“…In 27.5% ( n =36) of studies, there was sufficient information to determine the prevalence of current smoking among participants who were current smokers at cancer diagnosis (4, 5, 34-36, 39, 40, 44, 46, 56, 60, 65, 76, 80-84, 87, 97, 110, 112, 115, 117, 123, 125, 128, 129, 136-138, 142-144, 149, 153). In many cases, the definition used to classify current smokers at cancer diagnosis was unreported (38.9% ( n =14/36) (e.g., (4, 31, 87, 110, 128))).…”