Can cholera vaccine reduce the risk of death in colorectal cancer patients?

A Swedish study showed that vaccination with cholera after diagnosis of colorectal cancer can reduce the risk of colorectal cancer-related death and all-cause mortality. (Online version of Gastroenterology September 15, 2017).

This should be the first national population-based study to explore the relationship between vaccination with cholera after diagnosis of colorectal cancer and the risk of death. Previous studies have shown that the cholera vaccine may have multiple effects in regulating the body’s immune system and may also reduce the formation of colon polyps in mouse models.

The researchers believe that colorectal cancer is more common in developed countries than in developing countries. Perhaps less exposure to microbes in childhood is also associated with an increased risk of developing colorectal cancer in adulthood.

The researchers used the Swedish National Cancer Registration and Prescription Drug Registration Database to retrospectively analyze the data of 175 patients who received cholera vaccine after diagnosis of colorectal cancer from mid-2005 to 2012. As for the reason why the cholera vaccine is unknown, it may be that patients need to travel to other countries.

The analysis showed that compared with patients who were not vaccinated with cholera (525 patients), patients who received cholera vaccine after diagnosis of colorectal cancer had a 47% lower risk of colorectal cancer death and a 41% overall risk of death. This survival advantage exists in patients with different ages, genders, and stages of colorectal cancer at diagnosis.

The researchers hypothesized that the cholera vaccine may play a role in inhibiting the progression of colorectal cancer by stimulating immune cells such as CD8 positive T cells, macrophages and NK cells, and / or by affecting the expression of genes related to tumorigenesis. The researchers believe that if the results of these studies can be verified in other population-based studies or randomized clinical studies, then the use of cholera vaccine for adjuvant treatment of colorectal cancer is not impossible.

Researchers studying microbial infections and tumors have pointed out that more and more research evidence supports that microbes or their products can stimulate the body’s immune system and bring health benefits for the protection of certain types of tumors and immune-related diseases However, the improvement of sanitary conditions makes us less and less likely to obtain a healthy immune system caused by microbial exposure. A safe oral vaccine that can enhance immune function may bring us significant health benefits.