Immune checkpoint inhibitors and response analysis: a tough challenge. A case report

BACKGROUND: Treatment of metastatic NSCLC patients with immune-checkpoint medicine is intriguing for the potential efficacy; however it may be difficult to evaluate the clinical response due to the lack of reliable immune-monitoring markers up to now and the possibility of radiological pseudo-progression. CASE PRESENTATION: Herein we report the case of a patient ex-smoker with adenocarcinoma of the lung, stage IV for liver metastases, in progression after cisplatin-based chemotherapy and treated with antiPD-L1 (MPDL3802-Roche Genentech) e.v. every 3 weeks in a clinical trial. Treatment with antiPD-L1 was well tolerated and CT scan after 6 weeks of treatment showed stabilization of mediastinal lymph nodes, while progression of liver metastases; liver progression only was confirmed by further CT-scans. Patient was asymptomatic and it was unclear if we faced a pseudo-progression in the liver or a real progression. Data about his PDL1 expression were not available because the patient was in a clinical trial. Eventually a biopsy of the liver metastasis confirmed that there was a massive neoplastic invasion with tumor infiltrating lymphocytes <5 %. We stopped anti-PD-L1 therapy due to progression. CONCLUSION: Evaluation of response may be difficult with immune checkpoint inhibitors, in particular radiologic images may be a matter of debate; eventually we performed a biopsy to study tumor infiltrating lymphocytes to decide whether it was pseudo-progression or real progression.