Changes on bone mineral density after adjuvant treatment in women with non-metastatic breast cancer

. Adjuvant therapies have prolonged survival of non-metastatic breast cancer (NMBC) patients, but they also decrease bone mineral density (BMD). We have analyzed the effects of chemotherapy, hormone therapy with tamoxifen or both, on BMD of women with NMBC.

We prospectively included 168 women with NMBC (stage I-III) referred to the Medical Oncology Service of University Hospital of Canary Islands between 1997 and 2001 (55 +/- 12 years; 37% premenopausal; 43 +/- 13 months of follow-up). We measured lumbar and hip BMD (g/cm2) at diagnosis, after chemotherapy and after 12 months of tamoxifen. If a low BMD was detected, women were treated with bisphosphonates.

BMD after chemotherapy (n = 83) significantly decreased at lumbar (1.014 +/- 0; 0.995 +/- 0, p = 0.0001), trochanter (0.701 +/- 0; 0.690 +/- 0, p = 0.001), intertrochanter (1.095 +/- 0; 1.078 +/- 0, p = 0.0001) and total hip (0.924 +/- 0; 0.915 +/- 0, p = 0.046) areas. Although 60% of the premenopausal women suffered amenorrhea after chemotherapy, there were not significant differences in BMD between them and women who retained menses. BMD of women who received 12 months of tamoxifen after chemotherapy increased--total hip (0.907 +/- 0; 0.922 +/- 0, p = 0.005) and intertrochanter (1.071 +/- 0; 1.091 +/- 0, p = 0.003)--or remained stable--lumbar, femoral neck, trochanter, and Ward's triangle (n = 39). When tamoxifen was the only adjuvant treatment, BMD after 12 months (n = 22) increased in trochanter area (0.644 +/- 0; 0.663 +/- 0, p = 0.011), and remained stable in all other sites. 50 (30%) patients were treated with bisphosphonates because of osteopenia.

Women with NMBC are affected by early bone loss after adjuvant chemotherapy. This bone loss is attenuated by one year of tamoxifen treatment.