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Biomedical subjects

B W Corn

Publications and source records attributed to B W Corn.

89 records · Page 5Linked to original sources
PubMed1993

Positional stability of sources during low-dose-rate brachytherapy for cervical carcinoma.

PURPOSE: A presumed advantage of high dose rate gynecologic applicators is the fixed relationship maintained between applicator and anatomic structures during the brief exposure. However, it has never been demonstrated that movement of applicators during low dose rate procedures is significant. Therefore, we assessed the magnitude of changes in positioning and attendant alterations in dosimetry which occur during LDR applications. METHODS AND MATERIALS: Fifteen consecutive cervix cancer patients who were treated with combined external beam and brachytherapy (Fletcher-Suit-Delclos applicator), agreed to have orthogonal pelvic radiographs prior to after-loading and following removal of Cesium-137 sources. RESULTS: The median duration of the insertion was 56.5 hours. The average shift was 3.0 mm. Detailed analysis of source movement showed the following changes in median dose (external plus implant): point A, 1.4%; point B, 1.7%; point P, 0.9%; bladder point, 1.9%; rectal point, 2.6%. CONCLUSION: The geometric relationships between the intracavitary gynecologic applicator and the target tissue as well as the critical structures can be adequately maintained throughout the course of a low dose rate implant. Source movement does not result in significant dose changes in terms of decreased cure rates or added complications. Thus, while rationale for high dose rate applicators continues to be proposed, maintenance of a fixed geometric relationship should not be an impetus for the selection of high dose rate intracavitary applicators when treating cervical tumors.

Adult↗
PubMed1993

The justification for a surgical staging system in endometrial carcinoma.

Three hundred and one patients with endometrial carcinoma who were surgically staged and treated postoperatively with irradiation at the Fox Chase Cancer Center or the Hospital of the University of Pennsylvania were retrospectively substaged by the 1988 FIGO staging system. For pathological stage I endometrial carcinoma, FIGO substage (IA/IB vs. IC) in addition to depth by thirds (< or = 2/3 vs. > 2/3), grade (1 or 2 vs. 3), age (< or = 60 vs. > 60), and type of postoperative irradiation (vaginal alone vs. external +/- vaginal) were predictive for 5-year cause-specific survival in univariate analysis. For all pathological stages, excluding IIIB and IV endometrial carcinoma, FIGO stage (I or II vs. III) in addition to depth by thirds (< or = 2/3 vs. > 2/3), grade (1 or 2 vs. 3), age (< or = 60 vs. > 60), and type of postoperative irradiation (vaginal alone vs. external +/- vaginal) were predictive for 5-year cause-specific survival in univariate analysis. Clinical stage (I vs. II or III) was not a significant predictor of outcome in univariate analysis. Multivariate analysis of the above factors revealed FIGO stage in addition to grade, age and depth by thirds to be independent predictors of outcome. In conclusion, the FIGO surgical staging system better predicts outcome compared with the prior clinical staging system, although the FIGO substaging needs refinement. Grade, age, and depth by thirds are equally important prognostic factors in addition to FIGO stage and can add to the predictive value of the current FIGO staging system.

Endometrial Neoplasms↗
PubMed1993

Lymphangiography as a staging tool for cervix cancer: limited value after hip arthroplasty.

Lymphangiography (LAG) is often used in the work-up of cervical carcinoma. A patient with a history of bilateral hip arthroplasty, who presented with Stage IIIB squamous cell carcinoma of the cervix, was sent for lymphangiography. The LAG was deemed suboptimal, most likely because of altered lymphatic drainage engendered by the previous orthopaedic procedures. As the American population ages and hip arthroplasty becomes more common, the value of LAG in such patients will need to be reconsidered.

Aged↗
PubMed1993

Effects of radiation therapy on adult brain behavior: evidence for a rebound phenomenon in a phase 1 trial.

Although radiotherapy (XRT) is a necessary course of treatment to prolong life expectancy in patients with many types of brain neoplasms, it has damaging effects that are little understood. We used a comprehensive neuropsychological battery to evaluate five patients with low-grade brain tumors prior to XRT and then at 3-month intervals up to 9 months postcompletion of XRT. We matched patients by age and education with six normal control subjects to assess baseline impairment. In intrasubject comparisons, we examined change over time postcompletion of XRT. In spite of varying locations of tumors, all patients showed deterioration in long-term memory at a mean of 1.5 months postcompletion of XRT. Patients also consistently demonstrated a rebound effect between means of 4.7 and 7.6 months post-XRT. We found no changes over time in working memory, attention, visuospatial processes, or on any other neuropsychological test with the exception of information-processing speed, which quickened over time. Functional measures of fatigue and mood did not correlate significantly with the long-term memory scores. Long-term memory appears sensitive to the proposed white matter changes thought to be the mechanism for the early-delayed effects of XRT. Our findings suggest a neurobehavioral model for studying the effects of XRT on brain functioning.

Adult↗
PubMed1992

Endometrial cancer with para-aortic adenopathy: patterns of failure and opportunities for cure.

PURPOSE: To examine the outcome of patients with advanced endometrial cancer whose para-aortic involvement was diagnosed pathologically or lymphographically. METHODS AND MATERIALS: Fifty patients from four institutions were treated between 1959 and 1990 with preoperative, post-operative, and primary radiotherapy. Para-aortic disease was diagnosed pathologically in 26 patients and lymphographically in the remaining 24 patients. Pathologically diagnosed patients underwent debulking of grossly involved nodes. All patients received external beam treatment through pelvic and para-aortic portals. Median prescribed dose to the pelvic and para-aortic fields was 50 and 47 Gy, respectively. Those treated with primary or pre-operative irradiation also received intrauterine brachytherapy. RESULTS: The actuarial 5-year disease-free survival was 46% for all patients. Para-aortic failure was significantly decreased among patients undergoing lymph node resection (13% versus 39%, respectively). Relapse-free survival and pelvic control tended to improve among patients receiving surgery plus irradiation in comparison to those treated by irradiation alone. Distant metastases were most common among patients with high grade lesions. CONCLUSIONS: Long-term disease-free survival is achievable in endometrial cancer patients with para-aortic lymphadenopathy who are treated with extended-field radiotherapy. Cure is mot attainable among patients with well differentiated, early clinical stage disease who receive combined modality treatment. Survival and local failure are similar for radiologically and pathologically diagnosed patients; however, para-aortic failure as a component of local failure was increased in patients who did not undergo surgical debulking of the adenopathy.

Adenocarcinoma↗
PubMed1992

Localized urethral tumors in women: indications for conservative versus exenterative therapies.

The objectives of this retrospective review were to evaluate patient and tumor characteristics, survival, patterns of failure and sequelae of therapy for women with urethral carcinoma. Primary urethral carcinoma was diagnosed in 33 women referred to the Washington University Medical Center and the Mallinckrodt Institute of Radiology, Radiation Oncology Center from November 1959 through June 1988. Treatment consisted of surgery alone in 6 patients, surgery and irradiation in 7, and irradiation alone in 20. Median followup was 4.7 years. The 5-year overall and progression-free survivals for all patients were 41% and 36%, respectively. Tumor location, size and T stage were predictive for survival. No patient with a lesion of greater than 4 cm. survived at 5 years if treated with irradiation alone, surgery alone or irradiation and nonexenterative surgery. Exenterative surgery plus irradiation was curative in 1 of 4 patients. Pelvic failures occurred in approximately 50% of all patients. Severe complications of therapy occurred in 30% of the patients treated with irradiation alone, 1 of 7 treated with surgery and irradiation, and 0 of 6 treated with surgery only. Surgery only or irradiation only may be curative in patients with lesions less than 2 cm. Larger lesions require a combination of surgery and irradiation.

Adult↗
PubMed1992

Radiotherapy for gynecologic malignancies.

This review highlights the curative potential of radiation in gynecologic malignancies. The controversies concerning the role of surgery in the management of bulky cervical cancer is discussed. Prognostic factors associated with improved pelvic control with radiation alone are described, particularly the bulk of pelvic disease, which is not accounted for in the current International Federation of Gynecology and Obstetrics staging system. The potential for integration of radiation and chemotherapy into the management of vulvar cancer to improve cosmesis and function as well as to reduce the risk of locoregional recurrence is described. The role of whole abdominal radiation in the management of advanced endometrial and ovarian cancers as well as the role of hyperfractionation to reduce acute morbidity of large abdominal fields is reviewed. Prognostic factors associated with locoregional and distant failure for endometrial cancer are outlined and the new pathologic staging system is critically analyzed. Finally, the treatment of vaginal cancer with radiation alone (external beam plus interstitial-intracavitary radiation) or surgery is reviewed and the prognostic importance of the present modifications to the vaginal staging system are emphasized.

Carcinoma in Situ↗
PubMed1992

Outcomes in low-risk babies treated with half-dose chemotherapy according to the Third National Wilms' Tumor Study.

PURPOSE: To determine whether the 50% dose reduction of all chemotherapeutic agents recommended for babies (less than or equal to 12 months of age) by the Third National Wilms' Tumor Study (NWTS-3) produced acceptable toxicity without sacrificing any survival benefit. MATERIALS AND METHODS: The 365 babies enrolled in NWTS-3 had tumors of varying histologies and stages. The present analysis was restricted to the 256 infants who had tumors of favorable histology, were free of metastasis at diagnosis, and received treatment according to NWTS-3 guidelines. RESULTS: Despite the recommended attenuation of drug doses observed in 75% of the chemotherapy courses received, outcomes for these babies were comparable to those obtained in older children given full doses of chemotherapy. Four-year survival rates for 256 babies with stages I (n = 199), II (n = 38), and III (n = 19) favorable-histology tumors were 96%, 95%, and 90%, respectively. The figures for 498 stage I, 342 stage II, and 373 stage III older children with favorable-histology lesions were 92%, 94%, and 91% in that order. There were no deaths from hematologic toxicity or infection among babies who received half-dose chemotherapy. The death rates for their older NWTS-3 counterparts was 1%. CONCLUSION: Less aggressive therapies advocated for babies in NWTS-3 provide acceptable levels of morbidity without compromising the excellent results previously reported for low-risk patients of all ages.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Is craniospinal irradiation required to cure children with malignant (anaplastic) intracranial ependymomas?

Between 1970 and 1989, 17 children with histologically malignant intracranial ependymomas received treatment at the University of Pennsylvania (Philadelphia, PA). Eleven were treated with prophylactic cranial or craniospinal irradiation plus a local boost (CS-XRT), five with local (L-XRT) irradiation only, and one was treated without (NRT) irradiation. With a median survival of 2 years and a median follow-up time for long-term survivors of 6.0 years, five of 11 patients who received CS-XRT are alive compared with none treated with L-XRT and none treated with NRT. Two-year actuarial survival rates are 40% (L-XRT) and 52% (CS-XRT). When examined for other factors, age and local radiation dose remain the most significant prognostic indicators of survival. The 2-year actuarial survival for children younger than 4 years at diagnosis is 20% compared with 83% for their older counterparts. Likewise, the 2-year survival for patients treated with local radiation doses over 4500 cGy was 55% compared with 0% for patients treated with lesser doses. To date there are a total of 28 recurrences. All have occurred with local components except for six (unknown) who died before the exact site(s) could be determined. There is no significant difference in the failure rates outside the original tumor bed in the three groups. These data suggest that local relapse remains the most significant component of failure. Because intrinsic and extrinsic factors such as age and radiation dose seem to be interrelated and at least as important as the use of craniospinal irradiation, the need for prophylactic treatment for children with anaplastic ependymoma could neither be substantiated nor refuted. The use of local radiation alone, however, should be restricted to carefully designed clinical trials in which meticulous pretreatment evaluation is performed, and vigilant posttreatment evaluation of the spine and brain is mandatory.

Brain Neoplasms↗
PubMed1991

Results of the 1989 Association of Residents in Radiation Oncology survey.

To assess a variety of issues concerning physician-trainees in radiation oncology, a survey was conducted by the Association of Residents in Radiation Oncology (ARRO). Ultimately, 70% of residents responded to the survey. The survey identified perceived strengths as well as shortcomings in training programs. We conclude that residents are generally satisfied with their training. Future surveys are planned to expand this important database.

Adult↗
PubMed1991

Significance of prone positioning in planning treatment for esophageal cancer.

The treatment of esophageal cancer is made difficult by the close proximity of the esophagus to the spinal cord and the requirement to treat the esophageal target volume to doses greater than or equal to 60 Gy while limiting the spinal cord dose to less than or equal to 46 Gy. By placing the patient in the prone position, the esophagus can be displaced away from the spinal cord. We explored the results of this commonly used technique on 16 patients who have undergone simulation in both supine and prone positions. Both AP and lateral orthogonal radiographs were obtained in both positions. The distance between contrast material in the esophagus and spinal cord was noted in at least four transverse planes through the thoracic esophagus on each of the 16 patients. These four transverse planes were located at 3 cm above the carina, at the carina, 3 cm below the carina and 6 cm below the carina. The mean displacement (+/- 1 SD) of the esophagus away from the spinal cord when the patient was in the prone position compared to supine at each of these levels was 1.3 (+/- 0.8) cm, 1.8 (+/- 0.9) cm, 1.8 (+/- 1.0) cm, and 1.9 (+/- 1.1) cm. The range of displacement for all 64 displacement determinations was 0 to 4.2 cm with a mean of 1.7 cm. To evaluate further the consequences of prone positioning on treatment planning and doses received to target volumes and critical structures, we performed 3-dimensional treatment planning with a patient in both prone and supine positions. The requirements were to achieve a tumor volume dose of 60 Gy while keeping the spinal cord dose below 46 Gy. Two types of conventional treatment plans were examined in prone and supine positions. A 6-field plan consisted of delivery of 40 Gy through a large 3-field beam arrangement followed by delivery of 20 Gy through a similar 3-field cone down. An 8-field plan involved the delivery of 30 Gy through AP/PA beams followed by a 3-field beam arrangement to 40 Gy and a subsequent 3-field cone-down for the final 20 Gy. Comparison of dose volume histograms revealed that the 6-field plan spared relatively more heart whereas the 8-field plan spared relatively more lung. Regarding the primary consideration of coverage of target volume with avoidance of spinal cord, prone positioning was superior to supine positioning whether 6- or 8-field arrangements were used.

Esophageal Neoplasms↗
PubMed1990

Irradiation-related ischemic heart disease.

An expectation for long-term survival has emerged among several groups of cancer patients treated with therapeutic irradiation (eg, Hodgkin's disease, early stage breast cancer). Therefore, the cardiovascular sequelae of thoracic irradiation have recently come under scrutiny. Animal models have demonstrated that cardiac irradiation can directly damage the myocardial microvasculature and can indirectly damage the coronary macrovasculature when coupled with cholesterol feeding. A clear association between thoracic radiotherapy and ischemic heart disease was observed among older clinical studies using radiotherapeutic techniques that are no longer optimal by today's standards. Such a relationship could not be confirmed in modern studies in which treatment factors (such as dose and volume of heart irradiated) were more carefully controlled.

Animals↗
PubMed1987

Differential effects of radical scavengers on X-ray-induced mutation and cytotoxicity in human cells.

The cytotoxic and mutagenic effects of X irradiation on a human lymphoblast cell line were examined in the presence of two radioprotective agents which modulate damage to DNA. The cells were treated with X rays alone or in the presence of either dimethyl sulfoxide or cysteamine. Surviving fraction and mutation to trifluorothymidine resistance (tk locus) and to 6-thioguanine resistance (hgprt locus) were measured. Survival was enhanced when the cells were irradiated in the presence of dimethyl sulfoxide; the D0 rose from 58 to 107 rad. However, at both genetic loci the induced mutant fractions were identical in the presence or absence of dimethyl sulfoxide. Survival was enhanced to a greater degree when the cells were irradiated in the presence of cysteamine; the D0 rose from 58 to 200 rad. Cysteamine also protected the cells from X-ray-induced mutation; the frequencies of X-ray-induced mutation at both the tk and hgprt loci were reduced by 50-75%. No protective effects were observed unless dimethyl sulfoxide or cysteamine was present during irradiation. These findings are discussed in terms of the hypothesis that, unlike for cell killing, radiation-induced mutagenesis in human lymphoblast cells is not mediated by the actions of aqueous free radicals, but rather by the direct effects of ionizing radiation.

Cell Line↗
PubMedDate not supplied

Endometrial cancer.

Carcinoma of the uterine corpus (endometrial cancer) remains the gynecologic malignant disease with the highest annual prevalence in the United States. The most common histologic type is adenocarcinoma, although more aggressive variants (e.g., papillary serous carcinoma and clear cell carcinoma) have been identified. Risk factors that are strongly associated with the development of endometrial cancer include tamoxifen therapy, obesity, and stimulation from unopposed estrogen (from exogenous sources or endogenously secreting ovarian tumors). The current staging system of the International Federation of Gynecology and Obstetrics is based on surgical-pathologic findings. Survival has been directly correlated with tumor stage in this staging system. The cornerstone of therapy is total abdominal hysterectomy with bilateral salpingo-oophorectomy. Pelvic and para-aortic lymphadenectomy may provide additional prognostic information but probably does not confer a therapeutic advantage. Moreover, such nodal dissections predispose to the development of complications, especially in women who subsequently receive pelvic irradiation. Other than surgical treatment, irradiation is the single most active therapy for endometrial carcinoma. In fact, some women who are not candidates for hysterectomy because of medical contra-indications can be cured with radiation alone. Adjuvant therapy following hysterectomy is based on patient- and tumor-related features that provided prognostic information for incidence and pattern of recurrence. Adjuvant treatment usually includes pelvic irradiation for selected patients. Current investigational strategies are directed at the role of whole-abdomen irradiation, extended-field irradiation, and systemic chemotherapy. The most active systemic agents include cisplatin, doxorubicin, paclitaxel, and progestins.

Antineoplastic Agents↗
PubMedDate not supplied

Performance status and age as independent predictors of survival among AIDS patients with primary CNS lymphoma: a multivariate analysis of a multi-institutional experience.

PURPOSE: There is limited information about the outcome of AIDS patients with primary central nervous system lymphoma treated with definitive irradiation. The purpose of this study was to determine factors associated with increased survival in such patients. METHODS: An analysis was performed of 163 patients with AIDS who were evaluated at nine urban hospitals. These patients were treated for primary central nervous system lymphoma after the establishment of a tissue diagnosis or on a presumptive basis after failing empiric treatment for toxoplasmosis. All patients were treated between 1983 and 1995 with radiotherapy (median dose-fractionation scheme = 3 Gy x 10) and steroids (> 90% dexamethasone). Because multiple fractionation schemes were used, prescriptions were converted to biologically effective dose according to the formula Gy10 = Total Dose x (1 + fractional dose/alpha-beta), using an alpha-beta of 10. RESULTS: Longer median survival times were associated with high Karnofsky performance status (KPS > or = 70 vs < or = 60: 181 vs 77 days), young age (< 35 vs > 35: 162 vs 61 days), and high total definitive irradiation doses (> 39 Gy10 vs < 39 Gy10: 162 vs 40 days). Tissue diagnosis, gender, race, number of lesions (solitary vs multiple), and the presence of other cancers did not influence outcome. In multivariate analysis, young age, high Karnofsky performance status, and the delivery of higher biologically effective doses of irradiation retained independent significance relative to the endpoint of survival. CONCLUSIONS: Even at urban tertiary medical centers, few AIDS patients with intracranial lesions undergo biopsies to establish a precise tissue diagnosis. Survival following definitive irradiation is strongly related to two pretreatment factors (young age, high performance status) and one treatment factor (total biologically effective dose of cranial radiotherapy). These variables should be considered in selecting patients for definitive irradiation and in designing future studies.

Acquired Immunodeficiency Syndrome↗