January is observed as Cervical Cancer Awareness Month and effort is being made globally to prevent and control this cancer that is threatening to become a major health problem around the world.
Cervical cancer is the cancer of the mouth or the lowest part of the uterus called cervix. Most cervical cancers develop slowly, in the lining of the cervix. Due to human papilloma virus[HPV] infection, healthy cervical cells develop abnormal precancerous changeover a period of time. These cells can potentially develop into cancer. Not all precancerous cells become malignant [cancerous], and some may disappear without treatment.
When the cancer is limited to the lining of the uterus, it is called as carcinoma in situ, which has 100 percent cure rate. If the cancer is not treated in this early stage, it can invade the cervical tissue and is considered invasive cervical cancer. This can also spread to the adjacent pelvic tissues and to distant organs in later stages. It roughly takes 8-10 years for precancerous lesions to progress to carcinoma in situ and a similar time period to further progress to invasive cervical cancer.The precancerous lesions and carcinoma in situ are completely curable conditions, whereas the invasive cancer progresses, the 5-year survival rates go on decreasing. This emphasises the importance of early detection for cervical cancer.
Risk factors
The major risk factor for cervical cancer is exposure to a group of common viruses called human papillomavirus [HPV]. There are more than 100 types of HPV, but only a few of them have been associated with causing cervical cancer. Although many women are exposed to HPV, only a small percentage of them develop cervical cancer. Other risk factors include exposure to sexually-transmitted diseases such as Chlamydia and human immunodeficiency virus [HIV]. Having sexual intercourse at an early age and multiple sex partners, multiple deliveries, lower socio-economic status,smoking and oral contraceptives are other associated risk factors.
Signs and symptoms
Cancer of the cervix tends to occur during midlife, with half of patients diagnosed between 35 and 55 years of age. Cervical cancer rarely affects women under the age of 20. Women with pre-cancer or early cervical cancer usually have no signs or symptoms. Symptoms of cervical cancer typically appear when the cancer becomes invasive and spreads [metastasises] to nearby tissues. The symptoms are post-coital [after intercourse] bleeding, inter-menstrual bleeding [irregular bleeding between the periods], post-menopausal bleeding and foul smelling vaginal discharge. It is important to note that these symptoms may be caused by conditions other than cervical cancer. Patients experiencing any of these symptoms should immediately notify their physician. Depending on the type of tumour, there may be an ulcer or a cauliflower-like growth seen on the cervix and the cervix may feel hard to touch.
Screening and diagnosis
Here are some methods used for diagnosis:
Pap smear or vaginal cytology
The cells are collected from the cervix with the help of a spatula and are fixed on a slide.The slide is then fixed, stained and seen under the microscope. This is probably the only cancer in the body, where it can be caught in pre-malignant condition, a stage at which it is completely curable. Regular screening by Pap smear also lowers the incidence of invasive cervical cancer by catching the disease in its early stage.
Certain factors can affect the accuracy of the Pap test. To help make the Pap test as accurate as possible,patients should avoid sexual intercourse, vaginal douching, medications,tampons, birth control jellies and foams for 48 hours before the test.
According to Royal College of Obstetrician sand Gynaecologists, the screening should be started at the age of 25, in all women who are sexually active. The screening should be done at the interval of three years until the age of 50, and then at five yearly intervals until the age of 64 years.
HPV DNA
This is advisable inpatients with abnormal Pap smears to identify those patients who are at higher risk of developing cervical cancer subsequently.
Colposcopy
This entails visualising the cervix under magnification. It further identifies the abnormal areas from where the biopsy can be taken. Endocervical curettage or scraping also helps in the diagnosis.
Prevention
Preventing HPV infection is the primary line of action whereas secondary prevention is by regular screening by Pap smear where it is caught in a precancerous stage.
HPV infection can be prevented by:
- Refraining from sexual activity at an early age
- Limiting number of sexual partners
- Avoiding sex with men who have had multiple partners
- Using condoms consistently during every intercourse
- Vaccine against HPV virus.
Vaccine against HPV virus
Since HPV infection is the main risk for cervical cancer, vaccination against it is thought to protect and thus prevent cervical cancers. Gardasil, the first HPV vaccine, is approved by the US Food and Drug Administration. This vaccine protects against four strains of HPV: HPV-16 and HPV-18, which cause 70 per cent of cervical cancer cases, and HPV-6and HPV-11, which cause 90 per cent of genital warts. The vaccine is administered in three doses over a six-month period.
The vaccine is effective in preventing HPV infection and protecting women against advanced cervical pre-cancers caused by HPV-16 and HPV-18. The vaccine cannot be used to treat an existing infection [i.e., after an abnormal Pap test]. Vaccine is currently recommended for girls and women between the ages of 11-26 years, if they are not already infected by HPV. The current research shows that it gives protection for five years. The need for booster immunisation will only be clear after further trials.
Treatment
Treatment is based on many factors, including the patient’s age, health status, interest in future childbearing and mainly on the stage of the cancer. For pre-cancerous conditions and carcinoma in situ, conservative surgical methods like cryotherapy, laser and large-loop excision of the transformation zone [LLETZ]are successful. These do not affect a woman’s ability to become pregnant in the future. For advanced cases radical surgery [removal of uterus along with both tubes and ovaries], radiotherapy, chemotherapy or combination of these may be required depending upon the stage of the disease.