Hyaluronic acid spacer in focal prostate reirradiation: A single centre experience.

PURPOSE: The optimal management of locally recurrent prostate cancer after curative radiotherapy is still unknown. In this study, we evaluated the preliminary results of reirradiation using stereotactic body radiotherapy for locally recurrent prostate cancer after initial definitive local radiotherapy. MATERIALS AND METHODS: Between April 2016 and February 2019, 11 patients with recurrent disease at the previously irradiated prostate were treated. Local recurrence was detected by radiological with or without functional imaging modalities including prostate multiparametric/pelvic MRI or positron-emission tomography-computerised tomography with (68Ga)-labelled prostate-specific membrane antigen performed after rising prostate specific antigen serum level during follow-up. All patients received stereotactic body radiotherapy to the recurrent nodule to a total dose of 30Gy in five fractions. Hyaluronic acid spacer was injected between prostate and rectum in seven patients to decrease the rectal dose. Acute toxicity was evaluated by using Common Terminology Criteria for Adverse Events version 4.0, and late toxicity was evaluated by using Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer late radiation morbidity scoring schema. RESULTS: At the diagnosis, the median age was 64 years, and the mean prostate specific antigen serum concentration was 17.7ng/mL. The median interval time between local recurrence and initial definitive radiotherapy was 63 months. Mean prostate specific antigen concentration nadir value during follow-up was 0.43ng/mL. With a median follow up of 19 months, three patients developed either local or distant relapse. One patient had grade 3 acute rectal toxicity, and one patient had grade 2 late urinary toxicity. We did not observe any acute or late toxicity due to hyaluronic acid spacer injection. CONCLUSION: Reirradiation after local recurrence following initial definitive radiotherapy together with hyaluronic acid spacer use seems to be effective and safe.

Hypofractionated radiotherapy for non-metastatic bone and soft tissue sarcomas.

PURPOSE: To evaluate the efficacy and toxicity of hypofractionated radiotherapy in non-metastatic soft tissue and bone sarcomas. PATIENTS AND METHODS: Thirty patients underwent hypofractionated radiotherapy between 2007 and 2015. Overall, 17 patients underwent primary hypofractionated radiotherapy, nine underwent hypofractionated radiotherapy for reirradiation, and four received a boost dose via hypofractionated radiotherapy after external beam radiotherapy. Most common disease sites were head and neck and retroperitoneum. Hypofractionated radiotherapy was administered with a definitive, adjuvant, or neoadjuvant intent. RESULTS: Median age was 37 years (range: 11-82 years). Median hypofractionated radiotherapy dose was 35Gy (range: 20-50Gy) in three to five fractions. Median follow-up was 21 months (range: 1-108 months). One- and 2-year overall survival rate was 75% and 52%, respectively. One- and 2-year local recurrence-free survival rate was 59% and 48%, with local recurrence rates of 16% and 33% in 1 and 2 years, respectively. Univariate analysis revealed tumour size (P=0.04), hypofractionated radiotherapy intent (P=0.016) and reirradiation (P=0.001) as prognostic factors for local recurrence-free survival. Severe late toxicity was observed in one patient as grade 3 trismus. CONCLUSION: Hypofractionated radiotherapy as the primary treatment or for reirradiation has been shown to be safe in the treatment of bone and soft tissue sarcomas. It can provide relatively good local control and survival rates.

Assessment of concomitant versus sequential trastuzumab on radiation-induced cardiovascular toxicity.

There are limited data regarding effect of trastuzumab on radiation-induced cardiovascular toxicity when used sequentially or concomitantly. This experimental study aims to investigate effect of trastuzumab on radiation-induced cardiovascular toxicity with respect to the treatment sequence. One hundred and eight female Wistar albino rats were divided into six groups (G): G1 was control, G2 was trastuzumab, and G3 was radiotherapy (RT); G4 and G6 were sequential RT and trastuzumab; and G5 was concomitant RT and trastuzumab groups, respectively. Rats were killed at 6th h, 21st and 70th days after RT; thoracic aorta and heart samples were obtained. Transthoracic echocardiography and functional studies evaluating relaxation of thoracic aorta were performed. Subendothelial edema scores of thoracic aorta samples at 21st and 70th days were higher in RT groups (G3, G4, G5, and G6) ( p < 0.001). There was a deterioration of relaxation responses of thoracic aorta samples in RT groups ( p < 0.001). Cardiac fibrosis (CF) scores revealed detrimental effect of RT beginning from 6th h and trastuzumab from 21st day. RT groups showed further deterioration of CF at 70th day. Ejection fraction, left ventricular mass, and fractional shortening were significantly decreased in G4, G5, and G6. Trastuzumab may increase pathological damage in cardiovascular structures when used with RT regardless of timing.

Robotic Stereotactic Body Radiation Therapy in Patients With Recurrent or Metastatic Abdominopelvic Tumors: A Single Institute Experience.

BACKGROUND: The aim of this study was to evaluate the efficacy and toxicity of robotic CyberKnife (Accuray Incorporated, Sunnyvale, California)-based stereotactic body radiation therapy (SBRT) in patients with recurrent or metastatic abdominopelvic tumors. METHODS AND MATERIALS: A total of 69 patients treated between May 2008 and January 2011 were evaluated retrospectively. Indication for SBRT was persistent disease in 3 (4%) patients, local recurrence in 29 (42%) patients, regional recurrence in 13 (19%) patients, and oligometastatic disease in 24 (35%) patients. Forty-two (61%) patients were previously irradiated to the same region and 27 (39%) patients were treated for the first time. The median age was 59 years (range, 24-86 years). There were 31 (45%) male and 38 (55%) female patients. The median total dose was 30 Gy (range, 15-60 Gy) delivered with a median 3 fractions (range, 2-5 fractions). The tumor response to treatment was assessed by computed tomography, magnetic resonance imaging, or positron emission tomography. RESULTS: At the 12-month (range, 2-44 months) median follow-up, local control was 65% and median overall survival (OS) was 20 months. A larger gross tumor volume (≥ 67 cm(3)) was significantly correlated with worse 1-year OS (81% vs 48%, P = .03). The patients with local recurrence occurring <11 months had a significantly shorter 1-year local control rate than patients with ≥ 11 months (31% vs 91%, P < .001). Grade 3-4 acute and late toxicities were seen in 7% and 15% of patients, respectively. The patients with previous radiotherapy history had significantly higher rate of acute toxicity (19% vs 0%, P = .019). Late toxicity was significantly higher in pelvic tumors than in abdominal tumors (3% vs 28%, P = .004). CONCLUSION: The SBRT seems to be feasible and resulted in good treatment outcomes in patients with recurrent or metastatic abdominopelvic tumors.

Fractionated stereotactic radiosurgery treatment results for skull base chordomas.

Chordomas are uncommon neoplasms and there is still controversy regarding establishment of diagnosis and management. The aim of this study was to evaluate efficacy and toxicity of fractionated stereotactic radiosurgery (FSRS) in skull base chordomas. There were 4 female (36%) and 7 male (64%) patients. FSRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA). The median tumor volume was 14.7 cc (range, 3.9-40.5 cc). The median marginal tumor dose was 30 Gy (range, 20-36 Gy) in a median 5 fractions (range, 3-5 fractions). The median follow-up time was 42 months (range, 17-63 months). At the time of analysis, 10 (91%) patients were alive and 1 (9%) had died due to tumor progression. Of 10 patients, 8 (73%) had stable disease and the remaining 2 (18%) had progressive disease. The actuarial overall survival (OS) after FSRS was 91% at two-years. Two patients developed radiation-induced brain necrosis as a complication in the 8th and 28th months of follow-up, respectively. Our results with robotic FSRS in skull base chordomas are promising for selected patients. However, due to the slow growth pattern of skull base chordomas, a longer follow-up is required to determine exact treatment results and late morbidity.

Robotic stereotactic radiosurgery in patients with unresectable glomus jugulare tumors.

We evaluated the treatment results of robotic stereotactic radiosurgery (SRS) in our patients with unresectable glomus jugulare tumors (GJTs). The medical charts of fourteen patients with GJT, who were treated with robotic SRS, were retrospectively evaluated. The gross tumor volume was described as the clinical target volume. The median dose to the tumor was 25 Gy in median 5 fractions. The dose was normalized to 80% isodose line. All patients were evaluated for tumor growth and clinical outcome every 6 months in the first 2 years and then annually. Median follow-up was 39 months (range, 7-60 months). Lesions were stable in 8 patients, and tumor regression was observed in 6 patients. We did not observe any treatment related toxicity in our patients. In conclusion, according to our early experience, robotic SRS seems to be successful treatment option in the management of unresectable GJTs.

SU-E-T-208: The Secondary Malignancy Risk Estimation Due to the Neutron Contamination in 3D-CRT and IMRT Treatment Techniques by Using Bubble Detectors.

PURPOSE: In this study, the neutron measurements were performed in free in air and RW3 solid water phantom to estimate the secondary malignancy risk for three dimensional conformal radiotherapy (3D-CRT) and intensity modulated radiotherapy (IMRT) techniques in prostate cancer treatment. METHODS: Neutron dose were measured in 18 MV Elekta Synergy Platform and Varian Clinac linear accelerators by using bubble detector for personal neutron dosimetry (BD-PND). To determine the neutron equivalent dose in different depths and different distance from the edge of treatment field RW3 solid water phantom was used and organs location was defined in Alderson Rando phantom with respect to target (prostate) position in the treatment field. By using these data, we determined the neutron equivalent dose and effective dose for the standard prostate cancer patient treated with 3D-CRT and IMRT with 18 MV photon energy. The total dose was 70 Gy in 3D-CRT and 76 Gy in IMRT treatment in the current study. For both of these treatment techniques, we estimated the risk of secondary malignancies due to the neutron contamination by using the International Commission on Radiological Protection (ICRP) report 103. RESULTS: The equivalent dose and effective dose due the neutron contamination were considerably high in 18 MV IMRT technique. The secondary malignancy risk estimation for 3D-CRT and IMRT were found to be 0.44% and 1.15% for Elekta Synergy Platform linear accelerator, 0.92% and 2.38% for the Varian Clinac DHX High Performance linear accelerator, respectively. CONCLUSIONS: Therefore, one should take care of the secondary malignancy risk in case of using 18 MV in IMRT applications.

A randomized phase II study comparing induction or consolidation chemotherapy with cisplatin-docetaxel, plus radical concurrent chemoradiotherapy with cisplatin-docetaxel, in patients with unresectable locally advanced non-small-cell lung cancer.

BACKGROUND: In stage III non-small-cell lung cancer (NSCLC), the role of systemic chemotherapy preceding or following concurrent chemo-radiotherapy (CT-RT) is unclear. We carried out a randomized phase II study to study the toxicity involved-field CT-RT with either induction or consolidation cisplatin-docetaxel (Taxotere). PATIENTS AND METHODS: Patients were randomly assigned to receive two cycles of docetaxel (D) 75 mg/m(2) on day 1 and cisplatin (C) 40 mg/m(2) on days 1 and 2, either preceding (IND arm) or following (CON arm) concurrent CT-RT, where 66 Gy was delivered using involved-fields concurrent with weekly D 20 mg/m(2) and C 20 mg/m(2). Patients at higher risk for lung toxicity (V(20) > 35%) crossed over to IND arm. Seventy patients were needed to exclude grade (G)3-4 esophagitis in >25%. RESULTS: Of the 70 eligible patients, 26 were treated in IND and 34 CON; five with V(20) >35% switched from CON to IND. The differences in G3-4 esophagitis observed (32/2% IND versus 21/3% CON) were not significantly different from the hypothesized 25% rate. Rates of G≥2 pneumonitis were similar, but IND arm had less G3-4 neutropenia. One-year survival was 63.2% [95% confidence interval (CI) 48.4% to 78.0%] and 65.5% (95% CI 48.2% to 82.8%) for the IND and CON arms, respectively. CONCLUSION: Both study arms merit further testing in patients with limited volume stage III NSCLC.

Concomitant trastuzumab with thoracic radiotherapy: a morphological and functional study.

BACKGROUND: The purpose of this study is to elucidate if there is an additive or supra-additive toxic effects of radiotherapy (RT) and trastuzumab (T) on vascular structures when used concomitantly. METHODS: Female Wistar albino rats were treated with either 8 or 15 Gy of thoracic RT. T was applied i.p. with a dose of 6 mg/kg 2 h before RT. Four rats in each arm were killed at 6th h, 21st and 70th days after irradiation and thoracic aorta of each animal was dissected for electron microscopy. In addition, functional studies for evaluating the relaxation and contraction were carried out 21 days after RT. RESULTS: Only 15-Gy RT dose groups showed significant difference in terms of functional deterioration as more contraction than the others (P < 0.05) without any difference between RT and RT + T. However, T produced additional deficit in relaxation when added to RT, which was considered near significant (P: 0.0502). Electron microscopy showed endothelial and subendotelial damage signs in 15-Gy dose groups. T + 15-Gy arm showed more pronounced endothelial cell damage than 15-Gy RT-only arm, 70 days after RT. CONCLUSION: T and high-dose RT may lead to vascular damage that seems at least additive.

Primary low grade B-cell lymphoma of the dura in an immunocompetent patient.

Primary central nervous system lymphomas (PCNSL) represent only 1% of all non-Hodgkin's lymphomas (NHLs). A 66 year-old woman was hospitalized due to multiple episodes of syncope and seizures which occurred the week before admission to the hospital. A computerized tomography (CT) scan of the brain showed a right parietal lesion suggesting a subdural effusion. The patient was operated and a dural lesion extending to the epidural space and cerebral cortex was excised. Histologic findings suggested diagnosis of a low-grade lymphoma of the mucosa associated lymphoid tissue (MALT) type. The patient was treated with radiation therapy and has now completely recovered 12 months after surgery.

High-dose-rate mold brachytherapy of early gingival carcinoma: a clinical report.

Two elderly edentulous patients with the diagnosis of early stage cancer of the upper gingiva were treated by customized dental mold brachytherapy. Locoregional tumor control was achieved in both patients. One patient is alive without any evidence of disease 36 months after treatment, the other patient died of distant metastasis shortly after brachytherapy. Brachytherapy, being easy to apply with short treatment time and good acute tolerance, is a good choice and effective modality for the management of early stage gingival cancer, particularly in elderly patients.

Comparison of AJCC 1988 and 1997 classifications for nasopharyngeal carcinoma. American Joint Committee on Cancer.

PURPOSE: A comparison of American Joint Committee on Cancer (AJCC) 1988 and 1997 nasopharyngeal carcinoma (NPC) classifications was made in terms of patient distribution and efficacy in predicting prognosis. METHODS AND MATERIALS: Between 1993-1997, 90 patients (64 M, 26 F) with non-metastatic NPC were treated. The mean age was 42.02 (range: 9-82) years old. Histopathological diagnosis was WHO 2 and 3 in 83 (92.2%) patients. All patients were prospectively staged using AJCC 1988 and modified Ho's classifications (1989) and these data were stored in a computer database. Retrieval of this information enabled us to restage patients according to the AJCC 1997. Median follow-up was 38 months. RESULTS: According to the AJCC 1988 there were 2 (2.2%), 6 (6.7%), 13 (14.4%), and 69 (76.7%) patients in Stage I, II, III and IV, respectively. Same figures were 8 (8.8%), 21 (23.3%), 26 (28.9%), and 35 (38.8%), according to AJCC 1997. Three year overall survival (OS) rates were 100%, 100%, 67%, and 62% for patients Stage I, II, III, and IV according to the AJCC 1988 and 100%, 72%, 65%, and 55%, (I vs. IV; p = 0.03, I vs. III; p = 0.05) respectively, according to the AJCC 1997. Three year loco-regional relapse free survival (LRRFS) rates were 50%, 100%, 100%, and 83% (I vs. III; p = 0.03) for patients in Stage I, II, III, and IV according to the AJCC 1988. Same figures were 88%, 90%, 89%, and 85% according to the AJCC 1997. Three year distant metastasis free survival (DMFS) rates were 100%, 100%, 82%, and 67% for patients in Stage I, II, III, and IV according to the AJCC 1988. Same figures were 100%, 74%, 80%, and 57% (I vs. IV; p = 0.03) according to the AJCC 1997. We did not observe any significant difference in LRRFS among T stages for both staging system and the N stage was the primary determinant for DMFS in both systems. CONCLUSIONS: We observed a better patient distribution with AJCC 1997 comparing to AJCC 1988. The new classification also attained better statistical significances among stages in the OS and DMFS rates.

Colonic anastomotic healing after preoperative chemo-radiotherapy in rat.

PURPOSE: To prevent micrometastasis at an earlier stage and to increase the lateral or circumferential tumor free margins, there is a rationale for neo-adjuvant chemo-radiotherapy in patients with colorectal cancer. In order to investigate the effects of such a protocol on colonic anastomotic healing, an experimental study resembling the clinical use of neo-adjuvant concomitant 5-FU+ irradiation treatment of colorectal cancer was conducted. MATERIALS AND METHODS: Seventy-one male Wistar rats were divided into three groups: a control group (I) underwent left colon resection and primary anastomosis (n = 20); a sham-treated group (II, n = 20); and a study group (III) which received fractionated irradiation to the whole pelvis to a total dose of 22 Gy, 5.5 Gy per fraction, in four consecutive days with linear accelerator and concomitant intra-peritoneal 5-FU (20 mg/kg/day) for five consecutive days. The last fraction of irradiation and the last injection were given four and three days before colonic resection and anastomosis, respectively. Within each group one-half of the animals were anesthetized on the third postoperative day and one-half on the seventh postoperative day. Abdominal wound healing, intraperitoneal adhesions, anastomotic complications, and anastomotic bursting pressure measurements were recorded. Following these measurements the anastomotic segment was resected for hydroxyproline content, myeloperoxidase activity, and histopathological evaluation. RESULTS: There were no differences in the abdominal wound healing, intraperitoneal adhesions, and anastomotic complications between groups. At three and seven days, the mean bursting pressures of the anastomoses were 36.5 mm Hg and 208 mm Hg in group I, 34.5 and 228 in group II, and 27 and 167 in group III, respectively (p < 0.01, group III vs both groups I and II on day seven). The burst occurred at the anastomosis in all animals tested on the third postoperative day, and one in group I (10%), none in group II, and four in group III (40%) on the seventh postoperative day. CONCLUSION: Preoperative pelvic fractionated irradiation and concomitant 5-FU delays anastomotic healing.

Sucralfate in the prevention of radiation-induced oral mucositis.

Radiotherapy-induced mucositis decreases the quality of life by impairing eating, swallowing, and talking and by disturbing sleep. Mucositis may also predispose to local and systemic infections and may cause interruption of radiotherapy course. We studied the efficacy of sucralfate suspension in the prevention and management of oral mucositis and pain during radiotherapy in a double-blind, placebo-controlled, randomized, prospective trial. Twenty-eight patients with head and neck cancer were included in the study. The patients were randomized to use either sucralfate mouth washing (n = 18) or placebo washing (n = 10) during irradiation. Oral mucositis and symptoms were assessed by the same physician using Radiation Therapy Oncology Group Acute Radiation Morbidity Scoring criteria. All patients developed varying degrees of radiation-induced mucositis. Grade 4 mucositis was not encountered in any patient. One patient had grade 1, seven patients grade 2, and two patients grade 3 mucositis in placebo group. In sucralfate group, nine patients each had grade 1 and grade 2 with no grade 3 mucositis. Patients in the sucralfate group experienced significantly lower degree of mucositis than placebo group (p < 0.05). Sucralfate mouth washing is beneficial in decreasing the intensity of radiation-induced mucositis and oral discomfort. It is cheap, easy to administer with no serious side effect, and may be routinely used in patients receiving head and neck radiotherapy.

The Role of Interleukin-1 Inhibitors on Acute Myeloblastic Leukemia Blast Proliferation; Future Potential for Biotherapy.

UNLABELLED: The effect of interleukin-1 (IL-1) as an autocrine growth factor on the proliferation of the acute myeloblastic leukemia (AML) blasts was studied. Bone marrow specimens were obtained from nine patients with different subgroups of AML. IL-1 receptor antagonist (IL-1RA) and IL-1 ß neutralizing antibody (IL-1ß NA) alone or in combination were added to the culture mediums of the AML blast cultures for the detection of their inhibitory effect on AML blast cell proliferation and colony formation. Average colony numbers in the IL-RA, IL-ßNA, and IL-IRA plus IL-IßNA included culture flasks, were 63.7 ± 21.5 %, 69.5 ± 19 %, 53.4 ± 23.7 %, respectively, as compared to those of the control (p < 0.01). Inhibition of colony formation by IL-IRA plus IL-IßNA was more prominent than by IL-IßNA alone (p < 0.01). No correlation between the inhibition of AML blast colony ormation and FAB AML subgroups was seen. RESULT: Both IL-1RA or IL-IßNA or in combination induced varying degrees of inhibition on blast colony formation. IL-I inhibitory molecules could be considered as an alternative therapy for AML in patients whose blast cells are sensitive to IL-1 inhibition.

Histological evaluation of colonic anastomotic healing in the rat following preoperative 5-fluorouracil, fractionated irradiation, and combined treatment.

There is a growing interest in neoadjuvant chemo- and radiotherapy as a treatment modality for colorectal cancer which could affect mechanical and biochemical parameters of anastomotic healing. This study investigated the effect of such protocols on colonic anastomotic healing by evaluating the histopathological parameters. One hundred and sixty male Wistar rats were divided into six groups: a control group (I, n = 20), a saline group (II, n = 30) which received 1 ml NaC1 intraperitoneally, a sham-irradiated group (III, n = 20), a 5-fluorouracil (5-FU) group (IV, n = 30), which received 5-FU (20 mg/kg) intraperitoneally for 5 consecutive days, an irradiated group (V, n = 40) which received fractionated irradiation to the whole pelvis to a total dose of 22 Gy, 5.5 Gy per fraction on 4 consecutive days, and a concomitant 5-FU + irradiation group (VI, n = 20) which received 5-FU as in group IV and irradiated as in group V. All groups underwent left colonic resection with primary anastomosis, and the last fraction of irradiation and the last injection were given 4 and 3 days before the operation, respectively. Within each group one half of the animals were killed on the third postoperative day and the other half on the seventh postoperative day. After the resection of the anastomotic segments, histopathological examination was evaluated. Apposition of the wound edges of the mucosa and the muscularis were not affected by the therapy. The level of granulocytes was high, inflammatory exudate and necrosis persisted, granulation tissue formation was delayed, and the levels of macrophages and fibroblasts were low. We conclude that colonic anastomotic healing can be affected by the administration of preoperative chemotherapy, irradiation, and chemoirradiation.

Platelet activation during the early neonatal period.

The first week of life is a time when hereditary or more frequently acquired factors lead to some important differences in the hemostatic mechanism of the newborn. It has been well known that ill neonates are prone to both hemorrhage and thrombosis. The aim of this study was to answer the question of whether there is a difference in platelet activation in healthy neonates during the first days of life that may contribute to both hemorrhage and thrombosis in the presence of additional pathologic insults. Platelet activation was determined with flow cytometry using monoclonal antibodies in 63 healthy children (29 neonates, 17 infants, and 17 older children). There was no significant difference in platelet activation among these three age groups (p > 0.05). In addition, platelet activation did not show any significant relationship to age, sex, mode of delivery, or blood bilirubin concentration (p > 0.05). It has been previously reported that platelet activation occurs at the time of birth. We could not find any evidence that healthy newborns during the first 3 days of life exhibit increased platelet activation. Further studies on platelet activation in ill neonates will help to clarify whether platelet activation plays a role in the pathogenesis of thrombotic and/or hemorrhagic disorders.

Effects of preoperative fractionated irradiation on left colonic anastomoses in the rat.

PURPOSE: Radiotherapy is frequently used as a (neo)adjuvant to surgery in colorectal cancer patients, and because such therapy could influence the integrity of the anastomosis, we decided to investigate the effect of preoperative irradiation on colonic anastomosis. METHODS: Seventy-two male Wistar rats, weighing 200 to 348 g, were divided into three groups: a control group (I) underwent left colon resection and primary anastomosis (n = 20); a sham irradiated group (II, n = 20); a study group (III) that received fractionated irradiation to the whole pelvis (anterior-posterior pelvic field), for a total dose of 22 Gy, 5.5 Gy per fraction, on four consecutive days with linear accelerator (n = 32). Four days after irradiation, both Groups II and III underwent the same operation as performed in Group I. Within each group, one-half of the animals were anesthetized on the third postoperative day and one-half on the seventh postoperative day. Abdominal wound-healing, anastomotic complications, and anastomotic bursting pressure measurements were recorded. Following these measurements, the anastomotic segment was resected for hydroxyproline content and myeloperoxidase activity. RESULTS: Irradiated animals had more pronounced weight loss during therapy. There were no differences with abdominal wound-healing, intraperitoneal adhesions, and anastomotic complications between groups. At days 3 and 7, mean bursting pressures of the anastomosis were determined at 36.5 and 208 mmHg in Group I, 34.5 and 228 mmHg in Group II, and 25 and 150 mmHg in Group III, respectively (P < 0.01 Group III vs. both Groups I and II on days 3 and 7). The burst occurred at the anastomosis in all animals tested on the third postoperative day and one in Group I (10 percent), none in Group II, and six in Group III (37.5 percent) on the seventh postoperative day. In addition, hydroxyproline content and myeloperoxidase activity was significantly lower in Group III. CONCLUSION: Although preoperative fractionated irradiation significantly decreased the anastomotic bursting pressure and more burst occurred in the anastomotic line on postoperative day 7, the clinical outcome was similar among the groups.