Table 1. Studies of active surveillance in clinically localized prostate cancer T1-T2 (16).

Name	n	Age	Tumor category	Follow-up in months	Progression (%)	Tumor specific survival (%)	Abandonment of active surveillance
Mohler et al. (11)	27	69	T1c (100%)	23 (6–62)	33	100	4 patients because of progression
Choo et al. (12)	206	70	T1b (6%), T1c (57%), T2a (24%), T2b (13%)	29 (2–66)	17	100	69 patients: 15 because of clinical progression, 16 PSA, 5 histology, 23 patient’s wish, 6% protocol violation
Chen et al. (13)	52	71	T1a (100%)	87 (6–180)	8	100	4 patients because of progression (1 patient with bone metastases)
Khan et al. (14)	78	65	T1c (100%)	23	29	100
Patel et al. (15)	88	65	T1a/b (20%),	44 (7–172)	25	100	31 patients: 17 because of progression, 7 because of anxiety, 7 because of anxiety and other reasons
			T1c (58%),
			T2a–c (22%)

By searching Medline, the authors identified 88 publications of heterogeneous methodological quality. The 5 studies listed in this table are methodologically of the highest quality and form the evidence base for the recommendations of the NICE (National Institute for Health and Clinical Excellence) guideline for active surveillance (16).