Smoking And Cancer
Smoking is a habit that has developed all around the world. The common reasons being stress, as a source of comfort and even for social reasons. It is a negative lifestyle that is generally known to cause serious harm to one’s health, more specifically its link to various types of cancers. The International Agency for Research on Cancer found that of the 7000 thousand chemicals and compounds found in a cigarette, 72 of them are carcinogenic, which can induce the formation of cancer. Research has proven that smoking just one cigarette a day can reduce your lifespan by 11 minutes. With the growing amount of habitual smokers, it has stated that tobacco smoking (TS) is one of the causes of the incidence and mortality of cancer in the world (Khani, 2018).
Lung cancer is commonly known to be directly linked to cigarette smoking. This is because the lungs are taking in the contents of the smoke which are mostly toxic chemicals. According to Kligerman and White, the science behind it is that “cigarette smoke contains free radicals that will lead to oxidative damage in humans which will act as a catalyst in the development of lung cancer” (Khani et. al, 2018). Statistics have shown that out of the 1.25 billion smokers worldwide, more than 1 million die of tobacco-induced lung cancer every year. It can be said that smokers who start at a young are at a will face a higher risk of developing lung cancer.
In addition to that, the human upper aerodigestive tract (UADT) which is the combination of tissues and organs of the respiratory tract and the upper part of the digestive tract. According to Lee, UADT cancers that can be caused by smoking “include oral, pharyngeal, hypopharynx, larynx, oesophagus, nasal cavities, nasal, sinuses, pharynx and adenocarcinoma of oesophagus” (Khani et. al, 2018). Despite the fact that nasal cancer is rare, smoking significantly increases the risk of developing this disease. Fortunately, a study done by Bosetti et al. shows that discontinuation of smoking at any age has reduced the risk of UADT incidence (Khani et. al, 2018).
Smokers are also at a higher risk of developing pancreatic cancer and is responsible for 11-32% of pancreatic cancer worldwide. Iodice et al. mentioned that the risk of cancer is positively correlated with an increase in the number of cigarettes and duration of use (Khani et. al, 2018). Therefore, a regular smoker is more prone to developing this type of cancer in comparison to a non-smoker. According to a study carried out by Lynch, individuals who smoked 30 or more doses daily, relative risk (RR) was 1.75 and in those who smoked at least 50 years, while in people who had left smoking for more than 15 years, RR was similar to those who never smoked (Khani, 2018).
Furthermore, Hodgkin lymphoma is a rare type of cancer that forms in the white blood cells. Its link to cancer has been proven to be true based on a research conducted by Million Women Study which reveals that “the risks of Hodgkin lymphoma and mature T-cell lymphomas were doubled in women who smoked around 15 or more cigarettes a day” (Action on Smoking and Health, 2017). These findings are in line with previous research which found that the risk of Hodgkin lymphoma increased with the number of cigarette packs per day, this association being of particular importance for mixed cellularity subtypes (Jacob, 2018).
One interesting finding of one of the studies using real-world data from the UK is that smoking increased the risk of liver cancer in men. This could be explained by the fact that several tobacco components such as N-nitrosodimethylamine, 4-Aminobiphenyl, arsenic, and vinyl chloride that are known liver carcinogens. However, Khani et.al (2018) mentioned there are other risk factors to take into account such as hepatitis B, hepatitis C and high consumption of alcohol as well play an important role in the development of liver cancer.
Tobacco is known to contain cancer-causing chemicals and this could put the bladder at risk. This is because these chemicals pass through the smoker’s bloodstream and eventually end up being filtered by the kidneys, which could mean that these chemical deposits in the kidneys and may never leave your body. It has been found that “tobacco combustion release at least 69 carcinogens including nitrosamine, polycyclicaromatic hydrocarbon, 2-naphthylamine and other aromatic amines, all of which are directly responsible for the role of mutagens in bladder cancer formation” (Khani et. al, 2018). Interestingly, another work observed that smoking had a significant impact on renal cell carcinoma only in patients without obesity and hypertension. Meaning that, they could be an individual who does not suffer from any other health conditions, but they very fact that they smoke, puts their kidneys at greater risk of being attacked. According to Quirk et al. it was also observed in a U.S. population that there was a positive association between the use of tobacco and bladder cancer and that gender did not modify this association (Jacob et. al, 2018).
Finally, meta-analysis findings in women with human papillomavirus revealed that smokers were twice as likely to have cervical cancer as non-smoke (Yousef, 2018). It is believed that tobacco smoke has the ability to damage the DNA of cervix cells. A US study found that continued smoking among cancer survivors may increase their risk of subsequent tobacco-related malignancies and related death. Despite the risks, almost 40% of women diagnosed with cervical cancer continue to smoke after diagnosis. As with other cancers, stopping smoking can halt the growth of the cancer and reduce early cervical lesion size in women who give up smoking after diagnosis.
