A Bystander Effect of Lung Cancer Chemotherapy on Chronic Echinococcal Disease.

Hydatid cystic disease is a parasitic infestation caused by and commonly manifests as hepatic and pulmonary cysts. When feasible, based on cyst size and location, surgical resection is potentially curative. Post-surgical recurrence of disease is encountered in up to 25% of patients. Secondary peritoneal contamination is a recognized complication in 5-10% of cases. Disseminated disease is usually palliated using systemic anti-parasitic agents such as benzimidazoles, albendazole and mebendazole but worsening of disease post-systemic treatment is frequent in 14-25% of patients. In this report, we share our experience of a patient with long-standing, chronic disseminated hydatidosis and subsequent diagnosis of non-small cell lung cancer who manifested evidence of reduced activity of the echinococcal disease following institution of chemotherapy for his new diagnosis of lung cancer. There was significant reduction in the serum level of anti-echinococcal antibody titers in tandem with chemotherapy administration. There was also minimal but notable decrease in the size of the cysts on serial cross-sectional imaging obtained for monitoring cancer response to chemotherapy. This intriguing observation of a possible benefit of anticancer chemotherapy against echinococcal disease in this index case may provide new insights for therapeutic exploration in disseminated echinococcal disease.