Supplementary Material for: Photodynamic Therapy for Central Early-Stage Lung Cancer: A Retrospective Comparative Study of Photofrin, Chlorin e6, and Foscan

Introduction:
Photodynamic therapy (PDT) is a minimally invasive, organ-preserving treatment option for patients with centrally located early-stage non-small cell lung cancer (NSCLC). While first-generation photosensitizers such as Photofrin are well established, second-generation agents like Chlorin e6 offer improved pharmacokinetics and potentially better clinical outcomes. The objective of this study was to assess the safety profile and therapeutic efficacy of different photosensitizers used in PDT for centrally located early-stage lung cancer (CELC).

Methods:
We retrospectively analyzed 62 CELC lesions in 36 patients treated with PDT between 2015 and 2024. Patients received one of three photosensitizers—Photofrin, Chlorin e6, or Foscan—followed by bronchoscopic light activation. Outcomes included complete remission (CR), local tumor control (LTC), disease-free survival (DFS), and treatment-related adverse events.

Results:
CR rates were 87.5% (28/32) for Chlorin e6, 100% (3/3) for Foscan, and 68.8% (22/32) for Photofrin, with a non-significant trend favoring Chlorin e6 over Photofrin (p = 0.13). Mean DFS was longest in the Chlorin e6 group (43.3 months; 95% CI: 32.5–54.1), followed by Photofrin (24.0 months; 95% CI: 17.2–30.8) and Foscan (7.3 months; 95% CI: 6.3–8.4). Durable LTC was achieved in 84.1% of lesions without need for escalation to systemic or surgical treatment. Chlorin e6 demonstrated a more favorable safety profile than Photofrin.

Conclusion:
PDT is a safe and effective treatment modality for centrally located early-stage lung cancer, achieving high rates of local tumor control. Among the evaluated photosensitizers, Chlorin e6 showed a favorable balance of efficacy and safety.