Abstract:
Background: Breast cancer is the most commonly diagnosed cancers worldwide. It is
a cancer that develops from breast tissue and most common invasive cancer in women.
Recurrent events data have been increasingly important in clinical studies where individuals experience an event more than once and it is a major clinical indicator, which
represents the principal cause of breast cancer-related deaths.
Objective: The aim of the study was to investigate determinants of the recurrence of
breast cancer.
Methodology: To reach the aim, 421 women with breast cancer were included in
the study based on data taken from medical record card of patients enrolled starting
from 1
st
January 2013 to 30
th
January 2019. A retrospective study has been applied
to obtain data on women breast cancer that recorded in oncology department of Tikur
Anbessa Specialized Hospital. Unmeasured shared similarities due to the impact of
multiple events were modeled using a random e ect. Cox-PH model and Shared frailty
model were used to identi es which factor was signi cantly a ect the recurrence of
breast cancer.
Results: From the total of 997 recurrent events, about 609 (61.1%) of them experienced recurrence of breast cancer. The shared log-normal frailty model was chosen
as the best t for this breast cancer data set based on the value of Likelihood crossvalidation criterion. From the result of shared log-normal frailty model age, stage of
breast cancer, tumor size, histology grade, breast feeding and oral contraceptives were
signi cantly associated with recurrence of women breast cancer.
Conclusion and recommendation: The result of shared log-normal frailty model
shows that the stage (II, III, IV), tumor size ((3-5) cm, >5 cm), histology grade (poorly
di erentiated) and oral contraceptive were signi cantly increases the risk of recurrence
of breast cancer. While, breast feeding was signi cantly decreases the risk of recurrence of breast cancer. It is recommended that policy maker, ministry of health and
Tikur Anbessa Specialized Hospital are expected to make interventions based on these
hazardous groups for recurrence of breast cancer
