Urological Cancers in Burkina Faso: Epidemiological and Anatomopathological Aspects of 2204 Cases

Purpose: To study the epidemiological and anatomopathological aspects of urological cancers in Burkina Faso from 1988 to 2018. Patients and Methods: A cross-sectional, retrospective and descriptive study of histologically confirmed cancers that are collected from pathological anatomy laboratory records. The aspects studied were age, sex, location and histological type. Results: A total of 2204 cases of urological cancer were collected. The predominance was male with a sex-ratio of 9.6. The average age was 63.32 years. We found 1602 cases of prostate cancer (72.68%), 361 cancers of the bladder and excretory tract (16.4%), 180 cancers of the kidney (8.16%), 33 testis cancers (1.5%) and 28 penile cancers (1.3%). The predominant histological type of prostate cancer was adenocarcinoma (96.4%) with a Gleason score 7 in 30.4% of cases. Bladder cancer consisted of 50% epidermoid carcinomas. Kidney cancer was mostly nephrotoblastomas with 42.2% of cases. We noted 42.4% of seminomas among testis cancers and 89.3% of epidermoid carcinomas within penile cancers. Conclusion: The incidence of urological cancers is increasing in Burkina Faso. These cancers occur at a relatively advanced age with male predominance. Prostate cancers are at the forefront of these urological cancers. The establishment of a cancer registry would allow better follow up of cancers in our countries.


Introduction
Urological cancers are increasingly common in urological pathology and constitute a real public health problem [1]. They include a series of malignant tumors affecting the organs, the urinary tract ducts and the male genital system in particular. Today, epidemiological and histological data on these urological cancers are available in developed countries, dominated by prostate cancers, which constituted, according to Globocan 2018, the first urological cancer and the fourth location in terms of frequency in the world. Bladder cancer, the second most common urological cancer in the world, has a specificity related to urogenital bilharziosis in our countries. In fact, bladder epidermoid carcinomas are more common in parts of the world where bilharziosis is endemic [2].
In Africa in general and Burkina Faso in particular, data on urological cancers are scarce due to the unavailability of effective collection tools, notably a operational cancer registry [3]. In recent years, we have seen an increase in the frequency of urological cancers in the various urology divisions in Burkina Faso [4].
In order to obtain an estimate of the epidemiology and to study the anatomopathological aspects of urological cancers at the national level, our work consisted in identifying all histologically diagnosed cancer cases from 1988 to December 2018 in the various pathological anatomy laboratories in Burkina Faso.

Patients and Methods
This was a descriptive and cross-sectional retrospective study of all the urological cancers cases diagnosed between 1988 and December 2018 (31 years) in all the six pathological anatomy departments in Burkina Faso. These were three public laboratories. They are those of Yalgado Ouédraogo hospital, Tengandogo hospital and Sanou Souro hospital. The other three are private. These are the laboratories of Sandof, Schiphra and Philadelphia. All cases of cancer have been collected from the registries of these different pathological anatomy laboratories. Then all the cases of urological cancers whose results could be analyzed were selected. The variables studied were frequency, sex, age, location and histological type. Data analysis was performed using Epi-info software version 7.0.8. Then an export was made on the SPSS 2.0 software to perform statistical tests. The curves were formed from an Excel 2010 spreadsheet.

Frequency of Urological Cancers Compared to Other Cancers
During our study, we collected 2204 cases of urological cancers from a total of 14,587 cases of cancers diagnosed in the pathological anatomy laboratories of Burkina Faso. These urological cancers accounted for 15.1% of the cases ( Table 1). The urogenital tract was the 3 rd site of cancer localization in terms of frequency with 15.1% of the cancers diagnosed.

Evolution of Urological Cancers per Year
We collected 2204 cases of urological cancers over a 31-year period. There was an annual incidence of about 73 cases a year. There has been an increasing trend in urological cancers over the years. The largest number of cases was recorded in 2018 and 350 with a frequency of 15.9% ( Figure 1). Table 2 shows the annual incidence rates of urological cancers collected in BURKINA FASO; according to the population estimates of the World Bank.

Annual Incidence Rate of Urological Cancers
The results show abnormally increasing annual incidence rates of urological cancers. The highest incidences are recorded in 2018 with 1.77 per 100,000 inhabitants.

Age Distribution of Patients
Age was specified in 92.1% of cases. Figure 2 shows the representation of urological cancer cases according to age group (N = 2030).
The age group between 60 and 74 was the most represented with 1020 cases (50.24%). The average occurrence age of urological cancers was 63.32 years more or less 12.08 with 1 and 100 years.

Distribution of Prostate Cancers According to the Location
The distribution of urological cancers according to the location is shown in Figure 3.
In our study, we found 1602 cases of prostate or 72.68% of the cases of urological cancers collected. This cancer ranked first in terms of frequency compared to the other urological cancers and there was an annual incidence of about 53 cases per year.   The highest incidences are recorded in 2018 at 1.38 per 100,000 inhabitants (N = 272).

Distribution of the Cases Prostate Cancers According to Age Group
Age was specified in 92.9% of the cases. Figure 4 shows the distribution of prostate cancers according to age group (N = 1488).
The age group between 60 and 74 years was the most represented by 867 cases (58.3%). The average age was 69.48 years with extremes of 18 and 100 years.

Distribution of Prostate Cancers According to Sex
Sex was specified in 2183 cases. The male sex was predominant with 91% of the cases and we found a sex-ratio (M/F) of 9.6.

Prostate Cancer
Gleason's score was specified in 85.95% of the cases. Table 3 shows a distribution of prostate cancers according to the Gleason score (N = 1377).    The Gleason score 7 was the most represented by 30.4%. Table 4 shows a distribution of prostate cancers according to the histological grade ISUP.
The grades 2 and 3 corresponding to Gleason score 7 were the most represented by 30.4% of the cases. Table 5 shows a distribution of the cases according to the histological type (N = 1602).
Adenocarcinoma was the most represented by 96.4% of the cases.
We performed a statistical test on the distribution of the histological types of prostate cancer according to age. The results are shown in Table 6. Age was specified in 1488 cases.
There was a very significant statistical association of histological types and patients age. Adenocarcinoma was frequent in patients over 45 years especially in the 60 to 89 age group with 1244 cases or 86.4%.

Bladder and Excretory Tracts Cancer
In our series, we noted 361 (16.4%) cases of bladder and excretory cancer distributed in 357 cases of bladder cancer and 4 cases of urethral cancers.
Bladder cancer came in second place in terms of frequency with 16.2% of urological cancers. There was an annual frequency of 12 cases per year. Urethral cancer was scarce with 4 cases in 30 years. Table 7 shows the distribution of histological types of bladder cancers according to age. Age was specified in 321 cases.
There was a very significant statistical association of histological types and age of the patients. Epidermoid carcinoma was frequent in patients over 30 years      mostly in the age group of 45 to 74 years with 96 cases or 62.3%. Urethral carcinoma was mainly diagnosed in patients older than 45 years especially in the 60 to 74 years age group with 101 cases or 76.5%.

Other Urological Cancers
In our study, we found 180 cases of kidney cancer.

Discussion
Urological cancers are a real public health problem [5] [14].
The weaknesses of our study are the lack of information on the age, sex, origin and occupation of some patients, as well as the retrospective nature of the study.
Despite these limitations, these comments and discussions could be carried out.

Conclusion
Urological cancers were common in Burkina Faso and represented 15.1% of all cancers in the country. Urological cancers were common in elderly people.
Prostate cancer was by far the most common. The establishment of a cancer registry would enable a better follow up of the evolution of cancers in our country.

Conflicts of Interest
The authors do not declare conflict of interest.