BACKGROUND

Despite being the second least populated state, Mizoram exhibits the highest incidence rate of cancer in India. Its inhabitants, constituting an endogamous and isolated population, have embraced their own distinct culture, way of life and dietary preferences, setting them apart from the rest of mainland India. In 2003, the Mizoram Population Based Cancer Registry (PBCR) was established under the auspices of the National Centre for Disease Informatics and Research (NCDIR), a division of the Indian Council of Medical Research (ICMR), in collaboration with the Department of Health & Family Welfare of the Government of Mizoram, India.

METHODS

Cancer incidence and mortality data were extracted from the Mizoram PBCR spanning the years 2003-2020. The Age Standardized Incidence Rate (ASIR) and Age Standardized Mortality Rate (ASMR) were computed per 100,000 individuals, utilizing Segi's World Standard Population as the benchmark. The trajectory of these changes was analysed employing the Joinpoint Regression Analysis Program, Version 4.9.1.0.13, to unveil the Annual Percent Change (APC) with a 95% Confidence Interval and a Significance test (p < 0.05) using Monte Carlo Permutation. The resulting graphical visualizations were generated using Flourish Studio.15.

FINDINGS

The overall ASIR for all cancer sites among men was 197.2 per 100,000, while for women, it was 164.9 per 100,000. Among men, the most prevalent cancer site was the Stomach (ASIR = 41.4), followed by Head & Neck, Lung, Oesophagus, Colorectal, Liver, Urinary, Non-Hodgkin's Lymphoma and Prostate cancers. Conversely, among women, Lung cancer exhibited the highest incidence (ASIR = 26.7), succeeded by Cervical, Breast, Stomach, Head & Neck, Colorectal, Oesophagus, Liver and Ovarian cancers. Stomach cancer emerged as the leading cause of death among men (ASMR = 22.6) and among women, Lung cancer held the highest ASMR (15.9). Joinpoint regression analysis revealed a rising trend in incidence and mortality over time for overall cancer sites. Among the primary cancer sites contributing to incidence and mortality, an increase in APC was observable for all, except Stomach cancer, in both men and women. The diagnostic approach, except for cases of cancer with unknown primary sites, involved a microscopic method.

INTERPRETATION

This cross-sectional study examines PBCR reports spanning from 2003 to 2020, shedding light on a consistent uptick in cancer incidence and mortality trends in Mizoram. Stomach cancer emerges as the most prevalent and primary cause of cancer-related deaths among men, while Lung cancer takes a parallel role in women. The elevated cancer incidence and the growing trend among younger generations might stem from the static lifestyle and dietary patterns prevalent within the endogamous tribal population, potentially contributing to a genetic predisposition. The escalation in mortality rates could be attributed to a dearth of specialized diagnostic facilities and skilled human resources, treatment strategies guided by genomic research and transportation challenges. This underscores the urgent requirement for comprehensive scientific exploration across diverse facets. The implementation of easily accessible diagnostic facilities in proximity and genetic testing for pharmacogenomics to enhance prognoses would also aid in mitigating the burden and advancing the healthcare system's effectiveness.

FUNDING

Population Based Cancer Registry (PBCR) was supported by National Centre for Disease Informatics and Research (NCDIR) of the Indian Council of Medical Research (ICMR), India.