Demographics, pathological characteristics and survival in urothelial bladder cancer in a cohort of Sri Lankan patients.

Introduction: Bladder cancer has the 9th highest incidence among Sri Lankan males. This study describes the demographic profiles and survival in bladder cancer patients at two tertiary care centres in Sri Lanka. Methods: A group of patients with urothelial bladder cancer, presenting for the first time for definitive treatment, were prospectively enrolled from 2013 to 2017. Results: There were sixty-six patients, with median age of 65 years and male to female ratio of 7:1. Histopathologically pTa 24%, pT1 47% and pT2 29%. Of the pT1 tumours 61% were low grade (LG). The majority (71%) of non-muscle invasive bladder cancer (NMIBC) patients underwent transurethral resection of bladder tumour only. For the entire cohort the 5-year overall survival was 59% and cancer specific survival (CSS) was 65%. CSS in NMIBC was 75% and 30% in muscle invasive bladder cancer (MIBC). The 5-year female CSS (22%) was significantly lower than in males (71%). Conclusion: Our cohort has a high male to female ratio. The percentage of MIBC was lower than reported in previous Sri Lankan studies. Of the pT1 tumours there is a higher percentage of pT1 LG patients in comparison to Western reports. There is low utilisation of intravesical mitomycin / bacillus Calmette-Guérin (BCG) in the treatment of NMIBC. The 5-year CSS in the Sri Lankan (lower middle-income economy) cohort lies between the values of high-income economies and upper middle-income economies in Asia. The reasons for poor CSS among Sri Lankan women with bladder cancer needs to be further investigated.

Clinical Exome Gene Panel Analysis of a Cohort of Urothelial Bladder Cancer Patients from Sri Lanka.

BACKGROUND: Bladder cancer has a high rate of recurrence and high mortality rates in those who progress to muscle invasive disease. Biomarkers and molecular sub classification of tumours beyond standard histopathology has been proposed to address therapeutic dilemmas. The Cancer Genome Atlas project and other studies have contributed to the enhanced knowledge base of the mutational landscape of urothelial bladder cancer. Once again, these are mostly from Caucasian and Chinese patients, with data from the rest of Asia and Sri Lanka being sparse. The objective of this study was to assess the genomic variations of a cohort of urothelial bladder cancer patients in Sri Lanka. METHODS: The molecular genetic study was conducted on formalin fixed paraffin embedded tumour samples of 24 patients, prospectively enrolled from 2013 to 2017. The samples were sequenced and variant distribution performed based on a 70-gene panel. RESULTS: Total number of filtered mutations in the 24 patients was 10453. Median mutations per patient were 450 (range 22-987). The predominant mutational change was C>T and G>A. The top 5 mutated genes in our cohort were SYNE1, SYNE2, KMT2C, LRP2, and ANK2. The genes were clustered into 3 groups dependent on the number of mutations per patient per gene. The genes of cluster 1 and 2 mapped to Chromatin modifying enzymes and Generic Transcription Pathway. The chromatin remodelling pathway accounted for the largest proportion (22%) of mutations. CONCLUSIONS: Clinical exome sequencing utilising a gene panel yielded a high mutation rate in our patients. The predominant mutational change was C>T and G>A. Three clusters of genes were identified. SYNE1 was the gene with the most mutations. The mutations comprised predominantly of genes of the chromatin remodelling pathway.