Cervical cancer is the uncontrolled multiplication of epithelial cells lining the organ. It compromises the underlying tissue (the stroma) and can invade nearby or distant cells and organs (this phenomenon gives rise to metastases).
It is caused by a persistent infection with some oncogenic types of human papillomavirus (HPV). Genital HPV infection is very common and, in most cases, asymptomatic and self-limiting, with most women resolving this infection by the age of 30. In some cases, however, the virus may persist in the cells of the cervix, and this promotes cellular changes that can progress to the development of cancer.
Worldwide, cervical cancer is the fourth most common type of cancer in women, with about 570,000 new cases per year.
In Brazil, cervical cancer ranks third among the most common malignant tumors in the female population (behind breast and colorectal cancer, with the exception of non-melanoma skin cancer). The estimate for 2020, according to INCA (Brazilian Cancer Institute), was 16,710 new cases of the disease.
Types of cervical cancer
There are two main types of cervical cancer. Classified according to the origin of the compromised epithelium, they are:
- Squamous cell carcinoma – affects the squamous epithelium and is the most incident type (about 80% to 90% of cases); and
- Adenocarcinoma – affects the glandular epithelium and is rarer (about 10% to 20% of cases).
Symptoms and signs of cervical cancer
Cervical cancer is a slowly developing and initially silent disease. This means that you may not have symptoms in its early stages.
As it progresses, it presents with intermittent vaginal bleeding (which comes and goes) or after sexual intercourse, abnormal vaginal secretion and abdominal pain associated with urinary complaints. In more advanced cases, changes in bowel habits may occur.
Cervical cancer diagnosis
The main screening method for cervical cancer is the pap smear, also called the pap test. The diagnosis is confirmed using the following tests:
- Pelvic examination by speculum evaluation – examination of the vagina, cervix, uterus, ovary and rectum;
- Colposcopy – exam in which the vagina and cervix are visualized with a colposcope, a device capable of detecting abnormal lesions in these regions; and
- Biopsy – a small tissue sample is taken for examination under a microscope.
Surgery, chemotherapy and radiation therapy are among the possible treatments for cervical cancer. The decision for the type of treatment will depend on the disease staging (the stage it is in), the size of the tumor and personal factors such as the patient’s age and the desire to remain fertile.
In early stages, conservative surgical treatments such as conization (removal of part of the cervix) or radical trachelectomy (removal of the entire cervix) may be performed. This also applies to small invasive lesions, as it avoids complications and morbidities caused by more radical surgeries.
For more advanced stages and bulky lesions, scientific evidence indicates chemotherapy associated with radiotherapy.
Avoiding infection by HPV is the primary prevention of cervical cancer. As transmission occurs through contact, the use of condoms (male or female condom) during sexual intercourse only partially protects against the disease. It is not possible to say that protection is total because contagion can also occur through contact with the skin of the vulva, the perineal, perianal region and the scrotum.
Vaccination against HPV is another way to prevent cervical cancer. Since 2014, the vaccine has been offered at UBSs (Basic Health Units) throughout Brazil for girls aged 9 to 14 years and boys aged 11 to 14 years.
HPV vaccine coverage has been disappointingly low worldwide, and only 1.4% of all eligible women have received a full course of HPV vaccination. In addition, there is inequity in access to HPV vaccines: in high-income regions, 33.6% of women aged between 10 and 20 years received the full course of the HPV vaccine, compared with only 2.7% in regions of lower income. It can be seen, therefore, that the population of countries that carry most of the burden of HPV-related diseases worldwide has less access to vaccines.
Combined with vaccination, routine gynecological pap smear testing annually for two consecutive years and then once every three years from 25 to 64 years of age is an important means of treating precancerous lesions or act quickly against cervical cancer.
Even vaccinated women should have a pap smear periodically, as the vaccine does not protect against all oncogenic types of HPV. Vaccination protection covers human papillomavirus types 6 and 11 (which cause genital warts), 16 and 18 (responsible for about 70% of cervical cancer cases).
The WHO (World Health Organization) strategic plan for the elimination of this disease proposes a goal of cervical cancer incidence of four or fewer cases per 100,000 women/year. To achieve the target incidence, the WHO proposes targets of 90% of girls vaccinated against HPV by age 15 years, 70% of women screened twice in their lifetime (at 35 and 45 years), and 90% adherence to treatment recommendations for pre-cancer and invasive lesions.