The value of computed tomography in the management of bladder cancer

Features of Irradiated Urinary Bladder Tumors and Their Correlation with Malignancy Observed on Computed Tomography

CT features of 42 masses in the bladder wall were characterized and subjected to analysis to find indicators of malignancy. A CT technique with thin slices and intravenous contrast medium was used. Multiple regression and multivariate analysis showed good ability of contrast-enhanced CT to discriminate between benign and malignant masses in the bladder wall. Protrusion of a mass into the perivesical fat had some importance in discriminating between malignant tumors with and without perivesical growth although the detection of perivesical growth was less certain.

Computed Tomography of the Urinary Bladder Shortly after Radiation Therapy for Rectal Carcinoma

Eighteen patients with rectal carcinoma were examined with computed tomography (CT), before and shortly after preoperative irradiation. Changes in the bladder that could be mistaken for tumor growth did not occur at CT. However, considerable individual variations were seen. Radiation therapy did not result in increased contrast enhancement of the bladder wall after irradiation. The bladder wall thickness increased somewhat during and after treatment and the bladder volume was reduced. Localized thickening with little contrast enhancement was seen in the anterior bladder wall in 3 patients. One case of irradiation cystitis was noted. Edema was seen in the perivesical fat, but could in no case be mistaken for tumor growth.

Absorbed Dose Resulting from a Specially Designed Computed Tomography Technique for Examination of the Urinary Bladder

The absorbed spatial dose distribution resulting from a specially designed CT protocol for examination of the urinary bladder has been investigated with TLD rods in a body phantom containing tissue equivalent material. The CT examination consisted of scout view and both pre- and postcontrast scan series with 5 mm slice thickness and 5 mm unscanned intervals between successive scans. Cross-sectional dose distribution for one scan in the plane of the ovaries was measured as well as the dose profile for one scan along a line through the ovary parallel to the axis of rotation. Based on these measurements, the dose resulting from the whole CT examination was calculated, both with contiguous and noncontiguous scans. The ovarian dose was calculated for different positions of the ovaries in relation to the scanned area. The absorbed dose varied between 8.3 mGy and 9.7 mGy with the actual technique used. When contiguous scans with the same thickness were taken, the ovarian dose increased with a factor from 1.7 to 1.9. The dose resulting from the CT protocol of the urinary bladder was of the same magnitude as absorbed dose resulting from urography. When the diagnostic gain from a precise definition of tumor extent was taken into account, the dose resulting from the CT protocol was judged acceptable.

Contrast-Enhanced Computed Tomography to Show Perivesical Extension in Bladder Carcinoma

Fifty-two patients (53 lesions) with muscle invasive carcinoma (T2/T3) of the urinary bladder were examined with computed tomography (CT) before planned total cystectomy. The object of CT was to demonstrate perivesical growth. All patients were examined before and after intravenous injection of contrast medium. The stages obtained from the precontrast and postcontrast scans were compared with the histopathologic stage from the cystectomy specimen. CT staged correctly 35 of the 53 lesions in the precontrast series and 46 of the 53 lesions in the postcontrast series. The improved accuracy from contrast enhancement resulted primarily from fewer cases being overstaged. The use of intravenous contrast medium improved accuracy of CT in evaluation of perivescial tumor growth.

Bladder carcinoma. Experience with radical and preoperative radiotherapy in 421 patients

Four hundred twenty-one patients with bladder carcinoma were treated with radical intent between 1968 and 1981: 356 were treated with irradiation alone with megavoltage tumor doses of 60-66 Gy delivered over a period of 6 to 7 weeks. Actuarial 5- and 10-year survival was 66% and 58% for Stage A (58 patients), 42% and 35% for Stage B1 (62 patients), 35% and 28% for Stage B2 (120 patients), and 23% and 19% for Stage C (75 patients), respectively. Five-year survival after salvage cystectomy (47 patients) was 51% from the time of surgery, with 4 operative mortalities and a major complication rate of 30%. Sixty-five patients were entered into an integrated preradical cystectomy irradiation program. Fifty-three patients in stages B2-C-D1 received high-dose preoperative radiotherapy (40-50 Gy) before a planned, delayed radical cystectomy. The actuarial 5-year survival was 66% for 65 patients, and 64% for the 53 patients in the high-dose precystectomy program; major complications were encountered in 34% and there were 2 mortalities. Five-year actuarial survival for Stage B2-C was 30% but fell to 24% when patients with salvage cystectomy were excluded. Distant metastasis was found in 30% of patients in Stage B2-C-D1, and also in the high-dose precystectomy program patients. Two-thirds of patients with distant metastasis in the radiation alone group were never considered for salvage cystectomy as they had distant metastasis alone, persistent disease with metastasis within 6 months after initiation of irradiation, or local recurrence and distant metastasis simultaneously. Early local recurrence may be salvaged in 50% to 60% of patients without a significant increase in mortality or major complications. Accordingly, a program of radical irradiation with salvage cystectomy may avoid loss of the bladder in 45% of patients in Stage B2-C-D1 without compromising overall survival.

Computed tomography in the management of bladder carcinoma

Between 1978 and 1980, 30 patients were evaluated by computed tomography (CT). CT differed from clinical stage in 10 of 30 patients (30%). In 9 of the 10 patients the change in stage resulted because of extravesical extension or involvement of the prostate. Seventeen patients underwent pre-operative irradiation, and CT scans done post-irradiation showed a decrease in tumor stage in 5 patients (33%). The accuracy of CT in detecting nodal involvement was limited with an overall accuracy of 65%. CT has limited value in staging of bladder cancer.

Impact of CT-based treatment planning on radiation therapy of carcinoma of the bladder

Computed tomography (CT) has been an integrated step in the treatment planning of radiation therapy of carcinoma of the bladder in stages T1-T3 in 49 consecutive patients referred to Radiumstationen in Aarhus. The introduction of this technique has led to a considerable increase (26 +/- 4%) in the mean effective target volume of these patients compared with that of 51 conventionally simulated patients. The largest field expansions have been performed in the cranial and ventral directions. The field margins to the bladder have been correlated with the position of the tumour mass. The findings are compared with previously published results on CT-based treatment planning of patients with bladder carcinoma.

Computed tomography in the management of head and neck cancer

Computed tomography is indispensable in determining the deeper extensions of tumors and proper treatment planning as well as in documentation of tumor resolution for lesions arising in the nasal cavity, paranasal sinuses, orbit, and salivary glands. In the hypopharynx and larynx, computed tomography provides information of differing degrees of value according to the clinical stage, site of origin, and usual therapeutic approach for each tissue. Detection of subclinical cervical adenopathy needs further investigation. Computed tomography has not been of particular value for lesions arising in the oral cavity and oropharynx.

CT scanning in the male genital tract and in recurrent rectal carcinoma: a review

A review of the literature reveals that CT scanning of the prostate, seminal vesicles, and pelvic structures is an excellent diagnostic tool for treatment planning and radiation therapy. Structures such as the seminal vesicles, which can only be seen on invasive procedures, or tumors outside the bladder or lymph node enlargement may be easily viewed on CT. Most observers feel that the accuracy of CT scanning at diagnosing adenopathy is in the range of 70% to 80%. Most observers also agree that CT scanning alters the treatment plan in 30% to 40% of the cases. Recurrent carcinoma of the colon in soft tissue can be seen in the pelvis and presacral hollow in males who after abdominoperineal resection are left without an orifice to allow examination from the pelvis. CT scanning is an excellent diagnostic tool for treatment planning in therapeutic radiology.

Positive and negative contrast agents in CT evaluation of the abdomen and pelvis

The oral administration of a dilute positive iodinated contrast agent such as 2% Gastrografin is usually necessary to achieve optimal delineation of abdominal and pelvic organs. The amount of contrast agent administered and the timing of its administration depends on the site of suspected disease within the body. The simultaneous administration of antiperistaltic agents intravenously is generally unnecessary when utilizing the modern fast CT scanners. However, contrast agent-induced artifact may at times be troublesome, and we therefore suggest that lesions in the left lobe of the liver be scanned without positive contrast in the stomach. Negative contrast may also be useful in delineating disease: gas (carbon dioxide) has been shown to be useful in evaluating bladder tumors. We have also used air insufflation to facilitate the evaluation of small rectal tumors. Intravenous administration of contrast agent aids characterization of various disease entities and also facilitates the recognition of vascular structures (such as veins and arteries in the peripancreatic region). In our opinion both the infusion and bolus modes of contrast material administration have their place in the evaluation of abdominal and pelvic lesions by computed tomography. Newer techniques such as dynamic CT scanning will probably prove to be valuable both in delineating and characterizing disease.

Updating computed tomography of bladder carcinoma in assessing response to immunotherapy and attenuated irradiation

Computed tomography (CT) was utilized as part of the surgical-pathologic-radiologic evaluation of 21 patients who were treated for bladder carcinoma with attenuated irradiation and immunotherapy. Fifteen patients had moderately infiltrative (Stage B2-C or less) disease, and it was found that a routine high resolution CT technique using a modern fast scanner delineated the tumor in most cases. More accurate assessment of tumor response to therapy and evaluation of tumor progression were facilitated using a gas insufflation technique combined with intravenous contrast fusion. This was followed in selected cases by quantitative measurements of CT attenuation values using a recently introduced CT software program. Using this program, individual pixel values were obtained in selected areas and evaluation of the resulting numerical data and pixel histograms aided in the differentiation of tumor tissue from adjacent bladder wall and mapped out areas of tumor necrosis. Our preliminary observations suggest that quantitative CT studies incorporating assessment of printouts of attenuation values of adjacent pixels within a region of interest will improve the delineation of smaller (B1/B2) lesions and will aid objective characterization of tumor tissue during and following therapy.

The diagnosis and detection of urogenital cancers

Previously, histologic precision in the diagnosis of urologic cancers had, for some time, remained stable. More recently, variations in classifications of testis tumors, prostate cancer, and to some degree, bladder tumors, have been introduced. Most systems have in concurrence a desire or an attempt to infer better prognostic assessment in the overall results to treatment. With the advent of additional biological markers or direct enzymatic measurements, e.g., in prostate cancer, further improvements in identifying at risk populations, responses to treatment, and possible indications for variations in treatment, have ensued. These developments alone unquestionably mark the greatest area of change in the recent decade. The extent of disease assessment prior to definitive therapy, whether by arteriography, ultrasound, CAT scanning, or an occasional lymphangiography, has also influenced or modified treatment decisions. For continuing care and follow-up, several of these noninvasive techniques are now becoming included in the more standard approaches. Noninvasive techniques have been introduced for the therapy of renal tumors such as inducing infarction of the primary tumor. Endoscopic ultrasonic techniques have been particularly useful in assessing the size of pelvic tumors and response to treatment, even in detection of unexpected multiple primaries or metastatic extensions. Overall, the precision in urologic cancer, both for diagnostic and detection purposes, has been increased with these introductions.