- Research article
- Open Access
- Open Peer Review
Barriers and facilitators for clinical trial participation among diverse Asian patients with breast cancer: a qualitative study
© The Author(s). 2016
- Received: 18 August 2015
- Accepted: 12 July 2016
- Published: 22 July 2016
Recruitment rates for cancer trials are low for racial/ethnic minorities. Little is known about factors influencing trial recruitment in Asian patients. Our aim is to examine the barriers and facilitators for participation in trials among multi-ethnic Asian women with breast cancer.
We recruited a convenience sample from consecutive women seen at the National Cancer Centre. Two experienced bilingual (English and Chinese) moderators conducted focus groups to theme saturation. The question guide incorporated open-ended questions soliciting opinions about trial participation and knowledge. Women were first asked if they were willing, unwilling, or still open to participate in future trials. Sessions were audiotaped and transcribed. Transcripts were independently coded for emergent themes.
Sixteen of 103 women approached participated in five focus groups. Chinese, Malay, and Indian participants aged 29 to 69 represented different cancer stages. Five had no prior knowledge of trials. We identified three major themes comprising of 22 minor themes for barriers and facilitators. The major themes were: 1) patient-related, 2) trial-related, and 3) sociocultural factors. Women willing to join trials expressed themes representing facilitators (better test therapy, cost-effective profile, or trust in doctors and local healthcare systems). Women unwilling to participate expressed themes associated with barriers, while women still open to participation expressed themes representing both facilitators and barriers. Malay women were more likely to express themes related to ‘fatalism’ as a barrier.
We found that facilitators and barriers to trial participation among Asian women were similar to those previously reported in Western women. Knowledge of trials is limited among women receiving breast cancer treatment. Unique sociocultural factors suggest that approaches customised to local and community beliefs are needed to improve trial participation in minority groups.
- Focus Group
- Trial Participation
- Moderator Guide
- Trial Recruitment
- Theme Saturation
Breast cancer remains the most common cancer affecting women worldwide, accounting for 22.9 % of cancer incidence in women and a mortality of 13.7 % . Advancements in improving patient outcome require rigorous clinical research and application of trial results to clinical care. However, patient recruitment to clinical trials poses a challenge. Recruitment rates to breast cancer trials compared with other cancer trials in particular, are globally low. It has been estimated that only 2–3 % of all breast cancer patients actually participate in clinical trials throughout the course of their treatment [2–4]. Yet, trial participation has the potential to improve clinical outcomes; this is sometimes known as inclusion benefit and has been demonstrated in several studies [5–19]. In addition, treatment modalities and approaches may have different effects on different ethnic and racial groups, making recruitment of diverse populations imperative in trial recruitment .
Many factors potentially influence patient recruitment into clinical trials. These can be broadly classified as physician-, patient-, and system-related factors . In a recent study of patients, patient altruism and healthcare professionals’ attitudes were identified as powerful driving forces that motivated patients . Conversely, unease about randomisation, increasing demands of more complex trials, and limited healthcare resources are cited as patient-reported barriers. Other barriers included fear of potential side effects, lack of unawareness of trial opportunities, the idea that clinical trials are not appropriate for serious diseases, and fear that trial participation would have a negative impact on the patient-doctor relationship. Other studies have suggested patient mistrust of the healthcare system and inconvenience of study protocols as additional barriers .
These views reflect a Western perspective, with the majority of cited studies being from the United States and Canada. There is a need for understanding such factors in diverse global populations, especially in an Asian setting, since clinical trials now trend toward international multi-site settings with rapid growth in Asian countries. In particular, the recruitment rate of patients into clinical trials in Asia is much lower than in other parts of the world . A clearer understanding of barriers and facilitators in these settings will permit implementation of interventions to improve future trial recruitment.
Singapore is an island nation of five million in Southeast Asia, with a diverse, mainly English-speaking population consisting of ethnic Chinese, Indian, Malay, and a minority of other races . This unique multicultural setting provides a valuable opportunity to elicit views representative of different Asian subgroups. We conducted a focus group study of different ethnic groups to examine barriers and facilitators to cancer trial recruitment in patients, with particular focus on multi-ethnic Asian women with breast cancer.
The study was conducted at the National Cancer Centre Singapore (NCCS), a regional centre in Asia for the research and treatment of all cancers. The NCCS treats 75 % of cancer patients in Singapore, while the remaining 25 % are cared for in other private and public hospital settings. Yearly outpatient attendance at the NCCS is more than 130,000, and new cancer cases number more than 6,000 per year .
This qualitative study was approved by Centralised Institutional Review Board, Singhealth research. Between March and May 2013, NCCS patients attending the breast clinic of four oncologists were recruited by three medical students. The recruiters approached potential focus group participants in the waiting room from Monday to Friday between 9 am and 5 pm. The sample recruited consisted of female breast cancer patients older than 21 years, capable of both providing informed consent, and attending the focus group independently. Informed consent was obtained in the outpatient setting.
Focus group moderator guide and procedures
Moderator question key and guide for focus groups on barriers and facilitators to trial participation
1) Prevalent knowledge, understanding, and beliefs about clinical trials
• Have you heard about clinical trials?
• What do you understand about clinical trials?
• How do you feel about clinical trials?
2) Willingness to participate in clinical trials
• Open to listening
• Waiting to say ‘No’
3) Specific probes into facilitators and barriers to participating in clinical trials
What are the non-trial related factors that you will consider?
• Your current status of health?
• Ability and willingness to adhere to trial schedule?
• Opinions of family and friends?
What are the trial related factors that you will consider?
• How do you feel about the idea of randomisation?
• How do you feel about the new treatment?
• How do you feel about the closer monitoring?
• How do you feel about more blood tests?
We conducted five focus groups over three months, with each group consisting of three to five participants. Trained bilingual (English and Chinese) primary and a secondary moderator were present for each group. The sessions were audiotaped and transcribed in the original language. Chinese text was then translated into English for coding purposes. Translation was done with the help of medical students during the process of transcription from audio files. Each focus group session comprised three parts. First, the primary moderator explained what a clinical trial was; this determined existing levels and sources of knowledge about, as well as prevalent attitudes toward trials. Following that, we presented participants with a mock informed consent form (ICF) for a hypothetical clinical trial in order to provide uniform basic information about trial recruitment procedures; this simulated the type of information provided during a real-life enrolment. The second part of the focus group session assessed participants’ initial willingness and factors that influence their willingness and decisions to take part in trials. The discussions were initially open-ended. After no new factors were spontaneously suggested by participants, the primary moderator asked participants about factors identified from our literature review. These factors were included as standardised moderator probes in the moderator question guide (Table 1). The final part invited participants to suggest the ideal presentation of trial information to potential participants.
The primary moderator was responsible for leading the session while the secondary moderator took field notes. After every focus group discussion, debriefing between the two moderators took place to review and improve the question guide and the process for subsequent focus groups. The aim was to complete five focus groups or until theme saturation was reached, whichever came first.
Data analysis and coding
The primary data source was the typed transcripts for each focus group. The text was coded using content analysis procedures . Transcription and coding were completed within three days of each focus group so as to identify issues that could be addressed in subsequent focus groups. If indicated, the moderator guide was modified. In this way, the first focus group discussion also served as a pilot.
Each transcript was independently coded by the two primary coders. A codebook with themes and supporting quotes was then created by the primary coders, who met to discuss themes after each set of transcripts was analysed. If the agreement in themes was less than 90 %, two secondary coders were available to adjudicate. Major and minor themes were derived from a combination of pre-set questions in the moderator guide as well as from unique data in the transcript.
All transcripts were then recoded using the finalised version of the codebook. A summary of all the themes was generated and similar themes were grouped into broader and more abstract categories. We used qualitative data analysis software (NVivo 9, QSR International), to tabulate theme frequency using the codebook as a basis for counting and sorting the minor themes.
Patients’ demographics for five focus groups
Numbers (Total n = 16)
GCE ‘O’ level
GCE ‘A’ level
Stage of breast cancer
Results are presented in three parts. Part 1 reports prevalent knowledge and attitudes of participants toward clinical trials. Part 2 discusses 22 minor themes about barriers and facilitators under three major themes (patient, trial and sociocultural). Part 3 summarises participant suggestions for ideal presentation of trials to potential participants.
Minor theme frequency for three factors, organised as facilitators and barriers to clinical trial participation
Minor themes for three major factors (patient-, trial- and sociocultural-related)
Number of respondents
• Opinion of family and friends
• If test therapy is last resort (late stage/failure of current therapy)
• If overall benefits outweigh risks
• If general health is better
• Previous bad experiences with doctors, trials, and drugs
• Conservative attitude towards risk-taking
• Unique health situation
• Cancer is a serious illness
• Hope that test therapy is better treatment option
• Closer monitoring
• Lower cost of treatment
• Trust that care is adequate during trial procedure
• Risk of test therapy/Uncertainties inherent in investigational drugs
• Perceived risk associated with randomisation
• Additional visits required
• Systemic therapy
• Added stress from trials
• Additional tests required
Broader Socio-cultural/System-related factors
• Trust in physicians
• Trust in drug development/regulation and healthcare system
Part 1: Prevalent knowledge and attitudes toward clinical trials
“I am scared” or “I am nervous” (about joining a trial), “doesn’t really concern me” or “unless the doctor tells me that I need this, I will not be bothered”.
“I find it is okay (to join clinical trials), especially if it can help future generations.”
Part 2: Factors affecting decision whether to participate in clinical trials
In aggregate, participants offered many factors affecting their decisions to join clinical trials. We categorised them broadly into three areas: factors related to the individual patient, factors related to clinical trial characteristics, and factors related to broader systemic and cultural issues. The minor themes associated with each area are summarised in Table 3.
Factors related to the individual
Minor themes associated with this major theme fell into the categories of facilitators and barriers. For facilitators, an important minor theme was‘the opinion of family and friends’. Twelve participants cited the opinions of their friends and family as an important facilitator (if the opinions were positive) or barrier (if the opinions were negative).
A second minor theme was ‘test therapy is last resort’. In other words, participants were willing to participate when no other options were available, for example, at later/terminal stages of cancer. This theme was expressed by six participants, showing that trial therapy as a last resort is often a facilitator and is regarded as a last-ditch attempt; in the related minor theme of ‘if overall benefits outweigh risks’, two participants stated that they would participate in trials if the perceived overall benefit outweighed risks.
“If I am stage four, I do not mind trying.”
“If I am in an early stage and curable, why would I try a new drug?”
“I think it will come to a certain stage where you have no other option, when you face the wall; then you will go for the opportunity.”
“I would go for it. If nobody takes a step, then how will medicine advance?”
“I do not mind joining the trial if I can use the new medicine and help others at the same time.”
“I trusted the doctors and this is the end result (referring to late diagnosis). Now, unless I am very sure, I will not take part in clinical trials.”
“I am the sort who will go for lower gains but definite returns.”
“I want to try something new; I don’t want to stick to something old and not improved.”
“If my health is not good, I will not join.”
“People with different body constitutions will get different effects from the medication.”
“If it is a trial for something less life-threatening, maybe I will consider.”
“It is not like normal, like high blood pressure medication. High blood pressure is very common and if I try a new medication for that I can still do monitoring myself.”
Factors related to clinical trials
Facilitators for trial-related factors include the hope that test therapy is a better option. Nine participants indicated that the hope of the test therapy improving their condition was a prominent facilitator to participate in trials. The second minor theme is the lower cost of treatment. Three participants quoted lower costs of treatment when they participate in trials as an important facilitator. Other pertinent facilitators which contributed to the third minor theme include closer monitoring during the trial as well as trust that care is adequate during the trial procedure.
Trial conduct is important to participants. Clinical trials conducted in an ethical manner, with full description of compensation details should they suffer injury during the trial process, was the fourth minor theme appealing to trial participation. Two participants cited trust that care is adequate during trial procedure as facilitators. While closer monitoring was cited as a barrier for some participants, three participants felt that this is an important facilitator for trial participation.
“Chemotherapy already has so many side effects, let alone the new drug.”
“There is uncertainty with new drugs; there is no guarantee.”
“Seems like there is a lot of uncertainty, and the side effects seem pretty bad.”
Another minor theme highlighted as a barrier includes systemic versus local therapy. Discomfort with investigational drugs was more pronounced if the treatment were systemic compared to local/topical treatment.
“I want to decide for myself and not let luck or others decide for me.”
“I only want to take part if I can choose.”
Some protocol-specific factors were important to select participants. Participants who were unwilling to join trials reported that frequent blood tests or clinic visits were deterrents. They felt that additional monitoring added to the stress of therapy
Broader socio-cultural/system-related factors
Trust in physicians as well as local governance were the two most common minor themes quoted as facilitators (n = 15).
“I trust my doctor, which is why I leave my life in his hands.”
“I’ll discuss with my doctor first. And if my doctor recommends it then I will try (laughs).”
“If the government approves, and since our medicine is so advanced, then will believe that it is safe. You see even foreigners come here for treatment.”
A conservative attitude as well as fatalism was the most common minor themes associated with barrier under broader socio-cultural factors. Two participants also cited cultural differences as a reason for their reluctance to join trials. One patient elaborated: “We are Asian, you see; our mind-set is quite conservative, so we are not as daring.” Another participant commented that “because of our upbringing, we are not as adventurous.” It seems that Asian culture, where patients are less adventurous and more cautious, is one of the main themes that act as a barrier towards trial participation in this part of the world.
Part 3: Ideal presentation of trial information
In an attempt to understand and improve trial recruitment rates, we encouraged patients to discuss their ideal setting for clinical trial discussions. The suggestions put forth by participants can serve as a platform for the implementation of changes to aid in trial recruitment.
“I will think that if the doctor introduces the trial first I would consider (you know what I mean). Your own doctor will know your health condition better than anyone.”
“And maybe after the doctor has already explained to me, then the research assistant can give further explanations.”
Secondly, the setting of trial discussions should be formal, such as in a room or clinic and not along clinic corridors or waiting areas. A minority of patients (25 %) felt that the setting was not a priority, as long as they were approached in a polite manner.
“I also study TCM (Traditional Chinese Medicine). A lot of the time, the instructions were given in pictorial form so that it helps with understanding.”
“Use of videos will help us to understand more.”
Our study confirms findings from previous studies in identifying themes for both barriers (fear and uncertainty about new drugs, time restrictions, and mistrust of system) and facilitators (late stage disease, altruism, trust in physicians, and prior positive experience with trials) [21, 22]. We found new themes for both barriers (cultural beliefs for example, ‘fatalism’, and negative opinions of friends/relatives); and facilitators (optimism with improved health, and financial incentive, such as not having to pay for new drugs) among our participants. Our stratified thematic analysis found that participants willing to join clinical trials were more likely to cite trust in doctors (43 %) and local governance (50 %), as well as the hope of the test therapy being a better treatment option (56 %) as facilitators. Participants who were less willing to join clinical trials were more likely to cite barriers such as uncertainties inherent in investigational drugs and risks of trial therapy (81 %) as well as inconveniences associated with the trial set-up (31 %), and the perceived risks of randomisation (31 %) (Table 3). Respondents who expressed unwillingness to join clinical trials also emphasised cultural and personal barriers, lack of awareness about the trials, and the absence of facilitators; while those who had no opinion about joining clinical trials cited both barriers and facilitators equally.
Our study is unique in the recruitment of a diverse group of women (for age, ethnicity, language, and breast cancer stage) with clearly expressed opinions about their willingness to join clinical trials. We were able to reach theme saturation for both Chinese and Malay ethnic groups. While the cultural factors the women expressed may be unique to our setting, we posit that similar factors will be found among women from other cultural settings. This is especially so in the Asian context where decision-making often involved community and family as strong social influences. In addition, we were able to stratify the coding to three subgroups because participants were asked about their willingness to participate in trials, enriching the analysis. We believe that the data derived from this analysis is transferable to other settings with similarly diverse patients.
Although the total number of participants  is small, they represent the full profile of patients from the NCCS, in which they were not significantly different from non-participants (Table 2). Our data analysis suggests that having more focus groups would not have yielded more themes, as there was theme saturation after analysis of data from five focus group discussions. Since the study involved only women, the findings may not transfer to men for whom other barriers and facilitators may operate. Although the study involved only women with breast cancer, the responses and themes elicited suggest that the opinions were not unique to breast cancer patients.
Clinical trial recruitment is often limited by challenges of minority recruitment (barriers to recruiting, for example, urban African American women into research studies in community settings), and a clear understanding of the cultural issues and barriers is needed to increase recruitment . Our findings have implications for minority recruitment into cancer trials and suggest appropriate interventions that may improve recruitment. For example, patient autonomy is often the guiding principle in decision-making and trial recruitment often involves consent from the patient only. But in some Asian cultures where decision-making involves the community and family, influencing attitudes and opinions in the larger community may be an important first step before patient recruitment. In our study, both Chinese and Malay women expressed a lack of knowledge about the purpose and processes of clinical trials and inadequacy about making decisions. Patient education may need to be more intense and address literacy as well as cultural barriers to improve recruitment. Trust in their own (but not in other unknown) physicians was a dominant theme among participants, which suggests that recruitment might be more successful if conducted through the patients’ own primary care physicians and oncologists. Our findings suggest that researchers need to pay more attention to both individual and community cultural factors when considering recruitment strategies or training recruiters.
In conclusion, barriers and facilitators to trial participation are similar among multi-ethnic Asian women as those previously reported among Western women. Additional cultural and personal factors among Asian women suggest new potential strategies for enhancing future recruitment. More information is needed on the attitudes of men and of patients of both genders with cancer types other than breast cancer. Future studies will identify effective patient, physician, and community educational interventions to improve clinical trial participation among cancer patients.
ICF, informed consent form; NCCS, National Cancer Center Singapore; TCM, Traditional Chinese Medicine
Special acknowledgement to National Cancer Centre Research Fund G/L: 25560780 NRFBT13141-2, medical students Mr Nicholas Hong, Tiffany Wong and Cheryl Yong as well as medical writers Ms Yeo Ai Ling and Mr Ng Heok Hee for their help.
This research was made possible through the funding of National Cancer Center Research Fund (NCCRF).
Availability of data and materials
Data will not be shared as raw data includes audiotapes.
LGE was the main author for the paper. She participated in all stages of the research including the design, implementation, recruitment of participants, organising and carrying out focus group discussions, coding, translation, and finally writing of the paper. MO was the second author and she participated in the design, implementation, organising and carrying out focus group discussions, coding, and translation as well as editing of the paper. DL and RD undertook active role in the conception as well as design of the study. In addition, they also oversee the research and participated in editing and revision of the paper. They also gave the final approval for the paper. All the authors read and approved the final manuscript for submission.
The authors declare that they have no competing interests.
Dr Lee Guek Eng and Dr Rebecca Dent received travel funding from Roche, Novartis and Astrazeneca.
Consent for publication
Ethics approval and consent to participate
This study was approved by Centralised Institutional Review Board, Singhealth research. Document number: 205–001
The sample recruited consisted of female breast cancer patients older than 21 years, capable of both providing informed consent, and attending the focus group independently. Informed consent was obtained in the outpatient setting.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- GLOBOCAN statistics. http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx. Accessed Sept 2014.
- American Medical Association Council on Scientific Affairs. Viability and cancer clinical research: patient accrual, coverage, and reimbursement. J Natl Cancer Inst. 1991;83(4):254–9.View ArticleGoogle Scholar
- Lu Z, Zhang R, Carpenter J, Diasio RB. Decreased dihydropyrimidine dehydrogenase activity in a population of patients with breast cancer: implication for 5-fluorouracil based chemotherapy. Clin Cancer Res. 1998;4(2):325–9.PubMedGoogle Scholar
- Schmotzer GL. Barriers and facilitators to participation of minorities in clinical trials. Ethn Dis. 2012;22(2):226–30.PubMedGoogle Scholar
- Karjalainen S, Palva I. Do treatment protocols improve end results? A study of survival in patients with multiple myeloma in Finland. BMJ. 1989;299(6706):1069–72.View ArticlePubMedPubMed CentralGoogle Scholar
- Greil R, Holzner B, Kemmler G, et al. Retrospective assessment of quality of life and treatment outcome in patients with Hodgkin’s disease from 1969 to 1994. Eur J Cancer. 1999;35(5):698–706.View ArticlePubMedGoogle Scholar
- Lennox EL, Stiller CA, Jones PH, et al. Nephroblastoma: treatment during 1970–73 and the effect on survival of inclusion in the first MRC trial. Br Med J. 1979;2(6190):567–9.View ArticlePubMedPubMed CentralGoogle Scholar
- Meadows AT, Kramer S, Hopson R, et al. Survival in childhood acute lymphocytic leukemia: effect of protocol and place of treatment. Cancer Invest. 1983;1(1):49–55.View ArticlePubMedGoogle Scholar
- Davis S, Wright PW, Schulman SF, et al. Participants in prospective, randomized clinical trials for resected non-small cell lung cancer have improved survival compared with nonparticipants in such trials. Cancer. 1985;56(7):1710–8.View ArticlePubMedGoogle Scholar
- Stiller CA, Draper GJ. Treatment centre size, entry to trials, and survival in acute lymphoblastic leukaemia. Arch Dis Child. 1989;64(5):657–61.View ArticlePubMedPubMed CentralGoogle Scholar
- Boros L, Chuang C, Butler FO, et al. Leukemia in Rochester (NY). A 17-year experience with an analysis of the role of cooperative group (ECOG) participation. Cancer. 1985;56(9):2161–9.View ArticlePubMedGoogle Scholar
- Marubini E, Mariani L, Salvadori B, et al. Results of a breast-cancer-surgery trial compared with observational data from routine practice. Lancet. 1996;347:1000–3.View ArticlePubMedGoogle Scholar
- Feuer EJ, Frey CM, Brawley OW, et al. After a treatment breakthrough: a comparison of trial and population-based data for advanced testicular cancer. J Clin Oncol. 1994;12:368–77.PubMedGoogle Scholar
- Roy P, Vaughan Hudson G, Vaughan Hudson B, et al. Long-term survival in Hodgkin’s disease patients: a comparison of relative survival in patients in trials and those recorded in population-based cancer registries. Eur J Cancer. 2000;36(3):384–9.View ArticlePubMedGoogle Scholar
- Stiller CA, Eatock EM. Survival from acute non-lymphocytic leukaemia, 1971–88: a population based study. Arch Dis Child. 1994;70(3):219–23.View ArticlePubMedPubMed CentralGoogle Scholar
- Wagner HP, Dingeldein-Bettler I, Berchthold W, et al. Childhood NHL in Switzerland: incidence and survival of 120 study and 42 non-study patients. Med Pediatr Oncol. 1995;24(5):281–6.View ArticlePubMedGoogle Scholar
- Stiller CA, Eatock EM. Patterns of care and survival for children with acute lymphoblastic leukaemia diagnosed between 1980 and 1994. Arch Dis Child. 1999;81(3):202–8.View ArticlePubMedPubMed CentralGoogle Scholar
- Stiller CA, Benjamin S, Cartwright RA, et al. Patterns of care and survival for adolescents and young adults with acute leukaemia—a population-based study. Br J Cancer. 1999;79(3–4):658–65.View ArticlePubMedPubMed CentralGoogle Scholar
- Lantos JD. The “inclusion benefit” in clinical trials. J Pediatr. 1999;134(2):130–1.View ArticlePubMedGoogle Scholar
- Mills E, Seely D, Rachlis B, Griffith L, Wu P, Wilson K, Ellis P, Wright JR. Barriers to participation in clinical trials of cancer: a meta-analysis and systemic review of patient-reported factors. Lancet Oncol. 2006;7(2):141–8.View ArticlePubMedGoogle Scholar
- Grunfeld E, Zitzelsberger L, Coristine M, Aspelund F. Barrier and facilitators to enrolment in cancer clinical trials. Cancer. 2002;95(7):1577–83.View ArticlePubMedGoogle Scholar
- Russell KM, Maraj MS, Wilson LR, Shedd-Steele R, Champion VL. Barriers to recruiting urban African American women into research studies in community settings. App Nurs Res. 2008;21(2):90–7.View ArticleGoogle Scholar
- Murthy VH, Krumholz HM, Gross CP. Participation in cancer clinical trials: race, sex and age base disparities. JAMA. 2004;291(22):2720–6.View ArticlePubMedGoogle Scholar
- Singapore Cancer Registry Interim Report: Trends in Cancer Incidence in Singapore 2004–2008Google Scholar
- National Cancer Centre Singapore: Annual Report. http://www.nccs.com.sg/AboutUs/AnnualReport/Documents/NCCS_AR_FY2012.pdf. Accessed Sept 2014.
- Robertson NL. Clinical trial participation: viewpoints from racial/ethnic groups. Cancer. 1994;74(9Suppl):2687–91.View ArticleGoogle Scholar
- Siminoff LA, Zhang A, Colabianchia N, Sturm CM, Shen QS. Factors that predict the referral of breast cancer patients onto clinical trials by their surgeons and medical oncologists. J Clin Oncol. 2000;18(6):1203–11.PubMedGoogle Scholar
- Townsley CA, Selby R, Siu LL. Systematic review of barriers to recruitment of older patients with cancer onto clinical trials. J Clin Oncol. 2005;23(13):3112–24.View ArticlePubMedGoogle Scholar
- Krueger RA. Focus Groups: A Practical Guide for Applied Research. Newbury Park: SAGE Publications, Inc; 1988.Google Scholar