What are the risk factors of cervical cancer?
Cervical cancer is the second leading cause of cancer related death after breast cancer in young women between 20 to 40 years. The death rate due to this disease has declined over time due to better screening modalities, however it still remains the leading cause of death in many countries. It is particularly high in Latin America, southern and eastern Africa, India and Polynesia. Unlike to most types of cancer, there are specific risk factors that may lead to the development of cervical cancer.
Most cervical carcinomas arise at the junction between the primarily columnar epithelium of the endocervix (in the lumen of cervix) and the squamous epithelium of the ectocervix (part of cervix protruding into vagina). This junction is a site of continuous change in the lining epithelium of cells, which is greatest during puberty and first pregnancy. The greatest risk of cancerous transformation coincides with periods of greatest cellular activity during these periods of life. Squamous cell carcinoma accounts for 80%, and adenocarcinoma for 20% of cancer cervix.
The cancer becomes invasive after an average period of 15 years. Once invasive, the cancer penetrates through vascular channels. From the cervix, the tumour spreads to the uterus above, vagina below and to the rectum behind. In less than 5% cases, it may spread to the urinary bladder in front.
The earliest symptom of cervical cancer is an abnormal vaginal bleeding, which often occurs after sexual intercourse. It is associated with a clear or foul-smelling vaginal discharge. Pelvic pain may result from local spread of the cancer. There may be swelling of legs and sciatica like pain due to involvement of nerves. Advanced disease may present with bowel and urinary symptoms such as hematuria (passage of blood in urine), hemotochezia (passage of blood in stools) or the passage of urine / stools through vaginal opening.
Cervical cancer risk factors
The incidence of cervical cancer in various countries is dissimilar due to different attitude towards sexual promiscuity and the effectiveness of mass screening programs. The highest incidence is found in countries with poor screening rates, high human papilloma virus (HPV) infection and sexual promiscuity. Promiscuous sexual behavior in male partners is also a risk factor because it can also lead to transmission of human papilloma virus. On the positive side, a lower rate of HPV infection was found in circumcised males, leading to reduced risk of cervical cancer in their female sexual partners.
- Persistent HPV (human papilloma virus) infection with type 16 and 18 is associated with 70% cases. Most HPV infections are not persistent, especially in young women (<30 years)
- Smoking is associated is associated with higher risk of cancerous changes in the cervix
- Low socio-economic status – it is associated with lack of cervical cancer screening facilities. Lack of education and awareness may also be a factor adding to the risk
- Multiparity – history of multiple full-term pregnancies is a risk factor
- Contraceptive use – long term use of oral contraceptives (>5 years) is associated with a risk of cervical cancer
- Early age of onset of coitus is associated with higher risk of cancer cervix. A woman who has never been sexually active has a very low risk for developing cervical cancer
- Early first pregnancy
- Multiple sexual partners
- High-risk sexual partners
- History of sexually transmitted disease increases the chances of getting HPV infection
- Chronic immunosuppression, particularly HIV-related immunosuppression is associated with increased risk of genital HPV infection in females. Many scientific studies have shown an inverse relationship between CD4+ count (helper T lymphocyte cells in blood which boost immunity) and the risk of HPV infection. Patients with low CD4+ counts have higher HPV nucleic acid levels in their body. Drug induced immunosuppression in organ transplant recipients is also associated with an increased prevalence of cervical cancer.
Cervical cancer has high morbidity and mortality once it becomes invasive. It can be prevented by following the ‘safe sex’ practices. That includes the use of condoms, health education, avoiding tobacco and access to early screening.