Dimension Original surveyitems Promoters-treatmentsoutcomeexpectationa   Symptomsimprovement •  Possibilitythat experimental treatmentwouldnot cause adverse/severesideeffects •  Possibilitythat experimental treatmentwoulddecreasehospitalization •  Possibilitythat experimental treatmentwouldimprovecurrentsideeffects •  Possibilitythat experimental treatment is betterthanstandardtreatment •  Possibilitythat experimental treatmentwouldincreaseyourabilityto be active Disease control •  Possibility of diseaseimprovement •  Possibilitythat experimental treatmentwould control cancer •  Possibilitythat experimental treatmentwouldextendlength of life •  Possibilitythat experimental treatmentwould cure cancer High Quality Medical Care •  Possibility of obtainingcareful medical care and follow-up •  Possibility of obtaininghigh-quality medical care •  Possibilitythat experimental treatmentwouldimprovequality of life Hopefulness •  Nothaving a bettertreatmentoption available •  Desireto try something new •  Desireto be part of a researchstudy •  Joining the studygives hope Medical teaminfluence •  Advicereceivedfromown doctor tojoin •  Trial informationreceivedwasveryclear •  Desiretohelpfuturecancerpatients   Social influences •  Encouragementfromfriendstojoin •  Encouragementfromfamilytojoin •  Trust in the Center conducting the trial Barriersb   DecisionMakingProcess •  Lack of understanding of trial processes/purposesduetocommunicationproblems •  Lack of knowledgeabout the disease and treatmentoptions •  Lack of knowledge/informationabout available trials •  Doctors do notdiscuss trial optionwithpatients •  Beingtoointimidatedtoaskquestions •  Relianceon doctor as the mosttrustedsource of informationtomake the decision Trial related •  Havingbloodsamplestaken •  Number of times expectedfortreatment or evaluation •  Duration of trial Socio-economic •  Travelcost •  Cost/Lack of healthinsurance •  Time expectedtotravelto the center •  Distancefrom trial center •  Lack of family/social support Distrust of the medical system •  Distrust of researchersdueto prior personal/familyexperience •  Distrust of the medical system •  Languagebarriers Fear/uncertainty •  Fear of being a guinea pig •  Fear of sacrificingquality of life •  Fearthatresearchersconsider the scientificexperiment more importantthan the patients’ health •  Fear of unknownreactions/sideeffects Fatalistic/spiritual beliefs •  Feelings of hopelessness •  Beliefsthatdisease is God’swill and nothing can be done •  Beliefthatdisease is a deathsentence •  Religious and spiritual beliefs Response options: aNot important=1 to Very important=5, higher mean scores indicate higher importance; bStrongly disagree=1 to strongly agree=4, higher mean scores indicate greater agreement.

Table 2: Dimensions Identified through Exploratory Factor Analysis and Original Survey Items.