Defining Thermally Safe Laser Lithotripsy Power and Irrigation Parameters: In Vitro Model.

Introduction: High-power laser settings are commonly employed for stone dusting techniques. Previous in vitro and in vivo studies have demonstrated that a toxic thermal dose can result from treatment within a renal calix without adequate irrigation. Hence, both laser power and irrigation rate must be considered together to determine safe laser lithotripsy parameters. The objective of this in vitro study was to map parameter safety boundaries and create guidelines for selection of safe laser and irrigation settings. Methods: The experimental system consisted of in vitro models simulating ureter, renal calix, and renal pelvis placed in a water bath maintained at 37°C. Temperature was recorded during ureteroscopy with laser activation for 60 seconds. Trials were conducted at strategically selected power levels and irrigation rates. Thermal dose for each trial was calculated based on Sapareto and Dewey t43 methodology with thermal dose >120 equivalent minutes considered to result in thermal tissue injury. A parameter safety boundary was established by plotting the maximal safe power level for each irrigation rate. Results: The parameter safety boundary was found to be linear for each scenario with the renal pelvis able to tolerate the highest laser power and the renal calix the least power without injury. Conclusion: This study describes the methodology to determine parameter safety boundaries that can be used to guide proper selection of thermally safe laser settings and irrigation rates during ureteroscopy with laser lithotripsy. This work provides a framework to assess the effectiveness of various strategies to control and mitigate thermal dose.

Radiotherapy may improve overall survival of patients with T3/T4 transitional cell carcinoma of the renal pelvis or ureter and delay bladder tumour relapse.

BACKGROUND: Since transitional cell carcinoma (TCC) of the upper urinary tract is a relatively uncommon malignancy, the role of adjuvant radiotherapy is unknown. METHODS: We treated 133 patients with TCC of the renal pelvis or ureter at our institution between 1998 and 2008. The 67 patients who received external beam radiotherapy (EBRT) following surgery were assigned to the radiation group (RT). The clinical target volume included the renal fossa, the course of the ureter to the entire bladder, and the paracaval and para-aortic lymph nodes, which were at risk of harbouring metastatic disease in 53 patients. The tumour bed or residual tumour was targeted in 14 patients. The median radiation dose administered was 50 Gy. The 66 patients who received intravesical chemotherapy were assigned to the non-radiation group (non-RT). RESULTS: The overall survival rates for the RT and non-RT groups were not significantly different (p = 0.198). However, there was a significant difference between the survival rates for these groups based on patients with T3/T4 stage cancer. A significant difference was observed in the bladder tumour relapse rate between the irradiated and non-irradiated bladder groups (p = 0.004). Multivariate analysis indicated that improved overall survival was associated with age < 60 years, T1 or T2 stage, absence of synchronous LN metastases, and EBRT. Acute gastrointestinal and bladder reactions were the most common symptoms, but mild non-severe (> grade 3) hematologic symptoms also occurred. CONCLUSION: EBRT may improve overall survival for patients with T3/T4 cancer of the renal pelvis or ureter and delay bladder tumour recurrence in all patients.

Ionizing radiation and kidney cancer among Japanese atomic bomb survivors.

Understanding of the role of radiation as a cause of kidney cancer remains limited. The most common types of kidney cancer are renal cell carcinoma and renal pelvis carcinoma. It has been posited that these entities differ in their degree of radiogenicity. Recent analyses of cancer incidence and mortality in the Life Span Study (LSS) of Japanese atomic bomb survivors have examined associations between ionizing radiation and renal cell carcinoma, but these analyses have not reported results for cancer of the renal pelvis and ureters. This paper reports the results of analyses of kidney cancer incidence during the period 1958-1998 among 105,427 atomic bomb survivors. Poisson regression methods were used to derive estimates of associations between radiation dose (in sievert, Sv) and cancer of the renal parenchyma (n = 167), and cancer of the renal pelvis and ureter (n = 80). Heterogeneity by cancer site was tested by joint modeling of cancer risks. Radiation dose was positively associated with cancers of the renal pelvis and ureter [excess relative rate (ERR)/Sv = 1.65; 90% confidence interval (CI): 0.37, 3.78]. The magnitude of this association was larger than the estimated association between radiation dose and cancer of the renal parenchyma (ERR/Sv = 0.27; 90% CI = -0.19, 0.98). While the association between radiation and cancer of the renal parenchyma was of greater magnitude at ages <55 years (ERR/Sv = 2.82; 90% CI = 0.45, 8.89) than at older attained ages (ERR/Sv = -0.11; 90% CI = nd, 0.53), the association between radiation and cancers of the renal pelvis and ureter varied minimally across these categories of attained age. A test of heterogeneity of type-specific risks provides modest support for the conclusion that risks vary by kidney cancer site (LRT = 2.34, 1 d.f., P = 0.13). Since some studies of radiation-exposed populations examine these sites in aggregate, results were also derived for the combined category of cancer of the renal parenchyma, renal pelvis and ureters. Overall, there was a positive association between radiation and the combined category of cancer of the renal parenchyma, renal pelvis and ureters (ERR/Sv = 0.60, 90% CI: 0.09, 1.30). Updated follow-up of the LSS cohort provides substantial additional information on the association between radiation and cancer of the renal pelvis and ureter, a site not examined in recent reports on analyses of these data. The results are suggestive of differences between the different regions of the kidney in sensitivity to the carcinogenic effects of ionizing radiation.

Preoperative concurrent chemoradiotherapy against muscle-invasive bladder cancer: results of partial cystectomy in elderly or high-risk patients.

BACKGROUND: Good local control has been reported in cases of muscle-invasive bladder cancer treated by chemoradiotherapy and transurethral resection (TUR). However, definitive irradiation or extensive chemotherapy is often intolerable for elderly or poor-risk patients. We report here benefits of partial cystectomy after concurrent low-dose chemoradiotherapy for high-risk patients. METHODS: Thirty-seven patients with localized muscle-invasive bladder cancer (T2-T4) were treated with concurrent cisplatin (50-100 mg/body x 2 courses) and pelvic irradiation (40 Gy) preoperatively. Among 17 patients (46%) who achieved complete response (CR), 10 were not suitable for radical cystectomy and underwent partial cystectomy. Radical cystectomy was performed in 24 cases [CR = 6, partial response (PR) = 18]. Two patients (one CR and one PR) rejected open surgery and were treated by TUR of the primary site. One no change (NC) patient received no further treatment because of mental disorder. RESULTS: Median follow-up was 12 months (range 2-37 months). Fifteen of 36 evaluable cases (42%) achieved a pathological T0 response (no residual tumor). Estimated 3-year disease-free survival was 56% for all patients and 100% for T0 responders. Seven of 21 patients with pathological persistent tumor developed local recurrence (three patients) or distant metastasis (four patients). All of the 10 patients (eight with T0 response and two with a small residual tumor nest) who underwent partial cystectomy were recurrence-free for an observation period of up to 3 years. CONCLUSIONS: Bladder preservation by partial cystectomy may be a choice for patients who show a good response to preoperative chemoradiotherapy and are not suitable for radical cystectomy.

[Thorotrast kidney as a precancerous condition]. / Thorotrastose der Niere als Präkanzerose.

9 cases of "thorotrast kidney" after retrograde pyelography with reflux are presented. In 6 patients carcinoma of the renal pelvis developed 47--31 years after thorotrast pyelography. Because of this high rate of carcinoma induction, thorotrast kidney must be classified as a precancerous condition with high-rate tumor manifestation. Thorotrast kidney is diagnosed on X-ray by very opaque linear densities following the calices and pyelon. Early ureteronephrectomy is the treatment of choice in unilateral thorotrast kidneys. If uretero-nephrectomy is not possible, the patient should be followed up regularly with urinary cytologic examinations for early detection of malignancy.