Cognitive behavioral therapy to improve quality of life after surgical treatment of women with endometriosis

Endometriosis affects 10% of reproductive aged women and causes severe pain and
impaired quality of life. Surgery for endometriosis results in long term
symptom relief in only 40% of women. QoL in endometriosis improves after
surgery, but not to the level of healthy women. Mediators in QoL include pain
intensity, pain cognitions, and stress. In a preliminary study, patients with
negative pain cognitions reported higher pain intensities compared to patients
with positive pain cognitions. This indicates that psychological factors
explain considerable variance in pain, suggesting that changing these factors
by psychological interventions may contribute to improving QoL. Cognitive
behavioral therapy is proven effective as a psychological treatment for
pain-related symptoms. QoL after surgery for endometriosis should be improved.
Pain cognitions could be psychosocial targets in the treatment of endometriosis
related symptoms. We hypothesize that CBT focusing on cognitions towards pain
for women undergoing surgery for endometriosis improves pain cognitions,
leading to improvement of QoL.

The primary objective of this study is to investigate whether usual care
combined with CBT improves QoL in patients undergoing surgery for endometriosis
compared to usual care only. Secondary objectives are to investigate whether
pain intensity, pain cognitions, perceived stress and objectively measured
cortisol levels mediate the effects of CBT on QoL in both groups.

In a randomized controlled trial, 100 endometriosis patients undergoing surgery
will be randomized between usual care with CBT (CBT group) and usual care only
(control group). Women in the CBT group will receive, in addition to usual
care, one pre-surgery and six post-surgery sessions of CBT, aimed at positively
influencing mediators of QoL. Women in the control group will receive only
usual care. Follow up will be 7,5 months. In both groups QoL, pain intensity,
pain cognitions, perceived stress (using questionnaires) will be assessed one
month before surgery (baseline) and four months (T1) and 7,5 months (T2) after
surgery, and hair cortisol levels (using ELISA) will be assessed at baseline,
T1 and T2. Recruitment and treatment of patients will take place in Rijnstate
hospital, Radboud University Medical Center (UMC) and Catharina hospital.

Cognitive behavioral therapy administered in a total of seven sessions.

The control group will receive usual care. The intervention group will receive
usual treatment plus a total of seven sessions of CBT. In addition, all
participants are asked to fill in seven questionnaires at baseline assessment
(4 weeks prior to surgery) and at four and 7,5 months after surgery: the
EHP-30, SF-36, PSC, PASS, NRS and PSS. At baseline and T2 participants will
receive one extra questionnaire containing items about motivation towards
therapy and the use of additional psychological treatment during this study.
Furthermore, the researcher will carefully collect a scalp hair sample of at
least 0,5 cm thickness. This will be done at baseline assessment, T1 and T2.
The hair sample will be analyzed for cortisol levels in a laboratory. We expect
that the intervention has negligible risk although it could be a potential
psychological burden for patients to undergo CBT sessions. However, we expect
that this study will be beneficial to subjects since we expect that CBT will
increase QoL and reduce pain intensity.