Results of long-term follow-up of photodynamic therapy for roentgenographically occult bronchogenic squamous cell carcinoma

Background: Photodynamic therapy (PDT) is considered a useful and minimally invasive modality for treating centrally located early lung cancer. To date, there has been limited information on the long-term outcome of patients treated with PDT, especially those who are medically operable. Methods: Beginning in 1994, patients with roentgenographically occult bronchogenic squamous cell carcinoma (ROSCC) who met our criteria underwent PDT at Tohoku University Hospital and were followed up through 2006. Our criteria were as follows: (1) ROSCC without distant metastasis; (2) medically operable by means of lobectomy or further resection; (3) longitudinal tumor length of ≤ 10 mm; and (4) superficial bronchoscopic tumor findings. Results: A total of 48 patients with ROSCC underwent PDT. The complete response (CR) rate was 94% (45 of 48 of patients). Nine patients (20%) had local recurrence after CR. A total of 11 deaths was observed, with 6 resulting from multiple primary lung cancer and only 1 from the original ROSCC. The 5-year and 10-year overall survival rates for all 48 patients were 81% and 71%, respectively. The Cox proportional hazard model showed that only metachronous multiple primary lung cancer was an independent poor prognostic factor. Conclusions: PDT is thought to be a first-line modality for patients who have ROSCC with a tumor length of ≤ 10 mm, even if the tumor is medically operable. Most local recurrence can be cured by active therapy such as surgery, radiotherapy, or PDT. Multiple primary lung cancer subsequent to PDT is an important issue from the viewpoint of survival.