The purpose of this study is to translate and validate a Spanish translation of the SWOG QOL Questionnaire for use with patients speaking only Spanish or for those bilingual patients who prefer to use Spanish in both the Southwestern region of the U.S. and the state of California. The translation will target Hispanics of Mexican descent. Hispanic and non-Hispanic white patients with breast or prostate cancer have been selected for this research. Translation Phase: Iterative Spanish translations of the SWOG QOL Questionnaire will occur employing back translations into English and focus groups methods. Preliminary Spanish translations of two additional QOL questionnaires, the CAncer Rehabilitation Evaluation System (CARES) and the Functional Assessment of Cancer Therapy FACT, will be revised if necessary to achieve dialect consistency with the final translation of the SWOG Questionnaire. Validation Phase: The purpose of the validation study is to establish the equivalence of psychometric properties for English and Spanish versions of the SWOG QOL Questionnaire. Three Hispanic language groups will be involved: Spanish monolinguals; bilinguals who prefer to complete questionnaires in Spanish; bilinguals who can complete questionnaires in English and Spanish. Non-Hispanic white patients will complete questionnaires in English. The CARES and the FACT will be administered to compare construct validity for the English and Spanish versions of the SWOG QOL Questionnaire. Hispanic patients will also complete the eight- item HHANES Acculturation Scale. Field Study Phase: We will field test the Spanish translation of the SWOG QOL Questionnaire in at least two Phase III clinical trails (one breast and one prostate cancer) conducted by SWOG. Bilingual patients will complete the questionnaire in their preferred language. Those who speak only Spanish will be asked to complete the questionnaires in Spanish. An acculturation scale will be completed by Hispanic patients as for the validation study. The main objective of the field test is to evaluate the feasibility of administering Spanish translations of QOL questionnaires in multicenter, phase III clinical trials.