Piecemeal Versus En Bloc Resection of Large Rectal Adenomas

Currently, colonoscopy is the safest way to detect bowel tumors and polyps, since these can be biopsied and removed in one working process. If the size of adenomas is larger than 2 cm, resections are usually done in a hospital setting. For the resection of large adenomas, different approaches can be used. The so-called piecemeal resection is done with snares, to cut off parts of the adenoma piece by piece until the whole adenoma is resected. This technique is the standard therapy, but is not required for very large adenomas, which can often show cell alterations that indicate cancer. Therefore these adenomas should be resected in one piece. This is done by the so-called en-bloc resection. For this kind of therapy, different endoscopic knifes are use to cut off the adenoma as a whole. Both resection techniques are done usually by previous injection of saline or other liquids to elevate the lesion from its bottom tissue.
Although the piecemeal resection of large adenoma is the standard therapy, it shows recurrence rates of 10 to 25%, which afford repeated therapies and follow up controls. En-bloc resections, though, are expected to have less recurrence rates but are much more complex to perform. They have higher complication rates especially in the West, where it has bee introduced only a couple of years ago.
The data situation regarding safety and efficacy of both therapies is low. This study is the first one ever to compare piecemeal EMR and ESD in a randomized way. The study might have influence on the logistics of future adenoma processing and patient flow.