the efficacy of lowdose transdermal fentanyl in opioidnave cancer patients with moderatetosevere pain backgroundaims little is known about the efficacy of lowdose transdermal fentanyl tdf patches in opioidnave patients with moderatetosevere cancer painmethods this study had an openlabel prospective design and was conducted between april 2007 and february 2009 in seven tertiary cancer hospitals 98 patients were enrolled tdf was started using a lowdose formulation 125 ghr and the dose was adjusted according to the clinical situation of individual patients pain intensity the tdf doses used and adverse events aes were monitored over 4 weeks data were analyzed using the intenttotreat and perprotocol principlesresults of the 98 patients enrolled 64 65 completed the study the median pain intensity decreased from 60 to 30 p 0001 at the followup visit the efficacy of lowdose tdf on pain relief was consistent across groups separated according to gender p 0001 age p 0001 metastasis p 0001 previous treatment p 0001 and baseline pain intensity p 0001 the decrease in pain intensity was significantly greater in the severe group compared with the moderate group mean sd 510 248 vs 248 156 p 0001 tdf dose 278 ghr vs 248 ghr p 0423 and the mean treatment time 75 days vs 79 days p 0740 required for pain control were not different between the two painintensity groups patients had aes of only mild or moderate intensity among these nausea 38 was the most common followed by vomiting 22 and somnolence 22conclusions lowdose tdf was an effective treatment for patients with cancer pain of moderatetosevere intensity further randomized trials assessing the efficacy of tdf for severe pain andor optimal starting doses are warranted