Second primary malignancy post immunotherapy: A case report of 2 cases.

Rationale: Immune checkpoint inhibitors have shown high efficacies as the first-line treatment of various advanced malignancies. Yet, the effect and practice patterns of immune checkpoint inhibitors on the second primary tumors are still unclear. Second primary malignancy post immunotherapy, there is paucity in such cases being reported.

Patient Concerns: We report 2 cases of a 57-year-old woman with nonsmall cell lung cancer and a 69-year-old man with metastatic clear cell renal carcinoma treated with immunotherapy who developed second primary malignancies during the therapy.

Diagnosis: Second primary malignancy during the therapy.

Interventions: In addition to the treatments of the second primary malignancies, maintenance immunotherapy was continued for the patients.

Outcomes: Overall survival in both patients was longer than 12 months, and the treatments were well tolerated. The adverse reactions mainly included depigmentation of hair and facial and limb skin in patient 1 and diarrhea in patient 2.

Lessons: It is necessary to recognize that the second primary malignancy may occur during the immunotherapy, and more clinical studies and practices are still needed for the adjustment of the regimens of immunotherapy. Full diagnosis, timely treatment, and long-term regular follow-up have important significance for patients with malignancies.