Clinical Significance of Horizontal and Vertical Margin of En Bloc Resection for Nonmuscle Invasive Bladder Cancer

Abstract

Purpose:The primary advantage of en bloc resection of bladder tumors is to provide better diagnostic accuracy. However, the clinical significance of horizontal and vertical margin has not been demonstrated. We evaluated the clinical importance of surgical margins in patients who underwent en bloc resection of bladder tumors.Materials and Methods:We retrospectively analyzed the records of 140 consecutive patients who underwent en bloc resection of bladder tumors for nonmuscle invasive bladder cancer. We analyzed perioperative and oncological outcome, and compared patient demographics and recurrence-free survival for horizontal findings. The relationship between surgical margin and second transurethral resection outcome in pT1 bladder cancer was also analyzed.Results:Mean tumor diameter was 17.2±9.8 mm. Pathological stages were 93 cases in pTa and 47 cases in pT1. Diagnostic rates for the horizontal and vertical margins were 63% and 99%, respectively. The rates of sessile, carcinoma in situ, high grade, and pT1 tumors were significantly higher in the horizontal margin positive group (41) than in the negative group (47). There was no significant difference in 2-year recurrence-free survival based on horizontal margin findings (negative: 72.4%, positive: 75.4%, p=0.87). A second transurethral resection was performed in 31 of the 47 pT1 patients; pT1 residue was seen only in vertical margin positive cases, and 5 pTa/pTis residues at the transurethral resection scar were seen in 15 horizontal margin positive patients.Conclusions:Horizontal margin positive findings were not associated with recurrence-free survival, but careful assessment is warranted regarding residue at the original site. A second transurethral resection should be considered in patients with horizontal and vertical margin positive pT1 bladder cancer.

En bloc transurethral resection of bladder tumors: A review of current techniques

“…[12][13][14] A laser guide probe may be used with laser. 14 The choice of irrigation fluid relates to the energy source in use -glycine or mannitol is used in monopolar electrocautery (including monopolar HybridKnife®) [15][16][17][18] and 0.9% NaCl is widely used for bipolar electrocautery [19][20][21] and laser. [22][23][24][25] Distilled water has also been used with laser.…”

“…The clinical significance of positive horizontal margins remains uncertain, whilst positive vertical margins appear associated with residual tumour on reresection of T1 disease. 21 Where electrocautery or combined electrocautery/waterjet is the energy source in use, the coagulation current is sometimes advocated for this step. 15,20,28,32,33 With the use of laser technology, some authors alter the energy settings to provide a coagulation effect for the first line of demarcation, 14,25,34,35 whilst others describe an initial cutting incision.…”

“…21 Dissection within the muscularis layer, using retrograde or combined retrograde-antegrade approaches, with energy and/or blunt dissection is performed, until the tumour is lifted free of the base en bloc. 13,15,20,21,[26][27][28][29]32 Blunt dissection is performed with the electrode in electrocautery series, and has been described in laser series with the tip of the laser fibre, 36 retracting peaks of a laser guide probe, 14 or the tip of the resectoscope sheath. 23,25,37,38 The base and edges may be coagulated/fulgurated in the usual fashion where electrocautery is used, 13,15,19 or 'coagulated' with laser.…”

“…The electrode of choice is most commonly a standard loop, 5,13,19,26,28,32,39,40 which may be bent to 45 degrees to create an angled intersection with the bladder mucosa. 5,13,26,32 Some authors have found a flat loop to be useful in ERBT, 15,41 whilst others describe the use of a plasma button, 19,20 Collin's knife, 27,29 or needle electrode 21 either alone or in conjunction with a loop electrode. A novel approach of primarily cold excision with Zedd excision scissors and minimal electrocautery has recently been described.…”

“…The utility of enhanced visualisation techniques during ERBT has been poorly explored. Photodynamic diagnosis, 33, 41, 56, 65 narrowband imaging 17,21 and near-infrared molecular imaging 16 techniques have been described in a small number of studies using electrocautery and hydrodissection. Presumably enhanced visualisation techniques would offer similar advantage for ERBT as for cTURBT, however further ERBT-specific exploration is required.…”