Successful Treatment of Synchronous Double Lung and Colon Cancers Using Immune Checkpoint Inhibitors.
Shuichi Matsuoka, Hirokazu Tokuyasu, Katsunori Arai et al.
✦ AI-curated · Sources linked
Case in brief
A patient presented with synchronous advanced cancers: PD-L1-negative squamous cell carcinoma in the left upper lung lobe and adenocarcinoma of the ascending colon. With the lung cancer prioritized, treatment comprised anti-PD-L1 and anti-CTLA-4 antibodies with chemotherapy (the POSEIDON regimen). Both cancers responded effectively. Subsequent testing of the colon cancer showed high-frequency microsatellite instability (MSI-H).
What made this case unusual
The combined regimen was effective against both synchronous cancers despite the lung tumour being PD-L1-negative; the colon tumour was subsequently found to be MSI-H.
Diagnostic / clinical pearl
In this case, testing revealed MSI-H in the colon cancer after treatment had been selected with the lung cancer as the primary target; molecular findings across synchronous tumours may inform interpretation of treatment response.