[1] Umea Univ, Dept Radiat Sci Oncol, S-90187 Umea, Sweden
[2] Umea Univ, Dept Med Biosci Pathol, Umea, Sweden
[3] Karolinska Inst, Dept Med Epidemiol & Biostat, S-10401 Stockholm, Sweden
[4] Umea Univ, Dept Surg & Perioperat Sci Urol & Androl, Umea, Sweden