A Complete Spontaneous Regression of Lung Cancer with Variations in Size over 38 Months

Abstract

Background. Spontaneous regression (SR) is a rare phenomenon in cancer patients. Case. An 82-year-old man was referred to the outpatient department because of an abnormal chest shadow in July 2015. Although bronchoscopy led to a diagnosis of non-small cell carcinoma, the patient refused treatment and insisted upon follow-up observation only. The lesion remained relatively stable for 14 months. However, a follow-up visit in September 2016 revealed disease progression, and a repeat bronchoscopy revealed squamous cell carcinoma of the lung, as well as a decrease in the CD8⁺ T cell population. The patient continued to refuse treatment. Subsequently, the lesion grew smaller and exhibited a complete SR in November 2017. Conclusion. While the mechanisms underlying SR remain obscure, CD8⁺ T cells appears to play a crucial role. Still, remaining malignancy cannot be excluded even if a lesion has decreased in size.