What happened, in summary

A 76-year-old man with a smoking history had been followed for lung nodules for more than 1 year. He was admitted after half a month of shortness of breath, and imaging found a 5.8 x 4.9 cm mass in the right upper lung. Imaging showed involvement of the upper pulmonary vein, mediastinal lymph nodes, and right hilar lymph nodes. Needle biopsy showed poorly differentiated lung adenocarcinoma. Molecular testing found a MET exon 14 skipping mutation.

The cancer was classified as Stage IIIB, cT4N2M0, and was initially considered unsuitable for surgery. He began savolitinib 400 mg once daily as induction treatment before any possible operation.

After 2 months, CT showed an 82% reduction in the primary tumor, together with shrinkage of the involved lymph nodes. The strong response made surgery possible. He underwent video-assisted right upper lobectomy with systematic lymph-node dissection.

Pathology found only about 5% viable cancer remaining in the removed lung tissue. No cancer was found in the dissected lymph nodes. The postoperative stage was ypT2aN0M0, Stage IB, representing major downstaging from the original Stage IIIB diagnosis.

He recovered from surgery and continued savolitinib as adjuvant treatment. The strong response changed an initially unresectable Stage IIIB cancer into disease that could be removed surgically. The lower postoperative stage reflected the response to savolitinib, not a different initial diagnosis. He continued daily savolitinib after surgery, and no serious treatment-related side effect occurred during follow-up.