Characterisation and Epidemiology of Breakthrough Cancer Pain in Spain

Breakthrough cancer pain was defined as the temporary exacerbation of pain occurring either spontaneously or in relation to a specific, predictable or unpredictable trigger in spite of relatively stable and adequately controlled baseline pain.

Breakthrough cancer pain was defined as the temporary exacerbation of pain occurring either spontaneously or in relation to a specific, predictable or unpredictable trigger in spite of relatively stable and adequately controlled baseline pain.

Participants diagnosed during the study and were not diagnosed previously were reported as new participants with breakthrough cancer pain. Breakthrough cancer pain was defined as the temporary exacerbation of pain occurring either spontaneously or in relation to a specific, predictable or unpredictable trigger in spite of relatively stable and adequately controlled baseline pain.

Participants diagnosed during the study and were not diagnosed previously were reported as new participants with breakthrough cancer pain. Breakthrough cancer pain was defined as the temporary exacerbation of pain occurring either spontaneously or in relation to a specific, predictable or unpredictable trigger in spite of relatively stable and adequately controlled baseline pain.

The Alberta Breakthrough Pain Assessment Tool (ABPAT) consisted of a participant's self-reporting section (15 questions) out of which 4 questions of the tool were not included as they were related to the treatment for breakthrough cancer pain. The questions included: Q1-Relationship to baseline pain, Q2a-Last time experienced, Q3b-Frequency, Q4b-Intensity of pain at peak, Q5-Location (most frequent - ≥5%), Q6-Quality (those present in ≥20%), Q7-Time from onset to peak intensity, Q8-Time from onset [take medication] to end of episode, Q9-Cause(s) (triggers) (Those present in ≥20%), Q10-Predictability, Q11-General relief (those present in ≈20% or more participants) and questions completed by nurse/physician (N/P), Q1-Etiology of breakthrough pain, Q2-Inferred pathophysiology of breakthrough pain. Percentage of participants were categorized into the answers for each of these questions.

The BPI questionnaire was used to assess the pain intensity (4 items) and interference with activities of daily living (7 items). Each item was given a score on a numerical scale from 0 (no pain/interference with activities of daily living) to 10 (worst pain imaginable/maximum impact on activities of daily living). The total score for pain intensity is the average of the four pain items. The total score of pain interference is the average score of the seven interference items. The higher score represents high impact.

The SF-12 health questionnaire is a 12 question assessment of functional health and well-being. The survey asks about various health aspects, including physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health (psychological distress and psychological well-being). Two summary measures are derived: the Physical and the Mental Health Component Summary. For each component summary, survey items were weighted and summed to create a summary score between 0 (poor mental and physical quality of life) and 100 (better mental and physical quality of life).

Karnofsky performance score is used to quantify participant's general well-being and activities of daily life and participants are classified based on their functional impairment. Karnofsky performance score is 11 level score which ranges between 0 (death) to 100 (participant asymptomatic with no evidence of illness). Higher score means higher ability to perform daily tasks. Participants with missing values in the Karnofsky scale were assigned to the worst score of 0, however, in these cases it is not 'death'.