Lung Cancer Treatment Complicated by Atezolizumab-Related Pneumonitis

What happened, in summary

A 72-year-old man with chronic obstructive pulmonary disease and more than 50 pack-years of smoking history had a screening CT that found a 25 mm left upper-lung nodule and enlarged mediastinal lymph nodes. Initial mediastinal sampling did not show cancer, but a wedge resection confirmed poorly differentiated adenocarcinoma with cancer in a station 5 lymph node. The tumor was pT2aN2M0, consistent with Stage III disease, and the surgical margins were positive.

Because completion lobectomy was considered too difficult, he received paclitaxel and carboplatin with radiation. Imaging 2 months later suggested a partial response, but another scan 3 months after that showed progression. Testing found no EGFR or BRAF mutation and no ALK rearrangement. He started atezolizumab as second-line treatment.

Two months later, he developed worsening shortness of breath. Infection and cancer-related lung changes were considered, but the clinical assessment supported atezolizumab-related pneumonitis. The drug was stopped, and prednisone initially improved his breathing. Symptoms returned about 2 weeks after the taper ended, so a longer steroid course was started. He improved modestly but continued to need oxygen. A later scan found a right adrenal mass highly suspicious for malignancy, and he began pemetrexed.