Palmstedt, Emmeli2025-08-292025-08-292025-08-29978-91-8115-340-8 (tryckt)978-91-8115-341-5 (PDF)https://hdl.handle.net/2077/87265Overdiagnosis can have long-term consequences for both individuals and society, making it an important concern in the context of prostate cancer screening. The overall aim of this thesis was to explore different perspectives on overdiagnosis, from knowledge and understanding to strategies that can reduce the harm of overdiagnosis. Paper I used data from the Göteborg-1 trial to investigate if follow-up with biennial PSA testing is sufficient after an initial benign biopsy for men participating in screening. After 20 years of follow-up, prostate cancer mortality was 1.4%, suggest-ing that biennial testing is safe. Paper II evaluated how participants in the Göteborg-2 trial perceived their lifetime risk of prostate cancer. On average, men overestimat-ed their risk by 10 percentage points. Lower urinary tract symptoms and erectile dysfunction were associated with higher perceived risk, indicating a need for im-proved information. Paper III assessed long-term outcomes of active surveillance in men with screen-detected prostate cancer within the Göteborg-1 trial. Prostate can-cer-specific survival was 94% at 25 years, and treatment-free survival was 38% at 22 years, providing strong evidence that active surveillance is a safe long-term man-agement strategy. Paper IV explored men’s understanding and awareness of overdi-agnosis, and how it affected their willingness to participate in prostate cancer screen-ing. The results showed that prior awareness of overdiagnosis was low, and only 4 out of 10 men could correctly identify the concept after receiving detailed infor-mation. Willingness to participate in screening was significantly higher in a screen-ing scenario with 25% overdiagnosis compared to one with 75%, suggesting that the degree of overdiagnosis influences decision-making, even though the concept is difficult to understand. Overall: Overdiagnosis presents both clinical and communicative challenges in prostate cancer screening. Its negative consequences can be reduced through evi-dence-based screening regimes and surveillance strategies but most importantly, clear and accessible information must be provided so that men can make well-informed decisions about whether to undergo PSA testing or not.engactive surveillanceoverdiagnosisprostate cancerprostate-specific antigenrisk estimationscreeningtext