Ten Best Readings in Cancer
Screening
Robert Clark, MD
Chief, Radiology Service
H. Lee Moffitt Cancer Center & Research Institute
Fletcher SW, Black W,
Harris R, et al. Report of the International Workshop on Screening for Breast
Cancer. J Natl Cancer Inst. 1993;85:16441656.
This article summarizes
the eight major randomized, controlled clinical trials of breast cancer screening
with mammography, provides an objective critical review of the evidence for
screening, and assesses the current state of knowledge about breast cancer screening.
This report concludes that, for women between 50 and 69 years of age, screening
significantly reduces mortality from breast cancer by approximately 30%. For
women under 50 and over 69 years of age, trial data do not provide adequate
information to judge effectiveness. (See also "Deficiencies in the analysis
of breast cancer screening data," a dissention from the main conclusions,
in the same issue.)
Kerlikowske K, Grady
D, Rubin SM, et al. Efficacy of screening mammography: a metaanalysis. JAMA.
1995;273:149154.
This metaanalysis combines
the results of 13 controlled studies, both randomized and casecontrol varieties,
and concludes that screening mammography significantly reduces the mortality
from breast cancer in women between 50 and 74 years of age. Screening may be
effective in women between 40 and 49 years of age after 10 to 12 years, but
the same benefit might be achieved by beginning screening at age 50.
Lindfors KK, Rosenquist
J. The costeffectiveness of mammographic screening strategies. JAMA.
1995;274:881884.
The breast cancer screening
debate continues about when to start (age 40 or 50 years), when to stop (age
69, 74, or older), and how often to screen (annually or biennially). This article
compares the costeffectiveness of several different screening strategies and
concludes that the most costeffective strategy is biennial mammography for
women aged 50 to 79 years, but a strategy of annual mammography for women aged
40 to 49 years and biennial screening for those aged 50 to 79 years is more
costeffective than annual mammography for those aged 50 to 79 only.
Katz SJ, Hofer TP. Socioeconomic
disparities in preventive care persist despite universal coverage. Breast and
cervical cancer screening in Ontario and the United States. JAMA.1994;272:530534.
Screening costs and lack
of access to medical care usually are considered barriers that restrict women
from receiving cancer screening services. This article compares the breast and
cervical cancer screening behaviors of women in the United States and Ontario,
Canada. Canada offers universal insurance coverage through its "singlepayer"
national health care system, while a significant proportion of Americans are
uninsured. The results show that rates for Papanicolaou testing and clinical
breast examination were similar in both countries, but screening mammography
rates were two to three times higher in the United States across all age groups.
In both countries, women with less education and lower income were less likely
to receive screenings. This article concludes that universal coverage alone
is not sufficient to overcome the other economic, social, cultural, and informational
barriers related to cancer screening.
Lieberman D. Screening/early
detection model for colorectal cancer. Why screen? Cancer. 1994: 74(suppl
7):20232027.
Recent data have suggested
that screening for colon cancer with fecal occult blood tests and/or sigmoidoscopy
may reduce the mortality from the disease. However, this has not yet been confirmed
with randomized, controlled clinical trials. This review summarizes the current
evidence for screening and addresses clinical issues such as (1) the diagnostic
approach to a positive screening test, (2) the approach to further surveillance
in people with adenomas, (3) the options for screening strategies (eg, when
to start and stop screening and how often to screen), and (4) the future potential
to identify highrisk patients by using genetic or biologic markers.
Mettlin C, Littrup PJ,
Kane RA, et al. Relative sensitivity and specificity of serum prostate specific
antigen (PSA) level compared with agereferenced PSA, PSA density, and PSA change:
data from the American Cancer Society National Prostate Cancer Detection Project.
Cancer. 1994;74:16151620.
While screening for prostate
cancer with serum prostate specific antigen (PSA) is a promising screening tool,
its efficacy in reducing the mortality rate from prostate cancer has yet to
be shown in randomized, controlled trials. In the evolution and development
of this screening test, different indexes have been proposed that may enhance
the early detection capability of PSA. This article reviews a recent national
demonstration project in which the relative values of several indexes were compared
in 2011 men without prostate cancer and in 171 men with prostate cancer. In
this series, none of the indexes showed an advantage compared with the standard
serum PSA value, defined as 4.0 ng/mL.
Gohagan JK, Prorok PC,
Kramer BS, et al. Prostate cancer screening in the prostate, lung, colorectal,
and ovarian cancer screening trial of the National Cancer Institute. J Urol.
1994;152: 19051909.
This article describes the
current National Cancer Institute "PLCO" trial, an ongoing randomized,
controlled trial evaluating effectiveness of screening for prostate, lung, colorectal,
and ovarian cancer. Background data, rationale, design, and endpoints for the
prostate cancer screening arm of the trial are outlined.
Koh HK, Geller AC, Miller
DR, et al. The early detection of and screening for melanoma. International
status. Cancer. 1995;75(suppl 2):674683.
The worldwide incidence
of melanoma has been increasing rapidly for several years. The neoplasm is theoretically
ideal for screening, since the lesion is external and visible, its risk factors
and epidemiology are known, and early lesions, ie, thin tumors, are associated
with high survival rates. However, the efficacy of melanoma screening has not
yet been tested with randomized, controlled trials. This article summarizes
the preliminary data available from melanoma screening and early detection efforts
conducted in the last decade, presents the intermediate measures of efficacy,
acknowledging that mortality reduction data do not yet exist, and offers recommendations
for future studies in melanoma prevention, education, and screening.
Strauss GM, Gleason RE,
Sugarbaker DJ. Chest xray screening improves outcomes in lung cancer. A reappraisal
of randomized trials on lung cancer screening. Chest. 1995;107(suppl
6):270s279s.
Four randomized, controlled
trials of lung cancer screening in male adult smokers have been conducted, and
none has shown reduced mortality with screening. Currently, no organization
recommends screening for lung cancer. This article reassesses the data from
the trials and concludes that in two studies (the Memorial SloanKettering Lung
Project and Johns Hopkins Lung Project), annual chest radiography improved survivalrates
in both experimental and control groups compared with predicted survival rates
from National Cancer Institute Surveillance, Epidemiology, and End Results data
or American Cancer Society annual cancer statistics. In two other studies (the
Mayo Lung Project and the Czechoslovak Study), the groups screened with chest
radiography had improvements in stage distribution, resectability, and survival
compared with unscreened groups. However, in these two latter studies, the screened
groups had higher cancer incidence than control groups, negating mortality reductions.
This article argues that biases overdiagnosis, lead time, and length do
not adequately account for the data. This article argues cogently for another
trial to assess effectiveness of lung cancer screening; such a trial is ongoing
through the NCI "PLCO" screening study.
Mulshine JL, Scott F.
Molecular markers in early cancer detection. New screening tools. Chest.
1995;107(suppl 6):280s286s.
In previous trials of lung
cancer screening, sputum cytology studies did not favorably influence outcome.
However, sputum samples in the Johns Hopkins trial were archived. This study
used two immunostaining techniques with monoclonal antibodies and showed correlation
between positive staining and the development of lung cancer in the sampled
population. New tests awaiting prospective trials and the clinical issues of
atrisk populations, cost, and patient compliance are also discussed.
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