|Purpose||detection of cancer prior to onset of symptoms (via several tests/imaging)|
Cancer screening aims to detect cancer before symptoms appear.This may involve blood tests, urine tests, DNA tests other tests, or medical imaging. The benefits of screening in terms of cancer prevention, early detection and subsequent treatment must be weighed against any harms.
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans.
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a cholesterol test, are often grouped together into one test panel called a blood panel or blood work. Blood tests are often used in health care to determine physiological and biochemical states, such as disease, mineral content, pharmaceutical drug effectiveness, and organ function. Typical clinical blood panels include a basic metabolic panel or a complete blood count. Blood tests are also used in drug tests to detect drug abuse. In some of the United States, a blood test is required before marriage.
Medical imaging is the technique and process of creating visual representations of the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease. Medical imaging also establishes a database of normal anatomy and physiology to make it possible to identify abnormalities. Although imaging of removed organs and tissues can be performed for medical reasons, such procedures are usually considered part of pathology instead of medical imaging.
Universal screening, also known as mass screening or population screening, involves screening everyone, usually within a specific age group.Selective screening identifies people who are known to be at higher risk of developing cancer, such as people with a family history of cancer.
Screening can lead to false positive results and subsequent invasive procedures.Screening can also lead to false negative results, where an existing cancer is missed. Controversy arises when it is not clear if the benefits of screening outweigh the risks of the screening procedure itself, and any follow-up diagnostic tests and treatments.
Screening tests must be effective, safe, well-tolerated with acceptably low rates of false positive and false negative results. If signs of cancer are detected, more definitive and invasive follow-up tests are performed to reach a diagnosis. Screening for cancer can lead to cancer prevention and earlier diagnosis. Early diagnosis may lead to higher rates of successful treatment and extended life. However, it may also falsely appear to increase the time to death through lead time bias or length time bias.
In statistical hypothesis testing, a type I error is the rejection of a true null hypothesis, while a type II error is the failure to reject a false null hypothesis. More simply stated, a type I error is falsely inferring the existence or reality of something that is in fact not real or does not in fact exist, while a type II error is to falsely infer the absence or non-existence of something that is real or does exist. Much of statistical theory revolves around the minimization of one or both of these errors, though the complete elimination of either is treated as a statistical impossibility.
Lead time is the length of time between the detection of a disease and its usual clinical presentation and diagnosis. It is the time between early diagnosis with screening and the time in which diagnosis would have been made without screening. It is an important factor when evaluating the effectiveness of a specific test.
Length time bias is a form of selection bias, a statistical distortion of results that can lead to incorrect conclusions about the data. Length time bias can occur when the lengths of intervals are analysed by selecting intervals that occupy randomly chosen points in time or space.That process favors longer intervals and so skews the data.
The goal of cancer screening is to provide useful health information which can guide medical treatment. [ medical citation needed ] A good cancer screening is one which would detect when a person has cancer so that the person could seek treatment to protect their health. Good cancer screening would not be more likely to cause harm than to provide useful information. In general, cancer screening has risks and should not be done except with a medical indication.
In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosis is a particular [medical] condition while an indication is a reason for use. The opposite of an indication is a contraindication, a reason to withhold a certain medical treatment because the risks of treatment clearly outweigh the benefits.
Different kinds of cancer screening procedures have different risks, but good tests share some characteristics.If a test detects cancer, then that test result should also lead to options for treatment. Good tests come with a patient explanation of why that person has high enough risk of cancer to justify the test. Part of the testing experience is for the health care provider to explain how common false positive results are so that the patient can understand the context of their results. If multiple tests are available, then any test should be presented along with other options.
Screening for cancer is controversial in cases when it is not yet known if the test actually saves lives.Screening can lead to substantial false positive result and subsequent invasive procedures. The controversy arises when it is not clear if the benefits of screening outweigh the risks of follow-up diagnostic tests and cancer treatments. Cancer screening is not indicated unless life expectancy is greater than five years and the benefit is uncertain over the age of 70.
Several factors are considered to determine whether the benefits of screening outweigh the risks and the costs of screening.These factors include:
Breast cancer screening is the medical screening of asymptomatic, apparently healthy women for breast cancer in an attempt to achieve an earlier diagnosis. The assumption is that early detection will improve outcomes. A number of screening tests have been employed, including clinical and self breast exams, mammography, genetic screening, ultrasound, and magnetic resonance imaging. The use of mammography in universal screening for breast cancer is controversial as it may not reduce all-cause mortality and for causing harms through unnecessary treatments and medical procedures. Many national organizations recommend it for most older women.
Cervical screening by the Pap test or other methods is highly effective at detecting and preventing cervical cancer, although there is a serious risk of overtreatment in young women up to the age of 20 or beyond, who are prone to have many abnormal cells which clear up naturally.There is a considerable range in the recommended age at which to begin screening around the world. According to the 2010 European guidelines for cervical cancer screening, the age at which to commence screening ranges between 20–30 years of age, "but preferentially not before age 25 or 30 years", depending on the burden of the disease in the population and the available resources.
In the United States the rate of cervical cancer is 0.1% among women under 20 years of age, so the American Cancer Society as well as the American College of Obstetricians and Gynecologists strongly recommend that screening begin at age 21, regardless of age at sexual initiation or other risk-related behaviors.For healthy women aged 21–29 who have never had an abnormal Pap smear, cervical cancer screening with cervical cytology (Pap smear) should occur every 3 years, regardless of HPV vaccination status. The preferred screening for women aged 30–65 is "co-testing", which includes a combination of cervical cytology screening and HPV testing, every 5 years. However, it is acceptable to screen this age group with a Pap smear alone every 3 years. In women over the age of 65, screening for cervical cancer may be discontinued in the absence of abnormal screening results within the prior 10 years and no history of CIN 2 or higher.
Screening for colorectal cancer, if done early enough, is preventive because almost allcolorectal cancers originate from benign growths called polyps, which can be located and removed during a colonoscopy (see colonic polypectomy ).
The US Preventive Services Task Force recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy, in adults, beginning at age 50 years and continuing until age 75 years. years screening is not recommended. A new enzyme method for colorectal cancer screening is the M2-PK Test, which is able to detect bleeding and non-bleeding colorectal cancers and polyps. In 2008, Kaiser Permanente Colorado implemented a program that used automated calls and sends fecal immunochemical test kits to patients who are overdue for colorectal cancer screenings. The program has increased the proportion of all eligible members screened by 25 percent. DNA testing with Cologuard test has been FDA-approved.For people over 75 or those with a life expectancy of less than 10
In England, adults are screened biennially via faecal occult blood testing between the ages of 60 and 74 years.
When screening for prostate cancer, the PSA test may detect small cancers that would never become life-threatening, but once detected will lead to treatment. This situation, called overdiagnosis, puts men at risk for complications from unnecessary treatment such as surgery or radiation. Follow up procedures used to diagnose prostate cancer (prostate biopsy) may cause side effects, including bleeding and infection. Prostate cancer treatment may cause incontinence (inability to control urine flow) and erectile dysfunction (erections inadequate for intercourse).As a result, in 2012, the U.S. Preventative Services Task Force (USPSTF) recommended against prostate-specific antigen (PSA) based screening for prostate cancer finding, "there is a very small potential benefit and significant potential harms" and concluding, "while everyone wants to help prevent deaths from prostate cancer, current methods of PSA screening and treatment of screen-detected cancer are not the answer."
More recently, Fenton's 2018 review(conducted for the USPSTF) focused on the two highest quality randomized control studies of the costs and benefits of PSA screening, and the findings illustrate the complex issues associated with cancer screening. Fenton reports that the screening of 1,000 men every four years for 13 years reduces mortality from prostate cancer by just one. More specifically, of those 1,000 men: 243 received an indication of cancer during PSA screening (most of whom then had a biopsy); of those, 3 had to be hospitalized for biopsy complications; 35 were diagnosed with prostate cancer (and thus the false alarm rate from the original PSA screening was >85%); of those 35, 3 avoided metastatic prostate cancer and 1 avoided death by prostate cancer while 9 developed impotence or urinary incontinence due to their treatment and 5 died due to prostate cancer despite being treated. In their 2018 recommendations, the USPSTF estimates that 20%-50% of men diagnosed with prostate cancer following a positive PSA screening have cancer that, even if not treated, would never grow, spread, or harm them
Most North American medical groups recommend individualized decisions about screening, taking into consideration the risks, benefits, and the patients' personal preferences.
Screening studies for lung cancer have only been done in high risk populations, such as smokers and workers with occupational exposure to certain substances.In the 2010s recommendations by medical authorities are turning in favour of lung cancer screening, which is likely to become more widely available in the advanced economies.
In December 2013 the U.S. Preventative Services Task Force (USPSTF) changed its long-standing recommendation that there is insufficient evidence to recommend for or against screening for lung cancer to the following: "The USPSTF recommends annual screening for lung cancer with low-dose computed tomography in adults ages 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery".
Early detection of pancreatic cancer biomarkers was accomplished using SERS-based immunoassay approach.A SERS-base multiplex proteinbiomarker detection platform in a microfluidic chip to detect is used to detect several protein biomarkers to predict the type of disease and critical biomarkers and increase the chance of diagnosis between diseases with similar biomarkers (PC, OVC, and pancreatitis). It is generally agreed that general screening of large groups for pancreatic cancer is not at present likely to be effective, and outside clinical trials there are no programmes for this. The European Society for Medical Oncology recommends regular screening with endoscopic ultrasound and MRI/CT imaging for those at high risk from inherited genetics, in line with other recommendations, which may also include CT.
The US Preventive Services Task Force (USPSTF) in 2013 found that evidence was insufficient to determine the balance of benefits and harms of screening for oral cancer in adults without symptoms by primary care providers.The American Academy of Family Physicians comes to similar conclusions while the American Cancer Society recommends that adults over 20 years who have periodic health examinations should have the oral cavity examined for cancer. The American Dental Association recommends that providers remain alert for signs of cancer during routine examinations. Oral cancer screening is also recommended by some groups of dental hygienists.
There is insufficient evidence to recommend for or against screening for skin cancer,and bladder cancer. Routine screening is not recommended for testicular cancer, and ovarian cancer.
Full body CT scans are available for cancer screening, but this type of medical imaging to search for cancer in people without clear symptoms can create problems such as increased exposure to ionizing radiation. However, magnetic resonance imaging (MRI) scans are not associated with a radiation risk, and MRI scans are being evaluated for their use in cancer screening. [ citation needed ]There is a significant risk of detection of what has been called incidentalomas - benign lesions that may be interpreted as a cancer and be subjected to potentially dangerous investigations.
The Papanicolaou test is a method of cervical screening used to detect potentially precancerous and cancerous processes in the cervix. Abnormal findings are often followed up by more sensitive diagnostic procedures and if warranted, interventions that aim to prevent progression to cervical cancer. The test was independently invented by Dr. Georgios Papanikolaou and Dr. Aurel Babeș and named after Papanikolaou.
Prostate cancer is the development of cancer in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, some grow relatively quickly. The cancer cells may spread from the prostate to other areas of the body, particularly the bones and lymph nodes. It may initially cause no symptoms. In later stages, it can lead to difficulty urinating, blood in the urine or pain in the pelvis, back, or when urinating. A disease known as benign prostatic hyperplasia may produce similar symptoms. Other late symptoms may include feeling tired due to low levels of red blood cells.
Colorectal cancer (CRC), also known as bowel cancer and colon cancer, is the development of cancer from the colon or rectum. A cancer is the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, and feeling tired all the time.
Mammography is the process of using low-energy X-rays to examine the human breast for diagnosis and screening. The goal of mammography is the early detection of breast cancer, typically through detection of characteristic masses or microcalcifications.
rectal examination, commonly called a prostate exam, is an internal examination of the rectum, performed by a healthcare provider.
Fecal occult blood (FOB) refers to blood in the feces that is not visibly apparent. A fecal occult blood test (FOBT) checks for hidden (occult) blood in the stool (feces).
Screening, in medicine, is a strategy used in a population to identify the possible presence of an as-yet-undiagnosed disease in individuals without signs or symptoms. This can include individuals with pre-symptomatic or unrecognized symptomatic disease. As such, screening tests are somewhat unusual in that they are performed on persons apparently in good health.
Overdiagnosis is the diagnosis of "disease" that will never cause symptoms or death during a patient's ordinarily expected lifetime. Overdiagnosis is a side effect of screening for early forms of disease. Although screening saves lives in some cases, in others it may turn people into patients unnecessarily and may lead to treatments that do no good and perhaps do harm. Given the tremendous variability that is normal in biology, it is inherent that the more one screens, the more incidental findings will generally be found. For a large percentage of them, the most appropriate medical response is to recognize them as something that does not require intervention; but determining which action a particular finding warrants can be very difficult, whether because the differential diagnosis is uncertain or because the risk ratio is uncertain.
Prostate cancer screening is the screening process used to detect undiagnosed prostate cancer in those without signs or symptoms. When abnormal prostate tissue or cancer is found early, it may be easier to treat and cure, but it is unclear if early detection reduces mortality rates.
The stool guaiac test or guaiac fecal occult blood test (gFOBT) is one of several methods that detects the presence of fecal occult blood. The test involves placing a faecal sample on guaiac paper and applying hydrogen peroxide which, in the presence of blood, yields a blue reaction product within seconds.
Lung cancer screening refers to cancer screening strategies used to identify early lung cancers before they cause symptoms, at a point where they are more likely to be curable. More than 224,000 new cases of lung cancer are expected in 2016 with approximately 155,000 deaths expected in 2017. 57% were diagnosedin advanced stages where survival is poor. Screening research addresses potential differences in multiple parameters between groups of research subjects with and without screening. Because there is a substantially higher probability of long-term survival following treatment in localized (55%) than in advanced stage (5%), the specific rationale of lung cancer screening is to diagnose the disease in stage I. Research parameters include population cancer-specific mortality, all-cause mortality, long-term survival following diagnosis of cancer, risks of screening and cost-effectiveness. Screening studies for lung cancer have only been done in high risk populations in the U.S., such as smokers and workers with occupational exposure to certain substances. Results from large randomized studies have recently prompted a large number of professional organizations and governmental agencies in the U.S. to now recommend lung cancer screening in select populations.
The United States Preventive Services Task Force (USPSTF) is "an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services". The task force, a panel of primary care physicians and epidemiologists, is funded, staffed, and appointed by the U.S. Department of Health and Human Services' Agency for Healthcare Research and Quality.
Breast cancer screening is the medical screening of asymptomatic, apparently healthy women for breast cancer in an attempt to achieve an earlier diagnosis. The assumption is that early detection will improve outcomes. A number of screening tests have been employed, including clinical and self breast exams, mammography, genetic screening, ultrasound, and magnetic resonance imaging.
The general medical examination is a common form of preventive medicine involving visits to a general practitioner by well feeling adults on a regular basis. This examination is done generally yearly or less frequently. It is known under various non-specific names, such as the periodic health evaluation, annual physical, comprehensive medical exam, general health check, preventive health examination, medical check-up, or simply medical. If done for a group of people it is a form of screening, as the aim of the examination is to detect early signs of diseases to prevent them.
Cervical screening is the process of detecting and removing abnormal tissue or cells in the cervix before cervical cancer develops. By aiming to detect and treat cervical neoplasia early on, cervical screening aims at secondary prevention of cervical cancer. Several screening methods for cervical cancer are the Pap test, liquid-based cytology, the HPV DNA testing and the visual inspection with acetic acid. Pap test and liquid-based cytology have been effective in diminishing incidence and mortality rates of cervical cancer in developed countries but not in developing countries. Prospective screening methods that can be used in low-resource areas in the developing countries are the HPV DNA testing and the visual inspection.
The National Lung Screening Trial was a United States-based clinical trial which recruited research participants between 2002-2004. It was sponsored by the National Cancer Institute and conducted by the American College of Radiology Imaging Network and the Lung Screening Study Group. The major objective of the trial was to compare the efficacy of low-dose helical computed tomography and standard chest X-ray as methods of lung cancer screening. The primary study ended in 2010, and the initial findings were published in November 2010, with the main results published in 2011 in the New England Journal of Medicine.
Overscreening, also called unnecessary screening, is the performance of medical screening without a medical indication to do so. Screening is a medical test in a healthy person who is showing no symptoms of a disease and is intended to detect a disease so that a person may prepare to respond to it. Screening is indicated in people who have some threshold risk for getting a disease, but is not indicated in people who are unlikely to develop a disease. Overscreening is a type of unnecessary health care.
Cancer prevention is the practice of taking active measures to decrease the incidence of cancer and mortality. The practice of prevention is dependent upon both individual efforts to improve lifestyle and seek preventative screening, and socioeconomic or public policy related to cancer prevention. Globalized cancer prevention is regarded as a critical objective due to its applicability to large populations, reducing long term effects of cancer by promoting proactive health practices and behaviors, and its perceived cost-effectiveness and viability for all socioeconomic classes.
In medicine, breast imaging is the representation or reproduction of a breast's form. There are various methods of breast imaging.