New modality-based treatment strategies for multiple primary lung cancers

SESSION TITLE: Lung Cancer Posters 6 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/11/2023 12:00 pm - 12:45 pm PURPOSE: With the improvement of postoperative treatment outcomes for lung cancer, it is not uncommon to encounter multiple primary lung cancers (MPLC) after surgical treatment. Many of those patients are elderly, and it is necessary to develop various treatment strategies for MPLC in the future. Especially, we attempted a new endobronchial photodynamic therapy (PDT) using a new laser probe, and found that PDT was a feasible and non-invasive treatment modality for c-stage IA peripheral type lung cancers. METHODS: In order to develop a treatment strategy for metachronous MPLC, we retrospectively reviewed patients with metachronous MPLC who underwent surgery for primary lung cancer in our department between January 2013 and December 2022. RESULTS: Of the 1385 patients operated for primary lung cancer, 89 patients had metachronous MPLC. In the cases of metachronous MPLC, 73 patients underwent lobectomy or more at the first surgery, 14 patients underwent segmentectomy, and 2 patients underwent partial resection. The histological types were squamous cell carcinoma in 28 cases, adenocarcinoma in 59 cases, and large cell carcinoma in 2 cases. As treatment for secondary MPLC, surgical treatment was performed in 66 cases (lobectomy in 7 cases, segmentectomy in 13 cases, partial resection in 46 cases), photodynamic therapy (PDT) in 19 cases, and SBRT in 4 cases. Of the 19 patients who underwent PDT, 6 had centrally located early lung cancer, 13 had peripheral small lung cancer, and 4 patients who underwent SBRT had cancer ipsilateral to the first cancer. Three of the patients who underwent SBRT were ipsilateral to the first carcinoma, and their size was around 10 mm. Eleven of the 13 patients who underwent PDT for peripheral type lung cancer were ineligible for either surgery or SBRT because of low lung function and interstitial pneumonia. Of the 46 partial resections for second lung cancer, 1 patient had recurrence of second lung cancer, and home oxygen therapy was introduced in 3 patients. Two out of 19 patients treated with PDT died of recurrence of first lung cancer, and 1 patient died of other diseases. All four patients who underwent SBRT are alive without any recurrence. CONCLUSIONS: As a strategy for the treatment of metachronous MPLC detected during postoperative follow-up, early detection of these cancers can be curatively treated by partial resection, PDT, or SBRT without compromising the quality of life and preserving lung function. PDT may be a new, minimally invasive treatment option, especially for secondary primary lung cancer patients with low pulmonary function. CLINICAL IMPLICATIONS: In the treat of metachronous MPLC, due to limited resection such as partial resection, early detection of allows for a good prognosis with partial resection instead of lobectomy. We have conducted a physician mediated clinical trial of PDT for peripheral lung cancer in patients with low pulmonary function, and we are currently awaiting the result. PDT may be a promising treatment for patients with MPLC whose lung function has been reduced by lung cancer surgery. DISCLOSURES: No relevant relationships by Takumi Sonokawa No relevant relationships Added 03/30/2023 by Jitsuo Usuda, source=Web Response, value=Grant/Research Removed 03/31/2023 by Jitsuo Usuda, source=Web Response