Age of Patients Influences Breast Cancer Drug Side Effects

Adverse events from treatment for breast cancer may be determined by the age of the patient, a recent study suggests.

The study, published in The Lancet, evaluated long-term treatment outcomes among postmenopausal women administered 2 common breast cancer therapies.

Researchers noted that while the drugs anastrozole and tamoxifen are both safe and effective without having a negative impact on overall quality of life, the type and severity of side effects experienced by patients vary with each treatment, especially in different age groups.

Researchers from the UCLA Jonsson Comprehensive Cancer Center Prevention and Control Research program analyzed data from 1193 patients involved in a phase 3 clinical trial comparing anastrozole and tamoxifen in postmenopausal women with ductal carcinoma in-situ (DCIS) who received a lumpectomy plus radiotherapy.

The patients were evaluated for quality of life and other events, including hot flashes, vaginal dryness, muscle and joint pains. Patients were divided into age groups of older or younger than 60 years.

The results showed the pattern and severity of side effects differed in treatment with anastrozole and tamoxifen. Patients administered tamoxifen experienced more severe hot flashes, while patients administered anastrozole experienced greater vaginal dryness severity and worse muscle and joint pains.

Meanwhile, events such as hot flashes, weight problems, vaginal symptoms, and gynecological symptoms were worse in women less than 60 years of age than in women age 60 years or older.

There were no differences observed in the worsening of symptoms such as depression and fatigue on the 2 drugs during 5 years of treatment.

"Both of these drugs are excellent and can reduce the risk for breast cancer recurrence in postmenopausal women with DCIS that is hormone receptor positive," said study lead Dr. Patricia Ganz, director of the Jonsson Comprehensive Cancer Center Prevention and Control Research program. "Physicians and patients need to use this information along with the main trial outcomes to choose the optimal treatment for each woman. This is part of personalized or precision medicine."