Durable efficacy of early postoperative radiation therapy for high-risk pT3N0 prostate cancer: the importance of radiation dose

Objectives. To determine the durable efficacy of early postoperative radiation therapy (RT) in patients with pT3N0 prostate cancer who were at an increased risk of biochemical failure. We also evaluated the long-term benefit derived from using higher RT doses.Methods. Seventy-nine patients with pathologic Stage T3N0 prostate cancer and high-risk postoperative features underwent RT within 6 months after surgery. No patient received prior hormonal therapy. Fifty-nine patients had positive surgical margin, 29 had pathologic seminal vesicle invasion, and 27 had persistently elevated postoperative prostate-specific antigen (PSA) levels. Freedom from biochemical relapse (bNED) was defined as an undetectable (less than 0.2 ng/mL) PSA level. Median follow-up time was 39 months, and the median radiation dose was 64.8 Gy. All patients were followed for at least 2 years to be considered biochemically controlled.Results. Patients receiving adjuvant RT for an undetectable pre-RT PSA level had a 3-year bNED rate of 90%, compared with 44% for those receiving salvage RT for a detectable level (P < 0.0001). In the group of adjuvant patients, RT doses more than 61.2 Gy resulted in a 3-year bNED rate of 90% compared with 64% for those receiving a lower dose (P = 0.015). The salvage patients irradiated with a dose of 64.8 Gy or greater had a 3-year bNED rate of 52% compared with 18% for those irradiated with lower doses (P = 0.048). Severe late RT-related complications were infrequent and did not correlate with dose.Conclusions. In patients with high-risk pT3N0 prostate cancer, an RT dose response may exist. Although some studies suggest limited durable efficacy for early postoperative RT, our data suggest that RT doses of 64.8 Gy or more appear superior to prevent future biochemical failures. A prospective randomized study evaluating a postoperative RT dose response is warranted.     

Lithium usage and renal function testing in a large UK community population; a case–control study

Objective

This study investigates the prevalence of lithium use, monitoring practice and associated effects on renal function in a large UK community sample.

Method

A large population-based renal function database was cross-referenced with a general practitioner database of 404,673 patients. The renal function of patients prescribed lithium during the 2-year period was compared with that of matched controls. The renal monitoring patterns of these cases were investigated in a naturalistic observational study. Data underwent parametric testing — continuous variables by analysis of variance, with appropriate adjustment, and categorical outcomes by χ² testing. Block analysis of variance was undertaken on case–control data.

Results

A total of 422 patients in the database were prescribed lithium. Renal function monitoring in accordance with published guidelines occurred in 69% of patients. Patients taking lithium had a significantly higher serum creatinine (5.8 μmol/L, P< .001) and lower glomerular filtration rate (5.9 ml/min, P< .001) when compared to matched controls.

Conclusions

This is the first study carried out in a large community sample. Lithium remains widely prescribed in the community setting. The study confirms that lithium has a statistically and clinically significant negative effect on renal function. Despite published guidelines and recognition of the importance of serial measurements, monitoring of renal function is inconsistent.     

Superficial- and deep-tissue temperature increases in anesthetized dogs during exposure to high specific absorption rates in a 1.5-T MR imager

Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.     

Excretory urography in the emergency department: utility of teleradiology

To test the feasibility of teleradiology for use with excretory urograms obtained in the emergency department in cases for suspected renal colic, radiographs from 43 patients were digitized, transmitted via standard phone lines, and viewed on a video monitor 2 miles distant. Diagnostic interpretations of the video image and the original radiograph were reviewed for degree of concordance. The video and film images of the 27 examinations showing obstruction were interpreted with 100% correlation. Agreement as to the site of obstruction was present in 93% of cases. Only two-thirds of renal and ureteral calculi seen on the radiographs were discerned on the video images, however. Teleradiology proved as useful for ongoing monitoring and modification of these examinations as for initial interpretation.     

Osteoarthritis of the facet joints: accuracy of oblique radiographic assessment

Sensitivity and specificity of lumbar spine radiography in the assessment of facet joint osteoarthritis were evaluated, with computed tomography (CT) as the standard. Two independent radiologists used a four-point scale to blindly grade facet joint osteoarthritis on oblique radiographs and transaxial CT scans obtained within an 8-month period in 50 consecutive patients with pain in the lower back. The L-3 to L-4, L-4 to L-5, and L-5 to S-1 facet joints were evaluated, and 68% appeared abnormal on CT scans, with 28% exhibiting moderate or severe disease. Interobserver agreement was high for conventional radiography (perfect agreement in 57% and agreement to within one grade in 39%) and still higher for CT (perfect in 63% and to within one grade in 35%). Receiver operating characteristic curve analysis indicated that oblique radiography was most accurate (55% sensitivity, 69% specificity) in distinguishing the presence from the absence of disease; in distinguishing absent or mild from moderate or severe disease, the specificity of oblique radiography was higher, at 94%, but its sensitivity was much lower, at 23%. Conventional radiography is a useful technique in screening for facet joint osteoarthritis but is insensitive compared with CT.     

Detection of colonic polyps on single-contrast barium enema study: emphasis on the elderly

A systems approach was employed to improve results of the single-contrast barium enema examination for detection of colonic polyps. Improvements were made in each of the following areas: radiographic-fluoroscopic equipment, fluoroscopic-television images, screen-film combinations, barium suspensions, examination techniques, imaging sequences, and quality controls. Radiologic-endoscopic correlation was undertaken for 137 colonic polyps seen endoscopically in 91 patients. The average age of the patients was 69 years. The sensitivity of the single-contrast examination for detection of all polyps was 80%. Polyps 5-9 mm in size were detected with 66% sensitivity, while 94% of polyps 10 mm or larger were detected. The results indicate that the sensitivity of a suitably performed single-contrast barium enema examination may approach that of the double-contrast study for the detection of colonic polyps, even in an elderly and infirm patient population.     

The implications of stress patterns in the vertebral body under axial support of an artificial implant

Clinical studies show an association between changed load patterns both in the disc and its adjacent vertebral body, with painful degenerated discs. This suggests that failure to restore the normal loading pattern on implantation of a disc replacement could be a cause of lower clinical success rate. In the present study the variations of load patterns in the vertebra after disc implantation was studied using a simplified finite element models of natural and artificial discs. The effect of implant size and presence of voids at the implant–bony endplate interface were studied, for the worst case scenario of no bone remodelling. An altered stress pattern was observed in the vertebrae of implanted segments. The use of smaller size implants and presence of voids at the interface caused localized stress concentration in the endplate and adjacent cancellous bone. The study results support the hypothesis that current implants fail to restore normal loading patterns in the vertebral body, and the localized high stress regions could be the source of pain, and the cause of low success rate of TDRs.