Hyperprogressive disease in lung metastases without target lesion progression after durvalumab consolidation therapy: A case report

Hyperprogressive disease (HPD) is a novel progressive pattern that occurs after immune checkpoint inhibitor (ICI) administration. Here, a 74‐year‐old woman who had undergone right lower lobectomy for lung cancer received curative chemoradiotherapy followed by consolidation therapy with durvalumab for metastatic recurrence confined to the mediastinal lymph nodes. Three weeks later, multiple randomly distributed nodular shadows appeared on chest CT, and thoracoscopic lung biopsy led to the diagnosis of multiple pulmonary metastases. HPD may be suspected when multiple metastases appear in new organs early after the administration of ICIs. This phenomenon may occur not only with ICI monotherapy but also with the administration of ICIs after chemoradiotherapy. Therefore, patients who have received radiation therapy should also be given similar attention early after the administration of ICIs.