Photodynamic Therapy for the Prevention of Lung Cancer

Lung Cancer, Squamous Cell Lung Cancer

Autofluorescence Broncoscopy (AFB), Photodynamic Therapy (PDT), High Grade Lesions (HGLs), lung cancer, photosensitiser, Fotolon

PEARL is a phase III multicentre 2:1 randomised controlled trial, with an incorporated phase II (pilot) component. All patients consented/registered onto the trial will have an autofluorescence bronchoscopy (AFB) to check for the presence of high grade lesions (HGLs) in the lung, as verified by tissue biopsy. Only patients with one or more histologically confirmed lung HGL will be randomised to receive either photodynamic therapy (PDT) treatment with surveillance (=intervention), or surveillance alone (=control). The overall aim of the phase II pilot is to demonstrate a \>20% response in the PDT group (at least 3 out of 21 PDT patients), compared to a minimum response of 5%. This will be used as an efficacy signal to determine whether the trial will continue into phase III. Response will be measured by regression of high grade lesions (HGLs) to either low grade lesions (LGLs), or to normal epithelium at 6 months post treatment (blind assessment). The overall aim of the phase III is to show that the time period over which HGLs progress to invasive lung cancer is significantly longer when treated with PDT compared to surveillance alone.

Background: Squamous cell carcinoma of the lung develops through a transition of progressive cytological aberration, from normal to metaplasia, mild, moderate, and severe dysplasia and then carcinoma in situ (CIS) before becoming an invasive cancer. Progression rates to invasive carcinoma can vary depending on the initial grade of lesion and it is generally accepted that high-grade lesions are more likely to progress to invasive cancer than low-grade lesions. Early detection and treatment of these lesions is critical to improving survival. There is no evidence base examining how, or whether these high-grade lesions (HGLs) should be treated, resulting in diverse treatment practices both nationally and internationally. This is the first randomised clinical trial of a bronchoscopic intervention in treating HGLs using PDT. Treatment: Treatment-arm patients will receive two courses of PDT treatment using the photosensitiser drug Fotolon®. Fotolon®, which preferentially accumulates in HGLs, is first administered via IV infusion. Patients then undergo bronchoscopy during which their HGLs are irradiated with red light (via non-heat emitting laser). Red-light activation of the photosensitiser causes chemical transformation of the cells and cell death. Follow Up: Follow up in both arms consists of AFB surveillance at 6 and 12 months, then every 6-12 months (depending on the appearance of lesions), with annual CT scanning of the thorax, and annual spirometry. Biological samples for translational analysis will be taken at baseline and each subsequent trial visit. Duration of recruitment: Anticipated recruitment for phase II is 1 year (12 months), and an additional 2 years (24 months) for the phase III.

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