Nowadays the frequency of cancer is increasing regardless of the age range and has become the leading cause of mortality across the world. Mutations in the DNA, which guide the cells how to grow and divide, set the stage for cancer. This mutation can occur for both genetic and environmental factors. Normally cells are able to fix most of the mutations in their DNA, but when cells fail to repair this, the mutation that is responsible for the uncontrolled proliferation of the cells becomes malignant (Prakash et al., 2013).
Cancer and its Probable Causes
As per the WHO, cancer is defined as “a large group of diseases that can start in almost any organ or tissue of the body when the abnormal cells grow uncontrollably, go beyond their usual boundaries to invade adjoining parts of the body and/or spread to the other organs” (“The Global Challenge of Cancer,” 2020). Early epidemiological studies have identified exposure to occupational agents like soot, x–rays, shale oil, chromate, and coal tar, and non–occupational agents like tobacco snuff were significant causes of cancer (Blackadar, 2016). However, as of late, the significant causes of cancer have been identified as tobacco and viral infections like HIV, hepatitis B, Epstein–Barr virus. Other minor factors that lead to cancer development are poor diet, excessive consumption of alcohol, obesity, exposure to ionizing radiation, genetic disorders like Lynch syndrome, and excessive sun exposure. In addition, high-dose chemotherapy, hormonal drugs, immune-suppressing drugs, and exposure to radioactive materials like radon have also been implicated with an increased risk of cancer (Saini et al., 2020).
Figure 1.
Probable Causes of Cancer
Global Scenario of Cancer
The most typical source of death after cardiovascular diseases globally is cancer. According to the World Health Organization, cancer is a leading cause of one in six deaths (“The Global Challenge of Cancer,” 2020). The worldwide incidence of cancer is approximated to have gone up to new cases of 19.3 million and deaths of 10.0 million in the year 2020 (Sung et al., 2021). Globally, one in five individuals experiences cancer at some point in their life, and one in eight men and one in eleven women pass away from cancer.
Female breast cancer is reported as the most common type of cancer worldwide in a current report. Leukemia and pancreatic cancer are other common forms of cancer reported (Ferlay et al., 2015). Cancers of the lip and oral cavity account for the 16th most common form of cancers in the world. In South Asia, Pakistan had the highest incidence of cancer of the lip and oral cavity, 12.2 individuals per 100,000 people, followed by Bangladesh, 9.5 individuals per 100,000 people, and India, 9.1 individuals per 100,000 people (Bray et al., 2018).
Statistically, across the globe, the middle-income and the high-income countries have been suffering from cancer of the respiratory tract, which is tracheal, bronchus, and lung cancer, which raises death tolls there. It varies in the countries with lower-income status from colon and rectal cancer, liver cancer, cervical cancer, stomach cancer to breast and prostate cancer, and shuffling the list (D. Brown et al., 2021).
According to the World Health Organization (WHO), cancer's deadly strike will affect one in five men and one in six women before they reach the age of 75. Again, one in eight men and one in twelve women will be deceased from the disease. There is a chance of being affected by cancer within 2040 of around 27 million people (Boyle & Levin, 2008).