Correlation between thermosensor temperature and transrectal ultrasonography during prostate cryoablation.

OBJECTIVE: To determine if the adequacy of freezing in the neurovascular bundle region of the prostate during prostate cryotherapy can be monitored by transrectal ultrasonography (TRUS). PATIENTS AND METHODS: The study group consisted of 11 patients undergoing TRUS-guided prostate cryotherapy. The actual temperature in the gland was monitored with thermosensors placed in each prostatic neurovascular bundle. The 2 cryo-operators, working together and blinded to the actual temperature, used sonographic observations to estimate the temperature at the neurovascular bundles every 2 minutes until they believed that the gland was adequately frozen. The congruity between the estimated and measured temperatures was analyzed to determine if the operators could accurately monitor the progress of cryoablation by ultrasonography. RESULTS: There were a total of 85 data points for which the operators thought tumoricidal cryo-injury had been achieved at the neurovascular bundles (temperature -20 degrees C or below). For these points the measured temperature was on average 6.0 degrees C warmer than the estimated temperature (standard deviation, 22). For operator estimates of -20 degrees C or below, the measured temperature was -20 degrees C or below for 37 (44%) data points, between -19 degrees C and 0 degree C for 32 (38%) and greater than 0 degree C for 16 (19%). CONCLUSIONS: The operators were not able to accurately predict subzero temperatures at the neurovascular bundle region by TRUS evaluation. Moreover, the bias and magnitude of the error were significant and might lead to inadequate freezing of the prostate during attempted cryoablation.

Prostatic cryosurgery: use of MR imaging in evaluation of success and technical modifications.

PURPOSE: To evaluate the usefulness of contrast material-enhanced magnetic resonance (MR) imaging in objective assessment of prostatic cryosurgery and the role of MR imaging in the modification of prostatic cryosurgical technique. MATERIALS AND METHODS: Thirty-eight consecutive patients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enhancement before cryosurgery and unenhanced and gadolinium-enhanced MR imaging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging findings were correlated with those from transrectal ultrasound-directed prostatic staging biopsy. RESULTS: Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-enhanced images. With progressive modification of cryosurgical technique, complete cryoablation of the prostate was achieved in the latter nine of the 38 patients. When cryoablation was considered complete according to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor. CONCLUSION: Gadolinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging findings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.

Prognostic factors in colorectal carcinoma of young adults.

To determine why the prognosis for colorectal cancer in young adults is poor, survival and prognostic factors in patients under 40 years of age were compared with those in patients between 40 and 50 years of age. In a 10-year period, 122 patients less than 50 years of age (88 between 40 and 50 years) presented at the Victoria General Hospital in Halifax, NS, with colorectal cancer. Their charts were retrospectively reviewed. Follow-up was obtained for all patients. Of the 34 patients younger than 40 years, 71% (24) were men compared with 38% (33) of older patients. Symptoms, their duration and the location of primary tumours were similar in the two groups. Patients younger than 40 years presented with advanced lesions (Dukes' stages C and D) in 67% of cases compared with 52% of the older group. Mucinous tumours were twice as common in patients less than 40 years old (p = 0.036) and actuarial survival rates were lower at all stages for the same group. The authors conclude that the poorer prognosis in patients less than 40 years of age is not due to late symptom reporting or delay in diagnosis, but to more aggressive disease.