4P - Influence of anthracycline- and/or taxane-based chemotherapy on bone metabolism of patients with primary breast cancer

Abstract

Background: Cancer therapy-induced bone loss (CTIBL) is well-known sequela of adjuvant endocrine therapy in postmenopausal patients (pts) with primary breast cancer (PBC). Pts exposed to chemotherapy (Ctx) with alkylators for lymphoma/leukemia own a high risk of premature CTIBL which as in premenopausal PBC pts may be mainly an indirect endocrine effect of Ctx. In contrast, data on direct effects of modern perioperative Ctx on bone metabolism are limited. This retrospective study was initiated to gain more detailed insights into the influence of perioperative anthracycline (A)- and/or taxane (T)-based Ctx on bone turnover of pts with pre- and postmenopausal PBC.Methods: A total of 109 pts (premenopausal: 49; postmenopausal: 60) receiving neoadjuvant or adjuvant A- and/or T-based Ctx were included. Serum markers of bone metabolism including C-telopeptide of type I collagen (ICTP) indicating the osteoclast activity, N-propeptide of type I collagen (P1NP) indicating the osteoblast activity, and bone alkaline phosphatase (BALP) were determined at baseline and prior to each subsequent Ctx cycle (C) up to C6. Changes of ICTP, P1NP, and BALP over time were analyzed by repeated-measure ANOVA.Results: A total of 600 Ctx cycles were analyzed. Baseline levels of ICTP, P1NP, and BALP were significantly higher in post- versus premenopausal pts. ICTP and BALP did not significantly change during Ctx. Both an increase of ICTP from baseline until C6 in premenopausal pts and a decrease in postmenopausal pts did not reach statistical significance. In contrast, P1NP significantly declined in postmenopausal pts from baseline to C6 (p = 0.0152). In premenopausal pts, P1NP declined from baseline to C3 and then increased until C6. These changes were highly significant (p = 0.0024).Conclusion: Our study demonstrates that A- and/or T-based Ctx for PBC exhibits direct effects on bone metabolism. In postmenopausal pts, Ctx was associated with a sustained suppression of osteoblast activity. In premenopausal pts, early osteoclast suppression completely recovered during C4-6. Whether these effects will translate into an increased risk to further develop CTIBL needs to be clarified by long-term observations.Disclosure: All authors have declared no conflicts of interest. Background: Cancer therapy-induced bone loss (CTIBL) is well-known sequela of adjuvant endocrine therapy in postmenopausal patients (pts) with primary breast cancer (PBC). Pts exposed to chemotherapy (Ctx) with alkylators for lymphoma/leukemia own a high risk of premature CTIBL which as in premenopausal PBC pts may be mainly an indirect endocrine effect of Ctx. In contrast, data on direct effects of modern perioperative Ctx on bone metabolism are limited. This retrospective study was initiated to gain more detailed insights into the influence of perioperative anthracycline (A)- and/or taxane (T)-based Ctx on bone turnover of pts with pre- and postmenopausal PBC. Methods: A total of 109 pts (premenopausal: 49; postmenopausal: 60) receiving neoadjuvant or adjuvant A- and/or T-based Ctx were included. Serum markers of bone metabolism including C-telopeptide of type I collagen (ICTP) indicating the osteoclast activity, N-propeptide of type I collagen (P1NP) indicating the osteoblast activity, and bone alkaline phosphatase (BALP) were determined at baseline and prior to each subsequent Ctx cycle (C) up to C6. Changes of ICTP, P1NP, and BALP over time were analyzed by repeated-measure ANOVA. Results: A total of 600 Ctx cycles were analyzed. Baseline levels of ICTP, P1NP, and BALP were significantly higher in post- versus premenopausal pts. ICTP and BALP did not significantly change during Ctx. Both an increase of ICTP from baseline until C6 in premenopausal pts and a decrease in postmenopausal pts did not reach statistical significance. In contrast, P1NP significantly declined in postmenopausal pts from baseline to C6 (p = 0.0152). In premenopausal pts, P1NP declined from baseline to C3 and then increased until C6. These changes were highly significant (p = 0.0024). Conclusion: Our study demonstrates that A- and/or T-based Ctx for PBC exhibits direct effects on bone metabolism. In postmenopausal pts, Ctx was associated with a sustained suppression of osteoblast activity. In premenopausal pts, early osteoclast suppression completely recovered during C4-6. Whether these effects will translate into an increased risk to further develop CTIBL needs to be clarified by long-term observations. Disclosure: All authors have declared no conflicts of interest.