(CNN) — Adding a six-week course of chemotherapy to the standard course of treatment for locally advanced cervical cancer resulted in a significant increase in survival rates, a new study shows.

The study, published Monday in the journal The Lancet, involved 500 patients from 32 medical centers in Brazil, India, Italy, Mexico and the UK who were randomly assigned into two groups between 2012 and 2022. All had locally advanced cervical cancer, although none had tumors that had spread to other organs.

The control group received only chemoradiotherapy, a standard process that included treatment with radiation and the drug cisplatin. The experimental group received six weeks of treatment with carboplatin and paclitaxel chemotherapy before beginning chemoradiotherapy.

The researchers found that 80% of those who got a short course of chemotherapy first lived at least five more years, and 72% did not have any cancer return or spread. In the control group, 72% survived at least five years, and 64% had no cancer return or spread.

Most patients had some kind of adverse event during treatment, including fatigue or weakness, gastrointestinal problems, infections or low white blood cell counts. Severe or life-threatening events happened in 59% of the group that got initial chemotherapy, compared with 48% of those who got chemoradiotherapy alone.

The researchers say theirs is the first randomized phase three study to show a “significant survival advantage” using chemotherapy before chemoradiotherapy, representing a “clinically meaningful improvement” at a “relatively low cost.” The drugs are cheap and widely available, they say.

“This is the biggest improvement in outcome in this disease in over 20 years,” Dr. Mary McCormack of University College Hospital, lead author of the study, said in an interview with Cancer Research UK. “I’m incredibly proud of all the patients who participated in the trial; their contribution has allowed us to gather the evidence needed to improve treatment of cervical cancer patients everywhere.”

Cisplatin-based chemotherapy is one of the most commonly used methods of treating cervical cancer, improving survival rates by 30% to 50%. While tumor removal surgery is an option, some experts tend to prefer chemotherapy.

“We know that surgery is going to leave some of the cancer behind,” said Dr. Otis Brawley, a professor of oncology at Johns Hopkins University and former chief medical officer of the American Cancer Society, who was not involved with the new research. “If you can treat with radiation and chemotherapy, you have a chance that you’re going to sterilize the pelvis of all of the cancer. … We have the chances that we’re going to put women into a prolonged, complete remission.”

Cervical cancer was once the leading cause of cancer death for women in the United States, he noted. In 2008, Harald zur Hausen, a German virologist, won the Nobel Prize for his research demonstrating that cervical cancer in humans is caused by certain types of human papillomavirus, or HPV. This discovery led to the development of an HPV vaccine that can help prevent cervical cancer in women.

However, cervical cancer still kills about 4,000 women in the US each year. Warning signs include abnormal bleeding or discharge.

Brawley stressed the importance of routine cervical screening as advanced-stage cervical cancer rises among White and Black women in the US.

According to the US Centers for Disease Control and Prevention, cervical cancer screenings typically test for signs of HPV that can cause cell changes on the cervix. The screenings also include a Pap test to look for precancer cell changes.

The US Food and Drug Administration greenlit a new option this year for patients to collect their own vaginal samples to test for HPV, streamlining the screening process.

“It’s almost totally preventable with either the HPV vaccine or screening,” Brawley said. “Of the 4,400 deaths from cervical cancer, none of them get screened every year.”

Chemotherapy to treat cervical cancer can come with unpleasant side effects like nausea, vomiting and hair loss, Brawley noted. He hopes the future of treatment will involve more personalized options like immunotherapy, which uses a person’s own immune system to fight cancer.

“The greatest hope is immunotherapy,” he said. “We’re hoping we can actually help even more women with less side effects.”

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