Transformation or Progression from Adenocarcinoma to Small Cell Lung Cancer Detected by Serially Tracking Mutations in the Blood

• Main Authors: Arutha Kulasinghe, James Monkman, Mark Nalder, Connor O’Leary, Rahul Ladwa, Ken O’Byrne
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Reports
• Subjects: circulating tumour dna; non-small-cell lung cancer; mutations
• Online Access: https://www.mdpi.com/2571-841X/3/4/33

<b>Background</b>: Circulating tumour DNA (ctDNA) has emerged as a promising biomarker for monitoring non-small-cell lung cancer (NSCLC). This has enabled the monitoring of clinically actionable mutations over the course of therapy. <b>Case presentation:</b> We present the case of a 74-year-old female who was treated with EGFR inhibitors for NSCLC which later transformed to SCLC. The kinetics of ctDNA was monitored by measuring the EGFR Exon 19 mutant L747–A750 > P and PIK3CA E545K over the course of therapy. Stabilisation of the PIK3CA mutation was found in response to therapy, however there appeared to be increasing levels of the EGFR mutant, potentially reflective of untreated EGFR-driven disease. <b>Conclusion:</b> The key finding described here, revealed by mutational tracking of mutations from the blood, is that clinically actionable mutations are assessable and may demonstrate clinical utility in measuring disease burden, multiple clones and progression non-invasively for lung cancer.