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S H Levitt

Publications and source records attributed to S H Levitt.

At least 19 recordsLinked to original sources
PubMed1992

The role of radiation therapy in Hodgkin disease: experience and controversy. The 54th annual Janeway Lecture: 1989.

BACKGROUND: Beginning in 1970, a series of patients with Hodgkin disease were treated at the University of Minnesota, after staging laparotomy, with radiation therapy (RT) for Stage I, II, and IIIA Hodgkin disease. This report is an analysis of the results of the treatment and of treatment modifications. METHODS: From 1970 to 1974, all patients were treated with standard RT. In 1975, an analysis of these patients indicated that patients with large mediastinal mass (LMM) and patients with Stage IIIA spleen-positive (IIIAS+) disease had a higher recurrence rates than patients without these factors. Subsequently, a schema of radical radiation therapy (RRT) was devised, which included low-dose lung RT for patients with LMM and low-dose liver RT for patients with IIIAS+ disease. RESULTS: Analysis of the results of the two treatments indicates that the use of low-dose lung RT in patients with LMM and low-dose liver RT in patients with IIIAS+ Hodgkin disease produced survival and recurrence-free survival results equivalent to those achieved by use of combined modality treatment (CMT) or chemotherapy (CT) alone. CONCLUSIONS: The use of RT with whole lung and liver irradiation for patients with LMM and IIIAS+ Hodgkin disease, respectively, produces results that are equivalent to those of CMT or CT alone with the advantage of a decreased incidence of second malignant neoplasms. In addition, patients who do not respond to initial RT have a greater chance of being saved with chemotherapy than do patients initially treated with CMT of being saved with RT. The authors suggest that radical RT is the treatment of choice for patients with LMM and/or IIIAS+ Hodgkin disease.

Adolescent↗
PubMed1992

Beta irradiation of recurrent ptergia: results and complications.

Although postoperative beta irradiation for prevention of pterygium recurrence is widely used, its complication rate has not been widely appreciated. Thirty-six patients underwent pterygium excision followed by irradiation with 90Sr to between 1600 and 5300 cGy (median 2400) in two to four fractions over 7 to 27 days. A median of three fields were used in each treatment course (range two to 10). Most patients had undergone previous treatment for their pterygia, including surgery alone (25 patients), or both surgery and irradiation (5 patients). Overall, recurrences developed in 10 eyes (28%). Recurrence occurred in one eye after re-irradiation (20%), compared to 9 of 31 (29%) previously non-irradiated eyes (p greater than 0.1). There was no association with number of excisions and recurrences, although all but 6 patients had undergone more than one excision. Thirteen patients (36%) developed complications including: epithelial defect or corneal thinning (3), symblepharon (5), cataract (4) and corneal ulceration (1). Complications developed in 4 of the 5 (80%) re-irradiated eyes compared to 9 of 31 (29%) previously non-irradiated eyes (p less than 0.05). The power of the statistical analysis was limited by sample size, but no significant association was observed between the development of complications or recurrences and total dose, number of abutting fields, number of previous surgical excisions or patient age, even when re-irradiated patients were excluded. Recently described calibration uncertainties with the 90Sr applicator may explain in part these complications. Alternatively, technical factors such as the number of fields or volume treated may play a role. Excessive complications and recurrences with the use of postoperative beta irradiation in this series emphasize the danger of re-treatment and the need for alternative safe and effective therapies.

Adolescent↗
PubMed1992

Increases in tumor response by pentoxifylline alone or in combination with nicotinamide.

Pentoxifylline (PENTO), a derivative of methylxanthine, has been reported to improve fluidity of red blood cells (RBC), and thus improve the flux of RBC through narrow capillaries. Additionally, PENTO increases 2,3-DPG levels in RBC, thereby increasing the O2 release from RBC. Nicotinamide (NA) has been known to increase tumor blood flow, reducing the hypoxic cell fractions in the tumors. The purpose of this study was to examine the effects of PENTO alone or in combination with NA (PENTO + NA) on the oxygenation and radio-response of FSaII murine fibrosarcomas of mice. We observed a significantly enhanced, radiation-induced growth delay of the FSaII tumors by the treatment of either single or multiple injections of PENTO. The combination of PENTO and NA further delayed the growth of tumors. The TCD50 of control tumors was about 56.6 Gy, whereas that of PENTO + NA treated tumors was about 31.9 Gy. Thus, TCD50 was modified by a factor of 1.8. PENTO + NA exerted no effect on the acute skin damage of C3H mice after local irradiation and the gastrointestinal death after whole body irradiation. However, PENTO + NA slightly increased the bone marrow death as demonstrated by the decrease in LD50(30) from 5.5 Gy to 5.2 Gy. The average pO2 in the saline-treated control group of FSaII tumors was 8 mmHg and it significantly increased to 19 mmHg in the PENTO + NA treated group (p less than 0.001). We concluded that the PENTO + NA treatment increased the radio-response of tumors by improving tumor oxygenation.

Animals↗
PubMed1992

Relationship between vascular thermotolerance and intratumor pH.

The changes in blood flow, intratumor pH, and clonogenicity of tumor cells after one and two heatings were studied in SCK tumors of A/J mice. When SCK tumors were heated at 42.5 degrees C for 1 hr, vascular thermotolerance promptly developed and peaked at 18 hr post-heating. The intratumor pH was 7.05 +/- 0.14 (mean +/- S.D.) in control SCK tumors of A/J mice, with a significant decrease (p less than or equal to 0.001) to 6.86 +/- 0.08 and 6.70 +/- 0.08 when heated for 1 hr at 43.5 degrees C and 44.5 degrees C, respectively. However, when the vascular thermotolerance was at its peak, heating at the same doses caused little change in the intratumor pH. When SCK tumors were heated for the first time at 44.5 degrees C for 1 hr and left in situ, the number of clonogenic cells significantly declined. Such a secondary cell death could be attributed to the deterioration of the intratumor environment ensuing from the vascular damage. When the tumor vessels were thermotolerant, however, virtually no secondary cell death occurred after heating.

Animals↗
PubMed1992

Lack of prognostic value of histopathologic parameters in Hodgkin's disease, nodular sclerosis type. A study of 123 patients with limited stage disease who had undergone laparotomy and were treated with radiation therapy.

The value of histopathologic parameters in predicting the long-term overall survival probabilities was studied in a series of 123 patients with pathologic stage IA, IB, IIA, IIB, or IIIA Hodgkin's disease, nodular sclerosis type who were treated with curative radiation therapy. The parameters that were studied included the relative proportion of atypical vs reactive cells, amount of eosinophils, presence of necrosis, degree of mitotic activity, intensity of different types of mesenchymal reactions, classification in three subtypes (ie, lymphocyte predominance, mixed cellularity, and lymphocyte depletion) or in two grades (ie, grades 1 and 2), and identification of the syncytial variant. For each parameter, the association with clinical risk factors was also analyzed. The results of this study show that there are no pathologic features that carry a significant predictive value of the overall survival.

Adolescent↗
PubMed1992

Increase in tumor oxygenation and radiosensitivity caused by pentoxifylline.

The effects of pentoxifylline (PTX), a drug commonly used for vascular disorders in humans, on the pO2 in SCK tumors of A/J mice and FSa-II tumors of C3Heb/FeJ mice as well as on the radioresponse of SCK tumors were investigated. When the host mice were injected intraperitoneally (ip) with 5 mg/kg PTX, the tumor pO2 increased slowly, peaked 20-50 min postinjection, and returned to its original level in 70-90 min. The magnitude of the increase in tumor pO2 varied markedly depending on the site and tumors. The magnitude of the changes in tumor pO2 after an ip injection of 25 or 50 mg/kg PTX was similar to that caused by 5 mg/kg PTX, but the pO2 tended to remain elevated longer with the higher dose of PTX. When the A/J mice bearing SCK tumors in the legs were injected ip with 50 mg/kg PTX and the tumors were X-irradiated 20 min later, the radiation-induced growth delay of the tumors was greater than that caused by X irradiation alone. The present study demonstrated that PTX is potentially useful for increasing the pO2 and the radioresponse of human tumors.

Animals↗
PubMed1991

Precooling prevents overheating of subcutaneous fat in the use of RF capacitive heating.

The usefulness of precooling subcutaneous tissue in the hyperthermic treatment of deep-seated human tumors with capacitive application of radio-frequency (RF) was investigated. A capacitive hyperthermia unit operated at 8 MHz of radiofrequency was used to heat deep-seated human tumors. The electrode surfaces were covered with flexible vinyl sheets and the space between the electrode and the vinyl sheets perfused with 0.4% saline. The temperature of the saline was controlled by circulating the saline through built-in heat exchangers. The depth of heating was controlled by pairing electrodes of different diameters. When subcutaneous fat was less than 1 cm thick, various deep-seated tumors could be heated to a therapeutic temperature without significant discomfort in the subcutaneous tissue as long as the skin was properly cooled with the cold saline bolus. However, the same cooling method could not prevent the occurrence of pain in subcutaneous tissue in obese patients. The pain usually developed when the temperature of subcutaneous fat 1-2 cm below the skin surface exceeded 42 degrees C. We observed that cooling the human skin surface with 10 degrees C bolus for 20 min could substantially lower the temperature of fat as deep as 2.0-2.5 cm. Therefore, when the subcutaneous tissue was precooled with 10 degrees C saline for 20 min or longer before heating, it was possible to prevent successfully the overheating of subcutaneous fat as thick as 2.0-2.5 cm and to raise the temperature of deep-seated tumors to therapeutic levels.

Adipose Tissue↗
PubMed1991

Improvement in RBC flux, acidosis and oxygenation in tumour microregions by Fluosol-DA 20%.

Using laser Doppler flowmetry, we investigated the effects of Fluosol-DA 20% on RBC flux in FSaII tumours and on RBC flux in normal skin of C3H mice. The RBC flux in tumours was significantly increased; however, the RBC flux in normal skin fluctuated only slightly after the treatment with Fluosol-DA 20%. Since an increase in RBC flux by Fluosol-DA 20% may facilitate the removal of acidic metabolites from the tumours, the effects of Fluosol-DA 20% on intratumour pH was also measured. We also measured intratumour pO2 after various dosages of Fluosol-DA 20% with carbogen inhalation. We concluded that the administration of Fluosol-DA 20% selectively increased the RBC flux in tumours compared to that in normal skin. Moreover, carbogen inhalation combined with increasing dosages up to 36 ml/kg of Fluosol-DA 20% effectively enhanced tumour oxygenation in FSaII tumours.

Animals↗
PubMed1991

Irradiation of the lymphatics in the primary treatment of breast cancer.

Irradiation is a local treatment which must be delivered to the appropriate areas, with appropriate dosage and careful attention to avoiding excess dosage to normal tissues. Despite the negative reports of meta analyses of randomized adjuvant radiation trials, there has recently been a renewed interest in local regional irradiation by a number of factors: adjuvant chemotherapy fails to affect the incidence of locoregional recurrences in patients with four or more positive nodes; the benefits in prospective randomized and non randomized trials of large numbers of patients who were not treated with chemotherapy are well documented; analysis of the Cuzick meta-analysis and the recent long-term reports of the CRC and Manchester studies have demonstrated that they are not reliable. Locoregional recurrences following adjuvant chemotherapy alone are in the chest wall, internal memory and supraclavicular areas. We recommend no nodal irradiation in node negative patients and internal mammary and supraclavicular irradiation in node positive patients. However, irradiation to the axilla is indicated in patients in whom the axilla has not been dissected, the nodes are large and/or the tumor has extended from the nodes into the axilla. 50 Gy target dose is to be delivered in 1.8-2.0 Gy fractions and an additional 10 Gy boost to areas with possible tumor invasion in more advanced cancers.

Breast Neoplasms↗
PubMed1990

Radiation oncology.

Explore the source record for details and available documents.

Breast Neoplasms↗
PubMed1990

Aneurysm, arachnoiditis and intrathecal Au (gold).

This report is a 20-year follow-up of 14 patients treated with external beam craniospinal irradiation and intrathecal gold (10-45 mCi) for medulloblastoma. Six of the patients died within 2 years of treatment from persistent disease. No patients are alive without complications. Six of eight surviving patients developed arachnoiditis and cauda equina syndrome within 5 to 10 years of treatment. Seven of eight survivors developed aneurysms and/or cerebrovascular accidents 9 to 20 years after treatment. Four of the cerebrovascular events were fatal. Intrathecal gold pools in the basal cisterns and cauda equina delivering an extremely inhomogeneous dose throughout the neuroaxis. Its use is discouraged.

Adolescent↗
PubMed1990

Curative radiotherapy for laparotomy-staged IA, IIA, IIIA Hodgkin's disease: an evaluation of the gains achieved with radical radiotherapy.

Between 1970 and 1983, 179 patients with pathologically staged IA, IIA, and IIIA Hodgkin's disease were treated with curative radiotherapy. From 1970 to 1974, patients were treated with standard extended or total nodal field irradiation (Treatment Group 1). Since 1975, because of the high prevalence of recurrences in patients with large mediastinal mass and/or hilar disease and/or splenic involvement (LMM &/or H+ &/or S+), treatment was modified to include low-dose lung irradiation within the mantle field for those patients with LMM &/or H+ and low-dose liver irradiation within the infradiaphragmatic field for patients with S+ (radical XRT). Patients who did not have those characteristics were treated with standard radiotherapy (standard XRT). A total of 122 patients were treated from 1975 to 1983 (Treatment Group 2), of whom 61 received radical XRT and 61 received standard XRT. An analysis was done to evaluate whether the progressive-improvement in outcome since 1970 at the University of Minnesota Hospital resulted from the contribution of modified treatment or from progressive improvement in treatment overall. There was a statistical improvement in recurrence-free survival (RFS) in Treatment Group 2 (Tr Gr 2) compared to Treatment Group 1 (Tr Gr 1), with 10-year RFS of 80% versus 57% (p less than 0.001 for time to event). The improvement in RFS was attributed to treatment modification consisting of radical XRT for those patients with LMM &/or S+. There was no change in RFS for those patients without LMM &/or H+ &/or S+ who were treated in Tr Gr 1 and Tr Gr 2, with 10-year RFS of 78% versus 86% (p = 0.29), respectively. However, treatment results for patients with LMM &/or H+ &/or S+ improved considerably in the radical XRT group. Comparing standard versus radical XRT, 10-year RFS was 36% versus 78% (p = 0.001), and 10-year OS was 72% versus 92% (p = 0.034). Patterns of relapse also changed for patients with LMM &/or H+ &/or S+ who were treated with radical XRT. Rather than showing a high frequency of intrathoracic recurrence as was seen in those patients with LMM &/or H+ &/or S+ after standard XRT, the relapse pattern was similar to patients without LMM &/or H+ &/or S+. Salvage treatment was well tolerated for patients who failed after radical XRT. Delayed, life-threatening effects, such as pulmonary and cardiovascular complications and SMN, were equivalent for patients in Tr Gr 1 versus 2, and for those who received standard and radical XRT.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗