The outcome of prostate cancer patients treated with curative intent strongly depends on survival after metastatic progression

BACKGROUND: Five-year survival in patients with localized prostate cancer (PCa) is nearly 100%, but metastatic disease still remains incurable. Clinical management of metastatic patients has become increasingly complex as novel therapeutic strategies have emerged. This study aims at evaluating the impact of the first metastatic progression on the outcome of PCa patients treated with curative intent. METHODS: The analysis was conducted using data of 913 cases of localized PCa diagnosed between 2000 and 2014. All patients were treated with curative surgery (N = 382) or radiotherapy (N = 531) with or without adjuvant therapy. All metastases were radiologically documented. The prognostic impact of the first site of metastasis on metastasis-free survival (MFS) and PCa-specific survival (PCaSS) was investigated by univariate and multivariate analyses. RESULTS: One hundred and thirty-six (14.9%) patients developed a metastatic hormone-sensitive PCa and had a median PCaSS of 50.4 months after first metastatic progression. Bone (N = 50, 36.8%) and LN or locoregional (N = 52, 38.2%) metastases occurred more frequently with a median PCaSS of 39.7 and 137 months respectively (p < 0.0001). Seven patients developed visceral metastasis only (5.1%; liver, lung, brain) and 27 (19.9%) concurrent metastases; this last group was associated with the worst survival with a median value of only 17 months. Thus, each subgroup exhibited a survival after metastasis significantly different from each other. In multivariate analysis the site of the first metastasis was an independent prognostic factor for PCaSS along with Gleason score at diagnosis. The correlation between survival and first site of metastasis was confirmed separately for each therapy subgroup. Median metastasis-free survival from primary diagnosis to first metastasis was not correlated with the first site of metastasis. CONCLUSIONS: In non-metastatic PCa patients treated with curative intent, the PCa-specific survival time depends on the time after metastatic progression rather than the time from diagnosis to metastasis. Moreover, the site of first metastasis is an independent prognostic factor for PCaSS. Our data confirm that the first metastatic event may confer a differential prognostic impact and may help in identifying patient at high risk of death supporting the treatment-decision making process following metastatic progression. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12885-017-3617-6) contains supplementary material, which is available to authorized users.