“…Thirty-five studies reporting on risk factors for recurrence and/or mortality, and that included more than 100 patients with histologically proven ACC, were analyzed (1,8,20,25,26,29,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82) (see Appendix 2 for details of studies included, and Appendix 3 for an overview of all prognostic factors studied). The threshold of 100 cases was defined upfront as with n = 100 and an expected number of deaths of 50, statistical power was considered sufficient.…”