Factors affecting breast, cervical and prostate cancer treatment outcomes in Zambia

Abstract

Cervical, breast and prostate cancers represent 51% cancer mortality and morbidity in Zambia. This study aimed to show their prevalence, incidence trends, describe associated typical patient socio-demographic characteristics and survival factors using the Zambia National Cancer Registry (ZNCR) data collected during January 1st 2008 - December 31st 2015. We conducted secondary ZNCR data incidence and mortality analyses of by province for these cancers. Data were cleaned using Excel and Epi Info Version 7.2.1.0. Analysis was done in Stata-13 for socio-demographic, treatment and survival factors. We determined annual incidence rates, from the mid-year (2011) onwards; and overall incidence using the mid-year population. Chi tests for trend and independence were used. Of 10,765 cervical, breast and prostate cancer records analysed, there was an increase in incidence (p<0.001) and death rates during 2008 - 2015. Most breast cancer patients (56.9%) were aged between 30-54years, 56% were married, 64.3% lived in Lusaka, Eastern and Copperbelt provinces and were commonly treated by chemotherapy (32.9%) and surgery (32.2%). Highest breast cancer case fatality (CFR) and crude death rates (CDR) per 100,000 population were in Lusaka (32.9% and 82) and Eastern (18.9% and 107) respectively. For instance, controlling for marital status a positive HIV status reduced the odds of survival by 40%. Most cervical cancer patients (61.5%) were aged between 30-54years, 53.1% married, 57.9% lived in Copperbelt, Eastern and Lusaka provinces and were commonly treated by Chemotherapy (37.3%) and Radiotherapy (31.8%). Highest CFRs were in Lusaka (35.9%) and Eastern (14.3%) and lowest (2%) in Muchinga provinces, but Copperbelt province had the lowest CDR at 210/100,000 people. Controlling for marital status, HIV status and age, Radiotherapy increased the odds of survival by 70%. Most prostate cancer patients were aged between 60-84years, 54% were married and were commonly treated by Chemotherapy (34.1%) and surgery (29.6%). Lusaka (43%) and Eastern (13.1%) provinces had highest prostate cancer CFRs and a CDR of 310/100,00 population. Controlling for age, surgery, chemotherapy, radiotherapy and province of birth, being married increased the odds of surviving from prostate cancer 7.5 times. Breast and cervical cancers in Zambia mainly affected those younger than 55years while prostate mainly affected those older than 60 years and increased with age. Age, surgery, marital status and province of residence appear to have a major effect on morbidity and survival. Early screening programmes can help address these cancers. Key words: breast cancer, cervical cancer, prostate cancer, Zambia