Cervical cancer is the most common female cancer in low- and middle-income countries and ranks fourth in the cancers of the womankind. In more than 95% cases of cervical cancer are associated with persistent HPV or Human Papilloma Virus infection. HPV is a common sexually transmitted infection, which do not give any symptoms. Like common flu infection, in the most of the cases our immune system clears this infection. Persistence of this infection with High –Risk HPV can trigger changes in the cervical cells and lining giving rise to mild, moderate and severe dysplasia, ultimately turning into cancer over a period of 9-10 years. These early pre-cancerous changes in the cervical cells can be detected on the Pap smear (cytology) test. Recently tests are developed to pick up persistent HPV infection. These tests enable us to catch the disease in primitive or pre- cancerous stage.
A robust and effective use of screening in Europe and US. has resulted in a dramatic decline in cervical cancer mortality over the last three decades. The evidence has proven that the cervical cancer screening can reduce cervical cancer mortality by 80% or more among screened women. At international level, all the countries have made commitment to eliminate cervical cancer as public health problem by reducing number of new cervical cancer cases to less than 4 annually per 100.000 women by 2030. With early detection, cervical cancer can be cured completely. These screening programs had integrated cervical cytology (Pap smear) as primary screening test initially currently changing to co-testing (Pap smear and HPV test).
Cervical cancer screening aims to identify asymptomatic women with precancerous lesions which enables early diagnosis and treatment before cancer develops, hence decreasing the incidence of cervical cancer. Screening tests must be sensitive, reproducible, and easily performed. An effective screening test should accurately separate individuals at high risk of disease from those at low risk of disease, and minimize false-negative results. By these parameters, HPV testing is clearly superior to cytology testing alone as a screening test for cervical cancer, because it detects far more precancerous lesions per screen. Adding cytology to HPV testing alone (contesting) slightly increases the number of cases detected, but at the cost of more false-positive results and more invasive procedures (colposcopy with biopsy). HPV test can be self-collected by the patient or by the doctor and if negative then need to repeat after longer (5 yearly) interval than Pap smear test( 3 yearly).
The World Health Organisation’s global strategy encourages a minimum of two lifetime screens with a high-performance HPV test by age 35 and again by age 45 years.
If a woman can be screened only once in her lifetime, WHO recommends the best age is between 35 and 45 years. Ideal screening should start from 25 yrs of age till 65 yrs of age at an interval of 3-5 years depending on test implemented.
After a positive HPV or Pap screening test, patient is referred for colposcopy where cervix is visualised under magnification to look for precancerous changes, which may develop into cervical cancer if left untreated. Treatment may be offered in the same visit (the see and treat approach) or after a second test (biopsy test)as per recommendation .
Treatments of pre-cancerous are quick and generally painless causing infrequent complications and can be done in the either out- patient or in-patient set up under local or general anaesthetics. It involves-
• LEETZ (large loop excision of the transformation zone), which involves removing your abnormal tissues with an electrically heated loop; and/or
• A cone biopsy, which involves using a knife to remove a cone-shaped wedge of tissue
• Hysterectomy
If left untreated, approximately 30% of high-grade pre-cancerous lesions eventually become invasive cancers.
In conclusion, screening for cervical cancer is the key to achieve The World Health Organisation goals to eradicate cervical cancer.
Dr. Vaishali Joshi, Consultant, Obstetrician & Gynaecologist, Kokilaben Dhirubhai Ambani Hospital, Mumbai
