Objectives: For small cell lung cancer (SCLC), several imaging modalities can be used to determine cancer staging, which is important to ensure optimal management. Our aim was to synthesize the literature on whether some imaging modalities are better than others for the pretreatment staging of small cell lung cancer. We searched for evidence on comparative accuracy (sensitivity, specificity) as well as subsequent clinical outcomes (choice of treatment, survival, and quality of life).
Data sources: We searched EMBASE, MEDLINE, PubMed, and the Cochrane Library from 2000 through June 15, 2015, for full-length articles on the use of multidetector computed tomography (MDCT), positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI), combined PET/MRI, endobronchial ultrasound (EBUS), endoscopic ultrasound with fine-needle aspiration (EUS-FNA), and bone scintigraphy in the pretreatment staging of small cell lung cancer.
Review methods: We included studies of pertinent imaging tests on SCLC patients before treatment that reported one or more of the outcomes of interest (studies did not have to directly compare two or more imaging modalities). We extracted data from the included studies and constructed evidence tables. Comparative outcomes of interest included test concordance, staging accuracy (sensitivity and specificity), choice of treatment, timeliness of treatment, tumor response, harms due to overtreatment or undertreatment, survival, and quality of life. For each pair of tests and each assessed aspect (e.g., determination of metastases), we determined whether the evidence was sufficient to permit a conclusion of a difference, a conclusion of similar accuracy, or neither (i.e., insufficient). We rated the risk of bias of individual studies using an internal validity instrument and graded the overall strength of evidence of conclusions using Evidence-Based Practice Center guidance.
Results: The searches identified 2,880 citations; after screening against the inclusion criteria, we included seven primary studies that enrolled a total of 408 patients. Six of the seven studies were deemed moderate risk of bias (principally due to failure to report on patient selection, reader blinding to results of comparator tests, and possible spectrum bias), and one was deemed high risk of bias (due to failure to blind readers to results of comparator tests and presence of spectrum bias). One of the studies reported test concordance, three studies reported the comparative accuracy of two or more testing strategies (one of which had also reported test concordance), and four studies reported the accuracy of a single imaging modality. Staging determinations included limited versus extensive disease, osseous (bone or bone marrow) metastases, lymph node involvement, liver metastases, spleen metastases, adrenal metastases, brain metastases, and any distant metastases. The most frequently reported imaging tests were MDCT, [18F]-fluorodeoxyglucose (FDG) PET/CT, and bone scintigraphy. No studies were included for any other outcomes or for associations with patient comorbidity, body habitus, or tumor characteristics.
Conclusions: Evidence is sparse on imaging modalities in the pretreatment staging of small cell lung cancer. Nevertheless, we drew three conclusions about comparative accuracy: (1) FDG PET/CT is more sensitive than MDCT for detecting osseous metastases; (2) FDG PET/CT is more sensitive than bone scintigraphy for detecting osseous metastases; (3) Standard staging plus FDG PET/CT is more sensitive than standard staging alone for detecting any distant metastases. We assigned a grade of low to the strength of evidence for these conclusions, mostly due to risk of bias and a small number of studies. Research gaps include the dearth of evidence on several tests of interest (particularly MRI, EBUS, EUS, and PET/MRI), a lack of study designs to compare tests on patient-oriented outcomes such as survival, and a lack of data on whether comparative accuracy or effectiveness are associated with patient factors.