# Salvage Lung Resection of Aspergilloma Mimicking Tumor Regrowth after Immune Checkpoint Inhibitor Therapy for Stage IV Squamous Cell Lung Cancer: A Case Report

## TL;DR

A patient with stage IV lung cancer showed complete remission after immune therapy, but a salvage lung resection revealed a fungal infection rather than cancer recurrence.

## Contribution

This case report highlights the importance of considering non-cancerous complications like aspergilloma after immune checkpoint inhibitor therapy.

## Key findings

- Salvage lung resection revealed a pulmonary aspergilloma instead of tumor regrowth.
- Pathological complete remission was confirmed with no residual cancer.
- Antifungal treatment led to no recurrence of cancer or fungal infection over 1.5 years.

## Abstract

Recent advancements in chemotherapy, including immune checkpoint inhibitors, sometimes achieve complete remission in cases of stage IV lung cancer. On the other hand, immune-related adverse events may occur despite showing successful oncological effects. Herein, we report a rare case of a patient who underwent salvage lung resection after immune checkpoint inhibitor therapy for stage IVB lung cancer, which led to confirmed not only complete pathological remission but also complications with aspergilloma as a result of powerful effect for chemotherapy with immune checkpoint inhibitors.

A 71-year-old woman was diagnosed with stage IVB squamous cell carcinoma of the lung located in the right upper lobe, accompanied by distant organ metastases in the thoracic vertebrae and right adrenal gland. Because the tumor shrank after systemic cytotoxic chemotherapy plus immune checkpoint inhibitor therapy, a partial response was considered to have been achieved clinically, and chemotherapy was discontinued afterward. After 5 months, however, the primary lesion gradually regrew, and tumor regrowth was highly suspected. A bronchoscopic biopsy revealed Aspergillus organism infection other than lung cancer. As local recurrence could not be completely ruled out, salvage thoracoscopic right upper lobectomy with hilar lymph node dissection was performed uneventfully. The pathological diagnosis was pulmonary aspergilloma without residual cancer (pathological complete remission). After the surgery, an antifungal agent was administered for half a year and no obvious cancer recurrence or fungal relapse was detected over 1.5 years.

A salvage lung resection via thoracoscopic surgery was considered a feasible procedure. However, preoperative imaging does not always provide clear evidence of residual cancer, especially after chemotherapy with immune checkpoint inhibitors, as seen in the current patient. Therefore, salvage surgery should be considered comprehensively for selected patients with downstaged or relapsed lung cancer based on close image findings.