Screen-detected Cancer Cases Research Articles

Effectiveness Evaluation of Low-dose Spiral Computed Tomography for Lung Cancer Screening in Minhang District of Shanghai

Low-dose spiral computed tomography (LDCT) has been recommended for lung cancer screening in high-risk populations. However, evidence from Chinese populations was limited due to the different criteria for high-risk populations and the short-term follow-up period. This study aimed to evaluate the effectiveness in Chinese adults based on the Lung Cancer Screening Program in Minhang District of Shanghai initiated in 2013. A total of 26,124 subjects aged 40 years or above were enrolled in the Lung Cancer Screening Program during the period of 2013 and 2017. Results of LDCT examination, and screen-detected cancer cases in all participants were obtained from the Reporting System of the Lung Cancer Screening Program. The newly-diagnosed cases and their vital status up to December 31, 2020 were identified through a record linkage with the Shanghai Cancer Registry and the Shanghai Vital Statistics. Standardized incidence ratio (SIR) and 95%CI were calculated using the local population at ages of 40 or above as the reference. Proportions of early-stage cancer (stage 0-I), pathological types, and 5-year observed survival rates of lung cancer cases were estimated and compared between the cases derived from the screened and non-screened populations. Cox regression models were applied to evaluate the hazard ratio (HR) and 95%CI of LDCT screening with all-cause death of the lung cancer cases. The crude and age-standardized incidence of lung cancer in screened population were 373.3 (95%CI: 343.1-406.1) and 70.3 per 100,000 person-years, respectively, with an SIR of 1.8 (95%CI: 1.6-1.9), which was observed to decrease with following-up time. The early-stage cancer accounted for 49.4% of all lung cancer cases derived from the screened population, significantly higher than 38.4% in cases from the non-screened population during the same period (P<0.05). The proportion of lung adenocarcinoma (40.7% vs 35.9%) and 5-year survival rate (53.7% vs 41.5%) were also significantly higher in the cases from the screened population (all P<0.05). LDCT screening was associated with 30% (HR=0.7, 95%CI: 0.6-0.8) reduced all-cause deaths of the cases. The participants of the screening program are at high-risk of lung cancer. LDCT favors the early-detection of lung cancer and improves 5-year survival of the screened cases, indicating a great potential of LDCT in reducing the disease burden of lung cancer in Chinese populations.

Estimation of Breast Cancer Overdiagnosis in a U.S. Breast Screening Cohort.

Mammography screening can lead to overdiagnosis-that is, screen-detected breast cancer that would not have caused symptoms or signs in the remaining lifetime. There is no consensus about the frequency of breast cancer overdiagnosis. To estimate the rate of breast cancer overdiagnosis in contemporary mammography practice accounting for the detection of nonprogressive cancer. Bayesian inference of the natural history of breast cancer using individual screening and diagnosis records, allowing for nonprogressive preclinical cancer. Combination of fitted natural history model with life-table data to predict the rate of overdiagnosis among screen-detected cancer under biennial screening. Breast Cancer Surveillance Consortium (BCSC) facilities. Women aged 50 to 74 years at first mammography screen between 2000 and 2018. Screening mammograms and screen-detected or interval breast cancer. The cohort included 35986 women, 82677 mammograms, and 718 breast cancer diagnoses. Among all preclinical cancer cases, 4.5% (95% uncertainty interval [UI], 0.1% to 14.8%) were estimated to be nonprogressive. In a program of biennial screening from age 50 to 74 years, 15.4% (UI, 9.4% to 26.5%) of screen-detected cancer cases were estimated to be overdiagnosed, with 6.1% (UI, 0.2% to 20.1%) due to detecting indolent preclinical cancer and 9.3% (UI, 5.5% to 13.5%) due to detecting progressive preclinical cancer in women who would have died of an unrelated cause before clinical diagnosis. Exclusion of women with first mammography screen outside BCSC. On the basis of an authoritative U.S. population data set, the analysis projected that among biennially screened women aged 50 to 74 years, about 1 in 7 cases of screen-detected cancer is overdiagnosed. This information clarifies the risk for breast cancer overdiagnosis in contemporary screening practice and should facilitate shared and informed decision making about mammography screening. National Cancer Institute.

Overdiagnosis in lung cancer screening: Estimates from the German Lung Cancer Screening Intervention Trial.

Overdiagnosis is a major potential harm of lung cancer screening; knowing its potential magnitude helps to optimize screening eligibility criteria. The German Lung Screening Intervention Trial ("LUSI") is a randomized trial among 4052 long-term smokers (2622 men), 50.3 to 71.9 years of age from the general population around Heidelberg, Germany, comparing five annual rounds of low-dose computed tomography (n = 2029) with a control arm without intervention (n = 2023). After a median follow-up of 9.77 years postrandomization and 5.73 years since last screening, 74 participants were diagnosed with lung cancer in the control arm and 90 in the screening arm: 69 during the active screening period; of which 63 screen-detected and 6 interval cancers. The excess cumulative incidence in the screening arm (N = 16) represented 25.4% (95% confidence interval: -11.3, 64.3] of screen-detected cancer cases (N = 63). Analyzed by histologic subtype, excess incidence in the screening arm appeared largely driven by adenocarcinomas. Statistical modeling yielded an estimated mean preclinical sojourn time (MPST) of 5.38 (4.76, 5.88) years and a screen-test sensitivity of 81.6 (74.4%, 88.8%) for lung cancer overall, all histologic subtypes combined. Based on modeling, we further estimated that about 48% (47.5% [43.2%, 50.7%]) of screen-detected tumors have a lead time ≥4 years, whereas about 33% (32.8% [28.4%, 36.1%]) have a lead time ≥6 years, 23% (22.6% [18.6%, 25.7%]) ≥8 years, 16% (15.6% [12.2%, 18.3%]) ≥10 years and 11% (10.7% [8.0%, 13.0%]) ≥12 years. The high proportions of tumors with relatively long lead times suggest a major risk of overdiagnosis for individuals with comparatively short remaining life expectancies.

Effect of Screening on Variation in Cervical Cancer Survival by Socioeconomic Determinants--a Study from Rural South India.

Socioeconomic factors are associated with screening in terms of reducing the risk of cervical cancer. This study aimed to clearly establish the effect of screening on variation in socio-economic factor-specific survival estimates. Survival estimates were calculated using the life table method for 165 women from the routine care control arm and 67 from the visual inspection with acetic acid screening arm diagnosed with cervical cancer during 2000-2006 in rural south India. Kaplan-Meier survival curves were plotted to compare the variation in survival by socioeconomic factors. Whereas there was a significant variation in survival estimates of the different categories of age at diagnosis among the screen-detected cancers with women aged<50 years having an improved survival, no significant variation was noted among women diagnosed with cervical cancer from the control arm. Compared to the variation among the cancer cases detected in the unscreened control group, screening widened the variation in survival estimates by age and type of house, and reduced the variation by education. The direction of the magnitude of the survival estimates was reversed within the different categories of occupation, marital status and household income in the screen-detected cancer cases compared to control group cancer cases. Also, women diagnosed with stage 1 disease had a very good survival. Screening changed the pattern of survival by socio-economic factors. We found improved survival rates in screened women aged <50 years, with no formal education, manual workers and married women.

A Stochastic Model for Calibrating the Survival Benefit of Screen-Detected Cancers

Comparison of the survival of clinically detected and screen-detected cancer cases from either population-based service screening programs or opportunistic screening is often distorted by both lead-time and length biases. Both are correlated with each other and are also affected by measurement errors and tumor attributes such as regional lymph node spread. We propose a general stochastic approach to calibrate the survival benefit of screen-detected cancers related to both biases, measurement errors, and tumor attributes. We apply our proposed method to breast cancer screening data from one arm of the Swedish Two-County trial in the trial period together with the subsequent service screening for the same cohort. When there is no calibration, the results—assuming a constant (exponentially distributed) post-lead-time hazard rate (i.e., a homogeneous stochastic process)—show a 57% reduction in breast cancer death over 25 years. After correction, the reduction was 30%, with approximately 12% of the overestimation being due to lead-time bias and 15% due to length bias. The additional impacts of measurement errors (sensitivity and specificity) depend on the type of the proposed model and follow-up time. The corresponding analysis when the Weibull distribution was applied—relaxing the assumption of a constant hazard rate—yielded similar findings and lacked statistical significance compared with the exponential model. The proposed calibration approach allows the benefit of a service cancer screening program to be fairly evaluated. This article has supplementary materials online.

Variable size computer-aided detection prompts and mammography film reader decisions

IntroductionThe purpose of the present study was to investigate the effect of computer-aided detection (CAD) prompts on reader behaviour in a large sample of breast screening mammograms by analysing the relationship of the presence and size of prompts to the recall decision.MethodsLocal research ethics committee approval was obtained; informed consent was not required. Mammograms were obtained from women attending routine mammography at two breast screening centres in 1996. Films, previously double read, were re-read by a different reader using CAD. The study material included 315 cancer cases comprising all screen-detected cancer cases, all subsequent interval cancers and 861 normal cases randomly selected from 10,267 cases. Ground truth data were used to assess the efficacy of CAD prompting. Associations between prompt attributes and tumour features or reader recall decisions were assessed by chi-squared tests.ResultsThere was a highly significant relationship between prompting and a decision to recall for cancer cases and for a random sample of normal cases (P < 0.001). Sixty-four per cent of all cases contained at least one CAD prompt. In cancer cases, larger prompts were more likely to be recalled (P = 0.02) for masses but there was no such association for calcifications (P = 0.9). In a random sample of 861 normal cases, larger prompts were more likely to be recalled (P = 0.02) for both mass and calcification prompts. Significant associations were observed with prompting and breast density (p = 0.009) for cancer cases but not for normal cases (P = 0.05).ConclusionsFor both normal cases and cancer cases, prompted mammograms were more likely to be recalled and the prompt size was also associated with a recall decision.

Improved survival rate for women with interval breast cancer – results from the breast cancer screening programme in Malmö, Sweden 1976–1999

Breast cancers detected between screening examinations can influence the sensitivity of a screening programme. Studies of the prognosis of these so-called interval breast cancers show diverging results. We investigated the course of interval breast cancer over time in the Malmö Mammographic Screening Trial (MMST) 1976-86 and the Malmö Mammographic Service Screening Programme (MMSSP) 1990-99. Stage distribution and survival of interval cancers in MMSSP were compared with screen-detected and non-attender cancer cases in MMSSP, with interval cancers in MMST and with breast cancer cases in a non-screened population five years before the start of MMSSP (pre-screening cancer cases). In MMSSP 1990-99, the interval cancers did not differ in stage distribution or survival compared with cancer cases in non-attenders, while screen-detected cancer cases had more favourable stage distribution and rate of survival than had the interval cancer cases. The MMST interval cancer cases, 1976-1986, had more favourable stage distribution but higher overall case fatality rate, relative risks (RR) 1.78 (1.00-3.20), and breast cancer case fatality rate, RR 2.05 (1.05-4.00), compared with the more recent MMSSP interval cancer cases. No significant difference in five-year survival was seen in the MMSSP interval cancer cases compared with pre-screening cancer cases not exposed to screening. In this urban population invited to mammographic screening, the survival rate for women with interval cancer has improved over a period of 20 years. Further studies are needed to assess what factors might explain changes in the course of interval breast cancer.

Analysis of the results of a proficiency test in screening mammography at the CSPO of Florence: review of 705 tests

The aim of this study was to evaluate the performance of a sample of Italian radiologists undergoing a proficiency test of screening mammography. We retrospectively analysed the results of 705 tests (537 first tests, 168 repeat tests) taken during 1997-2005 by 537 Italian radiologists. The test, consisting of 17 screen-detected cancer cases and 133 negative controls, was validated by a panel of expert readers defining a minimum standard as to sensitivity for cancer and recall rate of negative controls. Success rates were assessed as a function of previous experience in mammography (years of experience, total mammograms read, mammograms read in the last year). A total of 176 radiologists successfully passed the test at their first attempt (32.7%). Success correlated with experience, measured in terms of years of experience (5-year cutoff: chi(2) for trend=4.17, p=0.04), total mammograms read (chi(2) for trend =11.8, p=0.002) or mammograms read in the last year (chi(2) for trend=6.27, p=0.04). Training improves performance at repeat testing: after a first negative attempt, a second attempt was successful in 50.6% of cases (74/146) and a third in 68.1% (15/22). A substantial proportion of Italian radiologists taking the test showed limited proficiency in screening mammography. This finding is consistent with several reports of poor performance of service screening compared with reference standards. As expected, test performance is associated with experience, suggesting that the current policy of employing non-dedicated, untrained, general radiologists in screening should be reconsidered. Test performance improves with training (courses, consultation of teaching atlases). Several screening programmes in Italy have been implemented without prior adequate radiologist training. Radiologist training needs to be considered a priority, at least in those screening programmes that are still to be implemented in one third of the country.

Non‐parametric estimation of the post‐lead‐time survival distribution of screen‐detected cancer cases

The goal of screening programmes for cancer is early detection and treatment with a consequent reduction in mortality from the disease. Screening programmes need to assess the true benefit of screening, that is, the length of time of extension of survival beyond the time of advancement of diagnosis (lead-time). This paper presents a non-parametric method to estimate the survival function of the post-lead-time survival (or extra survival time) of screen-detected cancer cases based on the observed total life time, namely, the sum of the lead-time and the extra survival time. We apply the method to the well-known data set of the HIP (Health Insurance Plan of Greater New York) breast cancer screening study. We make comparisons with the survival of other groups of cancer cases not detected by screening such as interval cases, cases among individuals who refused screening, and randomized control cases. As compared with Walter and Stitt's model, in which they made parametric assumptions for the extra survival time, our non-parametric method provides a better fit to HIP data in the sense that our estimator for the total survival time has a smaller sum of squares of residuals.

Evaluating the survival of cancer cases detected by screening.

Early detection of cancer by screening advances the date of diagnosis, but may or may not affect survival. To assess the survival benefit associated with early detection, one must estimate the distribution of time survived post lead-time, that is, after the unknown date when clinical diagnosis would have occurred in the absence of screening. One can then compare the adjusted survival of screen-detected cancer cases to other groups of cases not diagnosed by screening. This paper describes a model for the survival of screen-detected cases, with a hazard function that depends on an individual's lead time, the duration of preclinical disease, and the time since diagnosis. The model is fitted to the ten year survival data from the 132 screen-detected cases of breast cancer in the well-known HIP (Health Insurance Plan of Greater New York) study. Comparison with the survival of several groups of cancer cases not detected by screening (interval cases arising clinically in persons previously screened, cases among persons who refuse screening, and cases among randomized controls not offered screening) yields various estimates of benefit. Use of the interval cases for comparison gives an estimate of about 21 breast cancer deaths prevented among 20,166 women screened in the HIP study; use of the data from the randomized controls gives an estimate of about 25 prevented deaths. The former estimate derives from the screened group of women only, and so the same method of evaluation may also be applied to community screening programmes and other situations that do not entail randomization.