# Case Report: Personalized, functional drug sensitivity-guided chemotherapy achieves long-term disease-free survival in canine pulmonary adenocarcinoma

## TL;DR

A dog with lung cancer had its tumor cells tested to find the best chemotherapy drugs, leading to over 500 days of cancer-free survival.

## Contribution

Demonstrates the clinical benefit of using functional drug sensitivity testing and organoids for personalized chemotherapy in canine lung cancer.

## Key findings

- Doxorubicin and toceranib showed high cytotoxicity in ex vivo testing and were used for adjuvant therapy.
- The dog remained disease-free for 548 days after treatment with no recurrence or metastasis observed.
- Personalized chemotherapy based on functional testing led to improved outcomes in a high-risk canine PAC case.

## Abstract

Canine pulmonary adenocarcinoma (PAC) is a relatively uncommon primary lung tumor in dogs, with prognosis influenced by clinical stage, histological grade, and surgical margins. Despite surgical resection being the treatment of choice, long-term outcomes remain highly variable, and the benefit of conventional empirically chosen adjuvant chemotherapy remains limited, especially in high-risk cases.

A 10-year-old spayed female Maltese dog presented with a solitary pulmonary mass was diagnosed with moderately differentiated PAC after complete (R0) resection via right middle lung lobectomy. Given the tumor’s histological grade and suspected nodal involvement, ex vivo functional drug sensitivity testing using patient-derived tumor cells and three-dimensional organoid culture was performed to guide personalized chemotherapeutic selection.

Doxorubicin and toceranib exhibited the highest cytotoxicity and were sequentially administered as adjuvant therapy. The patient tolerated the treatment well without notable adverse effects, and serial thoracic imaging over 548 days revealed no evidence of recurrence or metastasis.

This case highlights the clinical utility of integrating functional drug sensitivity testing and organoid validation into personalized chemotherapy decision-making for canine PAC, demonstrating prolonged disease-free survival exceeding 500 days in a patient with intermediate-grade histology and suspected nodal involvement.