Bladder cancer is a heterogeneous disease, with 70% of patients presenting with superficial tumours, which tend to recur but are generally not life threatening, and 30% presenting as muscle-invasive disease associated with a high risk of death from distant metastases. The main presenting symptom of all bladder cancers is painless haematuria, and the diagnosis is established by urinary cytology and transurethral tumour resection. Intravesical treatment is used for carcinoma in situ and other high grade non-muscle-invasive tumours. The standard of care for muscle-invasive disease is radical cystoprostatectomy, and several types of urinary diversions are offered to patients, with quality of life as an important consideration. Bladder preservation with transurethral tumour resection, radiation, and chemotherapy can in some cases be equally curative. Several chemotherapeutic agents have proven to be useful as neoadjuvant or adjuvant treatment and in patients with metastatic disease. We discuss bladder preserving approaches, combination chemotherapy including new agents, targeted therapies, and advances in molecular biology.

Peroxisome proliferator-activated receptor ␥ (PPAR␥) is a nuclear hormone receptor that plays a key role in the differentiation of adipocytes. Activation of this receptor in liposarcomas and breast and colon cancer cells also induces cell growth inhibition and differentiation. In the present study, we show that PPAR␥ is expressed in human prostate adenocarcinomas and cell lines derived from these tumors. Activation of this receptor with specific ligands exerts an inhibitory effect on the growth of prostate cancer cell lines. Further, we show that prostate cancer and cell lines do not have intragenic mutations in the PPAR␥ gene, although 40% of the informative tumors have hemizygous deletions of this gene. Based on our preclinical data, we conducted a phase II clinical study in patients with advanced prostate cancer using troglitazone, a PPAR␥ ligand used for the treatment of type 2 diabetes. Forty-one men with histologically confirmed prostate cancer and no symptomatic metastatic disease were treated orally with troglitazone. An unexpectedly high incidence of prolonged stabilization of prostate-specific antigen was seen in patients treated with troglitazone. In addition, one patient had a dramatic decrease in serum prostate-specific antigen to nearly undetectable levels. These data suggest that PPAR␥ may serve as a biological modifier in human prostate cancer and its therapeutic potential in this disease should be further investigated.