Background

Tobacco consumption accounts for 1.6 million deaths annually in the South East Asia Region (SEAR). Notably, amongst the 10-20% of the global population consuming betel quid and tobacco, about an 81% concentration is in SEAR regions, including India and Bangladesh. The prevalence of HNSCC in these regions is rising alarmingly. For example, HNCs account for 23% of the total 156,775 cancer incidences in Bangladesh. Liquid biopsy tools are unavailable and expensive for most patients in this region. However, early cancer detection using tumor biomarkers, for example, circulating tumor cells (CTCs), is highly implicated. Furthermore, such biomarkers are being validated and have the potential for screening high-risk patients, such as those with a genetic predisposition or tobacco consumption. We report the first observational study in HNSCC patients in Bangladesh correlating the presence of CTCs to chronic tobacco consumption.

Methods

The study involved 70 cancer patients and 10 healthy volunteers (no prior cancer history). 87% of the patients had a specified history of chronic tobacco consumption. CTCs were isolated in 1.5 ml of blood using the OncoDiscover Liquid Biopsy Test, which is clinically approved by the Drug Controller General of India, and contains an enriching anti-EPCAM antibody immunomagnetic kit. CTCs are qualified as CK18+, DAPI+, and CD45-. Subsequently, CTCs were imaged using a Zeiss Axio Observer 7 and quantified for Mean Fluorescence Intensity (MFI) for clinicopathological parameters: age/gender, HNSCC sub-population, and CTC distribution.

Results

This is the 1st study on the Bangladesh phenotype accounting for the presence of CTCs in HNSCC patients. In this population, 34 males (66%) and 10 females (52%) accounted for 91 CTCs. CTC distribution was 0 to 6 with a mean and median of ~ 2.02 and 2, respectively. 25 patients (17 males, 8 females) were negative for any CTCs. Interestingly, 2 patients exhibited CTC clusters indicative of aggressive metastasis, in which 1 patient had no prior tobacco usage or family cancer history. There was no correlation between CTC presence in males (66%) and females (52%). Healthy volunteer samples exhibited no false positives. The MFI values ranged between 23 and 766, with mean and median MFI values of 157 and 96, respectively, indicative of CK overexpression on CTCs of HNSCC patients.

Conclusions

HNSCC patients with a history of chronic tobacco consumption in Bangladesh correlated with the presence of CTCs in 64% of the cases. Prospectively, CTCs may be validated as a biomarker for screening chronic tobacco users in Bangladesh to detect early cancers and HNSCC.

Clinical Trial Information

BMRC/Grants/2018/99 (1-100).