Electron microscopic and pathological changes of lung cancer after intratumoral injection of sodium bicarbonate

Background: Lung cancer can be treated with surgery, chemotherapy, radiation therapy, targeted therapy and palliative care. Palliative therapy is applied for inoperable lung cancer as it induces tumour necrosis. PH of tumour tissue is acidic; application of sodium bicarbonate (SB) into lung cancer locally via bronchoscopy can change its core pH, which may lead to tumour destruction. We aimed to study the ultrastructural characteristics of lung cancer and to assess the destructive effects of sodium bicarbonate 8.4% local injection on tumour tissue integrity by light and electron microscopies. Methods: This study was conducted on 21 patients with central bronchial carcinoma diagnosed according to WHO classification 2015. Three bronchoscopic biopsies were taken; two biopsies before and one after injection of sodium bicarbonate 8.4% solution of 20 ml via transbronchial needle. All biopsies were examined by both light and electron microscopes. The first biopsy was examined to diagnose the tumour morphologically with and without immunostaining. Second and third biopsies were taken before and after SB 8.4% injection to compare pathological changes in tumour tissue integrity as well as cellular ultra-structures. Different lung cancer pathological types were included in the study. Results: Tumour tissue integrity and pathological changes were examined in biopsies before and after injection of sodium bicarbonate 8.4%. Extensive necrosis in all cell types of lung cancer was seen after injection of SB; this important finding was delineated by both light and electron microscopies. Conclusion: Preliminary ultrastructural study of small biopsy of lung tumor has a complementary role to both morphological and immunohistochemical studies. Local injection of sodium bicarbonate into lung cancer induces extensive necrosis that may reflect its important therapeutic role in lung cancer.