Bombesin-drug conjugates in targeted therapy for small cell lung cancer.

Small cell lung cancer (SCLC) is a aggressive form of primary lung neoplasm that often presents in elderly smokers. While stage I SCLC can be managed with surgery, extensive-stage disease is managed with chemotherapy using etoposide and cisplatin among other agents, and often complemented by radiation therapy to the chest and cranium. Recent advances in pharmacological research have yielded novel antibody and peptide-conjugated adjunctive chemotherapy, of which bombesin and bombesin receptors have played an important role due to their overexpression in SCLC and other lung cancers. Chemotherapy agents conjugated to bombesin or bombesin-like peptides often demonstrate higher therapeutic efficacy, greater treatment specificity, as well as improved cytotoxicity towards SCLC cells that demonstrate drug resistance. Further modifications to the bombesin-drug conjugate, such as liposomal preparation, have further enhanced bio-availability and half-life of the compound. Additionally, bombesin-radioisotope conjugates can be used for early detection of SCLC using positron emission tomography, as well as subsequent targeted adjuvant radiotherapy to help minimize radiation-induced fibrosis of healthy tissue. Ultimately, further studies are imperative to capitalize on the various applications of bombesin conjugates in both the diagnosis and management of SCLC.