Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 9 3 2018 01 23 32 41 EN Ali Montazeri Mental Health Research Group, Health Metrics Research Center, Institute for Health Sciences Research, ACECR, Tehran, Iran Amir-Hosein Emami Mental Health Research Group, Health Metrics Research Center, Institute for Health Sciences Research, ACECR, Tehran, Iran. AND Hematology-Medical Oncology Ward, Cancer Research Center of Iran, Cancer Institute, Imam Khomeiny Complex, Tehran University of Medical Sciences, Tehran, Iran. Sanambar Sadighi Hematology-Medical Oncology Ward, Cancer Research Center of Iran, Cancer Institute, Imam Khomeiny Complex, Tehran University of Medical Sciences, Tehran, Iran. Mohammad-Ali Mohagheghi Surgery Ward, Cancer Research Center of Iran, Cancer Institute, Imam Khomeiny Complex, Tehran University of Medical Sciences, Tehran, Iran. Zahra Sedighi Hematology-Medical Oncology Ward, Cancer Research Center of Iran, Cancer Institute, Imam Khomeiny Complex, Tehran University of Medical Sciences, Tehran, Iran. 2017 04 16 2018 01 23 Background: The authors selected European Organization for Research and Treatment (EORTC) C30 and EORTC QLQ CR29 to specify bowel, bladder, and sexual dysfunction of Iranian colorectal cancer patients. Methods: A sample of 100 patients with colorectal cancer attending Iran Cancer Institute from March 2012 to March 2013 at first-line chemotherapy in the adjuvant or palliative settings participated in the study. Patients responded to the study questionnaires at the beginning and after 3-4 cycles of chemotherapies. Responses to the core questionnaire (QLQ-C30) and the QLQ-CR29 were linearly converted into 0-100 scores, using the EORTC guidelines. Correlations between the QLQ-C30 and QLQ-CR29 were examined, using Pearson’s product moment correlation in order to assess construct validity. Known groups’ comparon examined the ability of EORCT-CR29 to dtinguh between subgroups of patients with and without a stoma. Sensitivity to changes over time was examined by the response to chemotherapy in palliative or neoadjuvant settings. Internal constency was measured using Cronbach’s alpha coefficient with estimates of a magnitude of 0.7. Results: The mean age of patients was 53.6. Based on clinical and pathologic staging, 60% of the patients had presented while their cancer was in stage IV with dtant metastas at the time of referring to the clinic. Thirty-three percent of patients, almost all from rectal tumor group, had a permanent ostomy. In general, the correlation between the EORTC QLQ-C30 and QLQ-CR29 was in the expected directions, demonstrating that functional scales of both questionnaires had a positive correlation with each other while negative correlation was observed between functional and symptom subscales. In addition, the QLQ-CR29 differed considerably between patients with and without a stoma.The QLQ-CR29 results showed improved functioning scores after treatment and at the same time symptoms decreased. The Cronbach’s alpha for the scales ranged from 0.48-0.77. Conclusion: In general, the Iranian version of the EORTC QLQ-CR29 worked well and now could be used in outcome studies in colorectal cancer. https://bccr.tums.ac.ir/index.php/bccrj/article/view/234 https://bccr.tums.ac.ir/index.php/bccrj/article/download/234/03