# Repurposing hydrochlorothiazide (HCTZ) for colorectal cancer: a retrospective and single center study

## TL;DR

This study shows that hydrochlorothiazide, a blood pressure drug, may improve survival and reduce cancer recurrence in colorectal cancer patients.

## Contribution

The study identifies hydrochlorothiazide as a potential repurposed drug for improving colorectal cancer prognosis.

## Key findings

- HCTZ-treated CRC patients had a 79.1% 5-year survival rate, higher than other antihypertensive groups.
- HCTZ reduced recurrence rates to 18.3%, significantly lower than non-HCTZ groups and Hong Kong's CRC average.
- Lower pre-operative basophil levels correlated with better survival outcomes in HCTZ-treated patients.

## Abstract

Anti-hypertensive drugs have been reported to demonstrate anti-inflammatory and anti-angiogenic effects. This study aims to investigate the association between anti-hypertensive drugs and the prognosis of colorectal cancer (CRC) patients.

Clinical data of 1134 CRC patients with hypertensions and the prescription of anti-hypertensive drugs who had undergone curative surgery in our hospital between 2005 and 2015 were retrieved. Their survival data and immune cell population in circulatory blood were compared among different types of anti-hypertensive drugs and overall CRC patients.

The 5-year overall survival for the antihypertensives-treated patients (65.2%) was higher than the CRC patients in Hong Kong (58.2%). Hydrochlorothiazide (HCTZ) group showed the best prognosis (79.1%) among different antihypertensive drug, particularly for advance stage or elderly patients, which are poor prognostic factors for overall CRC patients, demonstrated an obviously improved prognosis upon HCTZ treatment. Moreover, our data showed the recurrence rate was significantly lower for HCTZ group (18.3%) compared to non-HCTZ group (26.8%) and the reported rate (31%) of CRC patients in Hong Kong. Finally, patients with a lower pre-operative basophil level showed better overall and disease-free survival following HCTZ treatment.

This study demonstrated the association of HCTZ treatment with a better prognosis of CRC patients.