Cancer screening

Cancer Risk in Beckwith-Wiedemann Syndrome: A Systematic Review and Meta-Analysis Outlining a Novel (Epi)Genotype Specific Histotype Targeted Screening Protocol

OBJECTIVE

To compare tumor risk in the 4 Beckwith-Wiedemann syndrome (BWS) molecular subgroups: Imprinting Control Region 1 Gain of Methylation (ICR1-GoM), Imprinting Control Region 2 Loss of Methylation (ICR2-LoM), Chromosome 11p15 Paternal Uniparental Disomy (UPD), and Cyclin-Dependent Kinase Inhibitor 1C gene (CDKN1C) mutation.

STUDY DESIGN

Studies on BWS and tumor development published between 2000 and 2015 providing (epi)genotype-cancer correlations with histotype data were reviewed and meta-analysed with cancer histotypes as measured outcome and (epi)genotype as exposure.

RESULTS

A total of 1370 patients with BWS were included: 102 developed neoplasms (7.4%). Tumor prevalence was 2.5% in ICR2-LoM, 13.8% in UPD, 22.8% in ICR1-GoM, and 8.6% in patients with CDKN1C mutations. Cancer ORs were 12.8 in ICR1-GoM, 6.5 in UPD, and 2.9 in patients with CDKN1C mutations compared with patients with ICR2-LoM. Wilms tumor was associated with ICR1-GoM (OR 68.3) and UPD (OR 13.2). UPD also was associated with hepatoblastoma (OR 5.2) and adrenal carcinoma (OR 7.0), and CDKN1C mutations with neuroblastic tumors (OR 7.2).

CONCLUSION

Cancer screening in BWS could be differentiated on the basis of (epi)genotype and target specific histotypes. Patients with ICR1-GoM and UPD should undergo renal ultrasonography scanning, given their risk of Wilms tumor. Alpha feto protein monitoring for heptaoblastoma is suggested in patients with UPD. Adrenal carcinoma may deserve screening in patients with UPD. Patients with CDKN1C mutations may deserve neuroblastoma screening based on urinary markers and ultrasonography scanning. Finally, screening appears questionable in cases of ICR2-LoM, given low tumor risk.

The impact of routine surveillance screening with magnetic resonance imaging (MRI) to detect tumour recurrence in children with central nervous system (CNS) tumours: protocol for a systematic review and meta-analysis

BACKGROUND

The aim of this study is to assess the impact of routine MRI surveillance to detect tumour recurrence in children with no new neurological signs or symptoms compared with alternative follow-up practices, including periodic clinical and physical examinations and the use of non-routine imaging upon presentation with disease signs or symptoms.

METHODS

Standard systematic review methods aimed at minimising bias will be employed for study identification, selection and data extraction. Ten electronic databases have been searched, and further citation searching and reference checking will be employed. Randomised and non-randomised controlled trials assessing the impact of routine surveillance MRI to detect tumour recurrence in children with no new neurological signs or symptoms compared to alternative follow-up schedules including imaging upon presentation with disease signs or symptoms will be included. The primary outcome is time to change in therapeutic intervention. Secondary outcomes include overall survival, surrogate survival outcomes, response rates, diagnostic yield per set of images, adverse events, quality of survival and validated measures of family psychological functioning and anxiety. Two reviewers will independently screen and select studies for inclusion. Quality assessment will be undertaken using the Cochrane Collaboration's tools for assessing risk of bias. Where possible, data will be summarised using combined estimates of effect for time to treatment change, survival outcomes and response rates using assumption-free methods. Further sub-group analyses and meta-regression models will be specified and undertaken to explore potential sources of heterogeneity between studies within each tumour type if necessary.

DISCUSSION

Assessment of the impact of surveillance imaging in children with CNS tumours is methodologically complex. The evidence base is likely to be heterogeneous in terms of imaging protocols, definitions of radiological response and diagnostic accuracy of tumour recurrence due to changes in imaging technology over time. Furthermore, the delineation of tumour recurrence from either pseudo-progression or radiation necrosis after radiotherapy is potentially problematic and linked to the timing of follow-up assessments. However, given the current routine practice of MRI surveillance in the follow-up of children with CNS tumours in the UK and the resource implications, it is important to evaluate the cost-benefit profile of this practice.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016036802.

Expectations and values about expanded newborn screening: a public engagement study

OBJECTIVES

Newborn bloodspot screening (NBS) panels have expanded to include conditions for which treatment effects are less certain, creating debate about population-based screening criteria. We investigated Canadian public expectations and values regarding the types of conditions that should be included in NBS and whether parents should provide consent.

METHODS

Eight focus groups (FG; n = 60) included education, deliberative discussion and pre-/post-questionnaires. Data were analysed quantitatively and qualitatively.

RESULTS

Quantitatively, the majority supported NBS for serious disorders for which treatment is not available (95-98, 82%). A majority endorsed screening without explicit consent (77-88%) for treatable disorders, but 62% supported unpressured choice for screening for untreatable disorders. Qualitatively, participants valued treatment-related benefits for infants and informational benefits for families. Concern for anxiety, stigma and unwanted knowledge depended upon disease context and strength of countervailing benefits.

CONCLUSIONS

Anticipated benefits of expanded infant screening were prioritized over harms, with information provision perceived as a mechanism for mitigating harms and enabling choice. However, we urge caution around the potential for public enthusiasm to foster unlimited uptake of infant screening technologies.

Potential of computer-aided diagnosis to improve CT lung cancer screening

The development of low-dose spiral computed tomography (CT) has rekindled hope that effective lung cancer screening might yet be found. Screening is justified when there is evidence that it will extend lives at reasonable cost and acceptable levels of risk. A screening test should detect all extant cancers while avoiding unnecessary workups. Thus optimal screening modalities have both high sensitivity and specificity. Due to the present state of technology, radiologists must opt to increase sensitivity and rely on follow-up diagnostic procedures to rule out the incurred false positives. There is evidence in published reports that computer-aided diagnosis technology may help radiologists alter the benefit-cost calculus of CT sensitivity and specificity in lung cancer screening protocols. This review will provide insight into the current discussion of the effectiveness of lung cancer screening and assesses the potential of state-of-the-art computer-aided design developments.

Principles of cancer screening: lessons from history and study design issues

Early detection of cancer has held great promise and intuitive appeal in the medical community for well over a century. Its history developed in tandem with that of the periodic health examination, in which any deviations--subtle or glaring--from a clearly demarcated "normal" were to be rooted out, given the underlying hypothesis that diseases develop along progressive linear paths of increasing abnormalities. This model of disease development drove the logical deduction that early detection, by "breaking the chain" of cancer development, must be of benefit to affected individuals. In the latter half of the 20th century, researchers and guidelines organizations began to explicitly challenge the core assumptions underpinning many clinical practices. A move away from intuitive thinking began with the development of evidence-based medicine. One key method developed to explicitly quantify the overall risk-benefit profile of a given procedure was the analytic framework. The shift away from pure deductive reasoning and reliance on personal observation was driven, in part, by a rising awareness of critical biases in cancer screening that can mislead clinicians, including healthy volunteer bias, length-biased sampling, lead-time bias, and overdiagnosis. A new focus on the net balance of both benefits and harms when determining the overall worth of an intervention also arose: it was recognized that the potential downsides of early detection were frequently overlooked or discounted because screening is performed on basically healthy persons and initially involves relatively noninvasive methods. Although still inconsistently applied to early detection programs, policies, and belief systems in the United States, an evidence-based approach is essential to counteract the misleading--even potentially harmful--allure of intuition and individual observation.

Cancer screening: the clash of science and intuition

The concept of early detection of cancer holds great promise and intuitive appeal. However, powerful biases can mislead clinicians when evaluating the efficacy of screening tests by clinical observation alone. Selection bias, lead-time bias, length-biased sampling, and overdiagnosis are counterintuitive concepts with critical implications for early-detection efforts. This article explains these biases and other common confounders in cancer screening. The most direct and reliable way to avoid being led astray by intuitions is through the use of randomized controlled trials.

Cancer Screening in Theory and in Practice

Improvements in technology have led to a number of tests that can be used to suggest that a patient has a cancer. Advances in cancer biology and medical imaging have led to a number of cancer screening tests. Cancer screening is commonly advocated, but its complexity is often lost in guidelines that have sound-bite quality. It is commonly viewed as of no harm, when in fact there are harms associated with every known screening test. Indeed, many screening experts believe a screening test should only be used when the potential for benefit clearly outweighs the potential for harm.

Cancer screening principles are classically within the realm of the epidemiologist. As more screening tests are developed, these principles have become more relevant to the practicing clinician. What is known and what is unknown about screening is distinctly different from what is believed by the public and many practicing clinicians.

Many tests have both screening and diagnostic uses, and it is only the context in which these are used that determines whether they are screening or diagnostic. A screening test is done on asymptomatic individuals who receive the test principally because they are of the age or sex at risk for the cancer. A diagnostic test is done on an individual because of clinical suspicion of disease.

Screening for cancer: Valuable or not?

Screening for cancer has become extremely common. The evidence supporting screening for breast, colon, and cervix cancer is strong, but it is unclear for skin cancer, problematic for prostate cancer, and ineffective for lung cancer. Despite the problems associated with many screening approaches for cancer, enthusiasm by the medical profession and the public remains high. The objective analysis for the major tumor types is presented in this review, but the ultimate decision on whether to be screened lies in the personal and societal arena of values.

Prostate cancer screening: Clinical applications and challenges☆

Prostate cancer is a serious illness warranting appropriate screening measures. However, current screening tests that include prostate-specific antigen and digital rectal examination must be proven to save lives to be considered truly legitimate and appropriate public health tools. Even though these tests are associated with the diagnosis of disease, important questions remain as to how well these tests identify all disease and whether screening leads to interventions that save lives. Prostate cancer is undoubtedly a killer, yet there appear to be large numbers of detectable prostate cancers that are of little threat to life. Some men with this grade of cancer receive curative treatment, even though their disease does not require treatment. Some studies suggest that more than three of four men with screen-detected localized disease may not need treatment. One of the great challenges of cancer communications is how to convey the hope of prostate cancer screening while adequately acknowledging the boundaries of our knowledge. The current absence of an appropriate informed consent tool points to the necessity to develop an easy to understand informed consent that allows men to evaluate screening decisions with a clear understanding of what is known, what is not known, and what is believed to be true about prostate cancer screening.

Diagnosing tests: using and misusing diagnostic and screening tests

Tests can be used either diagnostically (i.e., to confirm or rule out the presence of a condition in people suspected of having it) or as a screening instrument (determining who in a large group of people has the condition and often when those people are unaware of it or unwilling to admit to it). Tests that may be useful and accurate for diagnosis may actually do more harm than good when used as a screening instrument. The reason is that the proportion of false negatives may be high when the prevalence is high, and the proportion of false positives tends to be high when the prevalence of the condition is low (the usual situation with screening tests). My first aim of this article is to discuss the effects of the base rate, or prevalence, of a disorder on the accuracy of test results. My second aim is to review some of the many diagnostic efficiency statistics that can be derived from a 2 x 2 table, including the overall correct classification rate, kappa, phi, the odds ratio, positive and negative predictive power and some variants of them, and likelihood ratios. In the last part of this article, I review the recent Standards for Reporting of Diagnostic Accuracy guidelines (Bossuyt et al., 2003) for reporting the results of diagnostic tests and extend them to cover the types of tests used by psychologists.

Cancer screening

Cancer screening is a complicated science. Each screening intervention must be carefully assessed before it is widely implemented. A screening test can falsely appear useful as it finds disease at an early stage and leads to intervention and cure. Such a test can be harmful to the population screened if it commonly finds disease that fulfills the pathologic criteria of cancer but behaves indolently (meaning it would never harm the host). Such "pseudo-disease" or "overdiagnosed disease" has been demonstrated in many malignancies including cancers of the lung, breast, and especially the prostate. The nature of each specific screening test and each disease is such that some screened patients may receive unnecessary treatment with all its complications and risk. Alternatively, some screening technologies have been proven useful providing net benefit to the population screened. Often these beneficial technologies are underused. These screening technologies if widely implemented have the potential of saving countless lives. Many available screening tests have tremendous potential in terms of benefit, but have yet to be fully assessed. At the minimum, patients should be informed of what is known, what is not known, and what is believed about these tests.

Screening for family members of patients with nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is well known for its peculiarly skewed distribution with highest incidence in Southern Chinese population. Familial aggregation is evident, hence screening for early detection is offered by oncology centers in Hong Kong to first-degree relatives of patients with NPC. During the period 1994-2001, 929 family members were screened in our center. The screenees were advised to attend an annual examination that includes serological test against Epstein Barr Virus (EBV), physical examination to exclude cervical lymphadenopathy and cranial nerve palsy, and endoscopic examination of the nasopharyngeal region. Two different methods were used for the serology test: indirect immuno-fluorescent (IF) test for IgA against viral capsid antigen; and starting in 1997 enzyme-linked immunosorbent assay (ELIZA) against nuclear antigen and viral capsid antigen. Twelve cases of nasopharyngeal carcinoma were diagnosed, giving a detection rate of 5/1,155 (433/100,000) person-year for male and 7/1,404 (499/100,000) person-year for female participants observed. The corresponding average annual incidence in Hong Kong during this period was 24.1 and 9.6 per 100,000, respectively. Forty-one percent of these detected cases had Stage I disease, whereas only 2% of patients referred to the department for primary treatment presented with such early disease. Six cases were detected at first visit, and all were EBV-positive. Another 78 screenees with positive serology at first visit were followed up for 204 person years, and thus far NPC was detected in 3 after an interval of 6-32 months. Of the 845 initially EBV-negative screenees followed up for 2,337 person-years, NPC was detected in 3 after an interval of 12-45 months. One showed sero-conversion at the time of diagnosis. We conclude that family members of known patients do show a substantially higher risk of developing NPC, and regular screening by current method improves the chance of early detection.

DNA methylation as a cancer-specific biomarker: from molecules to populations

Cancer contributes to a large proportion of the mortality and morbidity in the United States and worldwide. Despite advances in diagnosis and treatment of various cancers, early detection and treatment of cancer remain a challenge. Diagnosis of cancer often occurs once the disease has progressed to a point where currently available intervention options provide limited success. Therefore, techniques that enable early detection followed by targeted interventions would influence stage at diagnosis and, in turn, mortality associated with cancer. Identification of molecular biomarkers, especially those that are associated with cancer initiation and progression, shows promise as an effective strategy in this regard. One potential early detection biomarker is DNA methylation of the promoter region of certain cancer-associated genes, which results in gene inactivation. Examination of serum for circulating tumor DNA with abnormal methylation patterns offers a possible method for early detection of several cancers and serves as a point for early intervention and prevention strategies. Additionally, it is imperative to consider how such a screening mechanism can be implemented in populations at risk, especially in resource-poor settings. Thus, the challenge is to validate DNA methylation as a cancer-specific biomarker, with the ultimate goal of designing a research plan that integrates the current knowledge base regarding cancer detection and diagnosis into specific prevention and intervention strategies that can be applied at a population level.

Mismatch repair genes and microsatellite instability as molecular markers for gynecological cancer detection

Due to major developments in genetics over the past decade, molecular biology tests are serving promising tools in early diagnosis and follow-up of cancer patients. Recent epidemiological studies revealed that the risk for each individual to develop cancer is closely linked to his/her own genetic potentialities. Some populations that are defective in DNA repair processes, for example in Xeroderma pigmentosum or in the Lynch syndrome, are particularly prone to cancer due to the accumulation of mutations within the genome. Such populations would benefit from the development of tests aimed at identifying people who are particularly at risk. Here, we review some data suggesting that the inactivation of mismatch repair is often found in endometrial cancer and we discuss molecular-based strategies that would help to identify the affected individuals in families with cases of glandular malignancies.

Value of surveillance imaging in the management of medulloblastoma

BACKGROUND

To investigate the value of surveillance scanning for the detection of recurrences in medulloblastoma.

PROCEDURE

The charts of 95 patients with medulloblastoma were retrospectively reviewed. Information regarding the patient characteristics, treatment modalities, dates, types and results of CT and MRI studies, the frequency with which recurrences were identified on surveillance images, changes in patient management, outcome of the patients following recurrences, and survival data were analyzed.

RESULTS

Thirty-one patients had a recurrence of tumor in the central nervous system; none experienced extraneural relapses. Of all recurrences, 21 were symptomatic and 10 were discovered by surveillance scans asymptomatically. None of the patients with a recurrence survived. For all 95 patients, 5-year overall and event-free survival rates were 47.1 and 49.8%, respectively. In patients with symptomatic and asymptomatic recurrences, the mean time to recurrence since initial diagnosis, the mean duration of survival post-recurrence, and the mean duration of overall follow-up were 19.2 and 26.1 months, 3.6 and 8.0 months, and 22.8 and 34.1 months, respectively. For 95 patients, 468 surveillance and 38 symptomatic images were reviewed as 313 CTs and 193 MRIs. Rate of diagnosis of recurrence per surveillance image was 2.1% (10/468).

CONCLUSIONS

In our study, surveillance scanning brought no survival advantage since it detected a minority of recurrences. Longer survival achieved by early detection of recurrences might be a reflection of lead-time and length biases. Surveillance procedures will gain more importance as new effective therapeutic options are developed for recurrent medulloblastoma.