What happened, in summary

A man in his 70s with a long smoking history was diagnosed with Stage IV lung adenocarcinoma in late 2019. Imaging showed a large mass in the left lower lung, other lung nodules, enlarged lymph nodes, and brain metastases. Tumor testing found KRAS Q61H and TP53 mutations.

He received 6 cycles of pemetrexed and cisplatin chemotherapy and had a partial response. He then continued pemetrexed alone as long-term maintenance treatment. Over time, the schedule was made less frequent because of recurring skin rash. Other treatment side effects, including changes in blood sugar and kidney function, were managed while therapy continued.

The brain metastases were treated with focused radiation soon after diagnosis. More than a year later, one treated brain lesion enlarged on scans. It was eventually removed surgically, and the findings were thought most consistent with radiation-related damage rather than active recurrent tumor. Follow-up brain imaging showed no residual or recurrent lesion.

He has now been followed for more than 60 months. The latest assessment found no current evidence of tumor progression, representing unusually prolonged control of Stage IV lung cancer on maintenance chemotherapy.