogebakan, Jane Lange, Christopher Slatore, Ruth Etzioni. Will novel systemic treatments alter the benefit of lung cancer screening?: A microsimulation study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 23.

Evaluation of Prostate Cancer Screening Strategies in a Low-Resource, High-risk Population in the Bahamas

Importance

The benefit of prostate-specific antigen screening may be greatest in high-risk populations, including men of African descent in the Caribbean. However, organized screening may not be sustainable in low- and middle-income countries.

Objective

To evaluate the expected population outcomes and resource use of conservative prostate-specific antigen screening programs in the Bahamas.

Design Setting and Participants

Prostate cancer incidence from GLOBOCAN and prostate-specific antigen screening data for 4300 men from the Bahamas were used to recalibrate 2 decision analytical models previously used to study prostate-specific antigen screening for Black men in the United States. Data on age and results obtained from prostate-specific antigen screening tests performed in Nassau from 2004 to 2018 and in Freeport from 2013 to 2018 were used. Data were analyzed from January 15, 2021, to March 23, 2022.

Interventions

One or 2 screenings for men aged 45 to 60 years and conservative criteria for biopsy (prostate-specific antigen level >10 ng/mL) and curative treatment (Gleason score ≥8) were modeled. Categories of Gleason scores were 6 or lower, 7, and 8 or higher, with higher scores indicating higher risk of cancer progression and death.

Main Outcomes and Measures

Projected numbers of tests and biopsies, prostate cancer (over)diagnoses, lives saved, and life-years gained owing to screening from 2022 to 2040.

Results

In this decision analytical modeling study, screening histories from 4300 men (median age, 54 years; range, 13-101 years) tested between 2004 and 2018 at 2 sites in the Bahamas were used to inform the models. Screening once at 60 years of age was projected to involve 40 000 to 42 000 tests (range between models) and prevent 500 to 600 of 10 000 to 14 000 prostate cancer deaths. Screening at 50 and 60 years doubled the number of tests but increased lives saved by only 15% to 16%. Among onetime strategies, screening once at 60 years of age involved the fewest tests per life saved (74-84 tests) and curative treatments per life saved (1.2-2.8 treatments).

Conclusions and Relevance

The findings of this decision analytical modeling study of prostate cancer screening in the Bahamas suggest that limited screening offered modest benefits that varied with screening ages and number of tests. The results can be combined with data on capacity constraints and evaluated relative to competing national public health priorities.

Identifying breast cancer recurrence histories via patient-reported outcomes

PURPOSE

To test accuracy of patient self-report of breast cancer recurrence for enhancing standard population-based cancer registries that do not routinely collect cancer recurrence data despite the importance of this outcome.

METHODS

Potential research subjects were identified in the Breast Cancer Research Database (BCRD) of the Swedish Cancer Institute (SCI). The BCRD has collected data within 45 days of each medical encounter on new primary breast cancer patients receiving all or part of their initial care at SCI. Females diagnosed with a new primary breast cancer 2004-2016, Stages I-III, and alive at the time of study initiation (2018) were identified. Recurrent breast cancer patients were matched 1:1 to surviving non-recurrent patients by patient age, date of diagnosis, and single or multiple primary tumors. Consented research subjects were surveyed about their initial and subsequent diagnostic, therapeutic, and recurrent events. PRO survey responses were compared with BCRD information for each individual participant. Discrepancies were reviewed in medical records.

RESULTS

A matched sample of 88 recurrent and 88 non-recurrent patients were used in analyses. Respondents correctly identified the date of diagnosis of first primary breast cancer within 1 year 94% (165/176). Recurrence was reported by 97% (85/88) of recurrent patients. No recurrence was reported by 100% (88/88) of non-recurrent patients. Recurrence date within 1 year was correctly identified in 79% (67/85). Recurrence site was correctly identified in 82% (70/85). Medical record review of survey-registry discrepancies led to BCRD corrections in 4.5% (8/176) of cases.

IMPLICATIONS FOR CANCER SURVIVORS

Breast cancer patients can accurately report their disease characteristics, treatments, and recurrence history. Patient-reported information would enhance cancer registry data.

Cancer Modeling as Learning Experience

Cancer modeling has become an accepted method for generating evidence about comparative effectiveness and cost-effectiveness of candidate cancer control policies across the continuum of care. Models of early detection policies require inputs concerning disease natural history and screening test performance, which are often subject to considerable uncertainty. Model validation against an external data source can increase confidence in the reliability of assumed or calibrated inputs. When a model fails to validate, this presents an opportunity to revise these inputs, thereby learning new information about disease natural history or diagnostic performance that could both enhance the model results and inform real-world practices. We discuss the conditions necessary for validly drawing conclusions about specific inputs such as diagnostic performance from model validation studies. Doing so requires being able to faithfully replicate the validation study in terms of its design and implementation and being alert to the problem of non-identifiability, which could lead to explanations for failure to validate other than those identified. See related article by Rutter et al., p. 775.

Clarifying the Trade-Offs of Risk-Stratified Screening for Prostate Cancer: A Cost-Effectiveness Study

Cancer risk prediction is necessary for precision early detection, which matches screening intensity to risk. However, practical steps for translating risk predictions to risk-stratified screening policies are not well established. We used a validated population prostate-cancer model to simulate the outcomes of strategies that increase intensity for men at high risk and reduce intensity for men at low risk. We defined risk by the Prompt Prostate Genetic Score (PGS) (Stratify Genomics, San Diego, California), a germline genetic test. We first recalibrated the model to reflect the disease incidence observed within risk strata using data from a large prevention trial where some participants were tested with Prompt PGS. We then simulated risk-stratified strategies in a population with the same risk distribution as the trial and evaluated the cost-effectiveness of risk-stratified screening versus universal (risk-agnostic) screening. Prompt PGS risk-adapted screening was more cost-effective when universal screening was conservative. Risk-stratified strategies improved outcomes at a cost of less than $100,000 per quality-adjusted life year compared with biennial screening starting at age 55 years, but risk stratification was not cost-effective compared with biennial screening starting at age 45. Heterogeneity of risk and fraction of the population within each stratum were also important determinants of cost-effectiveness.

A Quantitative Framework to Study Potential Benefits and Harms of Multi-Cancer Early Detection Testing

BACKGROUND

Multi-cancer tests offer screening for multiple cancers with one blood draw, but the potential population impact is poorly understood.

METHODS

We formulate mathematical expressions for expected numbers of: (i) individuals exposed to unnecessary confirmation tests (EUC), (ii) cancers detected (CD), and (iii) lives saved (LS) given test performance, disease incidence and mortality, and mortality reduction. We add colorectal, liver, lung, ovary, and pancreatic cancer to a test for breast cancer, approximating prevalence at ages 50, 60, or 70 using incidence over the next 5 years and mortality using corresponding probabilities of cancer death over 15 years in the Surveillance, Epidemiology, and End Results registry.

RESULTS

EUC is overwhelmingly determined by specificity. For a given specificity, EUC/CD is most favorable for higher prevalence cancers. Under 99% specificity and sensitivities as published for a 50-cancer test, EUC/CD is 1.1 for breast + lung versus 1.3 for breast + liver at age 50. Under a common mortality reduction associated with screening, EUC/LS is most favorable when the test includes higher mortality cancers (e.g., 19.9 for breast + lung vs. 30.4 for breast + liver at age 50 assuming a common 10% mortality reduction).

CONCLUSIONS

Published multi-cancer test performance suggests a favorable tradeoff of EUC to CD, yet the full burden of unnecessary confirmations will depend on the posttest work-up protocol. Harm-benefit tradeoffs will be improved if tests prioritize more prevalent and/or lethal cancers for which curative treatments exist.

IMPACT

The population impact of multi-cancer testing will depend not only on test performance but also on disease characteristics and efficacy of early treatment.See related commentary by Stephen Duffy, p. xxx.

Multi-Cancer Early Detection: Learning from the past to Meet the Future

Multi-cancer early detection (MCED) tests may soon be available to screen for many cancers using a single blood test, yet little is known about these tests beyond their diagnostic performance. Taking lessons from the history of cancer early detection, we highlight three factors that influence how performance of early detection tests translates into benefit and benefit-harm tradeoffs: the ability to readily confirm a cancer signal, the population testing strategy, and the natural histories of the targeted cancers. We explain why critical gaps in our current knowledge about each factor prevent reliably projecting the expected clinical impact of MCED testing at this point in time. Our goal is to communicate how much uncertainty there is about the possible effects of MCED tests on population health so that patients, providers, regulatory agencies, and the public are well informed about what is reasonable to expect from this potentially important technological advance. We also urge the community to invest in a coordinated effort to collect data on MCED test dissemination and outcomes so that these can be tracked and studied while the tests are rigorously evaluated for benefit, harm, and cost.

Accounting for uncertainty during a pandemic

We discuss several issues of statistical design, data collection, analysis, communication, and decision-making that have arisen in recent and ongoing coronavirus studies, focusing on tools for assessment and propagation of uncertainty. This paper does not purport to be a comprehensive survey of the research literature; rather, we use examples to illustrate statistical points that we think are important.

Economic Evaluation of Urine-Based or Magnetic Resonance Imaging Reflex Tests in Men With Intermediate Prostate-Specific Antigen Levels in the United States

OBJECTIVES

For men with intermediate prostate-specific antigen (PSA) levels (4-10 ng/mL), urine-based biomarkers and multiparametric magnetic resonance imaging (MRI) are increasingly used as reflex tests before prostate biopsy. We assessed the cost effectiveness of these reflex tests in the United States.

METHODS

We used an existing microsimulation model of prostate cancer (PCa) progression and survival to predict lifetime outcomes for a hypothetical cohort of 55-year-old men with intermediate PSA levels. Urine-based biomarkers-PCa antigen (PCA3), TMPRSS2:ERG gene fusion (T2:ERG), and the MyProstateScore (MPS) for any PCa and for high-grade (Gleason score ≥7) PCa (MPShg)-were generated using biomarker data from 1112 men presenting for biopsy at 10 United States institutions. MRI results were based on published sensitivity and specificity for high-grade PCa. Costs and utilities were sourced from literature and Medicare reimbursement schedules. Outcome measures included life years, quality-adjusted life years (QALYs), and lifetime medical costs per patient. Incremental cost-effectiveness ratios were empirically calculated on the basis of simulated life histories under different reflex testing strategies.

RESULTS

Biopsying all men provided the most life years and QALYs, followed by reflex testing using MPShg, MPS, MRI, T2:ERG, PCA3, and biopsying no men (QALY range across strategies 15.98-16.09). Accounting for costs, MRI and MPShg were dominated by other strategies. PCA3, T2:ERG, and MPS were likely to be the most cost-effective strategy at willingness-to-pay thresholds of $100 000/QALY, $125 000/QALY, and $150 000/QALY, respectively.

CONCLUSIONS

Using PCA3, T2:ERG, or MPS as reflex tests has greater economic value than MRI, biopsying all men, or biopsying no men with intermediate PSA levels.

The Impact of Intensifying Prostate Cancer Screening in Black Men: A Model-Based Analysis

BACKGROUND

Black men in the United States have markedly higher rates of prostate cancer than the general population. National guidelines for prostate-specific antigen (PSA) screening do not provide clear guidance for this high-risk population. The purpose of this study is to estimate the benefit and harm of intensified PSA screening in Black men.

METHODS

Two microsimulation models of prostate cancer calibrated to incidence from the Surveillance, Epidemiology, and End Results program among Black men project the impact of different screening strategies (varying screening intervals, starting and stopping ages, and biopsy utilization following an abnormal PSA) on disease-specific mortality and overdiagnosis. Each strategy induces a mean lead time (MLT) for detected cases. A longer MLT reduces mortality according to estimates combining the US and European prostate cancer screening trials but increases overdiagnosis.

RESULTS

Under historical population screening, Black men had similar MLT to men of all races, and similar mortality reduction (range between models = 21-24% vs. 20-24%) but a higher frequency of overdiagnosis (75-86 vs. 58-60 per 1000 men). Screening Black men aged 40-84 years annually would increase both mortality reduction (29-31%) and overdiagnosis (112-129 per 1000). Restricting screening to age 45-69 years would still achieve substantial mortality reduction (26-29%) with lower overdiagnosis (51-61 per 1000). Increasing biopsy utilization to 100% of abnormal tests would further reduce mortality but substantially increase overdiagnosis.

CONCLUSIONS

Annual screening in Black men is expected to reduce mortality more than that estimated under historical screening. Limiting screening to men below 70 years is expected to help to reduce overdiagnosis.

Incorporating Baseline Breast Density When Screening Women at Average Risk for Breast Cancer : A Cost-Effectiveness Analysis

BACKGROUND

Breast density classification is largely determined by mammography, making the timing of the first screening mammogram clinically important.

OBJECTIVE

To evaluate the cost-effectiveness of breast cancer screening strategies that are stratified by breast density.

DESIGN

Microsimulation model to generate the natural history of breast cancer for women with and those without dense breasts and assessment of the cost-effectiveness of strategies tailored to breast density and nontailored strategies.

DATA SOURCES

Model parameters from the literature; statistical modeling; and analysis of Surveillance, Epidemiology, and End Results-Medicare data.

TARGET POPULATION

Women aged 40 years or older.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

No screening; biennial or triennial mammography from age 50 to 75 years; annual mammography from age 50 to 75 years for women with dense breasts at age 50 years and biennial or triennial mammography from age 50 to 75 years for those without dense breasts at age 50 years; and annual mammography at age 40 to 75 years for women with dense breasts at age 40 years and biennial or triennial mammography at age 50 to 75 years for those without dense breasts at age 40 years.

OUTCOME MEASURES

Lifetime costs and quality-adjusted life-years (QALYs), discounted at 3% annually.

RESULTS OF BASE-CASE ANALYSIS

Baseline screening at age 40 years followed by annual screening at age 40 to 75 years for women with dense breasts and biennial screening at age 50 to 75 years for women without dense breasts was effective and cost-effective, yielding an incremental cost-effectiveness ratio of $36 200 per QALY versus the biennial strategy at age 50 to 75 years.

RESULTS OF SENSITIVITY ANALYSIS

At a societal willingness-to-pay threshold of $100 000 per QALY, the probability that the density-stratified strategy at age 40 years was optimal was 56% compared with 6 other strategies.

LIMITATION

Findings may not be generalizable outside the United States.

CONCLUSION

The study findings advocate for breast density-stratified screening with baseline mammography at age 40 years.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Impact of novel systemic therapies on the first-year costs of care for melanoma among Medicare beneficiaries

BACKGROUND

Since 2011, the therapeutic landscape of melanoma has changed dramatically because of the adoption of immune checkpoint inhibitor and targeted therapies. The authors sought to quantify the effects of these changes on short-term treatment costs by comparing the first-year cancer-attributable costs in novel (2011-2015) and historical (2004-2010) treatment eras.

METHODS

The authors estimated the first-year cancer-attributable and out-of-pocket (OOP) costs by cancer stage at diagnosis by using a case-control approach. Patients aged ≥67 years with melanoma results were used to calculate the total direct costs of treatment during the first year after the diagnosis of melanoma in the US Medicare population older than 65 years. Costs were reported in 2018 dollars.

RESULTS

Costs increased with the stage at diagnosis. Average first-year cancer-attributable costs per patient for stage IV patients increased significantly by 61.7% from $45,952 to $74,297 after the adoption of novel treatments. Per-patient OOP responsibility decreased by almost 30.8% across all stages of cancer but increased by 16.5% for stage IV patients from 2004 ($7646) to 2015 ($8911). The total direct cost of treatment for persons with melanoma older than 65 years increased by $16.03 million (4.93%) from $324.68 million in 2010 to $340.71 million in 2015. The largest increase in yearly total cost, $23.64 million (56.53%), was observed among stage IV patients.

CONCLUSIONS

The direct cost of melanoma increased significantly in the Medicare population, particularly for advanced-stage disease. Prevention and early detection initiatives may reduce the economic burden of melanoma.

Lifetime Benefits and Harms of Prostate-Specific Antigen-Based Risk-Stratified Screening for Prostate Cancer

Background

Studies conducted in Swedish populations have shown that men with lowest prostate-specific antigen (PSA) levels at ages 44–50 years and 60 years have very low risk of future distant metastasis or death from prostate cancer. This study investigates benefits and harms of screening strategies stratified by PSA levels.

Methods

PSA levels and diagnosis patterns from two microsimulation models of prostate cancer progression, detection, and mortality were compared against results of the Malmö Preventive Project, which stored serum and tracked subsequent prostate cancer diagnoses for 25 years. The models predicted the harms (tests and overdiagnoses) and benefits (lives saved and life-years gained) of PSA-stratified screening strategies compared with biennial screening from age 45 years to age 69 years.

Results

Compared with biennial screening for ages 45–69 years, lengthening screening intervals for men with PSA less than 1.0 ng/mL at age 45 years led to 46.8–47.0% fewer tests (range between models), 0.9–2.1% fewer overdiagnoses, and 3.1–3.8% fewer lives saved. Stopping screening when PSA was less than 1.0 ng/mL at age 60 years and older led to 12.8–16.0% fewer tests, 5.0–24.0% fewer overdiagnoses, and 5.0–13.1% fewer lives saved. Differences in model results can be partially explained by differences in assumptions about the link between PSA growth and the risk of disease progression.

Conclusion

Relative to a biennial screening strategy, PSA-stratified screening strategies investigated in this study substantially reduced the testing burden and modestly reduced overdiagnosis while preserving most lives saved. Further research is needed to clarify the link between PSA growth and disease progression.

A Latent Disease Model to Reduce Detection Bias in Cancer Risk Prediction Studies

In studies of cancer risk, detection bias arises when risk factors are associated with screening patterns, affecting the likelihood and timing of diagnosis. To eliminate detection bias in a screened cohort, we propose modeling the latent onset of cancer and estimating the association between risk factors and onset rather than diagnosis. We apply this framework to estimate the increase in prostate cancer risk associated with black race and family history using data from the SELECT prostate cancer prevention trial, in which men were screened and biopsied according to community practices. A positive family history was associated with a hazard ratio (HR) of prostate cancer onset of 1.8, lower than the corresponding HR of prostate cancer diagnosis (HR = 2.2). This result comports with a finding that men in SELECT with a family history were more likely to be biopsied following a positive PSA test than men with no family history. For black race, the HRs for onset and diagnosis were similar, consistent with similar patterns of screening and biopsy by race. If individual screening and diagnosis histories are available, latent disease modeling can be used to decouple risk of disease from risk of disease diagnosis and reduce detection bias.

Impact of cancer screening on metastasis: A prostate cancer case study

BACKGROUND

Trials of cancer screening present results in terms of deaths prevented, but metastasis is also a key endpoint that screening seeks to prevent. We developed a framework for projecting overall (de novo and progressive) metastases prevented in a screening trial using prostate cancer screening as a case study.

METHODS

Mechanistic simulation model in which screening shifts a fraction of cases that would be metastatic at diagnosis to being non-metastatic. This shift increases the incidence of non-overdiagnosed, organ-confined cases. We use estimates of the risk of metastatic progression for these cases to project how many progress to metastasis after diagnosis and tally the projected de novo and progressive metastatic cases with and without screening. We use data on stage shift from the European Randomized Study of Screening for Prostate Cancer (ERSPC) and data on the risk of metastatic progression from the Scandinavian Prostate Cancer Group-4 trial. We estimate the relative risk and absolute risk reductions in metastatic disease at diagnosis and compare these with reductions in overall metastases.

RESULTS

Assuming no effect of screening beyond initial stage shift at diagnosis, the model projects a 43% reduction in metastasis at diagnosis but a 22% reduction in the cumulative probability of metastasis over 12 years in favor of screening. These results are consistent with the empirical findings from the ERSPC.

CONCLUSION

Any reduction in metastatic disease at diagnosis under screening is likely to be an overly optimistic predictor of the impact of screening on overall metastasis and disease-specific mortality.

Abstract PO-211: Racial disparities in the quality of surgical care among Medicare beneficiaries with prostate cancer

Background: Black men in the US demonstrate a two-fold increase in prostate cancer mortality compared to men of other races/ethnicities. The aim of this analysis was to understand how access to high quality care—estimated using surgical volume— impacts disparities in prostate cancer mortality between Black and White men with localized prostate cancer. Methods: This is an analysis of a SEER-Medicare cohort of men diagnosed with localized prostate cancer (cT1-4N0M0) managed primarily by radical prostatectomy from 2005-2015. This analysis was restricted to Black and White men due to low representative numbers of men of other races/ethnicities.

Social, demographic, and clinical data were obtained. Both facility and provider data were obtained using administrative data in Medicare. Surgical volume for both providers and facilities were stratified into low, medium, and high. Simple descriptive analyses were performed. Multivariable Cox regression analyses was used to assess the relationship between race, surgical volume, and various clinical and social variables. Results: Black men represented 2,070 (7.1%) of the 29,071 men in this cohort. Black men in the cohort had a higher proportion of prostate specific antigen (PSA) greater than 20 ng/mL (7.0% vs 3.6%) and a higher proportion of men with cT1 disease at diagnosis (64.6% vs 56.1%) when compared to White men. Black men were also less likely to be married/partnered (63.5% vs. 79.9%), more likely to reside in an impoverished zip code (43.9% vs. 11.1%), and more likely to have significant comorbidities (7.2% vs. 2.9%). Black men in this cohort were most likely to be treated in the Southern US (42.8% of cases). Black men were more likely to be treated at a minority serving hospital/facility (24.6% vs. 3.1%, p < 0.001), more likely to be treated at a very large hospital/health system (p < 0.001), and less likely to be treated by a high-volume surgeon or facility (7.7% vs. 19.9%, p < 0.001) compared to White men. On multivariable analysis adjusted for race, hospital type, NCI comorbidity index, clinical stage, and prostatectomy volume; black men demonstrated an increased risk of prostate cancer mortality (hazard ratio 1.27, 95% CI 0.94, 1.72) compared to White men. On stratified analysis, there were no racial disparities in cancer-specific mortality among men treated by a high-volume provider/facility. In contrast, Black men treated by a low/medium volume provider/facility had a higher likelihood of prostate cancer related death following surgery (hazard ratio 1.41, 95% CI 1.02, 1.95, p = 0.04). Conclusions: Black Medicare beneficiaries with prostate cancer demonstrate unique patterns of surgical care utilization, with differences noted in the types and surgical volumes—and likely surgical quality—of their health facilities and providers. Our findings suggest that access to high-quality prostate cancer care is an important mediator of racial disparities in prostate cancer, even among men with access to health insurance.

Citation Format: Yaw A. Nyame, Sarah K. Holt, Ruth Etzioni, John L. Gore. Racial disparities in the quality of surgical care among Medicare beneficiaries with prostate cancer [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-211.

Prostate-Specific Antigen Screening and Recent Increases in Advanced Prostate Cancer

Recent studies show decreasing prostate-specific antigen utilization and increasing incidence of metastatic prostate cancer in the United States after national recommendations against screening in 2012. Yet, whether the increasing incidence of metastatic prostate cancer is consistent in magnitude with the expected impact of decreased screening is unknown. We compared observed incidence of metastatic prostate cancer from the Surveillance, Epidemiology, and End Results program and published effects of continued historical screening and discontinued screening starting in 2013 projected by 2 models of disease natural history, screening, and diagnosis. The observed rate of new metastatic prostate cancer cases in 2017 was 44%-60% of the projected increase under discontinued screening relative to continued screening. Thus, the observed increase in incident metastatic prostate cancer is consistent with the expected impact of reduced screening. Although this comparison does not establish a causal relationship, it highlights the plausible role of decreased screening in the observed trend.

Strategizing Screening for Melanoma in an Era of Novel Treatments: A Model-Based Approach

BACKGROUND

Benefit-harm tradeoffs of melanoma screening depend on disease risk and treatment efficacy. We developed a model to project outcomes of screening for melanoma in populations with different risks under historic and novel systemic treatments.

METHODS

Computer simulation model of a screening program with specified impact on overall and advanced-stage incidence. Inputs included meta-analyses of treatment trials, cancer registry data, and a melanoma risk prediction study RESULTS: Assuming 50% reduction in advanced stage under screening, the model projected 59 and 38 lives saved per 100,000 men under historic and novel treatments, respectively. With 10% increase in stage I, the model projects 2.9 and 4.7 overdiagnosed cases per life saved and number needed to be screened (NNS) equal to 1695 and 2632 under historical and novel treatments. When screening was performed only for the 20% of individuals with highest predicted risk, 34 and 22 lives per 100,000 were saved under historic and novel treatments. Similar results were obtained for women, but lives saved were lower.

CONCLUSIONS

Melanoma early detection programs must shift a substantial fraction of cases from advanced to localized stage to be sustainable. Advances in systemic therapies for melanoma might noticeably reduce benefits of screening, but restricting screening to individuals at highest risk will likely reduce intervention efforts and harms while preserving >50% of the benefit of nontargeted screening.

IMPACT

Our accessible modeling framework will help to guide population melanoma screening programs in an era of novel treatments for advanced disease.

Overdiagnosis and Lives Saved by Reflex Testing Men With Intermediate Prostate-Specific Antigen Levels

BACKGROUND

Several prostate cancer (PCa) early-detection biomarkers are available for reflex testing in men with intermediate prostate-specific antigen (PSA) levels. Studies of these biomarkers typically provide information about diagnostic performance but not about overdiagnosis and lives saved, the primary drivers of associated harm and benefit.

METHODS

We projected overdiagnoses and lives saved using an established microsimulation model of PCa incidence and mortality with screening and treatment efficacy based on randomized trials. We used this framework to evaluate four urinary reflex biomarkers (measured in 1112 men presenting for prostate biopsy at 10 US academic or community clinics) and two hypothetical ideal biomarkers (with 100% sensitivity or specificity for any or for high-grade PCa) at one-time screening tests at ages 55 and 65 years.

RESULTS

Compared with biopsying all men with elevated PSA, reflex testing reduced overdiagnoses (range across ages and biomarkers = 8.8-60.6%) but also reduced lives saved (by 7.3-64.9%), producing similar overdiagnoses per life saved. The ideal biomarker for high-grade disease improved this ratio (by 35.2% at age 55 years and 42.0% at age 65 years). Results were similar under continued screening for men not diagnosed at age 55 years, but the ideal biomarker for high-grade disease produced smaller incremental improvement.

CONCLUSIONS

Modeling is a useful tool for projecting the implications of using reflex biomarkers for long-term PCa outcomes. Under simplified conditions, reflex testing with urinary biomarkers is expected to reduce overdiagnoses but also produce commensurate reductions in lives saved. Reflex testing that accurately identifies high-grade PCa could improve the net benefit of screening.