MET-mutated lung cancer: testing savolitinib before surgery

What happened, in summary

A 68-year-old man with a 40-year smoking history and 20 years of type 2 diabetes was admitted after CT showed a left pleural effusion. Thoracoscopy confirmed adenocarcinoma in the left lung, and PET/CT measured the main lesion at 2.4 x 1.7 cm. Cancer cells were also found in pleural fluid, confirming spread to the pleura. Molecular testing showed a MET exon 14 skipping mutation together with TP53 and BRAF mutations. PD-L1 expression was 5%. The cancer was Stage IVA, cT2aN2M1a.

He received 3 cycles of nedaplatin, pemetrexed, and pembrolizumab. The tumor initially became smaller but then began growing again. Treatment was changed to savolitinib.

After nearly 3 months, imaging showed a partial response and suggested that the disease might have been downstaged enough for surgery. During the operation, however, small areas of pleural seeding were still visible. He underwent left lower-lobe segmentectomy, systematic lymph-node dissection, removal of pleural nodules, pleural fixation, and chemotherapy placed directly into the chest cavity.

Pathology confirmed that metastatic disease remained. One mediastinal lymph node was involved, and the final stage was still ypStage IVA.

The operation reduced the amount of visible disease but did not remove all cancer. Pleural seeding found during surgery showed that imaging had underestimated the remaining disease, and pathology also found one involved mediastinal lymph node. He recovered after the operation and continued oral savolitinib. His final stage remained ypStage IVA despite the earlier partial response and extensive local treatment.