Predicting factors for recurrence in low-grade Ta primary bladder tumours

Ta bladder tumors constitute 53% of primary bladder neoplasms, 70% of them being low-grade (G1). These tumors present a 15- 38% chance of recurrence during the first year. The aim of this paper is to identify the predicting factors of the first recurrence in a series of TaG1 primary bladder tumors.We have retrospectively analyzed patients who were diagnosed with TaG1 primary bladder tumor by transurethral resection between 2004 and 2012. We established their tumor grade and pathological stage according to the WHO's classification guides for 1973 and 2004 as well as 2009's TNM. Those patients who were diagnosed before 2009 did not receive any adjuvant treatment. Those who were diagnosed later on received 40 mg of endovesical Mitomycin C during their immediate post operative period as their only treatment. We define recurrence as the presence of tumor after the first cystoscopy and relapse-free survival (RFS) as the period of time (in months) until the first recurrence appeared. Follow up constitutes the period of time (in months) until the last check-up or first recurrence. We also analyzed different variables: age, gender, smoking habits, muscular representation in the sample, size of the tumor (or1 cm), multiple or single tumors and adjuvant treatment. The survival analysis was performed by the Kaplan-Meier method, using the long-rank test to evaluate the differences between groups.68 patients were included in the study (73.5% men, 75% smokers). The average age was 61.9 years (the median being 58.5). Average follow up was 33.2 months (median 28.4). 35.3% of patients experienced recurrence. Average RFS was 19.2 ± 12.7 months (median 13.5). The majority of tumors were of a single nature (77.9%), with a size of less than 1 cm (55.9%) and with muscle representation (52.9%). 57.4% of patients did not receive adjuvant treatment. Only the absence of adjuvant treatment was associated with recurrence in uni and multivariate analysis (p0,001), with a relative risk of 17,5 IC95% (7,6-30,2).The absence of adjuvant therapy with Mitomycin C is the only factor that, in a statistically significant way, increases the risk of recurrence, regardless of demographic factors and the characteristics of the tumor.