Test shows promise in detecting ‘hard-to-find’ cervical cancers

Scientists at the Montefiore Einstein Cancer Center (MECC) have developed a test for detecting a “hard-to-find” type of cervical cancer.

The novel test appears sensitive for detecting cervical adenocarcinoma [ADC], which accounts for up to 25 per cent of cervical cancer cases, as well as some lesions, called adenocarcinoma in situ [AIS], that often develop into ADCs.

Because ADCs are often missed by current screening methods, they have higher mortality rates than the more common cervical squamous cell cancer. Researchers at MECC are hoping to catch the disease early, before it develops into cancer.

The widespread use of the smear test, in which a doctor examines tissue samples for abnormal cells, has significantly reduced the incidence of cervical squamous cell cancer over the past six decades. However, the incidence of ADC has not decreased.

In recent years, testing for human papillomaviruses (HPVs), responsible for 99.7 per cent of cervical cancer cases, joined the smear test as a standard screening tool for cervical cancer.

Although there are more than 100 types of HPV, three types, HPV 16, 18, and 45, account for more than 70 per cent of all cervical cancer cases and more than 90 per cent of ADC cases.

The current HPV tests cover all three types and can alert infected women that they face a high risk for developing cervical cancer.

But while vaccines for preventing cervical cancer are safe and effective, researchers say several generations of women are above the age for receiving the vaccine.

The MECC-developed HPV test assessed HPV 16, 18, and 45 in a novel way by specifically looking at methylation levels. Methylation is a chemical modification of DNA and other molecules that may be retained as cells divide to make more cells.

“The advent of next-generation genetic testing has opened up opportunities for us to more accurately detect oncogenic HPV strains and patterns in the genomes that correspond with the development of AIS and ADC,” said Robert D. Burk, professor of pediatrics, of microbiology and immunology, of epidemiology and population health, and of obstetrics and gynaecology and women’s health at Einstein and MECC member, who co-led the study.

“Our findings, if confirmed by clinical trials, suggest that women with a high methylation score may benefit from colposcopy and specialised tissue evaluation, beyond just a Pap test, which could lead to early diagnosis and treatment for ADC or the removal of AIS lesions before they develop into ADC.”

He added: “Given that our test uses equipment that could be simplified, it has the potential to expand testing in lower-resourced countries.”

Cervical cancer remains the fourth most common cancer in women worldwide, with the burden significantly higher in lower- and middle-income countries, including those in Sub-Saharan Africa, where HIV-HPV co-infections are common.

There are also significant disparities within the United States. For example, in New York City, rates of cervical cancer in the Bronx, which is home to the poorest urban congressional district in the country, are 50 per cent higher than in Manhattan.

More frequent and effective screening could help address this health disparity, scientists believe.

“Ideally, the new HPV methylation test would only need to be done once every three to five years,” explained Howard Strickler, co-senior and corresponding author of the Journal of the National Cancer Institute (JNCI) and a member of MECC.

“We are hopeful that this test will be able to increase cervical cancer screening equity in the US.”