21 Urinary Bladder Cancer

Urinary Bladder Cancer

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THE GEC ESTRO HANDBOOK OF BRACHYTHERAPY | Part II: Clinical Practice Version 1 - 21/04/2015

8.1 Treatment of pelvic lymph nodes There are two policies towards the pelvic lymph nodes. Either the pelvic lymph nodes are treated with external beam radiotherapy prior to brachytherapy or the lymph nodes are surgically treat- ed. The standard pelvic area to treat is up to the common iliac bifurcation, and including the internal iliac, presacral, obturator fossa, and external iliac nodes, although there is debate on the extension of pelvic lymph node treatment (2). If the lymph nodes are treated with radiotherapy, a dose of 40 Gy in 2 Gy daily frac- tions is usually applied. During surgery lymph nodes areas are palpated to exclude or remove lymph node metastases. A lymph node dissection is only performed when suspicious lymph nodes are present. If the policy is to treat the lymph nodes surgically, a formal lymph node dissection should be performed. 8.2 Partial cystectomy For thick tumours in which a single plane implantation is not possible, partial cystectomy by removing the tumour should be done. A location at the dome can also be excised as these loca- tions are easily removed. Other indications to perform a partial cystectomy are a tumour located within a diverticulum, distal ureter, or in the urachus. 8.3 The classical suprapubic approach When performing the suprapubic approach, a median suprapu- bic or Pfannenstiel incision is performed. The bladder is opened at some distance from the tumour site, usually with a parame- dian incision opposite to the tumour side, to make the implan- tation easier. After inspection and palpation of the tumour site, the urologist and radiation oncologist make the final decision whether to perform a partial cystectomy or not. In difficult cases, biopsies and frozen section examination may guide the decision. The bladder wall is then implanted with curved hollow needles, or by commercially available Reverdin needles (22). Some of these needles need to be manoeuvered with a special holder for- ceps, others have a handle. The length and curvature of the nee- dles (Fig 22.4) are chosen depending on the site of the tumour in the bladder. Needles are implanted from the inner side of the bladder muco- sa, through the muscular bladder wall, reappearing back at the

mucosal surface. After that the catheters must be guided to leave the inner bladder surfacel through the bladder wall. The same hollow needle is used to bring the catheters through the blad- der wall (Fig 22.5). The catheters used are double-leader cath- eters. These are hollow closed flexible catheters with thin flexi- ble leader tubes at both ends as are also used in head-and-neck brachytherapy. The catheters can be pulled into the bladder wall by the flexible leaders. To implant deep localisations close to the bladder neck, it may be helpful to use a boomerang device (Fig 22.6), which helps to make a tight bend behind the pubic bone. Because curved catheters with a curved source track result in an asymmetrical dose distribution towards the concave side, the needles should be placed in the outer 2/3 of the bladder wall, so that the reference isodose will cover the entire thickness of the bladder wall. Usually 2 catheters parallel with the surgical scar will be suffi- cient to cover the target after partial cystectomy, while 2-4 cath- eters may be required in other cases when a larger surface must be covered (fig 22.7).

Fig 22.5: Catheters in the bladder wall and intravesical spacers

Fig 22.6: A “boomerang” device, used for endoscopical prostate resections, with a curved steel bladder implantation needle welded to it. Pressure on the button advances the needle in a semi-circular movement forwards and permits implantation deeply into the small pelvis.

Fig 22.7: Diagram showing the plastic tube technique for interstitial bladder implantation. A two catheter implant for small target volumes or after partial cystectomy (right picture). A three catheter implant for a larger implant (left and middle picture).

Fig 22.4: Bladder implantation needles of different curvature. Upper needle has a 40 degree curve and the lower needle has a 10 degree curve.