Regarding prostate cancer, variables showing a significant relationship with drug treatment costs were PSA level (range from mean cost USD 3148.33, 95% CI 1957.18–4622.64 for PSA level 10–20ng/mL, to mean cost USD 5070.86, 95% CI 4285.01–5922.84 for PSA level > 20ng/mL, when compared to PSA level < 10ng/mL) and distant metastases (determined) (mean cost USD 5949.04, 95% CI 4604.98–7466.69 compared to distant metastases (undetermined)). The gene discussed is KLK3; the disease is Familial prostate cancer.