McMaster University/St. Joseph’s Healthcare
The purpose of this study was to evaluate the additional diagnostic benefit of integrated PET/CT compared to CT alone in the pre-treatment staging of suspected lung cancer. We hypothesized that patients with early stage disease would not benefit from the addition of PET/CT for staging.
Materials and Methods:
We conducted a retrospective study of all patients at our academic institution with a histopathological diagnosis of lung cancer who underwent CT and PET/CT staging examinations between January 1, 2014 and August 30, 2019. Research ethics board approval was obtained. Univariate logistic regression was performed to assess for potential predictors of disease upstaging between CT alone and integrated PET/CT. The following variables were evaluated: gender, smoking status, number of lesions, size of the dominant lesion, characteristics of the lesion, chest wall or mediastinal invasion, suspicious lymph nodes, presence of metastasis and malignancy subtype. Corresponding odds ratios (OR) and p-values were calculated for each logistic regression. A p-value <=0.05 was considered statistically significant.
A total of 178 patients were included (73 males, mean age 69.6+/-8.2). The following variables were associated with upstaging of disease with PET/CT compared to CT alone: a dominant lesion >3cm (OR=2.79, p=0.012), lymphadenopathy (OR=3.30, p=0.007), and the presence of metastasis (OR=9.57, p=0.008). Gender, smoking status, number of lesions, characteristics of the lesion, chest wall or mediastinal invasion, and malignancy subtype were not significant predictors of PET/CT upstaging of lung cancer compared to CT alone (p=0.099-908).
Selective use of PET/CT to complement CT staging should be considered for pre-treatment lung cancer staging, as opposed to routine use, to optimize the diagnostic benefit and resource utilization. In pre-treatment staging for lung cancer, PET/CT offered added diagnostic value over CT alone in the presence of a dominant lesion >3cm, lymphadenopathy, and metastasis. The findings of this study support the selective, rather than routine, utilization of PET/CT to complement CT for lung cancer staging.