ity by 20%. However, this type of screening introduced the
problems of assessing asymptomatic pulmonary nodules
discovered on CT, false positives, and the risk of invasive
diagnostic procedures. Tis study addresses these issues and
provides models and calculators for the probability of nodules being malignant rather than benign. Statistical analysis of the 2 data sets produced positive predictors of cancer
that included older age, female sex, family history of lung
cancer, chronic obstructive pulmonary disease (COPD),
larger nodule size, upper-lobe nodules, fewer rather than
many nodules, and spiculaton. Perifssural nodules were
(See online supplemental material, Nodule risk calculators, and
NEJM Quick Take on the evaluation of CT-discovered pulmonary nodules http://bit.ly/1nM68e1
The National Lung Screening Trial research
team, recent papers6-9
Te NLST researchers randomized 53,454 individuals
who were at high risk for lung cancer to 3 annual screenings with either low-dose CT or chest X-ray.
Te original paper in 2011 and subsequent 3 papers
published in 2013 showed the following results, except:
a) Rate of death from any cause was reduced by 6.7% in
the CT group.
b) Te proportion of stage I lung cancers in the initial
screen was higher than that seen in other screening
c) Te greatest number of deaths from lung cancer were
prevented in high-risk individuals
d) By the 3rd annual screening, participants in the CT
group had twice as many stage I lung cancers com-
pared with those in the chest X-ray group.
Te original report of the NLST revealed a reduction of
20% in mortality from lung cancer, and an overall reduction of 6.7% in death from any cause in high risk individuals who were screened with low-dose CT rather than chest
X-ray. Te proportion of lung cancers discovered with the
initial screen that were stage I was only 55%, far lower than
in most other studies, but the percentage of stage I patients
was higher with subsequent screens (63% and 69% with
the subsequent 2 screens). CT screening prevented deaths
mostly in high-risk participants, and prevented little mortality in those at low risk.
(See online supplemental material, lung cancer risk calculator)
Two recently published studies of mammogram once again
stirred up the debate about the value of screening mammography. A Canadian study published in February 2014
summarized the results of a randomized screening trial of
89,835 women begun in 1980 with follow-up for a mean of
22 years. Te results indicated that annual mammography
did not reduce breast cancer mortality. In April, Harvard
physicians published a review of 54 years’ worth of randomized clinical trials, meta-analyses, and observational
studies. Teir review showed a modest beneft in terms of
breast cancer mortality, but at a huge cost of false positives
Specifc results of the Canadian study of mammogram
screening included all except:
a) No reduction in breast cancer mortality in women
aged 40-59 years.
b) An over-diagnosis incidence of 22% of cancers
c) Adjuvant therapy was not available for all women.
d) Mortality was the same in women who had been
screened with physical examination alone.
Te Harvard study results included:
a) A cumulative risk of a false-positive result of 61% after
10 years of screening.
b) An over-diagnosis incidence of 19%.
c) A 19% reduction in breast cancer mortality.
d) Reduction in breast cancer mortality was similar in all
Te USPSTF 2009 guidelines for breast cancer screening sparked a controversy with its recommendation against
routinely screening women younger than 50 years, biennial
screening from age 50-74 years, and concern about false
positives and over-diagnosis. Te recent 2 studies add to
Te Canadian study casts doubt on the overall value of
mammogram in terms of overall survival, although adjuvant therapy was available for all, so that delayed diagnosis
may have had less of an impact because of the treatment
efect. Over-diagnosis (about 20%) was a signifcant problem in both studies, and false positives were particularly
high in the Harvard study (61%). Reduction in breast cancer mortality was twice as high in women in their 60s compared with those in their 40s, probably owing to the more
virulent type of breast cancer seen in young women.
Overall, the Canadian study suggested futility in screening younger women, whereas the Harvard study recommended individualization based on risk profles and the