Critical appraisal:Bach PB, Mirkin JN, Oliver TK, Azzoli CG, Berry DA, Brawley OW, et al 2012 1

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Article
Bach PB, Mirkin JN, Oliver TK, Azzoli CG, Berry DA, Brawley OW, et al. Benefits and harms of CT screening for lung cancer: a systematic review. JAMA 2012 Jun 13;307(22):2418-29 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22610500.
Assigned to
User:Henry.marshall
Topic area
Guidelines:Lung cancer/Screening and early detection
Clinical question
Form
Form:Critical appraisal
Outcomes
Mortality
Study design
systematic review
Level of Evidence
I

Section below only relevant for Cancer Council Project Officer

Edit appraisal assignment


Critical Appraisal

Article being appraised

Bach PB, Mirkin JN, Oliver TK, Azzoli CG, Berry DA, Brawley OW, et al. Benefits and harms of CT screening for lung cancer: a systematic review. JAMA 2012 Jun 13;307(22):2418-29 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22610500.


Applicable clinical question

Key Facts

Study Design

systematic review

Study aims:

review the evidence of benefits and harms of lung cancer screening using low-dose computed tomography.

Number of Patients:

104,115

included RCTS (n=8, ppts n=83,331): NELSON, DLCST, ITALUNG, DANTE, Garg et al, NLST, LSS, Depiscan
included cohort studies (n=13, ppts n=20,784): Veronesi etal, Wilson etal, Menezes etal, Sobue etal, Swensen etal, Pastorino etal, Henschke etal, Bastarrika etal, Diederich etal, Novello etal, Callol etal, MacRedmond etal, Picozzi etal.
Reported outcome(s):

lung cancer mortality
all-cause mortality
nodule detection
FPR
invasive procedures
follow-up tests
smoking cessation

Results of outcome(s):

lung cancer mortality (n=3) NLST showed reduction; smaller DANTE and DLCST trials did not.

all-cause mortality (n=3) NLST showed reduction; smaller DANTE and DLCST did not.

nodule detection (all trials), marked heterogenity, variable definitions, inconsistent categorization and reporting; Based on each study’s own size cut-offs, the average nodule detection rate was 20% per screening round (range 3 to 30% in RCTs and 5% to 51% in cohort studies).

FPR: >90% in most studies

Follow-up tests: The frequency of further CT imaging among screenees ranged from 1% (Veronesi) to 45% (Sobue); frequency of PET imaging exhibited much less variation, (2.5% Bastarrika to 5.5% in the NLST).

invasive procedures: frequency was generally low but varied considerably. No patterns were apparent that
explained this heterogeneity.

In the NLST and NELSON studies, 1.2% of patients who were not found to have lung cancer underwent an invasive procedure such as needle biopsy or bronchoscopy; 0.7% and 0.6% respectively underwent thoracoscopy, mediastinoscopy, or thoracotomy without lung cancer being diagnosed.

Complications of Diagnostic Procedures.
- Only NLST reports this.
- the frequency of death occurring within 2 months of a diagnostic evaluation of a detected finding was 8 per 10 000 individuals screened by LDCT and 5 per 10000 individuals screened by chest radiographs.
- death rate within 2 months of bronchoscopy or needle biopsy was 3.4 per 10 000 screened by LDCT and 2.2 per 10000 screened by chest radiographs.
- 60-day perioperative mortality for patients with lung cancer who underwent a surgical procedure was 1% for the
LDCT group and 0.2% for the chest radiographs group.
- Overall frequency of major complications occurring during a diagnostic evaluation of a detected finding was
33 per 10 000 individuals screened by LDCT and 10 per 10 000 individuals screened by chest radiographs.
- complication rate after a bronchoscopy or needle biopsy was low (1.5 and 0.7 per 10 000 for LDCT and chest radiographs).
- overall, for an entire LDCT screened population, the risks of death and major complications following diagnostic events (including imaging) for benign nodules = 4.1 and 4.5 per 10 000, respectively. In the chest radiographs group =1.1 and 1.5 per 10 000 for risks of death and major complications respectively.

overdiagnosis: cannot yet be estimated.

Radiation Exposure. The effective dose of radiation of LDCT is estimated to be 1.5 mSv per examination. The reviewers estimated that NLST participants received approximately 8 mSv per participant over 3 years, including both screening and diagnostic examinations (averaged over the entire screened population). Using the NLST data, these models predict that approximately 1 cancer death may be caused by radiation from imaging per 2500 persons screened.

Quality of Life. The effect of LDCT screening on quality of life is uncertain.

smoking cessation: studies examining the smoking behavior of LDCT-screened individuals have not found evidence that cessation or reinitiation rates are meaningfully altered by participation in screening.

Patients Likely to Benefit:
- NLST population is the only one for whom a lung cancer mortality benefit from LDCT has been demonstrated.
- The value of LDCT screening is likely determined primarily by the risk of lung cancer vs competing causes of death.
- Little information exists regarding comorbidities, but presumably the NLST participants were deemed healthy.
- There is no evidence base for determining how selection criteria for screening should be refined. Incorporating other well-known risk factors has not been studied.

Includes an economic evaluation

no

Evidence ratings

Level of evidence

I

Risk of bias
Low risk of bias Comments: Please replace this text and include any additional comments in regards to your quality rating

Risk of bias assessment: systematic review

Studies included in the review
Was an adequate search strategy used?
Very thorough – included appropriate search terms and databases
Were the inclusion criteria appropriate and applied in an unbiased way?
Yes – pre-specified inclusion criteria applied independently by two people
Were the studies assessed for quality (relating to the minimisation of biases)?
Yes – appropriate quality issues were assessed independently by two people
Were the characteristics and results of individual studies appropriately summarised?
Yes – summary descriptive tables of subjects, interventions, outcomes etc are provided and estimates of treatment effect displayed
The following questions are only relevant for systematic reviews that pooled data
Were the methods used for pooling the data appropriate?
No response
If there was heterogeneity, were sources of heterogeneity explored?
No response
Size of effect
1 Reason for decision: Please replace this text and briefly describe the reasons for your rating
Relevance of evidence
1 Additional comments: direct evidence on mortality and a range of surrogate measures.
Result of appraisal

Jutta's tick icon.png Included




Completed by

Dr Henry Marshall FRACP