Epidemiology of ovarian cancers in Zaria, Northern Nigeria: a 10-year study

BACKGROUND: Globally, the absence of a premalignant stage of ovarian cancer and a reliable screening tool make early diagnosis difficult. Locally, poverty, ignorance, and lack of organized cancer services make prognosis poor. We describe the epidemiological features of ovarian cancer seen at Ahmadu Bello University Teaching Hospital Zaria, Northern Nigeria, a tertiary referral center, over a 10-year period in this challenging setting. METHODS: All cases of histologically diagnosed ovarian cancer between January 1, 2004 and December 31, 2013 were included in the study. Case notes were retrieved to collect clinical data including age, parity, clinical stage of disease at presentation, and known associated factors. Results were analyzed using Epi info™. RESULTS: A total of 78 patients were included in the study. About 4–13 cases were seen every year with a tendency to increasing incidence. The patients were aged 8–80 years with mean of 37 years. Sixty-two (79.5%) patients were premenopausal while postmenopausal women accounted for only seven cases or 9.0%. There were 17 cases (22.3%) of aggressive cancers in patients aged ≤20 years. A majority of the patients, 65 (83.3%), were parous with only nine (11.5%) patients being nulliparous. Serous cyst adenocarcinoma accounted for 32 (41%) cases. Granulosa cell tumor was the second commonest with 18 cases (23.1%). The mean age of occurrence of serous cyst adenocarcinoma was 31 years and for epithelial ovarian cancers in general it was 33.5 years. Endometrioid adenocarcinoma was rare with only one case in 10 years. Factors like age, parity, and premenopausal status did not appear to be protective to the occurrence of malignant ovarian tumor in this group. CONCLUSION: Increasing numbers of patients with ovarian cancer were seen over the 10-year period. Young, premenopausal, parous women made up the majority of cases. Serous cystadenocarcinoma was the most common histological variant.