Utility of Ki67 in Predicting Response to Neoadjuvant Chemotherapy in Women With Locally Advanced Breast Cancer at the Kenyatta National Hospital.

Abstract

Background: In Kenya, majority present with locally advanced breast cancer. Neoadjuvant chemotherapy(NACT) is useful in management of these patients, and is useful in predicting response to treatment. Ki67 levels have good prediction and prognosticating value in breast cancer treatment. There is limited data on Ki67 in Kenya. This study deciphers the role of Ki67 in predicting response to NACT. Patients and methods: This was a prospective cohort study carried out at the Kenyatta National Hospital. Women with locally advanced breast cancer, who met the inclusion criteria, were recruited consecutively and followed up over a period of six months from December 2017 to January 2019. Informed consent was sort and data obtained included pre-treatment tumour size by ultrasound, pre-treatment Ki67 levels, demography, tumour biology was collected.On completion of 3 cycles of first line chemotherapy, response by useof ultrasound was done. Response was defined as tumor reduction by 30% from the pretreatment size. Data was analyzed by using of SPSS (V 21.0). We analyze change in tumour size, tumour biology and compared them with pretreatment Ki67 levels. Results:The mean age was 45.9 (SD=10.4) years.The disease status on completion of 3 cycles was response at 39.4%, stable disease 50.8% and progressive disease is 9.8%. The sensitivity and specificity of Ki67 was 70.8% and 43.2% respectively ata cut off value of 32.5%. There was no association between lymphovascular invasion and KI67 levels, χ2 (1) = 2.198, p = .138, but there was statistically significant association between perineural invasion and KI67 levels, χ2 (1) = 10.509, p = .005. Conclusions: The cut off of Ki67 in this study is high at 39.4%.Majority of patient have stable disease on completion of the third cycle. In our study the only aspect of tumour biology that has some association with higher Ki67 is perineural invasion.