Screening

Screening

Screening advances that lead to early detection have been a major contributor to better survival. Some advances in this area include routine mammography for breast cancer; colonoscopy and fecal occult blood testing for colon cancer; and Pap smears for cervical and endometrial cancers. With colon and cervical cancer screening, doctors can often identify and remove pre-cancerous lesions toprevent cancer from developing.

Recently, a major clinical trial showed that CT scanning can reduce the risk of lung cancer in heavy smokers by catching more cases early. Research is also under way to develop effective screening approaches for ovarian, pancreatic, kidney, and other cancers. 

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2012

Experts caution against unnecessary PSA screenings for prostate cancer

Experts caution against unnecessary PSA screenings for prostate cancer

Debate continues on the value of prostate-specific antigen (PSA) testing for prostate cancer screening.

In May, the U.S. Preventative Services Task Force (USPSTF) recommends against PSA screening, concluding that it does little to reduce the number of deaths from prostate cancer and can lead to unnecessary biopsies and treatment.

Later that year, however, ASCO issues guidance recommending that physicians discuss the benefits and risks of PSA testing with their otherwise healthy male patients who have life expectancies of greater than 10 years. The guidance notes that PSA testing may still offer important benefits for this group of men, but that the risks outweigh the benefits for men with shorter life expectancies.

2010

CT scanning reduces lung cancer deaths among heavy smokers

CT scanning reduces lung cancer deaths among heavy smokers

Results from a large clinical trial show that annual screening with low-dose spiral CT (LDCT) scans reduces the risk of lung cancer death by 20 percent, compared to annual chest X-rays, in current and former heavy smokers.

The National Lung Screening Trial, funded by the National Cancer Institute, compared LDCT scanning to standard chest X-rays in this group of people at high risk for developing lung cancer. This finding marks the first-ever lung cancer screening approach that has been shown to reduce lung cancer mortality. The debate about the appropriate use of LDCT screening for lung cancer among the general population, however, continues.

2009

Men urged to discuss routine PSA testing with doctors

Men urged to discuss routine PSA testing with doctors

Three large, randomized trials provide conflicting results on the use of PSA screening and lead experts to question whether this screening method translates into improved survival and actually saves men's lives. Initial results from two of the trials indicate that PSA testing has a minimal effect on overall survival and leads to the diagnosis and treatment of slow-growing cancers that are unlikely to be life-threatening. The third study finds that PSA testing every two years among men age 60 and older reduces the risk of prostate cancer death by 40 percent. Given the conflicting evidence, leading medical societies urge men to discuss the risks and benefits of screening with their doctors.

Adequate bowel preparation essential for effective colonoscopy

Adequate bowel preparation essential for effective colonoscopy

Researchers show that proper bowel cleansing is essential to ensure the quality of results provided by routine colonoscopies. This cleansing includes adhering to a clear liquid diet and taking a bowel prep (involving a laxative or enema) the day before the procedure. Incomplete preparation is a fairly common problem, due to the dietary restrictions and the potential inconvenience involved.

2008

Flat colon growths more likely to be cancerous than more obvious ones
Microscopic examination improves accuracy of skin cancer screening

Microscopic examination improves accuracy of skin cancer screening

A review of published studies finds that a procedure called dermoscopy – involving direct, microscopic examination of moles and skin lesions – is more accurate than a doctor's visual examination for identifying potential melanomas on the surface of the skin. The review emphasizes the importance of using dermoscopy, which has been available since the 1990s, to ensure that more cancers are detected at an early stage when they are most responsive to treatment.

Specialized CT scan improves bladder cancer detection

Specialized CT scan improves bladder cancer detection

The so-called CT urograph emerges as an effective, non-invasive strategy for detecting new and recurring cancers. The test, which is done externally, evaluates both the upper and lower tracts of the bladder and nearby lymph nodes. CT urography can help determine which patients need more invasive diagnostic procedures, sparing those who do not.

2007

MRI screening recommended for women at high risk of breast cancer

MRI screening recommended for women at high risk of breast cancer

Based on new studies demonstrating its effectiveness, the American Cancer Society releases guidelines recommending routine MRI screening for women at increased risk of developing breast cancer, in combination with standard mammography. MRI is more sensitive than mammography for finding breast lesions, particularly in women with dense breast tissue that is difficult to assess using traditional mammography. Routine MRI is not recommended for the general population of women (those not at increased risk), due to its high cost and the likelihood that it will detect abnormalities that are not cancerous.

2006

Taking more time to perform colonoscopy increases screening accuracy

2005

Conventional colonoscopy established as optimal screening method

Conventional colonoscopy established as optimal screening method

Two studies show that conventional colonoscopy is better able to detect colon cancer than other, less invasive screening techniques such as "virtual colonoscopy," barium enema or fecal DNA testing. Researchers demonstrate that colonoscopy detects 98 to 99 percent of tumors – about twice as many as virtual colonoscopy (the use of CT scanning to provide a three-dimensional image of the colon) or barium enema. Current medical guidelines state that colonoscopy is the superior colorectal cancer screening tool, but emphasize that some form of screening with any of these tests is better than going without screening.

Digital mammography more accurate than standard mammography in younger women

Digital mammography more accurate than standard mammography in younger women

A study of more than 42,000 women reports that digital mammography is more sensitive than traditional film mammography for women under age 50, who are more likely to have dense breast tissue, which is more difficult to assess. Digital mammography enables the radiologist to alter features such as brightness and contrast, improving the detection of abnormalities in breast tissue.

Right-sided colon cancers present a challenge for colonoscopy

Right-sided colon cancers present a challenge for colonoscopy

Researchers find that undergoing a colonoscopy every 10 years reduces the risk of cancer on the left side of the colon, but not on the right side. Subsequent studies confirm that right-sided colon cancers are more likely than those on the left to be missed during the screening procedure because it is harder to reach the right side of the colon and right-sided lesions may be flat and harder to detect.

2004

Screening program for people at high-risk can detect potentially operable pancreatic tumors

Screening program for people at high-risk can detect potentially operable pancreatic tumors

Researchers begin using a combination of screening technologies – CT scan and endoscopic imaging – to screen for pancreatic tumors in patients with a strong family history or genetic predisposition to pancreatic cancer. The goal is to identify cancers at early stages so they can be removed surgically and are potentially curable. Because this screening program is expensive, involves invasive procedures, and has not yet been shown to be cost-effective, it is not appropriate for the general population.

2000

Trial improves management of abnormal Pap test results

Trial improves management of abnormal Pap test results

Ongoing results from a large clinical trial – called the ASCUS-LSIL Triage Study (ALTS) – provide important guidance on managing the mild abnormalities that often show up on Pap tests. These findings help doctors more accurately determine which women need further procedures, such as colposcopy (office procedure using a device that enables a physician to closely examine the cervix for abnormalities) and biopsy to detect pre-cancer or cancer, and which women can be spared from these procedures.

1999

DNA test approved to detect HPV virus, the virus that causes cervical cancer

DNA test approved to detect HPV virus, the virus that causes cervical cancer

The FDA approves a new test to detect the strains of the human papillomavirus (HPV) that are known to cause cervical cancer. The test, which identifies DNA from these high-risk virus types, is approved for use in women age 30 and older in combination with the Pap test, and for women of all ages who have an abnormal Pap test result. Subsequent studies show that HPV testing alone is significantly more sensitive at detecting advanced pre-cancers than the Pap test (96 percent vs. 55 percent), but HPV testing results in more false positive results. When combined, the HPV test and Pap tests are found to be 100 percent sensitive for identifying women at risk for cervical cancer. For women younger than age 30, however, the Pap test alone is sufficient and combined screening is not recommended.

Widespread screening reduces cases of advanced cervical cancer in older women

Widespread screening reduces cases of advanced cervical cancer in older women

A study shows that Medicare coverage for cervical cancer screening in women over age 65 led to a 19 percent reduction in cervical cancer diagnoses in this group since 1990, enabling detection of more lesions in their precancerous stages, before they progressed to cancer. Current screening guidelines state that screening can be safely stopped in women over age 65 or 70 who have had three or more consecutive normal Pap test results and who have not had an abnormal screening result within the past 10 years.

1998

New liquid-based Pap tests introduced

New liquid-based Pap tests introduced

FDA approves two new liquid-based Pap tests. Whereas conventional tests involve smearing a swab of cervical cells on a slide, in the new tests, the swab is placed into a special preservative solution. These liquid tests provide a clearer, easier-to-read sample for pathologists to review under a microscope, compared to the traditional method.

1990

U.S. government funds cervical cancer screenings for underserved women

U.S. government funds cervical cancer screenings for underserved women

The Breast and Cervical Cancer Mortality Prevention Act of 1990 provides access to free or low-cost breast and cervical cancer screenings to underserved women across the country. Since its inception, this program run by the U.S. Centers for Disease Control and Prevention has provided more than 9.2 million breast and cervical cancer screening examinations, and helped diagnose more than 2,554 cases of cervical cancer and 123,563 cervical "pre-cancers."

1988

Standard system established for evaluating Pap test results

1986

FDA approves PSA test for prostate cancer screening

FDA approves PSA test for prostate cancer screening

The FDA approves the first PSA (prostate-specific antigen) test to screen for prostate cancer in men aged 50 and older. PSA is a protein produced by cells in the prostate gland, and is often elevated in men with prostate cancer. Widespread use of PSA testing leads to a significant jump in early-stage prostate cancer diagnoses, sparking a debate that continues today about whether such screening improves survival or simply leads to over-diagnosis and treatment of cancers that would never have become life-threatening.

1980

New tools enable detection of early-stage prostate cancer

New tools enable detection of early-stage prostate cancer

Doctors begin using prostate ultrasound – in which sound waves are used to generate an image of the prostate – to detect abnormalities that may signal cancer. Together with a type of biopsy, in which a thin, hollow needle is used to extract prostate tissue for testing, doctors are far more able to detect the earliest stages of prostate cancer.

1977

Growing use of mammography saves lives

Growing use of mammography saves lives

Regular breast cancer screening with mammography becomes increasingly common, helping to detect cancers at an earlier, more treatable stage. By the mid-1980s, nearly one-third of U.S. women over age 40 are screened. By 2008, the proportion screened approaches 70 percent. High screening rates – and resulting early detection – have contributed to a 27 percent reduction in breast cancer mortality among U.S. women since 1975.

1971

Screening tests for colorectal cancer dramatically reduce deaths

Screening tests for colorectal cancer dramatically reduce deaths

In 1967, the guaiac fecal occult blood test (FOBT) is introduced as a screening test for colorectal cancer, one of the most common forms of cancer. This simple and inexpensive tool detects the presence of blood in stool, a sign that cancerous or precancerous growths (called polyps) may be present. Within the next few years, two new screening techniques – flexible sigmoidoscopy and colonoscopy – enable physicians to examine the colon using a small camera attached to a flexible lighted tube. The widespread use of these approaches leads to better detection of precancerous polyps and early stage cancers that are usually curable with surgery. Over the coming decades, routine screening contributes to major reductions in colorectal cancer mortality – a total decline of more than 40 percent since 1975.

Early prostate cancer screening regimen introduced

Early prostate cancer screening regimen introduced

Studies show that screening with annual rectal exams, followed by surgery to remove the prostate in men who are found to have cancer, enables men with the disease to live as long, on average, as those without cancer. However, such treatment comes at the expense of urinary continence and sexual function.

1943

Doctors begin routine Pap testing

Doctors begin routine Pap testing

The Pap test is first introduced into physician's offices, enabling doctors to detect and begin treating cervical cancer before it has a chance to spread. Over the following decades, the Pap test is credited with driving down cervical cancer death rates in the U.S. and other wealthy countries. Yet cervical cancer remains a major cause of death in low-resource settings around the world, where access to screening and treatment is limited.

1940

Diagnostic tool detects bladder cancer in urine

Diagnostic tool detects bladder cancer in urine

A new test called urine cytology emerges as a tool to detect recurrent bladder and urinary tract cancers.  The test involves examing urine samples under a microscope to look for abnormal cells.  Over time, researchers find the test is most effective for detecting more aggressive cancers, versus those that are slow-growing.

1928

Discovery lays groundwork for development of the Pap test, the first-ever cancer screening test

Discovery lays groundwork for development of the Pap test, the first-ever cancer screening test

George Papanicolaou discovers that vaginal cell smears can reveal the presence of cervical cancer. This finding paves the way for the development of the first effective cancer screening test over the next 15 years. With refinements over the following decades, the Papanicolaou test (or Pap test, or Pap smear) remains the gold standard for cervical cancer screening and has been credited with reducing cervical cancer deaths by 70 percent in the U.S.