Judy-Anne W Chapman, Kathleen I Pritchard, Paul E Goss, James N Ingle, Hyman B Muss, Susan F Dent, Ted A Vandenberg, Brian Findlay, Karen A Gelmon, Carolyn F Wilson, Lois E Shepherd, Michael N Pollak Judy-Anne W Chapman, NCIC Clinical Trials Group, Queen’s University, Kingston, ON, K7L 3N6, Canada Kathleen I Pritchard, Sunnybrook Odette Cancer Centre, Uni- versity of Toronto, Toronto, ON, M4N 3M5, Canada Paul E Goss, Massachusetts General Hospital, Harvard Univer- sity, Boston, MA 02114, United States James N Ingle, Mayo Clinic, Rochester, MN 55902, United States Hyman B Muss, Lineberger Comprehensive Cancer Center at the University of North Carolina at Chapel Hill, Chapel Hill, N C 27514, United States Susan F Dent, Ottawa Hospital Cancer Center, University of Ottawa, Ottawa, ON, K1H 8L6, Canada Ted A Vandenberg, London Health Sciences Centre, University of Western Ontario, London, ON, N6G 2V4, Canada Brian Findlay, Niagara Health System, McMaster University, St. Catharines, ON, L2R 2Z4, Canada Karen A Gelmon, BC Cancer Agency, University of British Co- lumbia, Vancouver, BC, V5Z 1L3, Canada Carolyn F Wilson, Lois E Shepherd, NCIC Clinical Trials Group, Queen’s University, Kingston, Ontario, K7L 3N6, Canada Michael N Pollak, Lady Davis Institute, Jewish General Hospi- tal, McGill University, Montreal, QC, H3T 1E2, Canada Author contributions: Chapman JAW designed the research; Goss PE, Ingle JN, Muss HB, Shepherd LE and Pollak MN con- tributed to conception; Pritchard KI, Goss PE, Dent SF, Vanden- berg TA, Findlay B, Gelmon KA, Wilson CF, Shepherd LE and Pollak MN contributed to data; Chapman JAW analyzed the data; Chapman JAW drafted the article with critical content review and revision by all other authors; all authors approved the version submitted for publication. Supported by the Canadian Cancer Society through a grant to the NCIC Clinical Trials Group from the Canadian Cancer Soci- ety Research Institute; Novartis provided the NCIC CTG MA.14 drug octreotide LAR Correspondence to: Judy-Anne W Chapman, PhD, Senior Biostatistician, NCIC Clinical Trials Group, Queen’s University, 10 Stuart Street, Kingston, ON, K7L 3N6, Canada. jchapman@ctg.queensu.ca Telephone: +1-613-5336430 Fax: +1-613-5332941 Received: December 22, 2013 Revised: April 30, 2014 Accepted: July 12, 2014 Published online: December 10, 2014 Abstract AIM: To show a new paradigm of simultaneously testing whether breast cancer therapies impact other causes of death. METHODS: MA.14 allocated 667 postmenopausal women to 5 years of tamoxifen 20 mg/daily ± 2 years of octreotide 90 mg, given by depot intramuscular injections monthly. Event-free survival was the pri- mary endpoint of MA.14; at median 7.9 years, the tamoxifen+octreotide and tamoxifen arms had similar event-free survival ( P = 0.62). Overall survival was a secondary endpoint, and the two trial arms also had similar overall survival ( P = 0.86). We used the median 9.8 years follow-up to examine by intention-to-treat, the multivariate time-to-breast cancer-specific (BrCa) and other cause (OC) mortality with log-normal survival analysis adjusted by treatment and stratification fac- tors. We tested whether baseline factors including In- sulin-like growth factor 1 (IGF1), IGF binding protein-3, C-peptide, body mass index, and 25-OH vitamin D were associated with (1) all cause mortality, and if so; and (2) cause-speciic mortality. We also it step-wise forward cause-speciic adjusted models. RESULTS: The analyses were performed on 329 patients allocated tamoxifen and 329 allocated tamoxifen+octreotide. The median age of MA.14 pa- tients was 60.1 years: 447 (82%) < 70 years and 120 (18%) ≥ 70 years. There were 170 deaths: 106 (62.3%) BrCa; 55 (32.4%) OC, of which 24 were other malignancies, 31 other causes of death; 9 (5.3%) pa- tients with unknown cause of death were excluded from competing risk assessments. BrCa and OC deaths were not signiicantly different by treatment arm ( P = 0.40): tamoxifen patients experienced 50 BrCa and 32 OC deaths, while tamoxifen + octreotide patients ex- perienced 56 BrCa and 23 OC deaths. Proportionately more deaths ( P = 0.004) were from BrCa for patients RETROSPECTIVE STUDY Competing risks of death in younger and older postmenopausal breast cancer patients Submit a Manuscript: http://www.wjgnet.com/esps/ Help Desk: http://www.wjgnet.com/esps/helpdesk.aspx DOI: 10.5306/wjco.v5.i5.1088 World J Clin Oncol 2014 December 10; 5(5): 1088-1096 ISSN 2218-4333 (online) © 2014 Baishideng Publishing Group Inc. All rights reserved. World Journal of Clinical Oncology W JC O 1088 December 10, 2014|Volume 5|Issue 5| WJCO|www.wjgnet.com