Jaw Dropping Cancer Therapy Side Effects

Breast cancer patients treated with zoledronate had slight increased risk of jaw osteonecrosis

(RxWiki News) Medications that fight cancer are designed to extend life. Some medicines, though, have serious side effects that can appear years after treatment. A new study looked at bone loss side effects of one medication.

Breast cancer survivors who took zoledronic acid after surgery were slightly more likely to develop jaw bone loss than women who didn’t take the medicine, according to the study.

This condition is called osteonecrosis (bone death) of the jaw (ONJ).

Zoledronic acid belongs to a class of medications called bisphosphonates, which are sold under such brand names as Aclasta, Reclast, Zomera and Zometa.

This study found that while ONJ occurred more frequently in women who took zoledronic acid, their overall oral health was the same as women who were not treated with the medication.

"Tell your dentist if you are taking bisphosphonates."

For this study, Emma J. Rathbone, PhD, of the Academic Unit of Clinical Oncology at Weston Park Hospital in Sheffield, England, and colleagues looked at the frequency of ONJ in cancer survivors taking zoledronic acid and overall oral health-related quality of life.

ONJ occurs when the bone of the jaw is exposed — that is, the bone is no longer covered by the gum. A number of conditions can lead to OJN, which can be treated with rinses, antibiotics and oral pain relievers. 

Most cases of ONJ can be resolved without the need for surgery. 

Data for this study was taken from the Adjuvant Zoledronic Acid to Reduce Recurrence (AZURE) trial. That study was designed to see whether the bisphosphonate zoledronic acid (zoledronate), in combination with standard adjuvant (after primary treatment) systemic therapy, reduced the risk of cancer return and helped women with stage II or III breast cancer live longer.

Standard adjuvant therapy for breast cancer can include chemotherapy, hormonal therapy to block hormones driving the cancer, targeted medicines that attack specific genetic mutations, radiation therapy or a combination of treatments.

A total of 3,360 breast cancer survivors in the AZURE trial were assigned to receive standard therapy with or without a five-year course of zoledronate.

At the completion of the trial, 486 study participants were invited to complete the Oral Health Impact Profile-14 (OHIP-14) to assess oral quality of life. This 14-question survey asked the women about their overall oral health, including functional limitations, physical pain, psychological discomfort, physical disability, psychological disability, social disability and handicap.

After a median follow-up of 74 months, 33 cases (2.1 percent) of ONJ had developed only among the women taking zoledronate.

"This is consistent with our experience," Adam Brufsky, MD, PhD, professor of medicine at the University of Pittsburgh, told dailyRx News. "I usually tell patients to let us know if they are getting a tooth extraction or any procedure like an implant, and we would hold the zoledronic acid," he said.

A total of 362 patients completed the oral quality of life questionnaire. The higher the OHIP-14 score, the worse the oral quality of life.

Scores were similar in both groups — 6.46 in the zoledronate treated group and 5.06 in the group who received standard adjuvant therapy.

"Adjuvant zoledronate used in the intensive schedule studied in the AZURE trial is associated with a low incidence of ONJ but does not seem to adversely affect [oral quality of life]," the authors concluded.

Findings from this trial were published July 20 in the Journal of Clinical Oncology.

The study was sponsored by the University of Sheffield with grant support from Novartis and infrastructure support from the National Institute for Health Research Cancer Research Network.

A number of the authors reported financial relationships with various pharmaceutical companies, including Novartis, Amgen, Bristol-Myers Squibb and Roche.

Review Date: 
July 23, 2013