Impact of adjuvant endocrine therapy related toxicities on treatment cessation in elderly breast cancer.

Abstract

e21528 Background: According to American Cancer Society estimates, 252,710 new cases of invasive breast cancer will be diagnosed in women in the U.S. in 2017. Elderly breast cancer patients tend to be undertreated due to age, potential toxicities of adjuvant therapies and intrinsic ageist biases. The purpose of this study was to investigate the incidence of adjuvant endocrine therapy related side effects and their impact on discontinuation of therapy in geriatric breast cancer population. Methods: Data were collected by retrospective medical record review at our institution among breast cancer patients diagnosed after age 65. Adjuvant endocrine therapy included tamoxifen, letrozole, anstrozole and fulvestrant. Grade 3 and 4 toxicities were analyzed by Fisher’s exact test to determine an association with therapy discontinuation. Binary logistic regression was used to assess whether a specific toxic effect could predict for early therapy termination. Treatment termination was defined as inability to complete the proposed duration of endocrine therapy. Results: Out of 269 eligible cases, 221 (82.15%) patients were offered endocrine therapy based on their tumor’s ER and PR receptor status. A total of 216 (97.73%) patients received endocrine therapy while 5 (2.26%) declined treatment. Frequencies of osteopenia (n = 22, 10.2%), osteoporosis (n = 18, 8.3%), arthralgia (n = 35, 16.2%), hot flashes (n = 49, 22.7%), vaginal dryness (n = 3, 1.4%), weight gain (n = 7, 3.2%), fluid retention (n = 4, 1.9%), mood swings (n = 3, 1.4%), deep venous thrombosis (DVT, n = 3, 1.4%), pulmonary embolism (PE, n = 3, 1.4%) and stroke (n = 2, 0.9%) were reported by patients who received endocrine therapy. Among the 44 patients who terminated endocrine therapy early, 38.6% listed arthralgia as the chief cause (OR = 5.37, 95%CI:2.33-12.39, p = 0.0001). We detected no significant correlation between endocrine therapy cessation and other side effects. Conclusions: Arthralgia and hot flashes were the most common side effects observed in elderly breast cancer patients receiving adjunct endocrine therapy. We found that the elderly patients tend to discontinue treatment more often if they develop endocrine therapy related arthralgia.