572 randomised trials. Early Breast Cancer Trialists’ Collaborative Group. Lancet 352:930–942 3. Fisher B, Costantino J, Redmond C, Poisson R, Bowman D, Couture J, Dimitrov NV, Wolmark N, Wickerham DL, Fisher ER, Wolmark N (1989) A randomized clinical trial evaluating tamoxifen in the treatment of patients with node-negative breast cancer who have estrogen-receptor-positive tumors. N Engl J Med 320:479–484 4. Fisher B, Dignam J, Wolmark N, DeCillis A, Emir B, Wickerham DL, Bryant J, Dimitrov NV, Abramson N, Atkins JN, Shibata H, Deschenes L, Margolese RG (1997) Tamoxifen and chemother- apy for lymph node-negative, estrogen receptor-positive breast cancer. J Natl Cancer Inst 89:1673–1682 5. Fisher B, Jeong JH, Bryant J, Anderson S, Dignam J, Fisher ER, Wolmark N (2004) Treatment of lymph-node-negative, oestro- gen-receptor-positive breast cancer: long-term ﬁndings from na- tional surgical adjuvant breast and bowel project randomised clinical trials. Lancet 364:858–868 6. Mirza AN, Mirza NQ, Vlastos G, Singletary SE (2002) Prog- nostic factors in node-negative breast cancer: a review of studies with sample size more than 200 and follow-up more than 5 years. Ann Surg 235:10–26 7. Kaplan EL, Meier P (1958) Nonparametric estimation from incomplete observations. J Am Stat Assoc 53:457–481 8. Putter H, Fiocco M, Geskus RB (2007) Tutorial in biostatistics: competing risks and multi-state models. Stat Med 26:2389–2430 Breast Cancer Res Treat (2008) 109:567–572 9. Arriagada R, Rutqvist LE, Kramar A, Johansson H (1992) Competing risks determining event-free survival in early breast cancer. Br J Cancer 66:951–957 10. Broet P, de la RA, Scholl SM, Fourquet A, Mosseri V, Durand JC, Pouillart P, Asselain B (1995) Contralateral breast cancer: annual incidence and risk parameters. J Clin Oncol 13:1578–1583 11. Chen Y, Thompson W, Semenciw R, Mao Y (1999) Epidemi- ology of contralateral breast cancer. Cancer Epidemiol Biomar- kers Prev 8:855–861 12. Baum M, Budzar AU, Cuzick J, Forbes J, Houghton JH, Klijn JG, Sahmoud T (2002) Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: ﬁrst results of the ATAC randomised trial. Lancet 359:2131–2139 13. Howell A, Cuzick J, Baum M, Buzdar A, Dowsett M, Forbes JF, Hoctin-Boes G, Houghton J, Locker GY, Tobias JS (2005) Re- sults of the ATAC (Arimidex, Tamoxifen, alone or in combina- tion) trial after completion of 5 years’ adjuvant treatment for breast cancer. Lancet 365:60–62 14. Gelman R, Gelber R, Henderson IC, Coleman CN, Harris JR (1990) Improved methodology for analyzing local and distant recurrence. J Clin Oncol 8:548–555 15. Satagopan JM, Ben Porat L, Berwick M, Robson M, Kutler D, Auerbach AD (2004) A note on competing risks in survival data analysis. Br J Cancer 91:1229–1235 123