A study carried out by researchers at the State University of Campinas (Unicamp), in the interior of São Paulo, uses a DNA test to detect the Human Papillomavirus (HPV) instead of the traditional Pap smear, a gynecological exam that tracks diseases in the cervix. uterus.
The DNA test is done in a very similar way to the Pap smear: a sample of secretion is collected during a gynecological examination. But, according to the study — published in September in the scientific journal Scientific Reports —, this technique could change the scenario of cervical cancer prevention in Brazil.
“Coverage of the program’s target population went from 30% to more than 90%”, highlights gynecologist Júlio Cesar Teixeira, professor and researcher at Unicamp who coordinated the study. “We had a four-fold increase in the detection of pre-cancer lesions, and cases of the disease identified at the microscopic stage, which are curable with simple and accessible procedures, increased from 10% to 66%.”
20,551 women participated in the study, aged between 25 and 64 years. The researchers compared data from the first round of five years (October 2017 to September 2022) of HPV screening using DNA testing with information obtained in the previous five years (2012 – 2016) in which the Pap smear was used. All exams had been carried out in the public health system, in the city of Indaiatuba (SP).
The location was chosen because it has a computerized health system, in which all care units are linked in a network, which allowed data to be monitored more effectively and enabled increased coverage, considered essential for the success of the program.
The results of the project have been monitored by the Ministry of Health and are being used as a basis for a change in public policies aimed at preventing cervical cancer in Brazil. In March 2024, the National Commission for the Incorporation of Technologies (Conitec) approved the use of HPV genotyping in the Unified Health System (SUS), and the expectation is that in 2025 the test will be made available in the public system.
Teixeira calculates that, if the project is implemented on a national scale, it could prevent deaths from the disease in the country. According to the 2023 annual report from the National Cancer Institute (Inca), among deaths of women caused by cancer in Brazil in 2021, deaths from cervical cancer occupied fourth place, representing 6.05% of the total, excluding those for non-melanoma skin cancer.
How is the test done?
While the Pap smear relies on human interpretation at different stages, the DNA test is automated, eliminating the risk of false negatives or positives. Genotyping can also identify the type of HPV present in the body — there are more than 200, of which at least 12 are considered oncogenic, according to Inca.
The traditional method, in turn, only identifies cells that are already sick. “In around 10% of cases, the results indicate the need to perform cytology (Pap smear) to help manage the case and, in this situation, the same material is used, without the need for new collection”, explains Teixeira. This more global view is important, as many young women present a positive result without having injuries.
In the study, 87% of the tests performed showed negative results. As it points out that there is no infection, the exam would only need to be redone after five years. The Pap smear must be repeated after three years, in cases where the woman has presented two consecutive negative results. Furthermore, with the recent technique, the average age of women with detected lesions has dropped by 10 years, considerably bringing forward the diagnosis.
Resource savings
Although the test is still little known and used, it is nothing new that HPV genotyping is a solution to improve the screening, prevention and treatment of cervical cancer. Since 2013, the World Health Organization (WHO) has advocated the need for changes, which include the preference for the HPV-DNA test over methods such as visual inspection with acetic acid (VIA) and the Pap smear.
Many countries already use the exam as a routine. “In the United States, protocols have been based on this type of testing for some time,” reports gynecologist and obstetrician Renata Lamego, from Hospital Israelita Albert Einstein. Here, in the supplementary health system, the DNA-HPV test is already carried out and helps guide the specialist’s conduct.
“In Brazilian public policies, it is more difficult to institute this type of procedure, as it is a more expensive test and the Pap smear is very cheap”, points out Lamego. “Furthermore, cytology is already culturally incorporated into Brazilian women, who know that they must undergo it annually, unless they present two normal results for the test, which allows them to perform it again after three years.”
The financial issue was also evaluated in Unicamp’s work. Although the test is more expensive, in the long term it can be more economical for the health system if implemented with an effective monitoring plan. In addition to being able to be carried out every five years, the exam anticipates the detection of cancers at the microscopic stage.
When the disease is more advanced, it is no longer operable and, in most cases, requires radiotherapy and chemotherapy, expensive methods that are not available everywhere in the country. “In addition to saving resources, if we associate an organized prevention program with vaccination against HPV under 15 years of age, cervical cancer will be eliminated in the future”, says Júlio Cesar Teixeira.
This content was originally published in DNA testing is an ally to detect HPV and can replace pap smears on the CNN Brasil website.
Source: CNN Brasil
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