Table 2:

Best evidence papers providing supporting evidence

Author, date and country Study type (level of evidence)	Patient group	Outcomes	Key results	Comments
Chiu et al., 2003, J Thorac Cardiovasc Surg, Taiwan [7] Single centre prospective cohort study (level IIa)	Part 1: 30 patients who underwent surgical resection of NSCLC subjected to CXR, LDCT, and SDCT to verify the diagnostic accuracy of LDCT Part 2: 43 patients were prospectively enrolled and followed up regularly after complete resection of NSCLC	Recurrent case-detection rates compared with SDCT	SDCT: 7 cases detected (100%) LDCT: 6 of 7 cases detected (85.7%) CXR: 2 of 7 cases detected (28.6%)	Authors state that postoperative follow-up of NSCLC patients with LDCT every 3 months in the first 2 years may be of considerable value in early detection of recurrent disease However, the study did not directly comment on survival
		Follow-up time (median months and range)	15.5 months (3.1–23.5)
		Recurrent case-detection rate using low-dose CT	78.6% (11 of 14 patients)
		Recurrent site-detection rate using low-dose CT	57.9% (11 of 19 sites)
Korst et al., 2005, J Thorac Cardiovasc Surg, USA [8] Single centre retrospective cohort study (level IIb)	A retrospective analysis was performed in 140 patients who presented for follow-up in 2002 after complete resection for NSCLC	Recurrence	32 of 105 (30%) of abnormal scans were suspicious for recurrence Further workup showed recurrent or new primary lung cancer in 16 of 32 patients Scans that were abnormal but not deemed suspicious (73 of 105 scans in 60 patients) revealed five additional recurrences	Authors concluded that surveillance CT is frequently abnormal after complete resection for NSCLC; however, the majority of these abnormalities are not clinically suspicious Only 30% of abnormal scans were deemed suspicious. This raises the obvious question as to the significance of the findings on the remaining 73 unsuspicious scans read as abnormal by the radiologists Although these patients have been followed into 2004, a clear weakness of this study is its cross-sectional nature, with lack of longer-term follow-up
Korst et al., 2006, Ann Thorac Surg, USA [9] Single centre retrospective cohort study (level IIb)	92 patients with previously resected NSCLC who underwent 105 surveillance CT scans of the chest and upper abdomen in 2002 that were read as abnormal by the radiologist	Follow-up results in the 60 patients with 73 abnormal but non-suspicious scans	Recurrence in 7 Alive without recurrence in 49 Died without recurrence in 4 None of the 60 patients with non-suspicious abnormal scans had recurrent or new primary lung cancer in the area read as abnormal by the radiologist in 2002	In this study the surgeon utilizing surveillance CT rarely missed recurrent NSCLC, but a significant number of negative investigations were generated by its use Focus is on the surgeon's accuracy in interpreting CT abnormality over the radiologist detection of CT findings Important to note that only 77 of the 92 patients had lobectomies. Others underwent other anatomic resections
		Accuracy of CT when used by thoracic surgeon	Sensitivity: 94.1% Specificity: 86.7% NPV: 99% PPV: 53%

CT: computed tomography; CXR: chest X-ray; LDCT: low-dose computed tomography; NPV: negative predictive value; NSCLC: non-small cell lung cancer; PET-CT: positron emission tomography-computed tomography; PPV: positive predictive value; SDCT: standard-dose computed tomography.