February 02, 2017
5 min read

Adjuvant endocrine therapy still misused, underused in patients with breast cancer

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Use of adjuvant endocrine therapy still varies widely and has not been optimal for women with breast cancer over the past decade, according to results of a retrospective cohort study.

“Endocrine therapy use has been steadily increasing, but optimal usage has not been achieved in the United States,” Dezheng Huo, MD, PhD, associate professor in the department of public health sciences at University of Chicago, told HemOnc Today. “Certain breast cancer patients are being deprived of this life-saving therapy.”

Dezheng Huo

Approximately 15,000 lives may have been saved in the past 10 years if adjuvant endocrine therapy (AET) guidelines were followed by all patients, Huo said. Endocrine therapy has shown clinical benefit in preventing recurrence and mortality, but underreporting and misuse or underuse of treatment has been an existing issue.

Researchers used the National Cancer Data Base to identify 981,729 women (mean age, 60.8 years; standard deviation, 13.3 years) with stage I to III breast cancer treated between 2004 and 2013 to determine specific temporal trends and factors related to receiving AET for breast cancer. Among the patients, 818,435 had hormone receptor–positive cancer and 163,294 had hormone receptor–negative cancer.

“AET misuse here indicates that patients with estrogen receptor–negative cancer received AET, which is not necessary,” Huo said. “Underuse of AET means that patients with estrogen receptor–positive disease did not receive AET.”

The number of patients with hormone receptor–positive cancer who received AET increased from 69.8% in 2004 to 82.4% in 2013, which represented an annual percentage change of 1.51% (95% CI, 1.48-1.54). The number of patients with hormone receptor–negative cancer who received AET decreased from 5.2% in 2004 to 3.4% in 2013, an annual percentage change of –0.17% (95% CI, –0.14 to –0.21)

Hospital-level adherence — defined as more than 80% of patients with hormone receptor–positive cancer receiving AET — increased from 40.2% in 2004 to 69.2% in 2013.

Whether a patient with hormone receptor–positive disease received AET varied based on age, race, geographic location and hormone receptor status. The rate was highest among women aged 50 to 69 years (> 80%) but low among patients aged 80 years and older (60.5%). A greater proportion of non-Hispanic white patients received AET (79%) compared with black (76.4%) and Hispanic patients (75.9%).

Use of AET was highest in New England (83.3%) and West North Central states (83.9%) but lowest in West South Central states (71.2%).

Further, only 51.2% of patients with ER–negative, PR–positive disease received AET.

The time to initiation of AET was more influenced by whether radiotherapy or chemotherapy were given than on surgery type. Median duration from diagnosis to AET was 75 days for patients who did not receive radiotherapy or chemotherapy, compared with 112 days for patients who received radiotherapy alone, 202 days for patients who received chemotherapy alone and 241 days for patients who received both (P < .001).

Of 174,786 patients who did not initiate AET, 19.6% were recommended the therapy but refused it, 4.6% were recommended therapy but were not given it without a reason, and 5.4% were not recommended for it based on certain risk factors.

Among HR–negative patients — 4.2% of whom inappropriately received AET — misuse of AET was more common among patients treated in low-volume hospitals (4.6%) and patients living in West South Central states (5.4%).

During a median follow-up of 4.9 years, 76,565 patients died. Adjusted multivariable Cox proportional hazards models showed the receipt of AET was associated with a 29% relative risk reduction in mortality (HR = 0.71; 95% CI, 0.7-0.73). Based on these data, researchers calculated that 14,630 lives would have been saved if AET was given according to guidelines for all women with hormone receptor–positive disease.

The researchers noted that AET is known to be underreported in registry data, which also lacks information on family history and genomic profile.

“More measures should be taken to further improve the use of AET in women who are supposed to receive the life-saving treatment,” Huo said. “Team-based oncological care may improve compliance to guidelines. Effective communication and education on the benefit of AET may also be important.” – by Melinda Stevens

For more information:

Dezheng Huo , MD, PhD, can be reached at Department of Public Health Sciences, University of Chicago, 5841 S Maryland Avenue, MC 2000, Chicago, IL; email: dhuo@health.bsd.uchicago.edu.

Disclosure : Huo reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.