Evaluation of Trace Elements’ Concentrations in Nails of Esophageal and Stomach Cancer Patients: as an Early Diagnostic Screening Tool

Abstract

This study aimed at investigating a possible early screening diagnostic tool for cancer. Cancer is ranked third among the leading causes of deaths in Kenya with an average of 75% of cancer patients being diagnosed at advanced stages of the disease. This late diagnosis is attributed to most patients only presenting themselves for check-ups when the disease has progressed. Information from various literature established that among the several causes of cancer, is prolonged exposure to toxic heavy metals and high concentrations of trace elements to the body. The study therefore aimed at evaluating the concentrations of Cr, Hg, Se, Pb, Cu, Zn, and Fe elements in the human body from esophageal and stomach cancer patients in Kenya. It was expected that this research work would identify a correlation between trace elements’ concentrations with esophageal and stomach cancers, which can be used as a prediction of the disease. This will allow for early intervention measures thereby reducing and mitigating the disease burden. It was a case-controlled study comprising 95 esophageal and stomach cancer patients and 31 non-cancer volunteers as a control group. Fingernail clippings were obtained by the researcher from newly diagnosed stomach and esophageal cancer patients at the Kenyatta National Hospital, Nairobi, Kenya who had consented to take part in the study. The study participants were recruited from adults aged between 32 to 65 years and were randomly selected from the health records at the Kenyatta National Hospital, Cancer Treatment Centre. The control group comprised of adult volunteers of matched age and sex and without any known cancer history, from orthopedic surgery, general surgery and ophthalmology wards at the Kenyatta National Hospital. Informed consent was obtained and written questionnaires administered by the principal investigator before participating in the study. The total number of esophageal cancer patients who participated in this study were 72, while 23 were stomach cancer patients and 31 non-cancer control group. An average of 50 mg of nail clipping samples were obtained from each participant using sterilized stainless nail cutters. Each of the nail samples were then cleaned by putting under continuous stirring according to sample washing procedure as suggested by International Atomic Energy Agency. Drying of the samples was done between filter papers for 24 hours and weighed before digestion. Wet acid digestion method using concentrated nitric acid was applied. The accuracy of the procedure was validated by analyzing three replicate samples; with Yttrium as the internal standard. Analysis of the samples was done using Total Reflection X-Ray Fluorescence technique for detection of the seven selected trace elements for the study; while R statistical software was used to analyze the data. Trace elements in finger nail clippings varied in concentrations. The mean concentrations of Cr, Fe, Cu, Zn, Se, Hg and Pb in esophageal cancer patients were 8.32 μg g-1, 212 μg g-1, 21. 8 μg g-1, 211 μg g-1, 2.04 μg g-1, 2.24 μg g-1, 9.01 μg g-1respectively; and 11.6 μg g-1, 209 μg g-1, 18.3 μg g-1, 265 μg g-1, 1.70 μg g-1, 2.56 μg g-1, 10.1 μg g-1 respectively in stomach cancer patients; while in the non-cancer patients, the mean concentrations were 3.17 μg g-1, 213 μg g-1, 28.1 μg g-1, 258 μg g-1, 1.06 μg g-1, 1.39 μg g-1, 10.5 μg g-1for Cr, Fe, Cu, Zn, Se, Hg and Pb respectively. The specific objectives of the study were therefore achieved. These findings revealed that evaluation of Cu, Cr, Pb, Se and Hg in nail clippings using TXRF can be used as an early screening diagnostic tool for cancer. There were no correlations established for Fe and Zn concentrations. Further research on analysis of other heavy metals and trace elements using different analytical tools are recommended to ascertain the conclusions of this study.