The study was a retrospective descriptive analysis conducted over 10 years, from January 1^st, 2013 to December 31^st, 2022. It took place in the oncology units of Yaoundé and Douala General Hospitals. Our study population comprised the medical records of all patients with histologically confirmed bladder cancer during this time frame. The inclusion criteria focused on advanced bladder cancer cases (stages T3 and above according to TNM classification) that were hospitalized within the past decade and exhibited evidence of metastases on imaging studies. We excluded records lacking imaging results and those with incomplete anamnesis data. Retrospective data were gathered from medical reports utilizing a pretested extraction form.

This study commenced after receiving ethical clearance from the Institutional Review Board of the Faculty of Health Sciences at the University of Buea, as well as other necessary administrative authorizations. Participants’ confidentiality was maintained; no patients’ names or identity card numbers were collected, and the data obtained from hospital records was kept confidential and used solely for research purposes.

A total of 10,684 files of oncology patients were reviewed in the YGH and DGH during our period of study. We had 7703 (72.09%) files from the YGH and 2981 (27.90%) files from DGH. We included 54 files in our study and excluded 12 (18.18%) files. We excluded records without histological confirmation, those missing key clinical data such as treatment history, absence of imaging records, and duplicated patients record ( Figure 1 ).

Data were extracted retrospectively using a standardized pretested data extraction form developed in Microsoft excel 2019. The form was structured to collect information on: 1) Socio-demographic characteristics including age, region of origin, marital status, and occupation; 2) Clinical features such as date of diagnosis, symptoms, duration of symptoms, imaging modalities, and sites of metastases; 3) Treatment modalities encompassing surgery, hormonal therapy, radiotherapy,

chemotherapy, or no treatment; and 4) Outcomes related to treatment response, including progression, regression, and stability.

To ensure data data validity and reliability, pre-testing was done with 10 files at the Douala General hospital. The extracted data were recorded were cleaned, checked for duplication and entered in Microsoft Excel version 2019 ensuring anonymity and password protected. The data were analyzed using Statistical Package for Social Sciences (SPSS) software, version 26 for Windows. Categorical variables were summarized with frequencies and percentages, while continuous variables were summarized using mean and standard deviation.

The primary outcome of this study was the prevalence of ABC among all cancer cases reviewed at the YGH and DGH over a 10 year period. Secondary outcomes included treatment response assessed through CT findings and clinical documentations, patterns of metastasis and treatment modalities.

A total of 54 participants were included in the study following a review of 10,684 medical records from both hospitals. Of these, 40 cases were identified at Yaoundé General Hospital (YGH) and 14 at Douala General Hospital (DGH), corresponding to a prevalence of 0.52% in YGH and 0.47% in DGH, and an overall prevalence of advanced bladder cancer across the two hospitals was 0.51% (see Figure 2 ).

The number of patients with ABC showed and increasing trend over the years. According to the findings of our investigation, there were 3 instances in 2013 and 10 patients by 2022 (see Figure 3 ).

Of the 54 participants in the study, 33 (61.1%) were of the age group 50 - 69, and 14 (25.9%) cases were between 24 - 49 years with a mean age of 56.78 ± 14.25 years (range = 24 - 80 years). 31 (57.4%) were males with a male to female sex ratio found was 1.3:1. 41 (75.9%) were married (as illustrated in Table 1 ).

The results of the study equally show that the regions of origin with the most cases were the center region with 22 (40.7%) cases followed by the west region with 14 (25.9%) participants ( Figure 4 ).

The most common clinical presentation on admission was hematuria 46 (85.2%), followed by back pain 4 (7.4%). 21 (38.9%) were graded T3 and 21 (38.9%) graded T4 from TNM classification ( Table 2 ).

Different diagnostic modalities were used by the two hospitals for diagnosis and extension of the disease. The Computed tomographic scan (CT) scan was used in 28 cases (51.9%), followed by Cystoscopy 25 (46.3%), then MRI which accounted for 5 (9.3%) ( Figure 5 ). The lungs 11 cases (20.4%) followed by the vertebrae 10 (18.5%) were the most common site of secondary localization (metastasis) (see Figure 6 ).

Initially, 21(38.9%) of the cases reviewed had a surgery for the management of the bladder cancer of which; 13 cases had a trans-urethral resection of the bladder tumor (TURBT) ( Table 3 ).

Among the current treatment modalities used, Chemotherapy was the most

explored treatment option 32 (59.3%) for both curative and palliative purposes ( Figure 7 ). Carbogemzar was the most commonly used protocol (56.3%) followed by Carbotaxol protocol ( Table 4 ).

The average duration of follow-up of patients with ABC at the DGH and YGH was 4 months. Majority of the cases (40 cases) were lost to follow up and 11 cases showed evidence of disease progression on imaging ( Table 5 ).

The prevalence of ABC in our study was of 0.51% among cancer patients over our

10 years of study. This prevalence is very low when compared to other studies done in Cameroon, by Engbang et al. Who reported a prevalence of 14.16% (96 cases) in 2014 and 16.1% (122 cases) in 2022 [2] [16] respectively and a prevalence of 12.1% (7 cases) reported by Sando et al. [15] . This difference can be explained by the different population considered. The authors in the previous study only considered urologic cancers in their prevalence, meanwhile in the current study all cancer patients found in oncology units were used as the denominator accounting for the lower prevalence.

The mean age of our patients was 56.78 ± 14.2 (Range 24 - 80 years) and the most represented age group was 50 to 69 years. This result is in accord with the study done by Engbang et al. [16] which reports a mean of 58.0 ± 13.3 (Range 24 - 91 years), Niang L et al. [17] and Diao B et al. [18] . Our result is high as compared to the mean age of 49.3 ± 23.7 years reported by Sando et al. in Yaounde [15] .

Advanced bladder cancer was more common in men with a Male to female ratio 1.3, which is similar to a study in Cameroon which reported a sex ratio of 1.5 [2] and in a study in Middle Africa with a male to female ration of 1.8 [19] . However, this is low compared to 6.25 [15] and 2.46 [17] .

Many patients affected with advanced bladder cancer present differently. Symptoms can be, macroscopic haematuria, dysuria, lower back pain or many others. In this study, macroscopic haematuria was the most common motive of consultation among these patients (in 46, (85.2%) cases). The same results have been reported in other studies 53% in UK [10] , 80% US [20] , 80 cases (65.6%) in Cameroon [15] and in other African studies [17] [21] who found gross hematuria accounting for 77.5%, and 61.1% of the presenting symptoms respectively.

The multiple metastasis found in our study along with the long and slow evolution of the disease are consistent with the late referral. Such a feature is common in most African series. Lung metastasis was the most prevalent distant secondary localization in our study consistent with previous studies [22] [23] .

In the present study, chemotherapy 32 (59.3%) was the most commonly used treatment modality in patients with advanced bladder cancer with Carbo-gemzar protocol 18 (33.3%) being the most widely use molecules. This can be explained the availability of the molecules and the decreased level toxicity as compared to other protocol like MVAC (methotrexate, vinblastine, doxorubicin, and cisplatin) [11] . It should equally be noted that most of these patients 21 (38.9%), placed on chemotherapy previously surgery for treatment of the bladder cancer. 14 (25.92%) of which was by TURBT. This is supported by a study in Senegal done in 2018 by Cissé et al. [24] , although literature encourages radical cystectomy with lymphadenectomy as gold standard treatment of muscle invasive bladder tumour (T2 - T4) [12] [25] .

The mean duration of follow-up of patients was 143.6 days ± 312.09, and an average duration of follow up of 4 months. This is better compared with the mean duration of 2.2 months found in Cameroon, Douala by Engbang et al. [2] but falls short of the overall follow-up time of 7.9 months and 48.5 months in the study done in USA and France by Flannery et al. [20] and George et al. [26] . These differences in average duration of follow-up can be explained by the difference in quality of the various hospitals, services offered and treatment modalities and protocol used. Most of the patients in the current study were lost to follow up. This would be justified either by an altered general condition preventing continuation of this chemotherapy or by the expensive cost of chemotherapy in our context, although it is subsidized.

This study had some limitations that should be considered when interpreting the findings. The study relied entirely on retrospective medical record review, which limited the control over data completeness, accuracy and standardization across patients record. Furthermore, a significant number of files were excluded due to missing data which may have introduced selection bias and affected the generalization of our findings. Additionally, due to limited follow-up duration, and high loss of follow-up, we could not assess overall survival which is a critical indicator in prostate cancer prognosis. The findings reflect the experience in two tertiary urban hospitals and may not represent the broader national situation