Introduction

Bladder cancer is a common tumor of the urinary tract. Staging of disease is important as it gives some indication of prognosis and helps determine clinical management. It also allows some comparison of treatment response and comparison between patients [1].

Staging of bladder cancer is based on depth of tumor invasion of the bladder wall, involvement of local structures, nodal involvement and metastases. The bladder can be divided into layers: The mucosa (epithelium) lies over the submucosa or lamina propria. Beneath this is the muscular layer and beyond this is the serosa (the serosa is not present over the entire bladder as it is synonymous with the peritoneal covering which is applied over the dome) [2–4]. Staging systems for local disease are based on these layers. There are two main staging classifications used for evaluating bladder carcinoma: the TNM classification [5] and the Jewett–Strong–Marshall classification [6]. The TNM classification was revised in 1997, with a new stage added to differentiate between microscopic and macroscopic perivesical disease, a modification which has been retained in more recent versions (Table 4.1).

Clinical staging is evaluated by a combination of imaging, bimanual palpation, cystoscopic evaluation and biopsy [1,2]. Ideally, imaging would be performed prior to cystoscopy and biopsy to minimize potential imaging artifacts. In practice, however, cystoscopy and biopsy are performed at the initial presentation. Cystoscopic resection may completely remove the tumor and allow staging based on the histology (see Chapter 1).

Introduction

In excess of 90% of tumors arising from the urinary bladder are urothelial carcinomas [1]. Alternative histological cell types which may rarely be encountered include squamous cell carcinoma, adenocarcinoma and tumors of mesenchymal origin.

Bladder cancer is a cause of significant morbidity and mortality throughout the world. Statistics demonstrate that between the years 2001 and 2003, 10 264 new cases of bladder cancer were diagnosed in the United Kingdom, and it was the seventh most common cause of malignancy-related death in males and eleventh most common cause in females [2]. Bladder cancer typically occurs in later life, with the peak incidence in the sixth and seventh decades. This, together with the strong association with environmental factors, likely accounts for the significant worldwide variation in incidence with, e.g. the incidence in the Italian male population being in excess of six times that in the Indian male population [3].

The prognosis of bladder cancer is dependent on a number of factors. Of particular importance are the depth of bladder wall invasion, the presence of metastases in lymph nodes and the presence of blood-borne metastases. In cases of superficial transitional cell malignancy, mean five-year survival of approximately 80% can be expected. Invasive tumors reduce five-year survival to less than 50%. If nodal metastases or blood-borne metastases are present then the five-year survival rate is worse still (15 and 5% respectively) [4,5]. Depending on local practice, up to one-third of patients may have metastatic disease at presentation [6].

Cancer of the urinary bladder encompasses a range of cell types, the most common in Western societies being transitional cell carcinoma (TCC). These neoplasms are characterized by a spectrum from indolent, polypoid tumors to sessile, more biologically aggressive lesions. Initial management relies heavily on cytoscopic procedures, but as disease becomes more advanced, imaging becomes central to decision making. This volume draws together contributions from various specialities, including pathology, surgery, and clinical and medical oncology. The aim is to inform the radiologist of the range of surgical procedures which has been developed, and the possibilities for management with radiotherapy. Cytotoxic chemotherapy can be used in neoadjuvant, adjuvant and palliative settings. The role of imaging in diagnosis of disease of the urothelium, the techniques for staging bladder cancer and detection of metastatic disease are each discussed in separate chapters. Imaging following treatment, including effects on normal tissues, is also covered, and the multidisciplinary nature of management of bladder neoplasms is emphasized. In line with the ethos of the Contemporary Issues in Cancer Imaging series, it is hoped that this volume will give radiologists a broader view of the technical aspects of treatment, and colleagues in other specialities will be able to further their understanding of the contribution imaging can make in our endeavors to cure the disease and control symptoms in patients with bladder cancer.