ECOG Performance Status Rating (ECOG PSR) is a five-point scale [8 ] ranging from 0 (fully ambulatory) to 4 (not being able to leave bed).
The Quality of Life Index (QL-I) [9 (link)] is a five-item questionnaire where each one of them explores a dimension or domain of quality of life: health, activity, daily living, support and outlook. Every item has three response categories indicating different levels of functional impairment. Although it was originally developed as an observer rated scale (QLI-d), it can also be used as a patient rated scale (QLI-p). For the purpose of the study, the QL-I was translated into Spanish following a forward and backward translation procedure, carried out by an English native speaking linguist and a native Spanish-speaking English translator. The Spanish versions of the two QLI questionnaires are available from the authors upon request.
The Functional Assessment of Cancer Therapy-General Questionnaire (FACT-G) Spanish Version 4[2 (link)] is a widely used QOL instrument. It comprises 27 questions that assess four primary dimensions of QOL: physical (PWB; 7 items), social and family (SFWB; 7 items), emotional (EWB; 6 items), and functional well-being (FWB; 7 items). It uses 5-point Likert-type response categories ranging from 0 = 'not at all' to 4 = 'very much'. The total FACT-G score is the summation of the 4 subscale scores and ranges from 0 to 108. Data from a previous study on the FACT-G Spanish version 2[6 (link)] conducted among Uruguayan cancer patients suggested that its reliability was acceptable to good in all subscales except for the EWB scale. An important question raised by these results was whether these subscales showed sufficient internal consistency to justify their use across cultures and whether there was equivalence of the Spanish EWB to its English counterpart. Ever since, developers of the FACT-G revised the questionnaire into its most recent version 4 [2 (link)]. Major changes were the inclusion of an additional item ("I worry my condition will get worse" – "Me preocupa que mi enfermedad empeore") in the EWB subscale, the removal of the two-item "Relationship with the Doctor" subscale and the rewording of 12 Spanish items to improve their readability.
The Profile of Mood States, Short Form (POMS-SF)[10 ] is a widely used scale measuring subjective mood states, such as anxiety, tension, vigor, depression, fatigue and confusion. The POMS-SF is a valid measure of affective states and psychological adjustment in cancer patients and is available in Spanish. A Total Mood Disturbance score (POMS TMD) may be obtained by summing the five scores of Tension, Depression, Anxiety, Fatigue and Confusion subscales and substracting Vigor from these scores. Only patients with a 6th grade or higher level of reading abilities were included in the analysis, according to the instrument developers' instructions.
The Marlowe-Crowne Social Desirability Scale (MCSDS) [11 (link)]. The 10 items short form of the MCSDS provides a measure of the degree to which participants endorse socially desirable characteristics. A validated Spanish version of the questionnaire [12 ] was completed by the study participants.
Demographic, disease and treatment information was collected from patients, the treating physician and verified by the research assistants with the participants' medical record.