Why we need international agreement on terms and definitions to assess clinical outcome after endometriosis surgery

Sir, We congratulate the authors of a prospective clinical outcome study after conservative surgery by the shaving technique for deep rectovaginal endometriotic (RVE) nodules (Donnez and Squifflet, 2010). We do however have some post publication peer review comments (Anderson, 1999). Firstly, only one group worldwide has published outcome data after the shaving technique in two studies in the last 16 years (Donnez et al., 1995; Donnez and Squifflet, 2010). Other groups have reported clinical outcome after conservative surgery for deep RVE nodules, but always in cohorts mixed with patients treated with bowel resection anastomosis (mixed study groups, n = 16: Meuleman et al., 2011a), except for one paper describing outcome after discoid excision only (Nezhat et al., 1994). In contrast, twice as many papers (n = 32) have documented the outcome of bowel resection anastomosis (Meuleman et al., 2011a) and overall, the endometriosis recurrence rate was lower in the bowel resection anastomosis group (5.8%) than in the mixed study group (17.6%) (Meuleman et al., 2011a). Secondly, the study (Donnez and Squifflet, 2010) included selected ‘good prognosis patients’ without previous surgery for endometriosis, including cases with non-adherent type II lesions (easy to dissect) and excluding cases with bowel endometriosis in other or in multiple parts of the bowel system (rectosigmoid, sigmoid, small bowel, etc.) and any conclusions made need to take this into account. It is unclear how many cases with rectosigmoid endometriosis were diagnosed on preoperatively, and how these cases were handled surgically. Thirdly, in this prospective study (Donnez and Squifflet, 2010), a number of key variables were either not reported, not standardized or not defined: no exact start and end dates of patient recruitment, no correction for the duration of follow-up per patient (no life table analysis), no documentation of follow-up (method, type of assessment during follow-up, number lost for follow-up, etc.). Outcome assessment of pain or quality of life was not patient based although validated and recommended methods exist (Vincent et al., 2010), have been applied (Meuleman et al., 2009; Meuleman et al., 2011b, submitted for publication), are recommended (Harvey and Warwick, 2010) and moreover underlined by the President of the World Endometriosis Foundation (Evers, 2010), and are essential to document possibly compromised sexual function after removal of the posterior vaginal fornix (Donnez et al., 2010). Complications or recurrences were not defined, even though recurrence of severe pelvic pain was high (20%) among non-conceiving patients in this good prognosis population (Donnez and Squifflet, 2010). Fourthly, Table III (Donnez and Squifflet, 2010) includes only 11 selected papers, whereas 32 papers have documented clinical outcome after bowel resection anastomosis resulting in a visually and/or histologically proven recurrence rate of 2.5% only (Meuleman et al., 2011a). Fifthly, our work (Meuleman et al., 2009) is not correctly discussed. We studied (Meuleman et al., 2009) clinical outcome in a highly selected (<3% of all laparoscopies between 1996 and 2004) group of patients with mostly (75%) recurrent deeply infiltrative endometriosis with colorectal extension requiring radical nodulectomy and multidisciplinary surgery. The more severe clinical picture of our study population (Meuleman et al., 2009) compared with the ‘good prognosis’ patients included in this study (Donnez and Squifflet, 2010) partially explains the longer duration of surgery. The duration of our surgery (Meuleman et al., 2009) was not exceptionally long, as five other studies reported a mean/median duration of surgery of at least 300 min (Lyons et al., 2006; Darai et al., 2007; Minelli et al., 2009; Pereira et al., 2009; Ruffo et al., 2010). Additionally, long duration of surgery has to be balanced against our low rate of complications, reinterventions and recurrences and high rate of pain relief, improvement of quality of life and fertility (Meuleman et al., 2009) confirmed prospectively (Meuleman et al., 2011b, submitted for publication), according to terms and definitions proposed recently in a CONSORT-based checklist (Meuleman et al., 2011a). Although the incidence of lower leg compartment syndrome was indeed 5% (3/56) in our series (Meuleman et al., 2009), subsequent measures have been successful to prevent this complication subsequently (Tomassetti et al., 2009). Furthermore, nerve sparing surgery is possible during colorectal segmental resection (Meuleman et al., 2009). Finally, the decision to do a bowel resection anastomosis does not need to be justified by the presence of mucosal infiltration in the resected specimens, but was based on limited integrity of the bowel wall after radical nodulectomy, not restorable by bowel suture, primarily in order to prevent post-operative bowel complications (Meuleman et al., 2009), and the same approach is advocated by other groups (Keckstein and Wiesinger, 2005; Serachioli et al., 2007; Dousset et al., 2010).