Isolated Fragments of Intact Microvessels: Tissue Vascularization, Modeling, and Therapeutics

The microvasculature is integral to nearly every tissue in the body, providing not only perfusion to and from the tissue, but also homing sites for immune cells, cellular niches for tissue dynamics, and cooperative interactions with other tissue elements. As a microtissue itself, the microvasculature is a composite of multiple cell types exquisitely organized into structures (individual vessel segments and extensive vessel networks) capable of considerable dynamics and plasticity. Consequently, it has been challenging to include a functional microvasculature in assembled or fabricated tissues. Isolated fragments of intact microvessels, which retain the cellular composition and structures of native microvessels, are proving effective in a variety of vascularization applications including tissue in vitro disease modeling, vascular biology, mechanistic discovery, and tissue prevascularization in regenerative therapeutics and grafting. In this review, we will discuss the importance of recapitulating native tissue biology and the successful vascularization applications of isolated microvessels.

Point-of-use, automated fabrication of a 3D human liver model supplemented with human adipose microvessels

Advanced in vitro tissue models better reflect healthy and disease tissue conditions in the body. However, complex tissue models are often manufactured using custom solutions and can be challenging to manufacture to scale. Here, we describe the automated fabrication of a cell-dense, thick (≤ 1 cm), human vascularized liver tissue model using a robotic biomanufacturing platform and off-the-shelf components to build, culture, and sample liver tissues hands-free without compromising tissue health or function. Fabrication of the tissue involved 3D bioprinting and incorporation of primary human hepatocytes, primary human non-parenchymal cells, and isolated fragments of intact human microvessels as vascular precursors. No differences were observed in select assessments of the liver tissues fabricated by hand or via automation. Furthermore, constant media exchange, via perfusion, improved urea output and elevated tissue metabolism. Interestingly, inclusion of adipose-derived human microvessels enhanced functional gene expression, including an enhanced response to a drug challenge. Our results describe the fabrication of a thick liver tissue environment useful for a variety of applications including liver disease modeling, infectious agent studies, and cancer investigations. We expect the automated fabrication of the vascularized liver tissue, at the point of use and using off-the-shelf platforms, eases fabrication of the complex model and increases its utility.

A Biofabrication Strategy for a Custom-Shaped, Non-Synthetic Bone Graft Precursor with a Prevascularized Tissue Shell

Critical-sized defects of irregular bones requiring bone grafting, such as in craniofacial reconstruction, are particularly challenging to repair. With bone-grafting procedures growing in number annually, there is a reciprocal growing interest in bone graft substitutes to meet the demand. Autogenous osteo(myo)cutaneous grafts harvested from a secondary surgical site are the gold standard for reconstruction but are associated with donor-site morbidity and are in limited supply. We developed a bone graft strategy for irregular bone-involved reconstruction that is customizable to defect geometry and patient anatomy, is free of synthetic materials, is cellularized, and has an outer pre-vascularized tissue layer to enhance engraftment and promote osteogenesis. The graft, comprised of bioprinted human-derived demineralized bone matrix blended with native matrix proteins containing human mesenchymal stromal cells and encased in a simple tissue shell containing isolated, human adipose microvessels, ossifies when implanted in rats. Ossification follows robust vascularization within and around the graft, including the formation of a vascular leash, and develops mechanical strength. These results demonstrate an early feasibility animal study of a biofabrication strategy to manufacture a 3D printed patient-matched, osteoconductive, tissue-banked, bone graft without synthetic materials for use in craniofacial reconstruction. The bone fabrication workflow is designed to be performed within the hospital near the Point of Care.

Quantifying Vascular Density in Tissue Engineered Constructs Using Machine Learning

Given the considerable research efforts in understanding and manipulating the vasculature in tissue health and function, making effective measurements of vascular density is critical for a variety of biomedical applications. However, because the vasculature is a heterogeneous collection of vessel segments, arranged in a complex three-dimensional architecture, which is dynamic in form and function, it is difficult to effectively measure. Here, we developed a semi-automated method that leverages machine learning to identify and quantify vascular metrics in an angiogenesis model imaged with different modalities. This software, BioSegment, is designed to make high throughput vascular density measurements of fluorescent or phase contrast images. Furthermore, the rapidity of assessments makes it an ideal tool for incorporation in tissue manufacturing workflows, where engineered tissue constructs may require frequent monitoring, to ensure that vascular growth benchmarks are met.

Electromagnetic fields alter the motility of metastatic breast cancer cells

Interactions between cells and their environment influence key physiologic processes such as their propensity to migrate. However, directed migration controlled by extrinsically applied electrical signals is poorly understood. Using a novel microfluidic platform, we found that metastatic breast cancer cells sense and respond to the net direction of weak (∼100 µV cm-1), asymmetric, non-contact induced Electric Fields (iEFs). iEFs inhibited EGFR (Epidermal Growth Factor Receptor) activation, prevented formation of actin-rich filopodia, and hindered the motility of EGF-treated breast cancer cells. The directional effects of iEFs were nullified by inhibition of Akt phosphorylation. Moreover, iEFs in combination with Akt inhibitor reduced EGF-promoted motility below the level of untreated controls. These results represent a step towards isolating the coupling mechanism between cell motility and iEFs, provide valuable insights into how iEFs target multiple diverging cancer cell signaling mechanisms, and demonstrate that electrical signals are a fundamental regulator of cancer cell migration.

The impact of mammography screening programmes on incidence of advanced breast cancer in Europe: a literature review

Background

Observational studies have reported conflicting results on the impact of mammography service screening programmes on the advanced breast cancer rate (ABCR), a correlation that was firmly established in randomized controlled trials. We reviewed and summarized studies of the effect of service screening programmes in the European Union on ABCR and discussed their limitations.

Methods

The PubMed database was searched for English language studies published between 01-01-2000 and 01–06-2018. After inspection of titles and abstracts, 220 of the 8644 potentially eligible papers were considered relevant. Their abstracts were reviewed by groups of two authors using predefined criteria. Fifty studies were selected for full paper review, and 22 of these were eligible. A theoretical framework for their review was developed. Review was performed using a ten-point checklist of the methodological caveats in the analysis of studies of ABCR and a standardised assessment form designed to extract quantitative and qualitative information.

Results

Most of the evaluable studies support a reduction in ABCR following the introduction of screening. However, all studies were challenged by issues of design and analysis which could at least potentially cause bias, and showed considerable variation in the estimated effect. Problems were observed in duration of follow-up time, availability of reliable reference ABCR, definition of advanced stage, temporal variation in the proportion of unknown-stage cancers, and statistical approach.

Conclusions

We conclude that much of the current controversy on the impact of service screening programmes on ABCR is due to observational data that were gathered and/or analysed with methodological approaches which could not capture stage effects in full. Future research on this important early indicator of screening effectiveness should focus on establishing consensus in the correct methodology.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4666-1) contains supplementary material, which is available to authorized users.

Monitoring and evaluating the UK National Health Service Breast Screening Programme: evaluating the variation in radiological performance between individual programmes using PPV-referral diagrams

A high quality breast cancer screening programme can be defined as one offering both a high cancer detection rate and a low referral rate of women for further investigation. Such a programme will have as few women as possible undergoing further investigations who do not have a final diagnosis of breast cancer—that is, a high positive predictive value of referral for further investigation. This paper introduces a graphical technique to illustrate individual programme performance. The graph plots positive predictive value of referral against referral rate, with the cancer detection rate expressed as “isobars” on the graph. Confidence limits can be expressed as “boxes” on the diagram. The graph not only illustrates programme performance but also enables suggestions to be made to improve performance. The definition of high quality screening is seen to have a subjective element as well as an objective element, as radiologists have to balance screening sensitivity with specificity. The technique is illustrated using data from the individual screening programmes in the UK National Health Service Breast Screening Programme for the screening year 1 April 1998 to 31 March 1999. The methodology could also be applied to other national screening programmes.

FIT for the future: a case for risk-based colorectal cancer screening using the faecal immunochemical test

Worldwide, the guaiac faecal occult blood test (gFOBT) is being replaced with the more accurate faecal immunochemical test (FIT) for colorectal cancer (CRC) screening. From January 2016, the National Screening Committee in the UK has recommended a change from the gFOBT to the FIT following a successful Bowel Cancer Screening Programme pilot study with over 40 000 participants. Although the test has shown improved uptake and the ability to detect significantly more colorectal cancers and advanced adenomas, the higher uptake and test positivity will challenge the capacity of colonoscopy services. One of the main advantages of the FIT is that it provides a quantitative haemoglobin concentration which has been shown to relate to the risk of CRC. Risk scoring systems which combine the FIT concentration with risk factor assessment have been shown to improve the sensitivity of the test. This individualized approach to screening could enable those at greatest risk to be referred for colonoscopy, optimizing resource use and ultimately patient outcomes.

Cost-effectiveness of prostate cancer screening: a simulation study based on ERSPC data

BACKGROUND

The results of the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial showed a statistically significant 29% prostate cancer mortality reduction for the men screened in the intervention arm and a 23% negative impact on the life-years gained because of quality of life. However, alternative prostate-specific antigen (PSA) screening strategies for the population may exist, optimizing the effects on mortality reduction, quality of life, overdiagnosis, and costs.

METHODS

Based on data of the ERSPC trial, we predicted the numbers of prostate cancers diagnosed, prostate cancer deaths averted, life-years and quality-adjusted life-years (QALY) gained, and cost-effectiveness of 68 screening strategies starting at age 55 years, with a PSA threshold of 3, using microsimulation modeling. The screening strategies varied by age to stop screening and screening interval (one to 14 years or once in a lifetime screens), and therefore number of tests.

RESULTS

Screening at short intervals of three years or less was more cost-effective than using longer intervals. Screening at ages 55 to 59 years with two-year intervals had an incremental cost-effectiveness ratio of $73000 per QALY gained and was considered optimal. With this strategy, lifetime prostate cancer mortality reduction was predicted as 13%, and 33% of the screen-detected cancers were overdiagnosed. When better quality of life for the post-treatment period could be achieved, an older age of 65 to 72 years for ending screening was obtained.

CONCLUSION

Prostate cancer screening can be cost-effective when it is limited to two or three screens between ages 55 to 59 years. Screening above age 63 years is less cost-effective because of loss of QALYs because of overdiagnosis.

Longer mean colonoscopy withdrawal time is associated with increased adenoma detection: evidence from the Bowel Cancer Screening Programme in England

BACKGROUND AND STUDY AIMS

Increasing colonoscopy withdrawal time (CWT) is thought to be associated with increasing adenoma detection rate (ADR). Current English guidelines recommend a minimum CWT of 6 minutes. It is known that in the Bowel Cancer Screening Programme (BCSP) in England there is wide variation in CWT. The aim of this observational study was to examine the relationship between CWT and ADR.

PATIENTS AND METHODS

The study examined data from 31 088 colonoscopies by 147 screening program colonoscopists. Colonoscopists were grouped in four levels of mean CWT ( < 7, 7 - 8.9, 9 - 10.9, and ≥ 11 minutes). Univariable and multivariable analysis (binary logistic and negative binomial regression) were used to explore the relationship between CWT, ADR, mean number of adenomas and number of right-sided and advanced adenomas.

RESULTS

In colonoscopists with a mean CWT < 7 minutes, the mean ADR was 42.5 % compared with 47.1 % in the ≥ 11-minute group (P < 0.001). The mean number of adenomas detected per procedure increased from 0.77 to 0.94, respectively (P < 0.001). The increase in adenoma detection was mainly of subcentimeter or proximal adenomas; there was no increase in the detection of advanced adenomas. Regression models showed an increase in ADR from 43 % to 46.5 % for mean CWT times ranging from 6 to 10 minutes.

CONCLUSIONS

This study demonstrates that longer mean withdrawal times are associated with increasing adenoma detection, mainly of small or right-sided adenomas. However, beyond 10 minutes the increase in ADR is minimal. Mean withdrawal times longer than 6 minutes are not associated with increased detection of advanced adenomas. Withdrawal time remains an important quality metric of colonoscopy.

Nottingham trial of faecal occult blood testing for colorectal cancer: a 20-year follow-up

BACKGROUND

Three large randomised trials have shown that screening for colorectal cancer (CRC) using the faecal occult blood test (FOBt) can reduce the mortality from this disease. The largest of these trials, conducted in Nottingham since 1981, randomised 152,850 individuals between the ages of 45 and 74 years to an intervention arm receiving biennial Haemoccult (FOB) test kit or to a control arm. In 2006, the National Bowel Cancer Screening Programme was launched in England using the FOBt, with the expectation that it will reduce CRC mortality.

AIMS

To compare the CRC mortality and incidence in the intervention arm with the control arm after long-term follow-up.

METHODS

The 152,850 randomised individuals were followed up through local health records and central flagging (Office for National Statistics).

RESULTS

At a median follow-up of 19.5 years there was a 13% reduction in CRC mortality (95% CI 3% to 22%) in the intervention arm despite an uptake at first invitation of approximately 57%. The CRC mortality reduction in those accepting the first screening test, adjusted for the rate of non-compliers, was 18%. There was no significant difference in mortality from causes other than CRC between the intervention and control arms. Despite removing 615 adenomas >10 mm in size from the intervention arm, there was no significant difference in CRC incidence between the two arms.

CONCLUSIONS

Although the reduction in CRC mortality was sustained, further follow-up of the screened population has not shown a significant reduction in the CRC incidence. Moreover, despite the removal of many large adenomas there was no reduction in the incidence of invasive cancer which was independent of sex and site of the tumour.

Screening outcomes in women over age 70 who self-refer in the NHSBSP in England

SETTING

The NHS breast screening programme (NHSBSP) in England currently invites women aged 50-70 every three years. Whilst screening is acknowledged as efficacious for women aged 50-69, several countries routinely invite women up to the age of 74. The NHSBSP in England is beginning to invite women up to the age of 73. Although the incidence of breast cancer increases with age, the possible benefits of screening older women must be balanced against shorter life expectancies and possible overdiagnosis. In England women can self-refer after reaching the invitation upper age limit.

OBJECTIVE

We examined the extent to which older women in England self-referred over a three-year period and studied the screening outcomes in these women.

METHODS

Routinely collected data from screening units in England were used to calculate screening performance measures for women who self-referred between 1 April 2005 and 31 March 2008. The tumour characteristics of all screen-detected cancers were examined by previous screening history and age group (71-74 and ≥75 years).

RESULTS

During the three-year period 139,910 women aged over 70 self-referred; equivalent to 4% of the female population aged over 70 having been screened. The majority of women who self-referred had been screened within the previous five years (76% of those aged 71-74 and 65% of those aged 75 or over). Approximately 4% of these women were recalled for assessment and cancer detection rates were similar in both age groups.

CONCLUSION

Only a small proportion of all women aged over 70 utilize the self-referral policy of the NHSBSP, and most such women are aged below 80.

Performance measures in three rounds of the English bowel cancer screening pilot

OBJECTIVES

To compare performance measures across all three rounds of the English bowel cancer screening faecal occult blood test pilot and their relation to social deprivation and ethnicity.

METHODS

In each round in three primary care trusts, data for a restricted population of over 48,500 aged 60-69 years were analysed. Individual-based data included postcode linked to area-based data on the Index of Multiple Deprivation (IMD) 2004, and ethnicity. Outcomes were the rates of screening and colonoscopy uptake, positivity and detection of neoplasia (adenomas or bowel cancer) and bowel cancer, and the positive predictive values (PPVs) of a positive test for neoplasia and bowel cancer. Sensitivity was calculated by the proportional incidence method using data on interval cancers identified from cancer registrations.

RESULTS

The overall uptake rate was 61.8%, 57.0% and 58.7% in the first, second and third rounds, respectively. Although the PPV for cancer decreased over the course of the three rounds (10.9% in the 1st round, 6.5% in 3rd round), the PPV for all neoplasia remained relatively constant (42.6% in 1st round, 36.9% in 3rd round). Deprivation and non-white ethnic background (principally Indian subcontinent in the pilot region) were associated with low screening and colonoscopy uptake rates, and this changed little over the three screening rounds. Uptake was lower in men, although differences in uptake between men and women decreased over time. Non-participation in previous rounds was a strong predictor of low uptake.

CONCLUSIONS

Performance measures are commensurate with expectations in a screening programme reaching its third round of screening, but a substantial ongoing effort is needed, particularly to address the effects of deprivation and ethnicity in relation to uptake.

An observational study to evaluate the performance of units using two radiographers to read screening mammograms

AIM

To examine the performance of screening units in which a proportion of mammograms were double read using "non-discordant radiographer only (double) reading" (NDROR).

MATERIALS AND METHODS

NDROR was used by seven pilot units between 2006 and 2009, and six further units in 2009 only. There were 51 comparison units. Screening performance outcome measures were calculated, and logistic regression was used to compare performance between the pilot and comparison units.

RESULTS

Phase 1 pilot units read between on average 15 and 48% of mammograms per year using NDROR between 2006 and 2009 (median, 33%) and in 2009, phase 2 pilot units used NDROR to read between 4 and 77% of mammograms (median, 34%). The results showed an increase in recall rates in the phase 1 pilot units relative to the comparison units at both prevalent and incident screens (adjusted OR 1.09, 95% CI 1.05, 1.14; and adjusted OR 1.10, 95% CI 1.07, 1.14, respectively). There were also increases in the phase 2 pilot units relative to the comparison units; adjusted OR 1.08 (95% 1.00, 1.17) at prevalent screens, and adjusted OR 1.07 (95% CI 1.02, 1.14) at incident screens. There was no evidence to suggest a difference in cancer-detection rates between the pilot units and the comparison units.

CONCLUSIONS

Evidence from the present study suggests that recall rates may increase as a result of units using radiographers to double read a proportion of their mammograms. However, there is little evidence to suggest that NDROR, as practiced by the pilot units in the present study, is likely to have major impacts on performance in the UK National Health Service Breast Screening Programme (NHSBSP), particularly if it is fully supported and closely monitored (particularly recall rates).

HPV testing as a triage for borderline or mild dyskaryosis on cervical cytology: results from the Sentinel Sites study

BACKGROUND

Earlier pilot studies of human papillomavirus (HPV) triage concluded that HPV triage was feasible and cost-effective. The aim of the present study was to study the impact of wider rollout of HPV triage for women with low-grade cytology on colposcopy referral and outcomes.

METHODS

Human papillomavirus testing of liquid-based cytology (LBC) samples showing low-grade abnormalities was used to select women for colposcopy referral at six sites in England. Samples from 10,051 women aged 25-64 years with routine call or recall cytology reported as borderline or mild dyskaryosis were included.

RESULTS

Human papillomavirus-positive rates were 53.7% in women with borderline cytology and 83.9% in those with mild dyskaryosis. The range between sites was 34.8-73.3% for borderline cytology, and 73.4-91.6% for mild dyskaryosis. In the single site using both LBC technologies there was no difference in rates between the two technologies. The positive predictive value of an HPV test was 16.3% for CIN2 or worse and 6.1% for CIN3 or worse, although there was considerable variation between sites.

CONCLUSION

Triaging women with borderline cytological abnormalities and mild dyskaryosis with HPV testing would allow approximately a third of these women to be returned immediately to routine recall, and for a substantial proportion to be referred for colposcopy without repeat cytology. Variation in HPV-positive rates results in differing colposcopy workload.

Identification and characterization of flowering genes in kiwifruit: sequence conservation and role in kiwifruit flower development

BACKGROUND

Flower development in kiwifruit (Actinidia spp.) is initiated in the first growing season, when undifferentiated primordia are established in latent shoot buds. These primordia can differentiate into flowers in the second growing season, after the winter dormancy period and upon accumulation of adequate winter chilling. Kiwifruit is an important horticultural crop, yet little is known about the molecular regulation of flower development.

RESULTS

To study kiwifruit flower development, nine MADS-box genes were identified and functionally characterized. Protein sequence alignment, phenotypes obtained upon overexpression in Arabidopsis and expression patterns suggest that the identified genes are required for floral meristem and floral organ specification. Their role during budbreak and flower development was studied. A spontaneous kiwifruit mutant was utilized to correlate the extended expression domains of these flowering genes with abnormal floral development.

CONCLUSIONS

This study provides a description of flower development in kiwifruit at the molecular level. It has identified markers for flower development, and candidates for manipulation of kiwifruit growth, phase change and time of flowering. The expression in normal and aberrant flowers provided a model for kiwifruit flower development.

Increasingly strong reduction in breast cancer mortality due to screening

BACKGROUND

Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted in the launch of population-based service screening programmes in many Western countries. We investigated whether improvements in mammography and treatment modalities have had an influence on the effectiveness of breast cancer screening from 1975 to 2008.

METHODS

In Nijmegen, the Netherlands, 55,529 women received an invitation for screening between 1975 and 2008. We designed a case-referent study to evaluate the impact of mammographic screening on breast cancer mortality over time from 1975 to 2008. A total number of 282 breast cancer deaths were identified, and 1410 referents aged 50-69 were sampled from the population invited for screening. We estimated the effectiveness by calculating the odds ratio (OR) indicating the breast cancer death rate for screened vs unscreened women.

RESULTS

The breast cancer death rate in the screened group over the complete period was 35% lower than in the unscreened group (OR=0.65; 95% CI=0.49-0.87). Analysis by calendar year showed an increasing effectiveness from a 28% reduction in breast cancer mortality in the period 1975-1991 (OR=0.72; 95% CI=0.47-1.09) to 65% in the period 1992-2008 (OR=0.35; 95% CI=0.19-0.64).

CONCLUSION

Our results show an increasingly strong reduction in breast cancer mortality over time because of mammographic screening.

Interval cancers in the NHS breast cancer screening programme in England, Wales and Northern Ireland

BACKGROUND

The United Kingdom NHS Breast Screening Programme was established in 1988, and women aged between 50 and 70 are routinely invited at three yearly intervals. Expected United Kingdom interval cancer rates have been calculated previously, but this is the first publication from an exercise to collate individual-based interval cancer data at a national level.

METHODS

Interval cancer case ascertainment is achieved by the regular exchange of data between Regional Breast Screening Quality Assurance Reference Centres and Cancer Registries. The present analysis includes interval cancers identified in women screened between 1st April 1997 and 31st March 2003, who were aged between 50 and 64 at the time of their last routine screen.

RESULTS

In the periods >0-<12 months, 12-<24 months and 24-<36 months after a negative screen, we found overall interval cancer rates and regional ranges of 0.55 (0.43-0.76), 1.13 (0.92-1.47) and 1.22 (0.93-1.57) per 1000 women screened, respectively. Rates in the period 33-<36 months showed a decline, possibly associated with early re-screening or delayed presentation.

CONCLUSIONS

Interval cancer rates were higher than the expected rates in the 24-month period after a negative screen, but were similar to published results from other countries. Increases in background incidence may mean that the expected rates are underestimated. It is also possible that, as a result of incomplete case ascertainment, interval cancers rates were underestimated in some regions in which rates were less than the expected.

Abstract P3-11-01: Longitudinal Changes in Mammographic Features and Subsequent Risk of Breast Cancer in Pre-Menopausal Women: Studies Nested within the Age Trial

Background: Mammographic percent density (PD) is one of the strongest known risk factors for breast cancer, with women with 75% or more density having approximately 4 times greater risk of developing breast cancer than those with little density (&lt;5%). Most studies have been conducted in peri-and post-menopausal women with very few studies of density in younger pre-menopausal women. Mammographic features change throughout a woman's lifetime, with the amount of stromal and epithelial tissue decreasing with age, parity and the menopause. As some of the greatest changes in density occur during the menopause, it would be very informative to know whether PD measured at a younger age or the rate of change in PD could be better predictors of subsequent breast cancer risk.

Methods: A nested case-control study of 350 cases and 450 controls was conducted within the intervention arm of the Age Trial of mammographic screening in young women, in which about 54,000 women wererandomised to receive yearly mammographic screening from ages 40 to 48. Women diagnosed with breast cancer were invited to participate in the study, and for each case, healthy controls were randomly selected matched to the cases on screening centre, age and date of mammogram. We are investigating how changes in PD over time in pre-menopausal women, measured on digitised films using a computer-assisted threshold method, relate to subsequent risk of breast cancer. Additionally, we are looking at associations of risk factor variables with baseline PD and changes in PD, investigated in longitudinal analyses in a sample of over 500 breast cancer-free women. Logistic regression models were used to estimate the effect of baseline mammographic density on subsequent breast cancer risk and multilevel linear models to assess the association between longitudinal changes in percent density and risk of breast cancer. Results: Over a 10 year period between ages 40 and 50, the mean reduction in percent density was 10.9% in our sample of breast cancer-free women. Change in percent density was greatest in the women's early forties, with a decrease of 1.9% per year, which reduced to about 0.2% in their late forties/early fifties. Baseline levels and rate of change of percent density were both associated with current and past anthropometric, reproductive and lifestyle factors. Change in percent density was associated with parity, with women who had three or more children experiencing a slower rate of change (P&lt;0.01), and with body mass index (BMI), with extremely overweight women at baseline (&gt;28 kg/m2) having a slower decline in PD than women of normal BMI (22-24 kg/m2). The analysis of the case-control data is currently in progress.

Conclusion: We demonstrated that change in PD was associated with known breast cancer risk factors in pre-menopausal women. The results from the nested case-control study will further our understanding of the life-course trajectory of mammographic density and its role as a mediator of breast cancer risk.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-11-01.

Randomized controlled trial of mammographic screening from age 40 ('Age' trial): patterns of screening attendance

BACKGROUND

The Age trial was a randomized controlled trial to study the effect on breast cancer mortality of invitation to annual mammography from age 40 to 41. Uptake of invitation to screening mammography in UK women aged below 50 is of interest, particularly in the light of the recent announcement that the national breast screening programme will begin inviting women from age 47.

METHODS

The trial took place in 23 National Health Service breast screening units in England, Wales and Scotland between 1991 and 2004. Data on invitation and attendance during 13 years of trial fieldwork were analysed. The participants were 53,884 women in the intervention arm of the Age trial who were randomized to receive annual invitation to mammography from age 40 or 41 up to age 48. The trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN24647151.

RESULTS

Uptake of invitation to routine screening was 68% at first round and 69% at subsequent rounds. A total of 43,709 women in the intervention arm (81%) attended at least one routine screen and 23,262 (43%) attended at least seven screens; 31,392 women attended 75% or more of all routine invitations they were offered. Previous trial attendance was a predictor of subsequent uptake; attendance was inversely related to Townsend deprivation score.

CONCLUSION

Uptake in this trial was comparable with that in the UK screening programme for women aged over 50. There was an inverse relationship between deprivation level and the number of screens attended.

Risk of cervical abnormality after age 50 in women with previously negative smears

There is discussion over the benefit of continuing cervical screening in women over the age of 50 with a history of negative cytology. We aimed to determine the risk of abnormal cytology in such women. Screening history data from 1985 to 2003 were obtained for a cohort of 2 million women from the NHS cervical screening programme from four Health Authorities in England. The 57 651 women in the cohort who reached age 40 between 1 January 1985 and 31 December 1990 and had at least one routine or opportunistic smear between ages 50 and 54 were included in the analysis. Exposure groups (negative cytology history, negative but including inadequate smears, and positive history) were defined on the basis of screening histories from ages 40 to 49. Sixty-four percent (134/206) (95% CI: 57–71%) of the moderate dyskaryosis or worse lesions at ages over 50 were detected from women in the negative smear history group. After allowance for time since last negative smear, the relative risk for the first primary smear over the age of 50 having moderate dyskaryosis or worse decreased from 0.60 (95% CI: 0.41–0.84) for two negative smear episodes to 0.25 (95% CI: 0.10–0.56) for four negative smear episodes, compared with the positive history group. If screening were discontinued for all women over 50 with a negative history, the majority of cytological abnormalities now being detected at these ages that lead directly to referral to colposcopy would be missed.

The use of screening episodes linked to CIN3 and invasive cancer registrations to study outcomes from the NHS Cervical Screening Programme

The use of screening episodes linked to CIN3 and invasive cancer registrations to study outcomes from the NHS Cervical Screening ProgrammeObjective: To examine how NHS cervical screening data can be collected and analysed in order to evaluate women's screening histories as episodes rather than as individual smears.

DESIGN

Analysis of routine cervical screening data grouped into screening episodes for a cohort of women regarding episodes starting in a given year.

SETTING

NHS Cervical Screening Programme.

POPULATION

Data from four Health Authorities (now eight Primary Care Trusts) from the NHS Cervical Screening Programme with primary smears (first in an episode) taken between 1 April 1999 and 31 March 2000.

METHODS

Cytology information obtained from the call/recall ('Exeter') computer system was linked to cervical intraepithelial neoplasia (CIN) 3 and invasive cancer outcome information obtained from cancer registries. Screening histories were divided into episodes, each starting with a primary smear that was followed up to episode closure or, for episodes still open followed for an average 4.25 years, from the primary smear. The episode was divided into two parts (up to referral to colposcopy and following the referral). The outcomes of the episodes are described including referral rate to colposcopy and CIN3 and invasive cancer rates by factors such as age.

MAIN OUTCOME MEASURES

Episode histories and rates of referral to colposcopy, CIN3 and invasive cancer.

RESULTS

There were 176 923 episodes from 176 319 women (1.003 episodes per woman) followed up to March 2004, the date at which the first phase of information accrual ceased. Of these episodes, 172 100 (97.3%) were closed either by a negative smear referring the woman back to routine recall or by default (defined as no smear recorded within 21 months following a smear requiring an action of repeat or refer to colposcopy). The remaining 4823 (2.7%) of episodes were still open, of which in 3121 (1.8%) the woman had been referred to colposcopy and in 1702 (1.0%) no referral decision had been made. Referral rates to colposcopy varied by age from 5.7% in women aged 20-24 years down to 0.9% in women aged 60-64 years. The overall efficiency of screening was highest for woman aged about 30 years, with a CIN3 detection rate of eight per 1000 women and a positive predictive value (for CIN3 or worse) of referral to colposcopy of 21%.

CONCLUSION

The study has shown that routinely collected NHS cervical screening data can be combined to give information on complete episodes, allowing important performance measures to be studied. We suggest that in future information in the NHS screening system should be structured to facilitate such analysis and to allow cytology and histology information to be readily linked.

An examination of the role of opportunistic smear taking in the NHS cervical screening programme using data from the CSEU cervical screening cohort study

OBJECTIVE

The objective of this study was to study the prevalence of opportunistic smear taking in the NHS cervical screening programme between 1999 and 2003 and the relationship of this to screening interval policy.

DESIGN

A cohort study of nearly 2 million women, with data on screening at ages 20-64 years from 1988 to 2003 has been constructed. Data from 1999 to 2003 have been used in this analysis. Screening episodes have been divided into those where the primary smear was initiated by the national call/recall system (invitational), normally at 3- or 5-yearly intervals, and those initiated by the GP or woman (opportunistic). Opportunistic smears were further classified as routine (occurring within 6 months of 3 or 5 years) or sporadic (occurring at other times).

SETTING

NHS cervical screening programme.

POPULATION

Four Health Authorities in England (now Primary Care Trusts) with supplementary studies on national data.

METHODS

Screening episodes have been defined. All episodes start with a primary smear defined as being invitational or opportunistic in origin.

MAIN OUTCOME MEASURE

Proportion of primary smear that were invitational or opportunistic.

RESULTS

In total, 72% of incident screen primary smears were invitational and 28% were opportunistic. The proportion of opportunistic primary smears was 17 and 43% in 3- or 5-yearly screening policy areas, respectively, resulting in a considerably reduced average screening interval for women aged 20-64 years in 5-year policy areas.

CONCLUSION

The NHS cervical screening programme is strongly influenced by opportunistic smear taking. In particular, nominally 5-year policy areas experienced much higher levels of opportunistic smear taking than those with a 3-year policy, causing the average interval in the 5-year areas to be much shorter than the policy would suggest. In future, with the change in national policy for inviting women aged 25-49 years every 3 years and those aged 50-64 years every 5 years, the level of opportunistic smear taking, particularly in the older group of women, needs to be carefully monitored. A lack of compliance may result in greater than predicted costs with little or no additional cancer prevention.

Does the accuracy of single reading with CAD (computer-aided detection) compare with that of double reading?: A review of the literature

AIM

To examine current evidence to determine whether the accuracy of single reading with computed-aided detection (CAD) compares with that of double reading.

METHODS

We performed a literature review to identify studies where both protocols had been investigated and compared. We identified eight studies that compared single reading with CAD against double reading, of which six reported on comparisons of both sensitivity and specificity.

RESULTS

Of the six studies identified, three showed no differences in either sensitivity or specificity. One showed single reading with CAD had a higher sensitivity at the same specificity, another that single reading with CAD had a higher specificity at the same sensitivity. However, one study, in a real-life setting, showed that single reading with CAD had a higher sensitivity but a lower specificity.

CONCLUSION

As the majority of the studies were not in a real-life setting, used test sets, lacked sufficient training in the use of CAD and simulated double reading (using a protocol of recall if one suggests), current evidence is therefore limited as to the accuracy, in terms of sensitivity and specificity, of single reading with CAD in comparison with the most common practice in the UK of double reading using a protocol of consensus or arbitration.

The effect of data quality at the time of introduction of population-based screening on the estimate of programme impact using surrogate outcome measures

OBJECTIVE

The aim of this study was to examine the availability and quality of surrogate outcome measure data to enable the evaluation of the breast screening programme. As the observed effect on mortality of a screening programme occurs many years after the introduction of screening, surrogate outcome measures offer an attractive alternative, allowing estimates of the effect to be calculated earlier.

METHODS

The exercise was undertaken by the Oxford Cancer Intelligence Unit and the Cancer Screening Evaluation Unit in collaboration with cancer registries in England, Scotland and Wales.

RESULTS

The conclusion of the exercise was that, in general, the available data quality was insufficient to allow a precise estimate of the overall mortality reduction from breast screening to be made using surrogate measures.

CONCLUSIONS

When a screening programme is started, it is vital that forward planning is undertaken to ensure that the necessary information is ready to be collected before the start of the programme. The use of surrogate measures is dependent on high-quality data in the uninvited group of women (pre-screening or from a staggered start over areas), and improving data quality over time after the start of the programme is of very limited value for a surrogate measures approach. The collection of appropriate high-quality information before the programme starts is, therefore, critical to measuring the success of the programme. Cancer registries and staff within the screening programme need to be ready to collect the appropriate data before the introduction of a screening programme. The exercise undertaken therefore has important implications where new screening programmes are being considered.

Improving the NHS cervical screening laboratory performance indicators by making allowance for population age, risk and screening interval

OBJECTIVE

One of the key performance measures in the monitoring of the NHS cervical screening programme is the targeting of laboratories with very high or low percentages (outside the 10th-90th percentile) of adequate smears that have moderate dyskaryosis or worse. These laboratories are assumed to include those laboratories that may have extremes of sensitivity and specificity. A clear limitation with this methodology is that laboratories do not examine smears from women with the same underlying risk, age distribution or screening interval and adjustment for these factors should considerably improve the method.

METHODS

This paper describes a method that allows for these confounding variables and a new age-risk-interval adjusted moderate dyskaryosis or worse rate (ARI-adjusted mod+ rate) can be calculated. The adjusted rate is the rate of moderate or worse dyskaryotic smears that the laboratory would have detected had it been screening women with an English 'average' age-risk-interval. All laboratories can therefore be compared using this method.

RESULTS

The methodology is illustrated using data from the NHSCSP South West Region. The particularly low percentage of moderate or worse smears detected by one or two laboratories can be shown to be due to a local screened population with a very low risk because of a high mean age, relatively short screening interval and census variables associated with a low risk, rather than any under-calling by the associated laboratories.

CONCLUSIONS

The ARI-adjusted mod+ rate requires to be calculated for all laboratories in England if it is to be used as a primary performance indicator. Alternatively, it can be used to further examine laboratories that are deemed to be outliers using the current methodology.

Cost-effectiveness of screening with contrast enhanced magnetic resonance imaging vs X-ray mammography of women at a high familial risk of breast cancer

Contrast enhanced magnetic resonance imaging (CE MRI) is the most sensitive tool for screening women who are at high familial risk of breast cancer. Our aim in this study was to assess the cost-effectiveness of X-ray mammography (XRM), CE MRI or both strategies combined. In total, 649 women were enrolled in the MARIBS study and screened with both CE MRI and mammography resulting in 1881 screens and 1–7 individual annual screening events. Women aged 35–49 years at high risk of breast cancer, either because they have a strong family history of breast cancer or are tested carriers of a BRCA1, BRCA2 or TP53 mutation or are at a 50% risk of having inherited such a mutation, were recruited from 22 centres and offered annual MRI and XRM for between 2 and 7 years. Information on the number and type of further investigations was collected and specifically calculated unit costs were used to calculate the incremental cost per cancer detected. The numbers of cancer detected was 13 for mammography, 27 for CE MRI and 33 for mammography and CE MRI combined. In the subgroup of BRCA1 (BRCA2) mutation carriers or of women having a first degree relative with a mutation in BRCA1 (BRCA2) corresponding numbers were 3 (6), 12 (7) and 12 (11), respectively. For all women, the incremental cost per cancer detected with CE MRI and mammography combined was £28 284 compared to mammography. When only BRCA1 or the BRCA2 groups were considered, this cost would be reduced to £11 731 (CE MRI vs mammography) and £15 302 (CE MRI and mammography vs mammography). Results were most sensitive to the unit cost estimate for a CE MRI screening test. Contrast-enhanced MRI might be a cost-effective screening modality for women at high risk, particularly for the BRCA1 and BRCA2 subgroups. Further work is needed to assess the impact of screening on mortality and health-related quality of life.

Is radiologists' volume of mammography reading related to accuracy? A critical review of the literature

The current UK quality assurance guidelines for radiologists in the NHS breast screening programme require those reporting screening mammograms to read a minimum of 5000 cases per year. We aimed to review the evidence for this and to assess whether there was justification for lowering the required level. A literature search was conducted to identify relevant studies where accuracy of reporting mammograms was related to reading volume. Three of the five studies reviewed suggested a positive association between reading volume and sensitivity, but there were few data on volumes above 5000 cases per year. The available evidence did not provide any basis for reducing the threshold volume. Further work is needed, in a UK or European setting, to study the relationship between reading volume and accuracy at higher volume levels and also the separate effects of reading volume and reading experience.

The effect of changing from one to two views at incident (subsequent) screens in the NHS breast screening programme in England: impact on cancer detection and recall rates

AIM

To assess the effect on cancer detection and recall rates of changing from one to two views for incident (subsequent) screens.

METHODS

Controlled, comparative, observational study of programmes in NHS breast screening programme in England.

SUBJECTS

women aged 50-64 years were screened by the NHSBSP between 1 April 2001 and 31 March 2003.

RESULTS

The effect of changing to two-view mammography was a 20% increase in overall incident screen cancer detection rate, with the biggest effect seen for small (<15 mm) invasive cancers. This increased detection rate was achieved with an 11% drop-in recall rate.

CONCLUSION

The introduction of two-view mammography for incident screens has resulted in considerable improvements in overall NHS breast screening performance.

Screening with magnetic resonance imaging and mammography of a UK population at high familial risk of breast cancer: a prospective multicentre cohort study (MARIBS)

BACKGROUND

Women genetically predisposed to breast cancer often develop the disease at a young age when dense breast tissue reduces the sensitivity of X-ray mammography. Our aim was, therefore, to compare contrast enhanced magnetic resonance imaging (CE MRI) with mammography for screening.

METHODS

We did a prospective multicentre cohort study in 649 women aged 35-49 years with a strong family history of breast cancer or a high probability of a BRCA1, BRCA2, or TP53 mutation. We recruited participants from 22 centres in the UK, and offered the women annual screening with CE MRI and mammography for 2-7 years.

FINDINGS

We diagnosed 35 cancers in the 649 women screened with both mammography and CE MRI (1881 screens): 19 by CE MRI only, six by mammography only, and eight by both, with two interval cases. Sensitivity was significantly higher for CE MRI (77%, 95% CI 60-90) than for mammography (40%, 24-58; p=0.01), and was 94% (81-99) when both methods were used. Specificity was 93% (92-95) for mammography, 81% (80-83) for CE MRI (p<0.0001), and 77% (75-79) with both methods. The difference between CE MRI and mammography sensitivities was particularly pronounced in BRCA1 carriers (13 cancers; 92%vs 23%, p=0.004).

INTERPRETATION

Our findings indicate that CE MRI is more sensitive than mammography for cancer detection. Specificity for both procedures was acceptable. Despite a high proportion of grade 3 cancers, tumours were small and few women were node positive. Annual screening, combining CE MRI and mammography, would detect most tumours in this risk group.

Monitoring and evaluating the performance of the UK NHS Cervical Screening Programme: monitoring performance by using cytology outcomes adjusted for population characteristics

Current quality assurance measures used in the NHS cervical screening programme (NHSCSP) include a review of laboratories with percentages of moderate/severe and borderline/mild smear results outside the 10th-90th percentiles. The method is limited by the fact that many of these outlier smear percentages may reflect laboratories covering populations with low or high risk and/or short or long average screening intervals. This paper outlines a new approach to aid the detection of outlier laboratories, by using data collected at the primary care trust (PCT) or health authority (HA) level and making allowances for population characteristics and screening interval. The setting is the NHSCSP in England using annual data provided by HAs. Data from the screening year 2000-01 is used to illustrate the methodology, although the methods can also be applied to data at the PCT level (now being collected for 2002-03 onwards). Percentages of smear results have been analysed against a series of explanatory variables using logistic regression models. These explanatory variables include Townsend deprivation index, uptake-corrected ethnic minority composition, a measure of screening interval, area type and region. An expected percentage of borderline/mild and moderate/severe smears is estimated from the models and an observed : predicted ratio (OPRmod/sev and OPRbord/mild) calculated. Low values are suggestive of relative undercalling and high values overcalling, after allowance for population characteristics. Analysis of data for 2000-01 showed that the OPRmod/sev for the 99 HAs varied from 0.68 to 1.44. Laboratories with low percentages of moderate/severe smears, but associated with PCTs or HAs with OPRmod/sev values closer to unity may not need to be investigated as their observed rates are consistent with predicted rates based on population characteristics. The method could also be directly applied to laboratories if further information on the population covered by each laboratory were routinely collected.

Protocol for a national multi-centre study of magnetic resonance imaging screening in women at genetic risk of breast cancer

The protocol of the national multicentre study of Magnetic Resonance Imaging (MRI) as a method of screening for breast cancer in women at genetic risk is described. The sensitivity and specificity of contrast-enhanced MRI will be compared with two-view X-ray mammography in a comparative trial. Approximately 500 women below the age of 50 at high genetic risk of breast cancer will be recruited per year for 3 years, with annual MRI and X-ray examination continuing for up to 5 years. A symptomatic cohort will be measured in the initial phase of the study to ensure consistent reporting between centres. The MRI examination will comprise an initial high-sensitivity screening measurement, followed by a high-specificity measurement in equivocal cases. Retrospective analysis will identify the most specific indicators of malignancy. Sensitivity and specificity, together with diagnostic performance, diagnostic impact and therapeutic impact will be assessed with reference to pathology, follow-up and changes in diagnostic certainty and therapeutic decisions. The psychological impact of screening in this high-risk group will be ascertained.

Does individual programme size affect screening performance? Results from the United Kingdom NHS breast screening programme

OBJECTIVE

The size (number of women screened) of the 95 individual NHS breast screening programmes (NHSBSPs) varies by a factor of 10. This study investigates the impact of size on the performance of individual programmes.

METHOD

Data were collated from the 95 United Kingdom screening programmes on the standard statistical returns for the past 5 years (1 April 1995-31 March 2000). Additional information was obtained from questionnaires. The number of women screened between 1 April 1999 and 31 March 2000 determined the size of a programme. The bottom 25% were defined as small, the middle 50% as medium, and the top 25% as large. On average large programmes screened about four times as many women as small programmes and medium programmes about twice as many. Performance was evaluated using cancer detection rates, referral rates for assessment, and positive predictive value (PPV) of assessment using PPV referral diagrams.

RESULTS

The performance of smaller programmes was shown to be marginally poorer than medium and large sized programmes in that they detected fewer cancers and had a lower PPV. The smallest 25% of programmes had an invasive cancer detection rate 13% less than the medium and large programmes. However, if these programmes had an equivalent detection rate to the medium/large programmes the national detection rate would only increase by about 2%. This is because the 75% of programmes described as medium and large screen about 90% of all women. It is therefore important to place the clinical importance of these findings in context when considering any envisaged possible solutions.

CONCLUSIONS

Although the performance of smaller programmes was shown to be poorer than that of the larger programmes, it is not clear from this study exactly why this is so. A likely contributory factor based on experience of evaluating the NHSBSP is that performance problems in larger programmes have been easier to detect by quality assurance staff. The size of the small programmes and the few screen detected cancers (and inherent statistical instability in detection rates) mean that problems are difficult to identify. As a consequence small programmes which are genuinely performing marginally below specific standards are likely to receive less attention than larger programmes, and even under close scrutiny the causes are less likely to be found.

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS)

The UK national study of magnetic resonance imaging as a method of screening for breast cancer (MARIBS) is in progress. The study design, accrual to date, and related research projects are described. Revised accrual rates and expected recruitment are given. 15 cancers have been detected to date, from a total of 1236 screening measurements. This event rate and the tumour grades reported are compared with recent reports from other studies in women at high risk of breast cancer.

Reasons for variation in coverage in the NHS cervical screening programme

In order to investigate reasons for variation in coverage of cervical screening, data from standard Department of Health returns were obtained for all Health Authorities for 1998/1999. Approximately 80% of the variation between health authorities is explained by differences in age distribution and area classification. Considerable differences between Health Authority and Office of National Statistics (ONS) population figures in City and Urban (London) areas for the age group 25-29 years and for City (London) for age group 30-34 years, suggest an effect of list inflation in these groups. Coverage as a performance indicator may be more accurately represented using the age range 35-64 years. Using this narrower age range, the percentage of health authorities meeting the 80% 5-year coverage target increases from 87% to 90%.

Routine breast screening for women aged 65-69: results from evaluation of the demonstration sites

Routine programme data and specially designed surveys from 3 demonstration sites were analysed to determine the implications of extending the NHS Breast Screening Programme (NHSBSP), to include routine invitations for women up to 69 years. All women aged 65-69 and registered with GPs in these areas received routine invitations for breast screening along with those aged 50-64. Overall uptake was 71% in women aged 65-69 compared with 78% in younger women, but was > or = 90% in both groups who had previously attended within 5 years. Recall rates were lower for older women, but with a higher positive predictive value for cancer. The percentages of invasive cancer in different prognostic categories were similar in the 2 age groups. Older women took no longer to screen than younger women. The costs per woman invited or per woman screened were also similar to those for women aged 50-64, whilst the cost per cancer detected was some 34% lower in older women. Breast screening is as cost effective for women aged 65-69 as for those aged 50-64, with a higher cancer detection rate balancing shorter life expectancy. The proposed extension to the national programme will have considerable workforce implications for the NHSBSP and require additional resources.

Results from the UK NHS breast screening programme 1994-1999

OBJECTIVE

To present results from the NHS breast screening programme (NHSBSP) from 1994 through to 1999 and to examine the extent to which interim targets are being achieved.

METHODS

Data were collated from all screening programmes in the UK on standard statistical returns. Performance of the screening programme was evaluated using calculated targets based on comparison with the Swedish two counties (STC) randomised controlled trial.

RESULTS

In the early years of screening (1988-1993), the NHS programme was detecting more DCIS but considerably less invasive cancers than expected, based on the STC trial. Since the screening year 1993/94 (1 April to 31 March) the standardised detection ratio (SDR) measure of the detection of invasive cancers has increased by 36% from 0.83 to 1.13. The SDR has been greater than 1 since 1996197 suggesting that the NHSBSP has only been screening as efficiently as the STC trial since this date. Uptake for screening has been relatively stable over time at approximately 75%.

CONCLUSIONS

The NHSBSP has made considerable advances in performance since its inception in 1988 and screening uptake and age standardised invasive cancer detection rates are (by 1999) well in excess of targets. The early years of screening were characterised by good uptake but a low sensitivity for the detection of invasive cancers. It is anticipated that the screening programme will have an increasing impact on breast cancer mortality, particularly in the 55-69 year age group over the coming years.

Faecal occult blood screening for colorectal cancer at Nottingham: details of the verification process

Cause specific mortality statistics derived from death certificates are highly dependent upon the accuracy of certification by the attending physician. In the Nottingham colorectal cancer screening trial, there were 12,624 deaths among the screening group and 12,515 among the control group during the period under consideration. There was no significant difference in all cause mortality rate (excluding deaths due to colorectal cancer) between the two study groups (rate ratio = 1.01, 95% confidence interval = 0.99 to 1.03). Disease specific mortality rates did not differ significantly between the two groups either. Overall, the agreement between verified and certified cause of death was 86%. Using the certified cause of death would have resulted in an underestimation bias of 6.27% for colorectal cancer deaths.

Pilot trial of interleukin-2 with granulocyte colony-stimulating factor for the mobilization of progenitor cells in advanced breast cancer patients undergoing high-dose chemotherapy: expansion of immune effectors within the stem-cell graft and post-stem-cell infusion

PURPOSE

To evaluate whether administration of interleukin-2 (IL-2) with granulocyte colony-stimulating factor (G-CSF) improves mobilization of immune effector cells into the stem-cell graft of patients undergoing high-dose chemotherapy and autografting.

PATIENTS AND METHODS

We performed a trial of stem-cell mobilization with IL-2 and G-CSF in advanced breast cancer patients receiving high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin and stem cells followed by IL-2. The trial defined immune, hematologic, and clinical effects of IL-2 in this setting.

RESULTS

Of 32 patients enrolled, nine received G-CSF alone for mobilization. Twenty-one of 23 patients mobilized with IL-2 plus G-CSF had stem cells collected with more mononuclear cells than those receiving G-CSF (19.3 v 10.4 x 10(8)/kg; P =.006), but fewer CD34(+) progenitor cells (6.9 v 22.0 x 10(6)/kg; P =.049). The IL-2 plus G-CSF-mobilized patients had greater numbers of activated T (CD3(+)/CD25(+)) cells (P =.009), natural killer (NK; CD56(+)) cells (P =.007), and activated NK (CD56 bright(+)) cells (P: =.039) than those patients mobilized with G-CSF. NK (P =.042) and lymphokine-activated killer (LAK) (P =.016) activity was increased in those mobilized with IL-2 + G-CSF, whereas G-CSF-mobilized patients had a decline in cytolytic activity. In the third week posttransplantation, immune reconstitution was superior in those mobilized with IL-2 plus G-CSF based on greater numbers of activated T cells (P =.003), activated NK cells (P =.04), and greater LAK activity (P =.003). The 16 of 21 IL-2 + G-CSF-mobilized patients with adequate numbers of stem cells (> 1.5 x 10(6) CD34(+) cells/kg) collected engrafted rapidly posttransplantation.

CONCLUSION

The results demonstrate that G-CSF + IL-2 can enhance the number and function of antitumor effector cells in a mobilized autograft without impairing the hematologic engraftment, provided that CD34 cell counts are more than 1.5 x 10(6) cells/kg. Mobilization of CD34(+) stem cells does seem to be adversely affected. In those mobilized with IL-2 and G-CSF, post-stem-cell immune reconstitution of antitumor immune effector cells was enhanced.

Lung cancer screening: improved survival but no reduction in deaths--the role of "overdiagnosis"

BACKGROUND

Randomized controlled trials (RCTs) of lung cancer screening consistently show an excess number of cancer cases and longer survival in screened groups, but no difference in mortality between screened and control populations.

METHODS

The current study reviewed the various types of biases that confuse comparisons based on intermediate endpoints such as stage distribution and survival and the reasons for basing evaluations in RCTs of screening for early cancers on mortality from a specific cancer.

RESULTS

Four RCTs all showed improved stage of disease and survival in screened subjects, but there was no difference in mortality between screened and unscreened populations. The possible explanations for the higher incidence are chance (failed randomization) or "overdiagnosis" (detection of cases by screening that otherwise would never have surfaced). Analysis of the trial results confirmed that chance alone was a very unlikely explanation. Evidence suggests that some overdiagnosis of lung cancer is likely in screened subjects. This is a consistent observation in all other programs of screening for early cancers (breast, prostate, and neuroblastoma).

CONCLUSIONS

Overdiagnosis of cancer cases resulting from the screening process itself will give rise to excess cases of disease, and may, at least in part, explain the observations in the randomized trials.

Lung cancer screening: improved survival but no reduction in deaths--the role of "overdiagnosis"

BACKGROUND

Randomized controlled trials (RCTs) of lung cancer screening consistently show an excess number of cancer cases and longer survival in screened groups, but no difference in mortality between screened and control populations.

METHODS

The current study reviewed the various types of biases that confuse comparisons based on intermediate endpoints such as stage distribution and survival and the reasons for basing evaluations in RCTs of screening for early cancers on mortality from a specific cancer.

RESULTS

Four RCTs all showed improved stage of disease and survival in screened subjects, but there was no difference in mortality between screened and unscreened populations. The possible explanations for the higher incidence are chance (failed randomization) or "overdiagnosis" (detection of cases by screening that otherwise would never have surfaced). Analysis of the trial results confirmed that chance alone was a very unlikely explanation. Evidence suggests that some overdiagnosis of lung cancer is likely in screened subjects. This is a consistent observation in all other programs of screening for early cancers (breast, prostate, and neuroblastoma).

CONCLUSIONS

Overdiagnosis of cancer cases resulting from the screening process itself will give rise to excess cases of disease, and may, at least in part, explain the observations in the randomized trials.