Management of invasive bladder cancer
Among patients with invasive bladder cancer, treatment must be individualized accounting for general medical condition, extent of cancer, and personal preferences.10 Once it has been decided that more aggressive therapy is needed in the way of external beam irradiation, systemic chemotherapy, surgery or any combination thereof, the safety of bladder preservation should be considered. Although radiotherapy alone allows the bladder to be preserved, the five-year survival for patients with tumors into the innermost part of the muscle layer of the bladder is 40%, into the deep muscle layer or just beyond the muscle layer is 20%, and into adjacent organs (prostate or vagina) is 10%.11 Similarly, intravenous chemotherapy given as the only method of treatment produces a long term complete response in only about 20%. Recently, the combination of radiation therapy and intravenous chemotherapy (which sensitizes the cancer to irradiation) has given a glimmer of hope.12 58% of patients treated with platinum-based combination chemotherapy and irradiation were able to preserve their bladders while remaining free of disease at 4 years. Long term follow-up is unavailable at this time and improvements using this strategy will rely on more effective chemotherapeutic agents.
For invasive cancer that appear to be within the bladder (stages T2-3a), complete surgical removal of the bladder provides the best chance of a cure. Partial removal of the bladder may be tried in some patients; it has the advantage of preserving bladder and sexual function. Patients with only one tumor located near the dome of the bladder and without carcinoma in situ in other areas of the bladder, are the best candidates for partial bladder removal. If patients with a single tumor located near the dome of the bladder have carcinoma in situ in other area, they may first be treated with intravesical BCG. If the carcinoma in situ is eradicated they may then be treated by partial bladder removal. Among some patients with locally extensive invasive tumor, if preoperative systemic chemotherapy shrinks the tumor, partial bladder removal may be tried.13 However, among patients treated with partial bladder removal, cancer may recur in the remaining bladder.
When complete surgical removal of the bladder is performed, usually, in place of the bladder, a segment of small bowel is used to transfer urine directly from the kidneys and ureters through a stoma on the skin and into an external collection bag. This is called an ileal conduit. Most patients undergoing this form of diversion psychologically adjust to the change in body image with time. Since it is performed relatively quickly and with a low complication rate, the ileal conduit remains the diversion of choice with most surgeons. Today many patients opt for a form continent urinary reservoir, which eliminates the need for an external collection bag.14 Although the procedure requires special skills and increases the length of the operation, all appropriate candidates should be offered this form of diversion. Some continent diversions have a small stoma on the abdominal wall. The urine is drained 4 to 6 times daily by placing a catheter through the soma into a urinary reservoir made of bowel. The stoma which is flush with the skin is easily concealed with a gauze sponge.
Other forms of continent urinary diversion have a urinary reservoir attached to the urethra and the patient voids normally through the penis. Proper selection is crucial to avoid reoperation. This includes documentation that high grade or invasive disease is not present in the bladder neck or prostatic urethra. Excellent results have been obtained with the use of small and/or large bowel. Unfortunately, most of these types of bladder substitutions have been used only in men because continence cannot be maintained in women.
One of the most difficult and controversial areas in treating invasive bladder cancer is the timing of systemic (in the vein) chemotherapy around bladder removal. Systemic chemotherapy may be given pre- or post-operatively. A phase II trial using M-VAC (methotrexate, vinblastine, adriamycin [doxorubicin] and cis-platinum) prior to surgery resulted in about a 70% overall response and a 30% 3-year survival.15 Ongoing studies may better tell physicians the optimal timing of chemotherapy. Some physicians feel that bladder removal should be performed prior to systemic chemotherapy since some surgically resectable tumors may progress and become impossible to surgically remove while on chemotherapy, cancer volume may be reduced by surgery so the chemotherapy has less cancer cells to kill, and by pathologically examining the surgical specimen the need for systemic chemotherapy is more precisely assessed. Additionally, patients are more likely to agree to undergo potentially curative chemotherapy if there is documented evidence of extravesical and/or nodal disease. Limited prospective randomized clinical trials of post-operative chemotherapy have not been conclusive in showing a survival benefit.16
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