Standard Brachytherapy Underused in Cervical Cancer

HONOLULU — Use of brachytherapy within 8 weeks improved survival for women with locally advanced cervical cancer, but this happened in just over a third of cases, and certain patient groups were less likely to receive the standard therapy at all, a pair of National Cancer Data Base (NCDB) studies found.

Median overall survival (OS) was close to 10 years for women who received standard of care chemoradiotherapy plus brachytherapy within the guideline-recommended time frame, nearly twice as long as those who received chemoradiotherapy alone, reported Travis-Riley Korenaga, MD, of the University of California San Francisco.

But only 37% of eligible patients received brachytherapy within this time frame, he said during his presentation at the Society of Gynecologic Oncology (SGO) meeting.

Prolongation of treatment is associated with higher rates of pelvic failure and worse survival, Korenaga explained, and national guidelines recommend completing external beam radiation therapy (EBRT) with concurrent cisplatin plus the brachytherapy boost in under 8 weeks.

Patients who received the boost outside this time frame had a median OS of 75.7 months, which was still higher than the 20% of patients who only received chemoradiation therapy, where OS was 58.5 months if treatment was within 8 weeks and 46.2 months if it went beyond 8 weeks.

“Despite the overwhelming amount of evidence showing the benefit of using brachytherapy, its use has declined over the past decades,” Korenaga said, pointing to use of new radiation technology such as intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), and decreased training exposure to brachytherapy as factors limiting patient access.

SGO discussant Catheryn Yashar, MD, of the University of California San Diego, highlighted a 2014 study showing that from 2004 to 2011, use of IMRT and SBRT increased from 3.3% to 13.9% for radiation therapy consolidation in cervical cancer, while use of brachytherapy declined from 96.7% to 86.1%. Median OS was 70.9 months for patients who received brachytherapy versus 47.1 months for those who did not. “That difference in mortality was equal to the gain that you give by giving chemotherapy,” she said.

“I would like to point out that IMRT has been shown to be inferior when used as a substitute for brachytherapy,” she said.

For SBRT, there’s “no randomized data, no good data, and yet we see this,” she added. “It’s a disturbing trend.”

She said it comes down to education and skill, and that as the incidence of cervical cancer has fallen, residents have been less exposed to the disease. She also suggested that some radiation oncologists are perhaps less comfortable with brachytherapy and may inadvertently steer patients toward EBRT consolidation.

The American Brachytherapy Society, of which she’s chair of the board, is making a concerted effort to provide more training and has asked the Accreditation Council for Graduate Medical Education to differentiate radiation oncologists experienced in interstitial and intracavitary brachytherapy, “so we can really see if people are getting trained.”

Study Details

For their study, Korenaga’s group identified 18,592 women in the NCDB treated from 2004 to 2015 with EBRT and chemotherapy for stage IIA-IVA cervical cancer. An estimated 95% of all cervical cancers cases are captured by the database, with follow-up data on more than 90% of patients. Most received brachytherapy (n=13,642), with just over half receiving a boost within the recommended 8-week time frame (n=6,871).

Roughly 20% did not receive brachytherapy (n=3,508). Black patients, those with government insurance, and those who lived farther from the treatment facility were significantly less likely to receive standard of care. And compared with stage II disease, those with stage III cancers were less likely to receive guideline-recommended treatment (OR 0.76, 95% CI 0.71-0.81, P<0.0001), as were those with stage IVA disease (OR 0.57, 95% CI 0.50-0.66, P<0.0001). No associations were seen for histology or tumor grade.

Black Patients and Brachytherapy

A second study of NCDB data focused exclusively on use of brachytherapy in black women with cervical cancer.

These patients were found to be 14% less likely to receive the standard therapy than non-black women (HR 0.86, 95% CI 0.77-0.95, P=0.003), reported Stephanie Alimena, MD, of Brigham and Women’s Hospital in Boston.

“Five-year survival in cervical cancer across stages is 71% in white women versus 58% in black women,” she said. “Studies have reached varying conclusions on the impact of race on brachytherapy utilization, with several smaller studies suggesting that minority women may be less likely to receive brachytherapy services compared to white women.”

Risk of death between black and non-black patients was similar when looking at those who received brachytherapy (adjusted HR 1.01, 95% CI 0.92-1.11, P=0.83)

For this study, Alimena’s group looked at 15,411 women (19.0% of whom were black) in the NCDB treated for stage IB2 to IVA cervical cancer from 2004 to 2014. Black women were significantly less likely than non-black women to receive brachytherapy (52.5% vs 59%, respectively) or chemotherapy (84.4% vs 87.7%), and to present with stage I disease (7.9% vs 9.4%). Median OS was 52.5 months in black patients versus 65.3 months in non-black patients.

The study also identified other factors significantly associated with not receiving brachytherapy, including age >70 (HR 0.59), and government (HR 0.89) or no insurance (HR 0.75).

Yashar said that these cervical cancer populations are underserved and vulnerable.

“We want to take great care of all our patients, but these patients are less likely and less able to get second opinions, less likely and less able to do a literature search and come with a sheaf of questions, less likely to challenge their doctors,” she said. “If we have responsibility to anybody, these are the people that we need to guard jealously, and make sure that we’re giving them the right treatment.”