[A Case of Drug-Induced Pneumomediastinum Preceding Interstitial Pneumonitis Onset during Treatment with a First-Line Regimen of GnP in a Patient with Unresectable Pancreatic Cancer].

BACKGROUND: The highest prevalence of drug-induced interstitial pneumonitis(IP)occurs in patients receiving antineoplastic agents, such as cytotoxic chemotherapeutic drugs, molecular targeted drugs, and immune checkpoint inhibitors. A certain period of the treatment for IP requires discontinuation of the anticancer therapy, resulting in progression of the malignant status. CASE: A 70-year-old man was incidentally diagnosed with locally advanced unresectable pancreatic cancer in the course of his treatment for ventricular dysrhythmia. After the insertion of a pacing instrument, he was ensured to be eligible to receive combination chemotherapy with gemcitabine and nab-paclitaxel(GnP)as the primary regimen. Shortly after the second course of GnP, the patient had high fever and developed pneumomediastinum 3 days prior to the onset of IP. The GnP treatment was suspended, and the IP was treated with pulse steroid therapy. The respiratory disorder took approximately 3 months to resolve; however, this concomitantly led to aggravation of the malignancy, which developed multiple metastases to the liver. The patient was no longer allowed to receive antineoplastic treatment. CONCLUSION: Although GnP may be a key regimen for the treatment of unresectable pancreatic cancer, patients should be closely monitored to ensure early detection of adverse events, such as interstitial pneumonia. Furthermore, drug-induced pneumomediastinum may be a precursor to the onset of interstitial pneumonia.

[A Case of Advanced Late Recurrence of Hormone Receptor Positive Breast Cancer Successfully Treated with Abemaciclib and Anastrozole].

BACKGROUND: In step with the aging of the Japanese population, late recurrence of hormone receptor positive (HR+) breast cancer occurring especially beyond 20 years after the initial diagnosis has been recognized as not rare anymore, as it has been occurring at a constant rate lately. The administration of an aromatase inhibitor with a CDK4/6 inhibitor has become the gold standard in Japan for cases of recurring HR+ breast cancer without severe visceral metastasis. CASE: A 73- year-old woman was diagnosed by chance with late recurrence of HR+ breast cancer 21 years after undergoing radical resection followed by adjuvant anastrozole for 5 years for stage Ⅲb right breast cancer. Asymptomatic multiple bone metastases on her ribs and sternum with bilateral lung metastasis and malignant effusion all disappeared while she was on a year- long administration of anastrozole and an optimal dose of abemaciclib(100 mg bid). However, because of the Grade 3 digestive adverse event that occurred at approximately 1 year of treatment, she could only maintain the treatment for up to 13 months. After then, no recurrence has been detectable for 6 months so far. CONCLUSION: CDK4/6 inhibitors, in combination with anastrozole, will play a pivotal role in the initial approach to elderly patients with HR+ late recurrence as a chemotherapy- free strategy.