Advancing Progress in the Development and Implementation of Effective, High-Quality Cancer Screening Proceedings of a Workshop (2021) / Chapter Skim
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Proceedings of a Workshop
Proceedings of a Workshop
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If the precancerous tissue is excised, these screenings can reduce cancer incidence as well as deaths from these cancers. All effective cancer screening tests, including those for breast cancer and lung cancer, can enable earlier detection and thus earlier treatment, thereby increasing the likelihood of better health outcomes.
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Screening tests may also cause physical, psychological, and economic harms by identifying abnormalities that would never become symptomatic or life-threatening -- a challenge referred to as cancer overdiagnosis.2 New technologies and improved understanding of the genesis and progression of various cancers have added to the enthusiasm for potential new strategies to improve screening and early detection of cancer. These strategies may enable a personalized or "precision" approach to cancer screening and apply such innovations as blood and urine tests (referred to as "liquid biopsies")
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These dimensions included factors such as use of evidence-based screening recommendations, informed and shared decision making, high-quality acquisition and interpretation of test results, affordability and accessibility, and appropriate follow-up care for diagnosis and treatment.4 CANCER SCREENING: PAST AND PRESENT "In the past, there was a lot of enthusiasm about cancer screening holding the potential for early detection to save lives. More recently, this has been 3 See https://www.nationalacademies.org/event/03-02-2020/advancing-progress-inthe-development-and-implementation-of-effective-high-quality-cancer-screening-aworkshop (accessed May 30, 2020)
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• Use stage shift as a study endpoint only if it is definitively linked to reduced cancer mortality or morbidity. (Krist)
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• Use prospective, randomized controlled trials as the gold standard for evaluating benefits and harms of new cancer screening tests. (Kramer, Krist, Papadopoulos)
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• Train clinicians in shared decision making and how to use decision aids, and measure whether they are used appropriately and effec tively. (Barry)
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(Miller, Pignone) • Consider what insurance companies can do to improve cancer screening (e.g., supporting clinical studies and the development of decision aids)
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Brawley said that well-designed clinical studies have demonstrated a cancer-specific mortality reduction through mammography screening for breast cancer; stool blood testing, sigmoidoscopy, and colonoscopy screening for colorectal cancer; Pap and visual screening for cervical cancer; and low-dose spiral computed tomography (CT) screening in those who are at high risk for lung cancer.
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The death rate for breast cancer has declined by 40 percent in the United States from 1975 to 2017 (ACS, 2020b) ; experts attribute approximately 40–50 percent of this decline to screening programs, Brawley noted, while the remainder is due to improvements in treatment (Berry et al., 2005)
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The Task Force is expanding its recommendation for colorectal cancer screening to adults aged 45–49 (the recommendation for this age group is grade B See Box 5 for more information on how USPSTF rates the evidence for specific screening recommendations)
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. "A lot of these very high cervical cancer rates are due to not having access to screening and not having the systems in place to take care of the women who have a positive screening test result," she stressed.
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(See Patient Access to Screening and FollowUp Care for more information on the cervical cancer screening, treatment, and prevention program in the Rio Grande Valley.) Lung Cancer Lung cancer screening with low-dose spiral CT can save lives among eople who are at high risk of developing the cancer due to their smoking hisp tory, Brawley said.
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. The PSA blood test has been extensively used to screen healthy men for prostate cancer, but clinical trials have yet to demonstrate the effectiveness of this screening test in reducing all-cause mortality (USPSTF, 2018)
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. Brawley noted that because of the uncertainty of whether PSA screening results in more benefit than harm, the American Urological Association calls for an individualized approach and shared decision making regarding the risks and benefits of testing before it is undertaken, proceeding based on a man's values and preferences.13 Brawley added that these discussions are "why the patient–physician relationship is important [for prostate cancer screening]
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Repeating CA125 blood tests at more frequent intervals than are currently used could potentially lead to more effective ovarian cancer screening, Menon suggested. Overdiagnosis Most cancer screening tests developed in the past few decades have focused on high screening sensitivity15 to enable more detection of life-threatening lesions, which in theory would make the screening beneficial, said Barnett Kramer, former director of Cancer Prevention at the National Cancer Institute (NCI)
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"We need to change the terminology as we learn more about the natural history of the screening-detected lesions. We should be removing the word ‘cancer' from the subset of tumors that we know are very slow growing and likely to be overdiagnosed in order to achieve better informed consent and informed decision making," Kramer said.
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One study found that nearly half of the per-patient reimbursement associated with a lung cancer screening program was related to the evaluation of incidental findings, she noted (Morgan et al., 2017)
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For example, patients are more likely to comply with having a single test on a regular basis than multiple screening tests for different cancers, especially if those other tests are more invasive and inconvenient, such as colonoscopies. In addition, a liquid biopsy is more likely to be accessible than a more involved screening procedure such as mammography, so it can be implemented for more populations and potentially be more cost effective, Papadopoulos said.
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. In addition, germline mutations in nine genes are known to confer greater risk of developing breast cancer, and there are other known genetic mutations that raise the risk of developing cancer in general.
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Esserman described several clinical trials aimed at personalizing breast cancer screening. She is currently leading the Women Informed to Screen Depending on Measures of Risk (WISDOM)
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" (See Box 2 for more information on WISDOM.) Esserman described two other randomized, controlled trials aimed at combining innovative technology with a risk-based strategy to screen women for stage II breast cancer.
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. Prostate Cancer Several workshop speakers called for improving prostate cancer screening beyond the traditional PSA test by adding MRIs, tests for genetic or protein markers for prostate cancer, and by taking age and other risk factors into account.
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group and the Prostate Cancer Prevention Trial group have also developed apps for calculating personalized prostate cancer risk. Albers described several clinical studies focused on refining PSA screening methods and guidelines.
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Ovarian Cancer In an attempt to improve the performance of CA125 for the early detection of ovarian cancer, the UK team have used a longitudinal algorithm called risk of ovarian cancer (ROC) that considers longitudinal changes in CA125 blood levels to trigger more frequent CA125 testing, imaging, or surgery, resulting in a multimodal screening strategy rather than an isolated screening test (Menon et al., 2009)
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Studies indicate that the multimodal screening strategy could potentially be cost effective, depending on the extent of the mortality reduction in the general population (Kearns et al., 2016; Menon et al., 2017; Moss et al., 2018) , although it may only be cost effective in women at high risk of developing ovarian cancer (Naumann and Brown, 2018)
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He described the current state of biomarkers for cancer screening as akin to having "Water, water everywhere and not a drop to drink." Srivastava, Chinnaiyan, and David Ransohoff, professor of medicine at the University of North Carolina at Chapel Hill, provided several reasons for the lack of validated cancer biomarkers despite the extraordinary effort being made in biomarker discovery, as described further below. Problems can occur at any step of the biomarker development and validation process.
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For example, one study that analyzed serum for early detection of ovarian cancer was fatally flawed because the cancer specimens were analyzed using mass spectrometry on a different day than the control specimens, Ransohoff said. Mass spectrometry can drift over time, so the two groups were not truly comparable (Baggerly et al., 2005)
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With EDRN's support, 9 cancer biomarker diagnostic tests have gained approval from the Food and Drug Administration and 13 biomarker assay tests are available in CLIA-certified laborato ries, although none are currently used for screening. a See https://edrn.nci.nih.gov (accessed June 2, 2020)
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Ransohoff described an example of a high-quality validation study that NCI conducted on five ovarian cancer blood tests for which researchers had claimed high sensitivity and high specificity but had yet to be validated. NCI designed a nested case-control study using serial blood samples from the biobank associated with the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO)
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Several speakers discussed the challenges in assessing the clinical value of a screening test, such as multiple types of bias, a nonrepresentative clinical population, insufficient time horizons in which to measure risks and benefits, findings that differ by subpopulation, and conflicting findings. As noted earlier, Brawley said that lead-time bias can contribute to an inappropriate assessment of a screening test because it may appear to increase survival; however, this increase in time can be attributed to the earlier detection of cancer.
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Demonstrating whether there is a benefit to screening can also be compli cated by variability among different populations. For example, breast cancer screening might be more valuable for African American women because they are more likely to develop triple negative breast cancer, which tends not to respond to current breast cancer treatments, Lichtenfeld said.
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USING MODELING TO COMPLEMENT CLINICAL EVALUATION OF SCREENING Modeling Outcomes Etzioni, Rutter, and Mandelblatt showed that modeling can be used to generate data from hypothetical trials, as well as to extend what is learned from traditional clinical trials, to provide information that policy makers can use to make screening recommendations. For example, modeling showed how the differences in study design in the prostate cancer screening trials previously described could lead to such different results, Etzioni said (de Koning et al., 2018)
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Even the societal perspective, which may be best for society overall, may not be best for all participants. Similar to the potential of study duration to affect observed mortality outcomes (see Challenges and Opportunities in Screening Test Development and Validation)
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It varies according to availability of financial resources, screening program goals, needs of the target population, and preference for the balance of benefit to harm. She illustrated this using the following four examples: Example 1: In CISNET analyses of the efficiency of mammography, Mandelblatt said they plotted the gain in life expectancy per 1,000 women screened against the number of lifetime mammograms per 1,000 women (Mandelblatt et al., 2009)
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She noted that CISNET models have been used for determining Medicare coverage, guideline recommendations, and to help construct patient decision aids for shared decision making in the clinic. Example 3: Women who received radiation to the chest as part of their treatment for childhood cancer have a risk of developing breast cancer that is similar to women who carry a mutation in the BRCA1 gene, Mandelblatt said.
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For that reason, he stressed, "We need to hold preventive services to a high bar before recommending them." Krist said the process of determining cancer screening recommendations should be systematic, transparent, and free from conflicts of interest. It should also be based on the evidence of specific health outcomes and should consider both the benefits and harms of the screening, he said.
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primary care pop ulation. It also assesses whether there are enough large studies with consistent findings to provide firm evidence for screening recommendations.
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. Pentz provided one example of a 15-member citizen jury -- balanced for sex, age, and education -- that evaluated the PSA test for prostate cancer screening.
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Thus, patients need to be informed about the potential harms of screening so that they can understand the specific harms and benefits to weigh when making a decision about a particular screening test. Public health ethics also include the principle of reciprocity; that is, any harms should be appropriately compensated, Pentz reported (see Box 5)
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Then clinical ethics principles should apply," she said. When screening is of high benefit and low risk, compliance with e thical principles calls for an organized system of screening with regular patient contact and provisions for appropriate follow-up care, Pentz stressed.
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When the risks and benefits of screening are equal and clinical ethics apply, then shared decision making between patient and clinician becomes critical and patient autonomy comes to the fore, Pentz noted. (For further discussion, see Shared Decision Making in the next section.)
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Public Health Service and medical director at the National Breast and Cervical Cancer Early Detection Program of the Centers for Disease Control and Prevention (CDC) , added that people with low health literacy or numeracy may not understand or may be mis informed by information on screening, due to the level of interpretation that TABLE 1 Phases of Shared Decision Making Phases of Shared Decision Making Definition Bearing Discusses the current health state and how screening fits in; ensures shared understanding of the present situation Pathways Explains both risks and benefits of screening Amplification Gives the patient the opportunity to express their reactions, thoughts, feelings, and to ask questions Declaration Provider makes an explicit screening recommendation Enunciation Patient articulates decision or delegates the decision to the provider Enactment Implements decision or describes next steps Emphasizing the Importance Invites the patient to become involved in the decisionof the Patient's Opinion making process and affirm the patient's opinion SOURCES: Pentz presentation, March 2, 2020; Bomhof-Roordink et al., 2019; Brown et al., 2004.
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Even though shared decision making involves consideration of a patient's values and preferences, Barry said that clinicians often misjudge those values and preferences. He noted a study showing that when physicians discussed with women the choice between a lumpectomy plus radiation versus a mastectomy and included a discussion of breast reconstruction, there was a lot of disagreement between what the physicians thought the patient was most concerned about and what the patients reported being most concerned about.
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. "Patients value different things," he stressed, noting marked differences have been found among various ethnic groups in the factors patients with breast cancer found very important when determining their surgical treatment (see Figure 5)
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80 70 60 50 40 30 % Very Important 20 10 0 Reduced need Keep from To do everything To do what Allowed you to Was least for more surgery worrying possible family wanted feel feminine expensive Importance of Factors in Decision Making White African American Latina Asian FIGURE 5 Proportion of patients with breast cancer indicating which factors were "very important" in their surgical treatment decision making, by race/ethnicity. SOURCES: Jimbo presentation, March 3, 2020; Hawley and Morris, 2017.
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" he asked. To facilitate communication while also reducing time pressures, Pignone said that practitioners can deliver screening information and decision aids to patients before or after an office visit, or irrespective of an office visit, but few studies have assessed which option works best.
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For example, when Kaiser Permanente Washington introduced decision aids for hip and knee arthroplasty in 2009, they saw a substantial decrease in patients electing to have knee and hip replacements in their well-educated and perhaps overtreated population, Barry said. But when those same decision aids were used with African American patients being treated in Veterans Health Administration clinics in the Philadelphia area, the number of knee replacements increased (Arterburn et al., 2012; Ibrahim et al., 2013, 2017)
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"Don't give people information that is not relevant to them, and don't make it so complicated that the implementation of the decision aid becomes too challenging or even impossible," Pignone said. Barry said he has found that decision aids have the most influence on patients who are undecided about a particular intervention.
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She added that clinicians work in teams with processes that can help or hinder the efficiency and effectiveness of obtaining follow-up care, depending on how they are organized. A sizable proportion of patients do not receive follow-up care after receiving abnormal findings from a screening test for breast, colorectal, or cervical cancer, Geiger said (Tosteson et al., 2016)
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She described another study that found that the percent of patients who obtained a followup colonoscopy within 12 months after receiving an abnormal colorectal cancer screening result varied from 58 to 84 percent depending on which of four different health care systems the patient attended, even though all four systems were strongly committed to screening (Chubak et al., 2016)
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BOX 6 Cervical Cancer Screening and Follow-Up Program at the MD Anderson Cancer Center Schmeler reported on the MD Anderson Cancer Center's cer vical cancer screening and follow-up program in the Rio Grande Valley, which is a rural area along the Texas–Mexico border. This population is 90 percent Hispanic, with many uninsured and undocumented individuals living in the area.
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To further improve the program, the MD Anderson Cancer Center researchers are trying to develop new technologies to make screening, diagnosis, and treatment more streamlined so fewer clinic visits are needed. Currently in the United States, cervical cancer prevention may entail three clinic visits.
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Research, Development, and Clinical Testing of Screening Technology Research and Development Krist stressed the necessity for greater awareness of what is needed for each step in the development and validation of cancer screening tests. "We need to think of this as a whole life cycle and not get stuck in one of its boxes -- there is no free ride at any step of this," he said.
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Kramer also pointed out that active surveillance -- which is offered to some patients with early-stage prostate cancer, Barrett's esophagus, and melanoma -- could be informative of the natural history of indolent lesions. In addition, he suggested the need for better animal models of tumor progression to gain insights into the early steps of tumor initiation and progression.
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Kramer and Krist cautioned that RCTs should remain as the gold standard for evaluating the benefits and harms of any new cancer screening test or strategy. Even the abundant real-world clinical data available from observational studies may not provide the reliable information about screening effects on cancer outcomes that are needed to make informed decisions, Kramer said.
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"It's very misleading and leads people to think there is benefit when there may be no benefit at all," Kramer said. Krist said that conducting RCTs of cancer screening tests can be challenging because participants in the control groups may end up getting screened on their own, but he added that "I don't think we can get out of having some element of RCT data." Kramer said exceptions may occur, such as in the case of cervical cancer screening, where screening was clearly proven to be of benefit years before a randomized trial showed the benefit, and "all the stars were aligned." However, he stressed that such situations are rare.
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Durado Brooks, vice president of cancer control interventions at the American Cancer Society, emphasized the critical need to include more minorities in screening studies and to conduct subpopulation analyses. For example, he stressed the importance of understanding the effectiveness and balance of benefits and harms of PSA testing in African American men and in men with a family history of prostate cancer.
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Pentz emphasized the need for research on best practices for shared decision making for screening. Kramer also stressed the need for de-implementation of cancer screening in certain circumstances, such as in older adult populations for whom the benefits do not outweigh the risks, stating: "The science of implementation is hard, but the science of de-implementation is different and even harder." Krist also noted the behavioral economics principle of the sunk cost fallacy.
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Schmeler said systems are needed not only to make sure patients are screened but to also ensure that patients with abnormal screening results receive the appropriate follow-up care for diagnosis and treatment. Stressing that screening impact is diminished when follow-up appointments are not conducted in a timely fashion, Gieger said studies have shown that patient navigators, reminders, and performance data for clinicians can all improve timely follow-up in asymptomatic adults with positive fecal blood test results (Selby et al., 2017)
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To improve the quality of cancer screening, Brawley said there may be a benefit to create specialty screening centers where patients could be directed, similar to the designated specialty centers that exist for pelvic surgery and cardiovascular surgery. Albers noted that his study of prostate cancer screening identified substantial variation in pathology evaluation of biopsies and in the interpretation of MRI images.
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That can be removed from a visit if we can provide a free decision aid prior to or after the visit via a patient portal." Esserman pointed out that clinicians welcomed the WISDOM study's virtual provision of screening information to patients. "Ninety-eight percent of physicians were saying ‘please have the discussion about breast cancer risk reduction because we don't have time and we are not experts at it,'" she said.
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Miller noted that to improve screening, health care organizations do not have to develop new systems from scratch but rather can build on systems already in place, such as telehealth, community health clinics, electronic health records, as well as cancer screening programs supported by CDC. She said CDC has been successfully integrating evidence-based interventions into its colorectal and breast cancer screening programs.
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Kramer stressed the necessity for educating both patients and clinicians about cancer overdiagnosis due to screening and changing the terminology of indolent tumors and other low-risk screen-detected lesions. "In order to achieve better informed consent and informed decision making, we should remove the word ‘cancer' from the subset of tumors and lesions that are very slow growing and likely to be overdiagnosed," Kramer said.
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"The initial screening test and all subsequent follow-up care should be covered by the same copay," he said. Lichtenfeld suggested more insurance coverage for the time that pri mary care clinicians spend communicating about cancer screening with their patients, noting that Medicare has made some changes over the past year to reimburse clinicians for engaging in shared decision making.
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She said there were many opportunities for improving the effectiveness of screening at the level of the individual, clinician, and organization, as well as opportunities to improve screening tests through increasing scientific knowledge and technology development. Dowling said there are no easy solutions but she identified several topics discussed during the workshop that are key to ensuring that effective screening tests are developed and implemented to enable better patient outcomes: • Improving understanding of the natural history of cancer • Strengthening the scientific rigor in the development and validation of potential cancer biomarkers by improving the understanding of early stage disease, ensuring appropriate incentives for research, and engaging
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2020a. American Cancer Society recommendations for the early detection of breast cancer.
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2015. Responses to a decision aid on prostate cancer screening in primary care practices.
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2004. Genetic testing for breast and ovarian cancer susceptibility: Evaluating direct-to-consumer marketing -- Atlanta, Denver, Raleigh-Durham, and Seattle, 2003.
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2020. Comparison of abbreviated breast MRI vs digital breast tomosynthesis for breast cancer detection among women with dense breasts undergoing screening.
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2009. Rethinking screening for breast cancer and prostate cancer.
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2010. Development of instruments to measure the quality of breast cancer treatment decisions.
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2018. Effect of a low-intensity psa-based screening intervention on prostate cancer mortality: The cap randomized clinical trial.
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2016. Involving a citizens' jury in decisions on individual screening for prostate cancer.
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. Single routine offer of a blood test for prostate cancer did not save lives.
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2016. Urine TMPRSS2:ERG plus PCA3 for individualized prostate cancer risk assessment.
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2018. Screening for prostate cancer: U.S.
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2019. Clinical outcomes and cost effectiveness of breast cancer screening for childhood cancer survivors treated with chest radiation: A comparative modeling study.
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