Sjögren syndrome during nivolumab treatment for HER2-positive metastatic gastric cancer

What happened, in summary

A 60-year-old man was treated for HER2-positive advanced gastric adenocarcinoma that had already spread to the liver and both lungs, making it Stage IV. First-line capecitabine plus cisplatin was combined with trastuzumab. Weekly paclitaxel followed as second-line therapy. After the lung metastases disappeared on imaging, he underwent total gastrectomy and radiofrequency ablation of the liver metastasis.

Six months after surgery, a left adrenal metastasis appeared. Irinotecan, radiation and ramucirumab were used, but the adrenal lesion continued to grow and multiple lung metastases returned. Nivolumab was then started as fifth-line treatment. After 4 cycles, imaging showed marked shrinkage of the lung metastases while the adrenal lesion remained stable.

During nivolumab treatment he developed severe persistent dry mouth. Testing ultimately confirmed Sjögren syndrome as an immune-related adverse effect. Steroid treatment and pilocarpine provided little improvement, and the symptoms interfered with eating and denture stability. Nivolumab was stopped after 21 courses because of persistent Sjögren syndrome and worsening chronic obstructive pulmonary disease.

Despite stopping nivolumab, cancer control persisted. One year later, the reduction in lung metastases was maintained and the adrenal metastasis remained unchanged. His dry-mouth symptoms, however, were still severe, illustrating the trade-off between a meaningful anticancer response and a lasting immune-related treatment complication.