Intensity-modulated radiation therapy administered to a previously irradiated spine is effective and well-tolerated

PURPOSE

This study sought to discern the clinical outcomes of intensity-modulated radiation therapy (IMRT) administered to the spine in patients who had undergone previous radiotherapy.

METHODS

A total of 81 sites of 74 patients who underwent previous radiotherapy administered to the spine or peri-spine and subsequently received IMRT for the spine were analyzed in this study. The prescribed dose of 80 Gy in a biologically effective dose (BED) of α/β = 10 (BED₁₀) was set as the planning target volume. The constraint for the spinal cord and cauda equine was D_0.1 cc ≤ 100 Gy and ≤ 150 Gy of BED for re-irradiation alone and the total irradiation dose, respectively.

RESULTS

The median follow-up period was 10.1 (0.9-92.1) months after re-irradiation, while the median interval from the last day of the previous radiotherapy to the time of re-irradiation was 15.6 (0.4-210.1) months. Separately, the median prescript dose of re-irradiation was 78.0 (28.0-104.9) of BED₁₀. The median survival time in this study was 13.9 months, with 1-, 3-, and 5-year overall survival rates of 53.7%, 29.3%, and 26.6%, respectively. The 1-, 3-, and 5-year local control rates were 90.8%, 84.0%, and 84.0%, respectively. Neurotoxicity was observed in two of 72 treatments (2.8%) assessed after re-irradiation.

CONCLUSION

Re-irradiation for the spine using IMRT seems well-tolerated. Definitive re-irradiation can be a feasible treatment option in patients with the potential for a good prognosis.

Parathyroid hormone-related peptide is a potent tumor angiogenic factor

Rat pituitary malignant tumor cells; mGH3, show hypervascularization in in vivo xenografts and overexpress parathyroid hormone-related peptide (PTHrP) compared to original GH3 cells. To elucidate whether PTHrP is involved in tumor-derived angiogenesis, we examined the effect of PTHrP on vascular endothelial cells both in vitro and in vivo. Results of in vivo diffusion chamber assay showed a clear hypervascularization on the outer surface of diffusion chambers containing mGH3 tumor cell implants but not in those containing GH3 cells. Co-incubation with antisense PTHrP oligonucleotide (10 microM), but not sense or mismatched PTHrP oligonucleotide, suppressed hypervascularization in diffusion chambers. To further examine the role of PTHrP on endothelial cell function, PTHrP(1-34) was added at various concentrations to cultured bovine endothelial cells (BAECs) harvested from the aorta. PTHrP(1-34) did not alter the proliferation or migration of endothelial cells, but rather dose-dependently increased capillary formation by endothelial cells on the collagen gel matrix. Furthermore, 0.1 mM of 8-bromo-cAMP caused a similar increase in tube formation, which was dose-dependently inhibited by H89, a protein kinase A inhibitor. Our results indicate for the first time that PTHrP is a potential paracrine factor acting via the PKA pathway to enhance angiogenesis through capillary tube formation by endothelial cells in malignant pituitary tumors.

Thoracic aortic aneurysmectomy with a sutureless intraluminal ringed graft

Forty-two patients underwent replacement of the thoracic aorta with a sutureless intraluminal graft. Early and long-term results were evaluated. The operative mortality rate was 7.1%. There were two postoperative complications related to a ringed graft. One complication, the formation of a pseudoaneurysm, was caused by insufficient fixation of the graft; the other, a cerebral infarction, was related to the location of the proximal anastomosis with respect to the origin of the left subclavian artery. The 3- and 5-year actuarial survival rates were 86 and 69.5%, respectively. These were similar to survival rates of age-matched controls in the general Japanese population. Replacement of the thoracic aorta using a sutureless intraluminal graft can be performed with acceptable operative mortality, with good long-term results.

[The effect of preclotting and collagen coating on endothelializing rate and thrombogenesity of Dacron grafts in the canine thoracic aorta]

Although high porosity knitted Dacron is generally recognized to have superior healing characteristics over woven Dacron, its porosity must be controlled at the clinical operation. This can be achieved with several materials, including geratin, insoluble collagen, albumin, and fibrin. We made atherocollagen coated graft using EX-313 as a new crosslinking agent. The purpose of this study is to compare the endothelializing rate and thrombogenesity of Dacron grafts coated by atherocollagen in the canine thoracic aorta with preclotting grafts with blood or albumin. Five groups were studied: Control group (n = 10), without preclotting; A-P group (n = 8), preclotting with albumin; B-P group (n = 5), preclotting with blood; W-C group (n = 5), atherocollagen coating with low cross-linkage; S-C group (n = 7), atherocollage coating with high cross-linkage. Thoracic aorta was replaced with 8 mm graft in length of 5.0 to 5.5 cm using temporary bypass with anthron tube. Grafts were harvested 3 months following implantation, and the endothelized surface ratio was calculated by microscopic line sampling method. Endothelized surface ratio of Control group, A-P group B-P group, W-C group and S-C group were 85%, 55%, 67%, 93% and 85%, respectively. Endothelized surface ratio of W-C group and S-C group were higher (p < 0.05) than those of A-P group, B-P group. There were thrombus in non-epithelized area. We conclude that atherocollagen coated graft had superior antithrombogenesity compared to albumin or blood preclotting graft.

[Effects of coronary artery bypass grafting for patients with totally occluded left anterior descending arteries]

Between April, 1987 and March, 1991, 21 patients with totally occluded left anterior descending arteries (TOLAD) underwent coronary artery bypass grafting (CABG) in our institute. All of them were diagnosed as angina pectoris and 15 (71%) of them have had episodes of myocardial infarction. Graftability of TOLAD was 90% (19/21) and two of the TOLADs were not suitable for CABG because severe atherosclerosis of these arteries were observed intraoperatively. There was no operative death. Short term (1-2 months) patency was 64% (7/11) for saphenous vein grafts (SVG) and 100% (8/8) for left internal thoracic artery grafts (LITA). Left ventricular wall motion assessed by left ventriculography showed impaired regional wall motion in 63% segments of the segment #2, #3 and #6 preoperatively. However, the regional wall with impaired motion decreased to 31% after CABG. Thallium-201 scintigraphy showed impaired perfusion in 62% segments of the left anterior wall, apex and interventricular septum preoperatively. However, the regional wall with impaired perfusion decreased to 42% after CABG. Exercises tolerance assessed by treadmill test was improved from 3.8 +/- 0.7 Mets preoperatively to 6.5 +/- 0.7 Mets with patent coronary bypass grafts. These data suggested that CABG can improve the wall motion of the regions perfused by TOLADs and the LIMA is more suitable than the SVG for CABG to TOLAD.

[Successful post-left ventricular aneurysmectomy left ventricular assist with a centrifugal pump]

A 71-year-old male with a left ventricular aneurysm underwent aneurysmectomy. The patient could be weaned from cardiopulmonary bypass with high-doses of dopamine and dobutamine, followed by immediate left ventricular failure and systemic hypotension. IABP could not be applied to the patient because of the kinked bilateral common iliac arteries. In this condition a centrifugal pump system was connected between left atrium and ascending aorta. With a pump flow of 2 L/min the patient returned to an intensive care unit. After 48 hours of left heart bypass with minimal anticoagulation with systemic heparinization the device could be removed. The patient recovered without any complications, such as thromboembolism, renal failure or mediastinitis. He discharged in fair condition 3 months after the operation.

[Coronary artery bypass grafting using right gastro-epiploic artery and cholecystectomy]

A 59-year-old male with ischemic heart disease and cholecystolithiasis underwent coronary artery bypass grafting (CABG) using the right gastro-epiploic artery (GEA) and cholecystectomy simultaneously CABG was performed under standard extracorporeal circulation followed by cholecystectomy at the same incision. The opening in the dome of the diaphragm where the pedicle of GEA was brought up was closed with fibrin glue. Then, sternum was closed and cholecystectomy was performed with no elongation of the incision. The postoperative course was uneventful without mediastinitis or other infectious events. The postoperative angiography showed good patency of the GEA graft. Combined CABG using GEA and cholecystectomy is beneficial for the selected patients.

[Peritoneal dialysis in neonates and infants after open heart surgery]

Peritoneal dialysis was required in 20 (12.8%) of 156 neonates and infants for acute renal failure following open heart surgery using cardiopulmonary bypass. Cardiac diagnosis was TAPVD (7 cases), PA with IVS (2), ECD (2), coarctation of the aorta with VSD (2) and other cardiac malformations (7). The indication for dialysis was oliguria of less than 1.0 ml/kg over 4 hours resistant to volume repletion, inotropic agent and diuretics. Peritoneal dialysis was performed using dialysis catheter and glucose containing dialysis solutions. The mean predialysis BUN and serum creatinine were 30.4 mg/dl and 2.7 mg/dl respectively. The highest serum creatinine during dialysis was 4.5 mg/dl, and all but one patient had BUN level of under 100 mg/dl. Dialysis with glucose containing solution could allow sufficient fluid removal as a result, fluid overload was restored. Plasma protein and electrolytes balance were corrected within 48 hours. Two neonates and 4 infants survived. Thirteen patients died on dialysis: nine of those deaths were related to low cardiac output, 2 death were attributable to respiratory insufficiency, and 2 cases died due to sepsis. One infant died of an unexplained cardiac arrhythmia after renal failure had been improved. It is concluded that peritoneal dialysis is beneficial in neonates and infants who become oliguria following open heart surgery.

[Pulmonary vascular disease in shunted and nonshunted patients with tetralogy of Fallot]

Histometric analysis of pulmonary vascular disease was performed in 21 nonshunted patients and in 13 shunted patients with tetralogy of Fallot and in 29 normal controls. There was no significant difference in the medial thickness of the small pulmonary arteries between cases of tetralogy of Fallot and normal controls. However, the media in the shunted cases of tetralogy of Fallot gave the impression of being thicker than these in the nonshunted cases. Intimal fibrosis, regarded as organized thrombi, and thrombi of small pulmonary arteries were observed generally after 4 years of age in shunted and nonshunted cases of tetralogy of Fallot. Intimal proliferation of musculoelastosis which was formed longitudinal smooth muscle bundles and elastic fibers was characteristic in shunted patients, especially after the central palliation procedure, Waterston anastomosis and modified Blalock-Taussig (B-T) anastomosis using a Gore-Tex tube graft. However, musculoelastosis was not usually seen in the B-T anastomosis cases. Unexpected pulmonary hypertension due to shunt operation is thought to be the cause of musculoelastosis, because musculoelastosis was observed even in a patient with pulmonary hypertension 3 weeks following surgery. We, therefore, recommend original B-T anastomosis as the shunt procedure. When considering use of the other shunt operations which entail pressure load on the pulmonary vascular bed, attention must be given to the size of the anastomosis or artificial tube graft.

Successful surgical treatment of pulmonary artery sling and partial anomalous pulmonary venous drainage in an infant

A 8 month old infant with pulmonary artery sling and partial anomalous pulmonary venous drainage was reported. The patient was seen initially with severe stridor. Diagnosis was made by barium swallow study, echocardiography, bronchoscopy, and pulmonary arteriography. The patient was operated on through a median sternotomy; the left pulmonary artery was dissected deep between the trachea and esophagus, and then reimplanted to the side of the main pulmonary artery. Systemic heparinization and microsurgical technique were used. Simultaneous intracardiac repair was carried out by means of extracorporeal circulation. The patient improved dramatically after operation. Postoperative pulmonary arteriogram revealed a wide patent left pulmonary artery, and postoperative perfusion lung scan confirmed improved perfusion of the left lung. It is concluded that pulmonary artery sling should be treated surgically as soon as diagnosed. From the surgical point of view, the left pulmonary artery should be anastomosed to the main pulmonary artery with micro-surgical technique to avoid late occlusion of the left pulmonary artery.