ORLANDO, June 5 — A third of patients with metastatic breast cancer receive off-label therapy at some point during treatment, according to a study reported here.

• Explain to interested patients that metastatic breast cancer often is treated with drugs that are not approved for use in breast cancer.
• Explain, however, that few of the study patients received medically inappropriate therapy.
• Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

More than 70% of the drugs used off label lacked evidence to support their use in breast cancer, but these drugs were used in only a small percentage of patients, Sharon Giordano, M.D., of the University of Texas M.D. Anderson Cancer Center in Houston, said at the American Society of Clinical Oncology meeting.

Few patients received what was judged to be medically inappropriate therapy, she said.

“Although off-label drug use is widespread among patients with metastatic breast cancer, the vast majority of patients who received off-label drugs were treated with chemotherapy that was considered appropriate for use in treatment of breast cancer,” Dr. Giordano said in an interview.

Estimates of the frequency of off-label therapy in medical practice range from 21% to 51%. Off-label use of chemotherapy drugs is thought to be widespread, but few studies have examined the issue, particularly with respect to the medial appropriateness of off-label therapy.

The last study to evaluate off-label chemotherapy practices was conducted about 20 years ago and covered cancer in general, not just breast cancer, Dr. Giordano said.

In an effort to develop a knowledge base specific to breast cancer, she and her colleagues analyzed merged data from the NCI Surveillance, Epidemiology, and End Results program and Medicare. They limited the analysis to women ages 65 and older who had a diagnosis of metastatic breast cancer from 1991 to 2002.

Investigators used the DRUGDEX drug compendium to evaluate the appropriateness of off-label therapy.

The study involved 2,082 women. Overall, 34.9% of the patients received at least one off-label therapy. Off-label treatment was least common in patients older than 80 (24.4%) and most common those ages 65 to 70 (37.7%, P=0.004).

Off-label drug therapy became less frequent over time. More than half of the therapy in 1991 (52.4%) was off label. Off-label therapy reached a nadir of 29.7% in 1997, rose to 37.6% over the next two years, and then declined again, accounting for 31.5% of treatment in 2002 (P=0.025).

The frequency of off-label therapy varied geographically, from 42.7% in Connecticut to 12.5% in rural Georgia (P=0.019).

The analysis uncovered off-label use of 36 different chemotherapeutic agents. Used most frequently were vinorelbine (Navelbine), 15.98%; gemcitabine (Gemzar), 8.37%; carboplatin, 7.03%; and mitoxantrone, 6.83%.

All four drugs had supporting evidence for breast cancer.

Dr. Giordano said 71% of the drugs lacked evidence for use in breast cancer, making the use medically inappropriate. However, only 6.7% of the patients received medically inappropriate therapy.

Because the study was limited to women 65 and older, the findings may understate the extent of off-label therapy, the researchers acknowledged.

Dr. Giordano has plans for additional studies of off-label therapy across a spectrum of tumor types and stages. She also hopes to examine off-label use in younger breast cancer patients.

Dr. Giordano and her coinvestigators reported no disclosures.

Primary source: Journal of Clinical Oncology

Source reference:

Dean-Colomb W et al. “Off-label drug use in women with breast cancer” J Clin Oncol 2009; 27(15 suppl): Abstract 1016.

No Comments »

No comments yet.

RSS feed for comments on this post. TrackBack URL

Leave a comment

You must be logged in to post a comment.