Optimizing Psychological Treatment for Pain After Breast Cancer: A Pilot Study

The NRS is a validated, self-report instrument assessing pain intensity during the last week. Answer format range: 0 (no pain) to 10 (worst possible pain); total score range: 0-10. Higher scores yield more pain.

The BPI is a validated, self-report instrument assessing clinical pain. The BPI pain interference subscale assesses pain interference during the last week across 7 domains, i.e., general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. Answer format range: 0 (no interference) to 10 (maximal interference); total score range: 0-10. Higher scores yield more pain interference.

Pain intensity during the last 24 hours will be assessed every day for 6 days following the first session (Td) for each treatment component using the NRS. Answer format range: 0 (no pain) to 10 (worst possible pain); total score range: 0-10. Higher scores yield more pain.

Pain interference during the last 24 hours will be assessed every day for 6 days following the first session (Td) for each treatment component using 1 aggregated item assessing pain interference across the 7 domains measured with the BPI interference subscale, i.e., general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. Answer format range: 0 (no interference) to 10 (maximal interference); total score range: 0-10. Higher scores yield more pain interference.

The NRS is a validated, self-report instrument assessing pain burden during the last week. Answer format range: 0 (no burden) to 10 (maximal burden); total score range: 0-10. Higher scores yield more pain burden.

The pain descriptors from the MPQ constitutes a validated, self-report instrument assessing pain quality (i.e., pain type, namely continuous pain, intermittent pain, neuropathic pain, affective pain) during the last week. Answer format range: 0 (no pain) to 10 (worst possible pain); total score range: 0-60 (continuous, neuropathic and intermittent pain), 0-40 (affective pain). Higher scores yield more pain.

The PCS is a validated, self-report instrument assessing pain catastrophizing. Answer format range: 0 (not at all) to 4 (all the time); total score range: 0-52. Higher scores yield more pain catastrophizing.

The HADS is a validated, self-report instrument assessing psychological distress during the last week. Answer format range: 0 (not at all or never) to 3 (most or all of the time); total score range 0-42. Higher scores yield more distress.

The FCRI is a validated, self-report instrument assessing fear of cancer recurrence during the last month. Answer format range: 0 (not at all) to 4 (a great deal); total score range 0-36. Higher scores yield more fear of cancer recurrence.

The WHO-5 is a validated, self-report instrument assessing current well-being. Answer format range: 0 (at no time) to 5 (all the time); total score range: 0-100. Higher scores yield more well-being.

Participants will be invited to participate in a 30-minutes semi-structured individual interview 10-14 days after their last session. The interview serves to support the validation of the treatment components and to provide in-depth knowledge about the participants' experiences through their qualitative comments.

Socio-demographic characteristics will be assessed using single questions (e.g., municipality, marital status, income, work status).

Clinical characteristics will be assessed using single questions (e.g., date of surgery, adjuvant therapy).

Treatment expectancy will be assessed using a single question regarding the extent to which the participant believes that the intervention will reduce pain and increase overall well-being. Answer format range: 1 (not at all) to 5 (a great deal); total score range: 1-5. Higher scores indicate stronger expectations that the intervention will lead to a positive outcome.

The WAI is a validated, self-report instrument assessing therapeutic alliance. Answer format range: 1 (never) to 7 (all the time); total score range: 12-84. Higher scores yield a stronger therapeutic alliance.

Homework will be assessed with 4 single items related to i) whether home work has been conducted (yes/no), and the ii) type, iii) frequency (number of days per week), and iv) duration of completed homework (average number of minutes per day).

The MAAS is a validated, self-report instrument assessing individual differences in the frequency of mindful states over time. Answer format range: 1 (almost always) to 6 (almost never); total score range: 1-6. Higher scores yield higher levels of mindful attention.

MAAS items 13 and 7 will be assessed before each session (Ts). Answer format range: 1 (almost always) to 6 (almost never). Higher scores yield higher levels of mindful attention.

MAAS item 6 will be assessed every day for 6 days following the first session (Td) for each treatment component. Answer format range: 1 (almost always) to 6 (almost never). Higher scores yield higher levels of mindful attention.

The EQ is a validated, self-report instrument assessing decentering. Answer format range: 1 (do not agree at all) to 5 (agree completely); total score range: 11-55. Higher scores yield higher levels of decentering.

EQ items 5 and 7 will be assessed before each session (Ts). Answer format range: 1 (do not agree at all) to 5 (agree completely). Higher scores yield higher levels of decentering.

EQ item 5 will be assessed every day for 6 days following the first session (Td) for each treatment component. Answer format range: 1 (do not agree at all) to 5 (agree completely). Higher scores yield higher levels of decentering.

The CPAS is a validated, self-report instrument assessing pain acceptance and activity engagement. Answer format range: 0 (never true) to 6 (always true); subscale score range: 0-54 (pain acceptance subscale), 0-66 (activity engagement subscale). Higher scores yield more acceptance and activity engagement.

CPAS items 1 and 12 will be assessed before each session (Ts). Answer format range: 0 (never true) to 6 (always true). Higher scores yield more acceptance and activity engagement.

CPAS item 1 will be assessed every day for 6 days following the first session (Td) for each treatment component. Answer format range: 0 (never true) to 6 (always true). Higher scores yield more acceptance and activity engagement.