21 Urinary Bladder Cancer

Urinary Bladder Cancer

4

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

3. ANATOMICAL TOPOGRAPHY

T2a Tumour invades superficial muscle (inner half) T2b Tumour invades deep muscle (outer half) T3 Tumour invades perivesical tissue: T3a Microscopically T3b Macroscopically (extravesical mass) T4 Tumour invades any of the following: prostate stroma, semi- nal vesicles, uterus, vagina, pelvic wall, abdominal wall T4a Tumour invades prostate stroma, seminal vesicles, uterus, or vagina T4b Tumour invades pelvic wall or abdominal wall There is an abundant network of lymph channels originating from the submucosa entering the muscle layers and ending at the outer surface of the bladder. From there the drainage goes to the external iliac nodes. The posterior wall of the bladder drains into the external and internal iliac lymph nodes. The inferior part can drain to the presacral nodes and common iliac lymph nodes. The obturator, external iliac, internal iliac, common iliac, and presacral nodes are considered as the regional lymph nodes for the bladder. Most bladder cancers are urothelial carcinoma (UC). About 75% of cases present with non-muscle invasive bladder cancer (NMIBC). NMIBC is usually papillary in appearance. They are histopathologically graded as low- or high-grade according to the World Health Organization classification and the Interna- tional Society of Urologic Pathologists (8). Carcinoma in situ (CIS) has a flat erythematous appearance and tends to spread diffusely through the bladder mucosa. Muscle-invasive bladder cancer (MIBC) usually has a solid appearance. Invasive tumours are always high-grade. Squamous cell carcinoma is more often seen in patients with a history of local bladder irritation. Ade- nocarcinoma arising from residual urachus is rare. Other his- tologies that may arise are sarcomas, lymphomas, carcinoid tu- mours, and small cell cancers. Depth of invasion, lymph node status, and blood vessel invasion are the most important prognostic factors for local control, dis- ease-free survival and overall survival (9). Substaging into pT2a and pT2b appears to be associated with prognosis (10, 11). The indications for brachytherapy depend on the size of the tu- mour, its location (bladder neck versus upper trigone and dome), the depth of invasion, and the presence or absence of multifocal disease elsewhere in the bladder mucosa. 4. PATHOLOGY

The bladder is roughly pyramidal in shape when empty and be- comes ovoid when filled. When full, the bladder dome extends out of the pelvis into the abdomen. The trigone, at the bladder base, is triangular and is situated deeply in the true pelvis, be- hind the pubis, so that it is less accessible to implantation pro- cedures. The ureters enter the bladder at the superolateral angles of the trigone, and the urethra leaves the bladder at the inferior angle. The wall consists of mucosa, submucosa and the muscle layers of the detrusor. The mucosa is smooth at the trigone, but is thrown into folds at the dome when the bladder is empty. The bladder wall endoluminally is covered by urothelial cells of the mucosal membrane. Beyond the mucosa there is a thin layer of submucosa. The outer layer of the bladder wall is formed of three smooth muscle layers that contract during voiding. The three muscle layers are arranged as the inner longitudinal, outer spi- ral, and outer longitudinal layer. The outer longitudinal layer is covered by adventitia containing arteries, veins and lymphatic vessels. The bladder on itself is surrounded by perivesical fat at its fixed inferior part, while the dome is covered by abdominal peritoneum. The rectum or rectovaginal septum is at the poste- rior side of the bladder. Anteriorly and laterally the bladder is bounded by the pubic bone. Laterally the bladder is supported by the obturator internus muscle and inferiorly by the levator ani muscle as part of the urogenital diaphragm. In men the prostate lies between the bladder and the urogenital diaphragm. The tumour originates from the epithelial lining of the bladder wall. Invasion of the tumour takes place through the bladder wall layers and ultimately into the perivesical fatty tissue or adjacent organs. This extension of tumour invasion is reflected in the TNM classification (7).

5. WORK UP

Fig 22.1: T classification UICC 2009.

After recording the patient’s history and a full clinical examina- tion, fresh urine is sampled for cytological examination and a cystoscopy is carried out for diagnosis and biopsy. Positive cytol- ogy raises the suspicion of the presence of urothelial tumours, in particular high-grade tumours or carcinoma in situ.

T stage according to TNM staging system (fig 22.1) Tx Primary tumour cannot be assessed T0 No evidence of primary tumour Ta Non-invasive papillary carcinoma Tis Carcinoma in situ: “flat tumour” T1 Tumour invades subepithelial connective tissue T2 Tumour invades muscle

For staging, the primary tumour should be assessed by biman-