Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice
Background: Australian clinical guidelines recommend endocrine therapy for all women with hormone-dependent early breast cancer. Guidelines specify tamoxifen as first-line therapy for pre-menopausal women, and tamoxifen or an aromatase inhibitor (AI) for post-menopausal women depending on the risk o...
| Main Authors: | , , , , , , , |
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| Format: | Journal Article |
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Public Library of Science
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/56032 |
| _version_ | 1848759769058246656 |
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| author | Kemp, A. Preen, D. Saunders, C. Boyle, F. Bulsara, M. Holman, C. Malacova, Eva Roughead, E. |
| author_facet | Kemp, A. Preen, D. Saunders, C. Boyle, F. Bulsara, M. Holman, C. Malacova, Eva Roughead, E. |
| author_sort | Kemp, A. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Background: Australian clinical guidelines recommend endocrine therapy for all women with hormone-dependent early breast cancer. Guidelines specify tamoxifen as first-line therapy for pre-menopausal women, and tamoxifen or an aromatase inhibitor (AI) for post-menopausal women depending on the risk of recurrence based on tumour characteristics including size. Therapies have different side effect profiles; therefore comorbidity may also influence choice. We examined comorbidity, and the clinical and demographic characteristics of women commencing different therapies. Patients and Methods: We identified the first dispensing of tamoxifen, anastrozole or letrozole for women diagnosed with invasive breast cancer in the 45 and Up Study from 2004-2009 (N = 1266). Unit-level pharmacy and medical service claims, hospital, Cancer Registry, and self-reported data were linked to determine menopause status at diagnosis, tumour size, age, comorbidities, and change in subsidy restrictions. Chi-square tests and generalised regression models were used to compare the characteristics of women commencing different therapies. Results: Most pre-menopausal women commenced therapy with tamoxifen (91%). Anastrozole was the predominant therapy for post-menopausal women (57%), followed by tamoxifen (28%). Women with osteoporosis were less likely to commence anastrozole compared with tamoxifen (anastrozole RR = 0.7, 95% CI = 0.5-0.9). Women with arthritis were 1.6- times more likely to commence letrozole than anastrozole (95% CI = 1.1-2.1). Tamoxifen was more often initiated in women with tumours > 1 cm, who were also =75 years. Subsidy restriction changes were associated with substantial increases in the proportion of women commencing AIs (anastrozole RR = 4.3, letrozole RR = 8.3). Conclusions: The findings indicate interplay of comorbidity and therapy choice for women with invasive breast cancer. Most post-menopausal women commenced therapy with anastrozole; however, letrozole and tamoxifen were more often initiated for women with comorbid arthritis and osteoporosis, respectively. Tamoxifen was also more common for women with tumours > 1 cm and aged =75 years. Subsidy restrictions appear to have strongly influenced therapy choice. © 2014 Kemp et al. |
| first_indexed | 2025-11-14T10:05:08Z |
| format | Journal Article |
| id | curtin-20.500.11937-56032 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:05:08Z |
| publishDate | 2014 |
| publisher | Public Library of Science |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-560322018-01-10T03:22:10Z Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice Kemp, A. Preen, D. Saunders, C. Boyle, F. Bulsara, M. Holman, C. Malacova, Eva Roughead, E. Background: Australian clinical guidelines recommend endocrine therapy for all women with hormone-dependent early breast cancer. Guidelines specify tamoxifen as first-line therapy for pre-menopausal women, and tamoxifen or an aromatase inhibitor (AI) for post-menopausal women depending on the risk of recurrence based on tumour characteristics including size. Therapies have different side effect profiles; therefore comorbidity may also influence choice. We examined comorbidity, and the clinical and demographic characteristics of women commencing different therapies. Patients and Methods: We identified the first dispensing of tamoxifen, anastrozole or letrozole for women diagnosed with invasive breast cancer in the 45 and Up Study from 2004-2009 (N = 1266). Unit-level pharmacy and medical service claims, hospital, Cancer Registry, and self-reported data were linked to determine menopause status at diagnosis, tumour size, age, comorbidities, and change in subsidy restrictions. Chi-square tests and generalised regression models were used to compare the characteristics of women commencing different therapies. Results: Most pre-menopausal women commenced therapy with tamoxifen (91%). Anastrozole was the predominant therapy for post-menopausal women (57%), followed by tamoxifen (28%). Women with osteoporosis were less likely to commence anastrozole compared with tamoxifen (anastrozole RR = 0.7, 95% CI = 0.5-0.9). Women with arthritis were 1.6- times more likely to commence letrozole than anastrozole (95% CI = 1.1-2.1). Tamoxifen was more often initiated in women with tumours > 1 cm, who were also =75 years. Subsidy restriction changes were associated with substantial increases in the proportion of women commencing AIs (anastrozole RR = 4.3, letrozole RR = 8.3). Conclusions: The findings indicate interplay of comorbidity and therapy choice for women with invasive breast cancer. Most post-menopausal women commenced therapy with anastrozole; however, letrozole and tamoxifen were more often initiated for women with comorbid arthritis and osteoporosis, respectively. Tamoxifen was also more common for women with tumours > 1 cm and aged =75 years. Subsidy restrictions appear to have strongly influenced therapy choice. © 2014 Kemp et al. 2014 Journal Article http://hdl.handle.net/20.500.11937/56032 10.1371/journal.pone.0084835 http://creativecommons.org/licenses/by/4.0/ Public Library of Science fulltext |
| spellingShingle | Kemp, A. Preen, D. Saunders, C. Boyle, F. Bulsara, M. Holman, C. Malacova, Eva Roughead, E. Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title | Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title_full | Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title_fullStr | Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title_full_unstemmed | Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title_short | Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: The impact of comorbidity and demographics on initial choice |
| title_sort | women commencing anastrozole, letrozole or tamoxifen for early breast cancer: the impact of comorbidity and demographics on initial choice |
| url | http://hdl.handle.net/20.500.11937/56032 |