Type of cancer Comparative studies (N)  Type of comparative study Total number of patients in comparative studies 
 Randomized Controlled Trial  Non-randomized controlled trial Cohort study Case-control study Other
 Bile duct [18-22]  5 2 0 2 1 0 327
 Breast [35]  1 1 0 0 0 0 68
 Cervical [41-43]  3 1 2 0 0 0 99
 Esophageal - early [50]  1 0 0 1 0 0 88
 Esophageal – advanced/ inoperable [51,74,75]  3 1 0 1 0 1 251
 Gastrointestinal [95]  1 0 1 0 0 0 11
 Head and neck – nasopharyngeal [101]  1 1 0 0 0 0 30
 Lung [133-141]  9 2 0 7 0 0 597*
 Mesothelioma [160,161]  2 1 1 0 0 0 62
 Skin – basal cell [175-183]  9 9 0 0 0 0 942
 Skin – squamous [184-186]  3 1 2 0 0 0 288
 Skin – Bowen [187-189]  3 3 0 0 0 0 96
 Skin – multiple (non-melanoma) [190]  1 1 0 0 0 0 23
 Vulval [257,258]  2 0 1 1 0 0 226
 Total  44 23 7 11 1 1 3108
*Number of patients not reported for one study (reported number of lesions instead)
Table 1: Number of comparative studies according to cancer type.