How Does ‘Smoking Cause Cervical Cancer’?

Cigarette smoking causes cervical cancer. Shocked? Women who smoke are twice as likely as non-smokers to get cervical cancer.¹ Around 6,04,000 new cases of cervical cancer occurred in 2020 and 342,000 out of those resulted in death. Cervical cancer is the fourth most occurring cancer among women globally.² 

Almost 99% of cervical cancer cases are associated with the infection from high-risk human papillomavirus (HPV) transmitted through sexual contact. Most HPV infections show no symptoms and resolve spontaneously, but persistent infection can cause cervical cancer.³ However, there are a few other factors associated with increased risk of cervical cancer: Long-term use of oral contraceptives, sexual promiscuity, chlamydia infection, multiple full-term pregnancies, weekend immune system, etc.¹

Before moving ahead, let us know a few surprising and awakening facts. Cigarette smoking has become a global problem and the primary avoidable cause of morbidity and mortality worldwide. Each year, more than 8 million deaths are caused due to tobacco. Out of those deaths, more than 7 million were due to the direct use of tobacco, while 1.2 million were due to second-hand smoke. It was also recorded that in 2020, 22.3% of the global population used tobacco, out of which 36.7% were men and 7.8% were women.⁴ 

When someone smokes, they expose themselves and people around them to carcinogenic and toxic substances like nicotine, benzopyrene and carbon monoxide. These tobacco by-products were detected in cervical mucus of women who smoke, thereby establishing that smoking causes cervical cancer.¹

This article is to explore the connection between smoking and cervical cancer. It also gives you an overview of cervical cancer, risk factors, the connection between smoking and cervical cancer, and ways to prevent it. 

Overview Of Cervical Cancer

Cervix is the narrow, lower part of the uterus which is a strong, muscular tube-like structure in the female reproductive system. It connects the lower part of the uterus to the vagina and forms a birth canal through it during pregnancy. When infected by the human papilloma virus (HPV), the healthy cervical cells on the surface grow uncontrollably forming a mass of cells called tumors.⁵ Usually HPV infections get resolved spontaneously with no major symptoms, but high-risk HPV infections can result in the formation of tumor that may, in some cases, also develop into cancer.³

Initially, the changes in the cells are not cancerous and known as atypical cells. This precancerous phase is called ‘cervical dysplasia’- the abnormal growth of cells.⁵ There are two main types of cervical cancer depending on the type of cells where it starts.

• Squamous cell carcinoma - It makes up approx 80%-90% of all cervical cancers. These cancers start in the cells on the outer surface covering of the cervix.⁵
• Adenocarcinoma - Approx 10% to 20% of all cervical cancers are Adenocarcinoma. They start in the glandular cells that line the lower birth canal in the internal portion of the cervix.⁵

What Are The Risk Factors Associated With Cervical Cancer?

• HPV (Human Papillomavirus infection) -Long-term infection by Human Papilloma Virus (HPV) is the most common cause of cervical cancer. HPV virus spreads through sexual contact or direct contact with the genitals.⁶ The infection usually does not cause any symptoms making it difficult to be detected. Most women between ages 20-30 get HPV infection at some point in their lives.² Long-term, untreated infection may turn cells precancerous and eventually result in cervical cancer among women.⁷
• HIV (Human Immunodeficiency Virus) - Women with HIV have a high risk of cervical cancer as HIV infection weakens the immune system. The persistent infection makes it difficult to clear up on its own over time resulting in a higher risk of development of abnormal precancerous cells in the cervix, and eventually cervical cancer in women.⁸
• Smoking - Tobacco smoking causes cervical cancer and is a well-established HPV cofactor for increasing the risk of invasive cervical cancer development in women with oncogenic HPV.⁹

• Using birth control pills for a long time - As per a study, women who use birth control pills for less than 5 years have 10% increased risk, 5-9 years of use can lead to a 60% increased risk and a doubling of the risk with 10 or more years of use.¹⁰

• Having given birth to three or more children - This increases risk of developing cervical cancer due to the increased exposure to HPV infection with sexual activity.¹

• Having several sexual partners can cause cervical cancer development.¹¹

Let us now understand in detail  how smoking is linked to cervical cancer.

Why Does Smoking Cause Cervical Cancer?

Before exploring the connection between smoking and cervical cancer, let’s look at why smoking is even associated with cancer. Each puff of tobacco smoke contains more than 60 well-established carcinogens.¹² In general, when you think of smoking, it gets associated with lung cancer. Nine of every ten cases of lung cancer are caused due to tobacco smoking.13 It can expose you to many cancer-causing chemicals that block your body from fighting against them.¹³ It affects many organs in the body like bladder, blood, cervix, colon and rectum, esophagus, kidney and renal pelvis, liver, lungs, bronchi, trachea, mouth, throat, pancreas, stomach, voice box (Larynx), etc.¹⁴

• Coming back to how smoking causes cervical cancer, the molecular mechanism by which smoking increases cervical cancer is still unknown.¹⁵ There are several plausible explanations to how smoking contributes to cervical cancer. 
• Smoking causes cervical cancer by weakening your immune system that helps in fighting HPV infection.¹
  High nicotine concentrations have been found in the cervical mucus of smokers. The high concentration of nicotine can damage or change the DNA in cells, causing uncontrollable growth and leading to a tumor.¹⁶

Symptoms Of Cervical Cancer

Symptoms of cervical cancer may include extreme pain during sex, unusual vaginal bleeding and discharge, blood spots or light bleeding between or following periods, persistent pelvic or/and back pain along with weight loss and fatigue.⁵

Can Quitting Smoking Help You Lower Risk Of Cervical Cancer?

Quitting smoking and avoiding second-hand smoking can lower your risk of developing cervical cancer right from the first year of cessation.¹⁷

A Final Note About Smoking And Cervical Cancer

In this article, we have discussed why smoking causes cervical cancer. It is evident that there is a well-established connection between smoking and cervical cancer. Although, 99% of the cervical cancer cases are due to HPV infection, tobacco smoking is a crucial co-factor of HPV infection which can lead to cervical cancer if left untreated for long. 

The symptoms of HPV infection are not very evident due to which it may go undiagnosed and ultimately untreated. You can reduce the risk of cervical cancer by getting regular pelvic exams, quitting smoking, and getting the HPV test.

Remember-’SMOKING KILLS’. It might make you a cervical cancer patient. So, stop smoking before it stops you.