Note: Some citations in the text of this section are followed by a level of evidence. The PDQ editorial boards use a formal ranking system to help the reader judge the strength of evidence linked to the reported results of a therapeutic strategy. (Refer to the PDQ summary on Levels of Evidence for more information.)

Stage 0 bladder cancer is defined by the following TNM classifications:

• Ta, N0, M0
• Tis, N0, M0

Patients with stage 0 bladder tumors can be cured by a variety of treatments, even though the tendency for new tumor formation is high. In a series of patients with Ta or T1 tumors, who were followed for a minimum of 20 years or until death, the risk of bladder cancer recurrence following initial resection was 80%.[1] Patients at greatest risk of recurrent disease are those whose tumors are large, poorly differentiated, multiple, or associated with nuclear p53 overexpression. In addition, patients with carcinoma in situ (Tis) or dysplasia of grossly uninvolved bladder epithelium are at greater risk of recurrence and progression.[1,2,3]

Transurethral resection (TUR) and fulguration are the most common and conservative forms of management. Careful surveillance of subsequent bladder tumor progression is important. One retrospective series addressed the value of performing a second TUR within 2 to 6 weeks of the first.[4][Level of evidence: 3iiDiii] A second TUR performed on 38 patients with Tis or Ta disease found that nine patients (24%) had lamina propria invasion (T1) and three patients (8%) had muscle invasion (T2). Such information may change the definitive management options in these individuals. Patients who require more aggressive forms of treatment are those with extensive multifocal recurrent disease and/or other unfavorable prognostic features. Segmental cystectomy is applicable to only a small minority of patients because of the tendency of bladder carcinoma to involve multiple regions of the bladder mucosa and to occur in areas that cannot be segmentally resected.

Intravesical therapy with thiotepa, mitomycin, doxorubicin, or bacillus Calmette-Guérin (BCG) is most often used in patients with multiple tumors or recurrent tumors or as a prophylactic measure in high-risk patients after TUR. Administration of intravesical BCG plus subcutaneous BCG following TUR was compared with TUR alone in patients with Ta and T1 lesions. Treatment with BCG delayed progression to muscle-invasive and/or metastatic disease, improved bladder preservation, and decreased the risk of death from bladder cancer.[5,6] Another randomized study of patients with superficial bladder cancer also reports a decrease in tumor recurrence in patients given intravesical and percutaneous BCG compared with controls.[7] Two nonconsecutive 6-week treatment courses with BCG may be necessary to obtain optimal response.[8] Patients with a T1 tumor at the 3-month evaluation after a 6-week course of BCG and patients with Tis that persists after a second 6-week BCG course have a high likelihood of developing muscle-invasive disease and should be considered for cystectomy.[8,9,10] A randomized study that compared intravesical and subcutaneous BCG with intravesical doxorubicin showed better response rates and freedom from recurrence with the BCG regimen for recurrent papillary tumors as well as for Tis.[11] A randomized trial from the Swedish-Norwegian Bladder Cancer Group compared 2 years of intravesical treatment with mitomycin C versus BCG. No difference was observed in tumor progression or overall survival (OS) between the two arms at 5 years.[12][Level of evidence: 1iiD] Although BCG may not prolong OS for Tis disease, it appears to afford complete response rates of about 70%, thereby decreasing the need for salvage cystectomy.[13] Studies show that intravesical BCG delays tumor recurrence and tumor progression.[6,14] Preliminary results from a prospective randomized trial suggest that maintenance BCG, when given to patients who are disease-free after a 6-week induction course, improves survival.[15] One study that compared mitomycin with interferon-a-2b showed an improved outcome with mitomycin, even though interferon was better tolerated.[16]