Table 2 shows that the minimal surveillance regimen is preferred by international and North American RCTs (P = 0.001) and by LY2603618 datasheet trials involving more than one country (P = 0.004), while there is no relationship with the number of participating
centers (P = 0.173), the pharmaceutical industry sponsorship (P = 0.80), trials enrolling > 1000 patients (P = 0.14). Breast cancer follow-up guidelines, recommending the minimal approach, were published by the American Society of Clinical Oncology in 1997 [128]. Interestingly, no differences in follow-up modalities have been detected in RCTs enrolling patients before and after 1998 (P = 0.58). Stratifying data according to the date of beginning of patients enrollment (i.e. before or after 1998), even if numbers are small, in more recent studies there is a higher use of the minimal approach by international and North American RCTs (P = 0.01) and by trials involving more than one country (P = 0.01), and more than 50 buy AZD0156 participating centers (P = 0.02), with a trend toward statistical significance for trials enrolling > 1000 patients (P = 0.06) (Table 3). Table 2 Follow-up methodologies in RCTs Follow-up Approach P value Minimal Intensive No. (%)
No. (%) Geographic location International 12 (92) 1(8) 0.001 North America (USA and Canada) 7 (70) 3 (30) Western Europe 13 Leukotriene-A4 hydrolase (34) 25 (66) East Asia (Japan, Vietnam, China) 1 (20) 4 (80) Number of participating countries 1 country see more 16 (37) 27 (63) 0.004 > 1 country 17 (74) 6 (26)
Number of participating centers ≤ 50 11 (38) 18 (62) 0.173 > 50 10 (59) 7 (42) Industry sponsorship Yes 18 (49) 19 (51) 0.80 No 15 (52) 14 (48) Number of enrolled patients ≤ 1000 patients 14 (41) 20 (58) 0.14 > 1000 patients 19 (59) 13 (41) Date of beginning of patients enrollment From 1981 to 1997 23 (48) 25 (52) 0.58 From 1998 to 2002 10 (56) 8 (44) Legends: RCTs = randomized clinical trials. Table 3 Follow-up methodologies in RCTs according to the date of beginning of patients enrollment Date of beginning of patients enrollment Before 1998 After 1998 Follow-up approach Follow-up approach Minimal Intensive Minimal Intensive No. (%) No. (%) P value No. (%) No. (%) P value Geographic location International 7 (87) 1 (13) 5 (100) – 0.01 North America (USA and Canada) 3 (60) 2 (40) 4 (80) 1 (20) Western Europe 12 (37) 20 (63) 1 (16) 5 (83) East Asia (Japan, Vietnam, China) 1 (33) 2 (67) 0.07 – 2 (100) Number of participating countries 1 country 13 (39) 20 (60) 3 (30) 7 (70) 0.01 > 1 country 10 (66) 5 (33) 0.08 7 (87) 1 (87) Number of participating centers ≤ 50 11 (46) 13 (54) – 5 (100.0) 0.02 > 50 6 (54) 5 (46) 0.