EGFR-Mutant Lung Adenocarcinoma That Transformed to Small Cell Lung Cancer

What happened, in summary

A 44-year-old woman who had never smoked was diagnosed with Stage III poorly differentiated lung adenocarcinoma carrying an EGFR exon 19 deletion. She received 3 cycles of cisplatin and vinorelbine before radiation and a left lower lobectomy. Within months, the cancer recurred in lymph nodes, and she began erlotinib.

When a later lung biopsy found the EGFR T790M resistance mutation, treatment was changed to osimertinib. She initially improved, but the cancer progressed again. She received focused radiation to a lung lesion while continuing osimertinib and also received a personalized neoantigen vaccine.

By month 38, multiple liver metastases had appeared. A liver biopsy showed that the cancer had transformed into small cell lung cancer and no longer showed the earlier EGFR mutations in that sample. Six cycles of carboplatin and etoposide produced an initial response, but the disease progressed again soon afterward. A later mediastinal biopsy again showed small cell cancer with the original EGFR exon 19 deletion but without T790M.

She went on to receive carboplatin and paclitaxel, mediastinal radiation, and afatinib as breathing problems and progressive disease worsened. She died 49 months after her original lung-cancer diagnosis.