Treatment of Esthesioneuroblastoma and Nonsmall Cell Lung Cancer with Phenylbutyrate

Abstract

Esthesioneuroblastoma is a malignant tumor, arising in the upper nasal cavity, that could spread to the frontal lobe of the brain as well as metastasize to the lymph nodes. Due to the low incidence of this tumor, FDA-approved treatment modalities do not exist and clinical trials have not been performed. We present an interesting case of a 66-year-old female, diagnosed with Kadish stage B esthesioneuroblastoma and stage IIA nonsmall cell carcinoma of the lung, who benefited from our treatment. Both malignancies were diagnosed in 2002 at which time the patient consented to undergo left upper lobectomy for her lung cancer, but she refused the craniofacial resection and radiation therapy recommended for treatment of her esthesioneuroblastoma. From 2003 to 2004 she received treatment at the Burzynski Clinic with oral sodium phenylbutyrate (0.2 g/kg/day). She tolerated the treatment very well without significant adverse events. Gradual reduction in her tumor size was confirmed by repeat MRIs. From treatment start in March 2003 to December 2003 her tumor decreased by 40%. Subsequent MRI from March 2004 revealed increased tumor size, which, however, was still a 13% reduction from the baseline MRI. What is important to mention is that in addition to shrinkage of the esthesioneuroblastoma, the patient obtained the clinical benefit of 3.5-years longer survival than was predicted for her lung cancer—whereas the median survival for a patient with stage IIA adenocarcinoma of the left upper lobe of the lung is approximately two years, our patient survived more than five and a half years. The effect of phenylbutyrate (PB) and its metabolite phenylacetate on neuroblastoma and lung cancer is documented by numerous preclinical studies and is also evident in this case. It is proposed that the activity of these two compounds is mediated through increased expression of the p21 tumor suppressor gene. p21 is a strong inhibitor of cyclin-D and cyclin-dependent kinase 4, which contribute to undifferentiated phenotype in neuroblastoma and are instrumental in cell cycle progression from G₁ to S phase. It is hoped that future research and combination of PB with other chemotherapeutic and targeted agents will provide better control of esthesioneuroblastoma and lung cancer.