Focal 18F-FDG uptake predicts progression of pre-invasive squamous bronchial lesions to invasive cancers

Introduction: Pre-invasive squamous lesions of the central airways can progress into invasive lung cancers. Identifying these high-risk patients could enable detection of invasive lung cancers at an early stage. In this study, we investigated the value of ¹⁸F-fluorodeoxyglucose ( ¹⁸F-FDG) positron emission tomography (PET) scans in predicting progression in patients with pre-invasive squamous endobronchial lesions. Methods: In this retrospective study, patients with pre-invasive endobronchial lesions, who underwent an ¹⁸F-FDG PET scan at the VU University Medical Center Amsterdam, between January 2000 and December 2016, were included. Autofluorescence bronchoscopy (AFB) was used for tissue sampling and was repeated every 3 months. The minimum and median follow-up was 3 and 46.5 months. Study endpoints were the occurrence of biopsy proven invasive carcinoma, time-to-progression and overall survival (OS). Results: A total number of 40 of 225 patients met the inclusion criteria of which 17 (42.5%) patients had a positive baseline ¹⁸F-FDG PET scan. A total of 13 of 17 (76.5%) developed invasive lung carcinoma during follow-up, with a median time to progression of 5.0 months (range, 3.0–25.0). In 23 (57.5%) patients with a negative ¹⁸F-FDG PET scan at baseline, 6 (26%) developed lung cancer, with a median time to progression of 34.0 months (range, 14.0–42.0 months, p < 0.002). With a median OS of 56.0 months (range, 9.0–60.0 months) versus 49.0 months (range, 6.0–60.0 months) (p = 0.876) for the  ¹⁸F-FDG PET positive and negative groups, respectively. Conclusions: Patients with pre-invasive endobronchial squamous lesions and a positive baseline ¹⁸F-FDG PET scan were at high-risk for developing lung carcinoma, highlighting that this patient group requires early radical treatment.