Improvement in Survival of Breast Cancer Patients - Trends in Survival over Two Time Periods in a Single Institution in an Asia Pacific Country, Malaysia

Background: There is improvement in breast cancer survival in the developed world, but information on breastcancer survival trends in the Asia Pacific region is limited. The aim of the study was to evaluate survival trendsand factors that affect survival in Malaysia. Methods : Two prospective groups of 423 and 965 newly diagnosedbreast cancer patients in University of Malaya Medical Centre, Kuala Lumpur, Malaysia diagnosed in two timeperiods ie. 1993 to 1997 and in 1998 to 2002 were studied. Vital status was obtained from the National Registryof Births and Deaths. The overall survival was calculated from the date of diagnosis to the date of death fromany cause. The survival differences between the two groups were analysed using the log-rank or Peto-Wilcoxonmethod. Survival estimates and independent prognostic factors were estimated by the Kaplan-Meier method andmultivariate analysis using Cox proportional hazard models. P values less than 0.05 were considered statisticallysignificant. Analyses were performed using SPlus 2000 Professional Release 2. Results and Discussion : Medianfollow-up for the two groups were 55 months (SD 29.2 months) in the first group and 52 months(SD 24.43) inthe second group. There was improvement in 5-year observed survival from 58.4% (CI 0.54-0.63) to 75.7% (CI0.73-0.79). The improvement in survival was significantly seen in all co-variates (p<0.05) except for those aged 40years and below(p= 0.27), tumour size 2 to 5 cm (p=0.11), grade 3 (p=0.32) and patients with Stage IV disease(p=0.80). Stage of disease, lymph node (LN) involvement, size and grade were identified as independent prognosticfactors in cohort one. For the second cohort; stage and LN involvement remained independent factors with theaddition of ER status and ethnicity. Conclusions : There was improvement in 5-year observed survival. Besidesknown prognostic factors, Malay ethnicity was an independent prognostic factor.