Progress in the management of retrorectal tumours

Tumours in the retrorectal space are rare and pathologically heterogeneous. The roles of imaging and preoperative biopsy, nonoperative management and the indications for surgical resection are controversial. This study investigated a series of retrorectal tumours treated in a single institution with the aim of producing a modern improved management algorithm.

A retrospective analysis was conducted of the management of all retrorectal lesions identified between 1998 and 2013 from a radiology database search. Patient demographics, presenting symptoms, imaging, biopsy, management and the results were recorded. Descriptive statistics were used and Kaplan-Meier survival analysis was performed.

Sixty-nine patients with a confirmed retrorectal tumour were identified. The median age was 50 (36-67 interquartile range) and 42 (56%) were female. Twenty (29%) of the tumours were malignant: 4 of 41 cystic lesions were malignant (12.9%) vs. 16 of 28 solid (or heterogeneous) lesions (57.1%) (P < 0.0001). Imaging demonstrated a 95% sensitivity and 64% specificity for differentiating benign from malignant tumours. Magnetic resonance imaging (MRI) was significantly better at distinguishing between benign and malignant tumours than computed tomography (94% vs. 64%, P = 0.03). Percutaneous biopsy was performed in 16 patients and only 27 underwent resection. There was no evidence of local recurrence associated with biopsy. Solid lesions were associated with a nonsignificant decreased overall survival (P = 0.348).

This study demonstrated that MRI should be the investigation of choice for retrorectal lesions. Biopsy of solid lesions is safe and useful for guiding neoadjuvant and surgical therapy. Cystic lesions without suspicious radiological features can be followed by serial imaging without resection.