Intestinal helminths and protozoan infections in patients with colorectal cancer: prevalence and possible association with cancer pathogenesis
The purpose of the present study was to determine the prevalence of intestinal helminths and protozoa in colorectal cancer (CRC) patients and to evaluate the possible association between the prevalence and CRC pathogenesis. A total of 200 CRC patients and 200 residents of Tashkent, who had no complaints related to the gastrointestinal tract, were examined by triple coproscopy using a concentration method and estimations of protozoan infection intensity. Of the CRC patients tested, 144 were classified as T1-4N0M0 (without metastases) and 56 were classified as T1–4N1–2M0–1 (with metastases). Parasitological examination was performed during CRC diagnosis before and after surgery and chemotherapy. A significantly higher prevalence of Blastocystis sp., Chilomastix mesnili, Jodamoeba butschlii, and Endolimax nana was found in CRC patients than in the control population (p < 0.0001), amounting to 80, 20, 22.5, and 11.5%, respectively. The high prevalence of Blastocystis sp., as well as the patterns of infection intensity, was stable at all stages of examination. The ratio of the number of CRC patients with and without Blastocystis sp. in the T1–4N0M0 and T1–4N1–2M0–1 groups amounted to 3.3 and 7.0, respectively. The ratios for C. mesnili, E. coli, J. butschlii, and E. nana in both groups were 0.2 and 0.2, 0.07 and 0.07, 0.3 and 0.16, and 0.18 and 0.01, respectively. The prevalence of helminths and Giardia lamblia in CRC patients and the control population was not significantly different. Taken together, these data indicate a possible role for Blastocystis sp. in CRC pathogenesis. Diagnosis, treatment, and further observation of patients with Blastocystis sp. are necessary at all stages of CRC, including during diagnosis and before and after surgery and chemotherapy.
KeywordsColorectal cancer Blastocystis sp. Intestinal helminths Protozoan infections CRC
Funding was provided by the Ministry of Public Health of the Republic of Uzbekistan (ADCC 15.21.2). The Ministry of Public Health of the Republic of Uzbekistan had no role in the design of the study or in any aspect of conducting the study (the collection, management, analysis, and interpretation of the data or the preparation, review, or approval of the manuscript).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
The study was approved by the Medical Ethics Committee of the Ministry of Health of the Republic of Uzbekistan in accordance with the Declaration of Helsinki (World Medical Association 2013). The trial is registered at the US National Institutes of Health (ClinicalTrials.gov) #NCT03173001. Both informed and written consents were obtained from the patients and controls.
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