The Impact of Obesity on Prostate Cancer and Progression to Castration Resistance—Real-World Data from a Romanian Center

<b>Background</b>: The primary endpoint was to assess the nutritional status in patients diagnosed with prostate cancer (PCa) in Romania. The secondary endpoint was to analyze the impact of obesity on mortality and disease recurrence. <b>Methods</b>: In this retrospective cohort study, we analyzed the files of 354 patients diagnosed with PCa between August 2001 and May 2022 and referred to the Medical Oncology Department of Neolife Medical Center. A total of 257 patients fulfilled the inclusion criteria and were the subject of this study. <b>Results</b>: Excess weight was seen in 190 (73.9%) patients, with 119 (46.3%) being overweight and 71 (27.6%) having obesity. Subgroup analysis showed that at diagnosis, patients with obesity (PwO) were younger (<i>p</i> = 0.022), had lower PSA (<i>p</i> = 0.016), and had lower 10-year all-cause mortality rates (<i>p</i> = 0.04) than patients without obesity. Patients with metastases had lower weight (<i>p</i> = 0.001) and BMI (<i>p</i> = 0.033), higher PSA (<i>p</i> < 0.001), Gleason scores (<i>p</i> = 0.002), ISUP grade group (<i>p</i> < 0.001), and 10-year all-cause mortality rate (<i>p</i> < 0.001) than patients without metastases. Weight (AUROC = 0.637, 95% CI: 0.557-0.717, <i>p</i> = 0.001; cut-off = 77.5 kg, Se = 52.5%, Sp = 71.2%) and BMI (AUROC = 0.591, 95% CI: 0.507-0.676, <i>p</i> = 0.033; cut-off = 23.5 kg/m², Se = 25.4%, Sp = 91.9%) were independent predictors of the presence of metastases at diagnosis. In the androgen deprivation therapy (ADT) group, PwO had a shorter time to castration resistance than patients without obesity (Log Rank test: χ2 = 4.395, <i>p</i> = 0.036). <b>Conclusions</b>: Weight and BMI are accessible tools that could be useful in determining the presence of metastatic disease. PwO on ADT may develop castration resistant PCa faster than patients without obesity.