{'fraction_non_alphanumeric': 0.015541264737406217, 'fraction_numerical': 0.0021436227224008574, 'mean_word_length': 5.597173144876325, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Is there a risk of carcinoma dissemination in the percutaneous access for endoscopical treatment of upper urinary tract urothelial tumors?].

OBJECTIVES
The incidence of transitional cell carcinoma of the renal pelvis and ureter is low, and the standard treatment is nephroureterectomy with a bladder cuff. However, there are special circumstances, from both patient and tumor characteristics, which are subsidiary of a minimally invasive endoscopic treatment, such as percutaneous resection. Very satisfactory results have been obtained with this technique, which has been performed since 1985. Nevertheless, theoretically there exists a potential risk of disseminating tumor cells when performing this technique. The objective of this article is to review our experience, and that of other groups, performing percutaneous resection of upper urinary tract tumors, and to determine the incidence tumor dissemination.


METHODS
We performed a bibliographic search in Medline (PubMed) and reviewed the articles about upper urinary tract tumors treated by percutaneous resection. We also evaluated the incidence of tumor dissemination related to surgery


RESULTS
Published data show a very low incidence of tumor dissemination after endoscopic resection by a percutaneous approach. Theoretically tumor dissemination can be the result of dissemination to the blood or lymphatic circulation, or the implant of tumor cells in the contiguous or distant urothelial mucosa, or propagation of these tumor cells to the retroperitoneal space or the nephrostomy track.


CONCLUSIONS
Percutaneous endoscopic resection of upper urinary tract urothelial tumors is a safe and effective technique that enables a minimally invasive and nephron sparing treatment. If some precautions are taken, this surgical technique does not involve a significant risk for tumor cell dissemination.