What happened, in summary

A 71-year-old woman was diagnosed with lung adenocarcinoma in December 2015. Molecular testing identified an ALK fusion. She initially declined crizotinib and received pemetrexed plus cisplatin, followed by another chemotherapy course in 2017 when the cancer enlarged. By May 2019, the cancer had spread to multiple bones, including the cervical spine, sacrum, right ilium and first rib. She then started crizotinib and the lung and metastatic tumors shrank substantially. Within several months, however, large cystic lesions developed in both kidneys and the liver. Biopsies showed inflammation and necrosis rather than cancer, confirming a treatment-related complication. Crizotinib was stopped, and the cysts gradually regressed. She later switched to alectinib. At the latest follow-up described, the cystic lesions remained controlled and the lung cancer and hilar lymph nodes were stable.