Incidence of second tumours in high risk prostate cancer patients according to the primary treatment applied. / Incidencia de segundos tumores en pacientes con cáncer de próstata de alto riesgo según el tratamiento primario aplicado.

ABSTRACT

INTRODUCTION AND OBJECTIVES: The onset of second primary tumours should be considered in high-risk prostate cancer patients in the natural course of the disease. Our aim was to evaluate the influence of primary treatment with curative intent for these patients on the development of second primary tumours. MATERIAL AND METHODS: A retrospective study of 286 patients diagnosed between 1996 and 2008, treated by radical prostatectomy (n=145) or radiotherapy and androgen blockade (n=141). The homogeneity of both series was analysed using the Chi-squared test for the qualitative variables, and the Student's t-test for the quantitative variables. A multivariate Cox regression analysis was performed to assess whether the type of primary treatment influenced the development of second tumours. RESULTS: The median age was 66 years, and the median follow-up was 117.5 months. At the end of follow-up, 60 patients (21%) had developed a second primary tumour. In the prostatectomy group it was located in the pelvis in 13 (9%) cases, and those treated with radiotherapy and hormonotherapy in 8 (5.7%) cases (P=.29). The most common organ sites were colo-rectal in 17 (28.3%) patients, the lung in 11 (18.3%), and the bladder in 6 (10%) patients. In the multivariable analysis, the risk of a second tumour doubled for those treated with radiotherapy and hormonotherapy (HR=2.41, 95%CI 1.31-4.34, P=.005) compared to the patients treated by prostatectomy. Age and rescue radiotherapy did not behave as independent predictive factors. CONCLUSIONS: The onset of a second primary tumour was related with the primary treatment given; thus the risk for those treated with radiotherapy and androgen deprivation therapy more than doubled.