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S H Levitt

Publications and source records attributed to S H Levitt.

At least 19 recordsLinked to original sources
PubMed2001

The rush to judgment: Does the evidence support the enthusiasm over three-dimensional conformal radiation therapy and dose escalation in the treatment of prostate cancer?.

PURPOSE: To discuss the assumptions behind and current clinical evidence on three-dimensional conformal radiation therapy (3D-CRT) and dose escalation in the treatment of prostate cancer. METHODS: We first define 3D-CRT in comparison to standard radiation therapy and discuss the assumptions on which the technology of 3D-CRT and dose escalation are based. We then examine the evidence on the benefits and limitations from the current most commonly cited studies on dose-escalation trials to treat prostate cancer. RESULTS: The assumption that 3D-CRT can provide a tighter margin around the tumor area to allow for dose escalation is not yet proven by studies that show continual difficulty in defining the planning treatment volume because of extrinsic and intrinsic difficulties, such as imaging variabilities and patient and organ movement. Current short-term dose-escalation studies on the use of 3D-CRT to treat prostate cancer are limited in their ability to prove that increasing dose improves survival and does not incur potential long-term complications to normal tissue. CONCLUSION: Although 3D-CRT is a promising technology that many radiation oncologists and clinics are quickly adopting to treat such tumors as prostate cancer, the long-term evidence on the benefits and limitations of this technology is still lacking. Until we have solid long-term evidence on the true clinical potential of this new technology, let us not rush to judgment, but exercise caution, diligence, and thoughtfulness in using this new technology to treat our patients.

Clinical Trials as Topic↗
PubMed2001

Radiation oncology: contributions of the United States in the last years of the 20th century.

The advancements in radiation oncology in the past 50 years in the United States were probably more dramatic than those in the first half of the 20th century. Not only were there major technical achievements, but there was also an associated increase in the overall cure rates of cancer, from 20% at 5 years 50 years ago to now nearly 60% at 5 years. The cure rates in selected tumor sites at 5 years in 1950 and in 2000, respectively, were as follows: breast, 50% and 80%; colon and rectum, 40% and 85%; lung, 5% and 15%-20%; prostate, 40% and 80%; Hodgkin disease, 50% and more than 90%; cervix, 40% and 70%-80%; uterus (endometrium), 80% and more than 90%; bladder, 30% and 50%; head and neck, 30% and 60%; and esophagus, 2% and 15%. Much of this has been due to a broader array of techniques in radiation therapy available for treatment but also because of new emphasis on combined integrated modalitities (surgery, radiation therapy, and chemotherapy). New imaging techniques have contributed substantially, allowing better selection of patients for treatment and better selections of treatment modalities.

Combined Modality Therapy↗
PubMed2000

Impact of managed care on scholarly activity and patient care: case study of 12 academic radiology and radiation oncology departments.

Six departments of radiology and six departments of radiation oncology from areas with low, medium, or high managed care penetration were asked to complete a questionnaire designed to address the impact of managed care on research and scholarly activity. Information, when available, was taken from fiscal years 1993 and 1998. Questionnaires were followed by site visits to the 12 departments. The study showed that departments with medium to high managed care penetration reported more dissatisfaction in their ability to remain active in their education and research goals. Results indicated that for the period surveyed, the departments needed to increase clinical time to make up for decreasing patient care revenues. In turn, this has reduced the time and money devoted to scholarly activities. Information from this study will be used to develop a trends database for all U.S. radiology and radiation oncology departments. This, together with a more comprehensive study by the RSNA, will assist in measuring the current and potential long-term impact of managed care and other system changes on the practice of radiology and radiation oncology.

Academic Medical Centers↗
PubMed1999

Cost-benefit analysis of 3D conformal radiation therapy--treatment of prostate cancer as a model.

Three-dimensional conformal radiation therapy (3D-CRT) is a promising new treatment technique based on the principle that improved precision in both tumor definition and dose delivery will enhance outcomes by maximizing dose to the tumor area while minimizing dose to normal tissue. Using a cost-benefit analysis, in terms of outcomes, we first examined the overall risks and benefits of 3D-CRT. We then used the treatment of prostate cancer as a model to compare actual clinical outcomes reported between 3D-CRT and standard radiation therapy (SRT). Our analysis shows that application of 3D-CRT to the clinical setting remains difficult because of the continual difficulties of target definition, and that dose escalation cannot yet be justified on the basis of the lack of benefit found, and suggested increased late toxicity, in most of the dose escalation series compared with SRT.

Cost-Benefit Analysis↗
PubMed1998

Adjuvant therapy of breast cancer--an overview.

Adjuvant therapy in the treatment of breast cancer commonly refers to therapies that supplement primary treatment, traditionally mastectomy and, more recently, breast-conserving surgery. The present paper examines the evolution of systemic therapies and radiotherapy in their role as adjuvants to mastectomy, and offers a brief description of current treatment regimens for early and locally advanced disease.

Antineoplastic Agents↗
PubMed1998

The management of metastatic squamous cell carcinoma in cervical lymph nodes from an unknown primary.

A patient is diagnosed with an unknown primary of the head and neck when metastatic disease is present in the cervical lymph node or nodes and no primary lesion is detected by thorough physical examination, directed biopsies of suspicious or most likely primary sites, and imaging studies. The optimal management of patients who have this syndrome is still unclear and controversial. We report our results and analysis of the management of 24 patients with this syndrome. From 1976 through 1992, 24 patients who had metastatic squamous cell carcinoma in the cervical lymph nodes were seen in our medical center. A thorough search did not detect a primary lesion in any of them. Patients underwent radical neck dissection of the involved neck; 23 had unilateral and I had bilateral neck disease. Postoperative radiotherapy was delivered to both sides of the neck and to the potential primary mucosal and submucosal sites. The relation between clinical N stage, histologic findings of numerous involved lymph nodes, presence of extracapsular tumor extension, and survival were statistically analyzed. The Kaplan-Meier method was used for the survival analysis. The p values of log-rank test for the comparison of the two groups 1) N1 and N2 versus N3, and 2) presence of extracapsular tumor extension versus its absence are less than 0.005, with extracapsular tumor extension versus nonextracapsular tumor extension slightly smaller. The 5- and 10-year disease-free survival rate for the entire group was 54.2% (70.5% for N1 and N2, and 14.2% for N3). Three patients had locoregional failure, two in the primary sites, one in the nasopharynx, and the other in the oropharynx (the latter also had recurrent disease in the undissected neck). In 8 patients, distant metastases developed 7 to 38 months after radiotherapy. All 11 patients (45.8%) who had recurrent disease had advanced clinical N stage, microscopic findings of numerous involved lymph nodes, and prominent extracapsular tumor extension to the surrounding soft tissue and blood vessels. The high incidence of distant metastases shortly after treatment suggests a hematogenous spread before treatment in patients who had extensive nodal and extranodal disease. Our long-term disease-free survival beyond ten years seems to indicate combined treatment modalities, including radical neck dissection with postoperative radiotherapy of the neck, and the potential primary site in patients with N2 and N3 disease (our N1 group is too small for analysis). Further improvement of cure rate can be expected in the future with early detection and treatment.

Aged↗
PubMed1998

The role of radiotherapy in the management of carcinoma in situ of the glottic larynx.

Carcinoma in situ of the glottic larynx is a rare malignancy, comprising only 1% to 2% of laryngeal biopsy. The management of these lesions remains controversial. In this article, the authors present results and analysis of the management of 20 patients having these lesions treated by radiotherapy. A total of 20 patients who had carcinoma in situ of the glottis were treated with curative intent with radiotherapy at the Veterans Administration Medical Center, Minneapolis, Minnesota, U.S.A. from November 1972 through March 1993. Before radiotherapy, eight patients had only biopsies of the glottic larynx, five had one stripping procedure, and seven patients had two or three stripping procedures. Of the 20 patients, 19 are available for retrospective analysis, with a minimum follow-up of 4 years and a median follow-up of 7.3 years. Treatment was given to all patients by megavoltage units (cobalt 60, 2; 4-mV linear accelerator, 18). Patients were treated using bilateral opposed wedged 6-cm x 6-cm fields, with a dose of 1.75 Gy per fraction to a total median dose of 68.4 Gy in 40 fractions over 56 elapsed treatment days. The Kaplan-Meier method was used for survival analysis. The 4-year disease-free survival was 95% after irradiation. The actuarial disease-free survival for 5 and 10 years was 95%. Surgical salvage failed in one patient who had a laryngectomy for recurrent invasive squamous cell carcinoma at 34 months after radiotherapy. Two patients developed severe shortness of breath because of laryngeal edema, which required tracheostomy. Sixteen patients reported subjective significant improvement of their voice quality, and four reported no change. Radiotherapy is an excellent choice for patients who have recurrent carcinoma in situ after undergoing stripping procedures or for those patients who live too far from a medical facility to allow close follow-up and repetitive surgical procedures. These results are comparable to those of other investigators who used radiotherapy with higher dose per fraction.

Adult↗
PubMed1998

Curative radiotherapy for stage II-III squamous cell carcinoma of the glottic larynx.

The authors report the analysis and outcome of curative radiotherapy for stage II and III squamous cell carcinoma of the glottic larynx. Thirty-nine men with invasive, previously untreated squamous cell carcinoma of the glottic larynx were referred for curative radiotherapy from May 1976 through June 1991, to the Veterans Administration Medical Center in Minneapolis, Minnesota, U.S.A. Thirty-eight patients had T2N0 disease, and one had T2N1 disease. All patients were treated by megavoltage units (two by cobalt 60 and 37 by 4 mV-linear accelerator). The median fractional dose was 1.80 Gy, and the median total tumor dose was 70.20 Gy. Surgical salvage was reserved for irradiation failure. All patients had a minimum 5-year follow-up. The Kaplan-Meier method was used for survival analysis. The 5-year disease-free survival with voice preservation after radiotherapy was 70.2% (80% for T2a and 64% for T2b patients). The ultimate 5-year disease-free survival for all T2 patients after surgical salvage was 91%. In nine patients, ten second primary malignancies were diagnosed during follow-up. Nine of these second lesions occurred in the aerodigestive tract. Curative radiotherapy using conventional fractionation regimen with surgical salvage for irradiation failure is an efficacious modality for T2N0 and T2N1 squamous cell carcinoma of the glottic larynx. A high incidence of second malignancy was noted in our series.

Aged↗
PubMed1997

External beam radiation therapy for squamous cell carcinoma of the soft palate.

PURPOSE: External beam radiation therapy for carcinoma of the soft palate aims to achieve loco-regional control with normal speech, nasal function, swallowing mechanism, and minimal side effects such as nasal speech and regurgitation of food into the nasopharynx. In this report we present our results of radiotherapy in the treatment of 24 patients with squamous cell carcinoma of the soft palate. METHODS AND MATERIALS: A total of 24 patients with squamous cell carcinoma of the soft palate were treated at the Veterans Administration Medical Center Minneapolis, MN, between February 1977 and May 1992. Of the 24 patients 2 had T1, 19 T2, 1 T3, and 2 had T4 lesions. Nineteen patients did not have clinical nodal disease, stage (N0), 1 had N1, 2 N2, and 2 N3 disease (Table 1). All the patients were treated by 4 MeV linear accelerator. A 1.75 Gy median dose was administered per fraction to a total of 70 Gy median dose. Bilateral opposed compensated shrinking fields technique was used. RESULTS: The 3-year disease free survival rate after external beam radiation therapy was 100% (1 out of 1), 64.7% (11 out of 17), 100% (1 out of 1), and 0%, for patients with T1, T2, T3, and T4 disease, respectively. Salvage surgery for recurrent disease was successful in 57.1% (4 out of 7 patients (Table 2). The ultimate 3-year disease free survival rate for the entire group, including surgical salvage, was 81% (17 out of 21) (Fig 1). CONCLUSION: Radiation therapy alone in our institution resulted in tumor control and survival rates compare favorably to previously published reports in the literature. Surgery can be reserved as salvage procedure.

Aged↗
PubMed1997

Cost-benefit analysis of 3D conformal radiation therapy.

BACKGROUND: The potential of 3D conformal radiation therapy to improve the efficacy of radiotherapy is one of the most important technical advances in recent years. The potential benefit of improved local control from dose escalation must be weighed against the potential cost of increased complications to normal tissue. METHOD AND RESULTS: We evaluated the cost-benefit of 3D conformal radiation therapy in terms of the benefit to tumor cure weighed against the cost of complications to normal tissue. Assessment of current data shows that problems remain in adequately defining variables that contribute to both the tumor cure probability (benefit) and normal tissue complication probability (cost). For tumor cure probability, identifying the dose escalation needed for cure for the most tumor sites as well as precisely defining tumor volume remain problematic. For normal tissue complication probability, inadequate clinical data on toxicity to normal tissue for different tumor sites continue to make it difficult to use methods that estimate complications, such as dose-volume histograms as proposed by Lyman, to the clinical setting. CONCLUSION: 3D conformal radiation therapy is a promising new technology that may substantially improve the efficacy of radiation therapy. More clinical research, however, is needed to recognize the costs and benefits of this new technology: 1. Tumor control probability: More information is needed on the accurate definition of the target volume as well as on the amount of radiation necessary to cure different tumor sites. 2. Normal tissue complication probability: Methods for determining toxicity to normal tissue are needed. Current calculations based on various models are insufficient.

Cost-Benefit Analysis↗
PubMed1996

Radiation therapy in early carcinoma of the glottic larynx T1N0M0.

PURPOSE: The Purpose of this report is to present the local control rate and survival of patients treated by radiation therapy for T1N0M0 squamous cell carcinoma of the glottic larynx. METHODS AND MATERIALS: A total of 41 patients with squamous cell carcinoma of the glottis were treated at the Veterans Administration Medical Center Minneapolis, MN, between 1976 and 1990. Of the 41 patients, 40 are available for retrospective analysis with a minimum of a 2-year follow-up and a median follow-up of 5.8 years. Treatment was given to all the patients by a 4 MeV linear accelerator. The vast majority of the patients were treated with bilateral laryngeal opposed wedged 6 x 6 cm fields with a dose of 1.75 Gy per fraction to a total of 70 Gy in 40 fractions over 56 elapsed treatment days. RESULTS: The data indicated local control and survival of 92.3 % at 2 years and 91.8 % at 3 years, post irradiation, with ultimate disease-free survival after surgical salvage of 97.4 % and 97.2 % at 2 years and 3 years, respectively. These local control and survival rates are comparable to those published in the literature when a higher fractional dose was given. No patients developed notable complications with our technique. CONCLUSIONS: A dose of 1.75 Gy to 1.8 Gy per fraction to a total of 70 Gy in 56 elapsed treatment days is well tolerated and yields ultimate disease free-survival of 97.2% at 3 years. This time-dose fractionation could be used safely for treating patients who demonstrate low tolerance to irradiation with a risk of laryngitis, laryngeal edema, or difficulty of swallowing, with a higher fractional dose.

Adult↗
PubMed1996

Delayed/salvage radiation therapy in patients with elevated prostate specific antigen levels after radical prostatectomy. A long term follow-up.

BACKGROUND: In this article the authors report an analysis and long term results of delayed/salvage radiation therapy administered to asymptomatic patients who had an elevated prostate specific antigen (PSA) level, many months to many years after radical prostatectomy. METHODS: During 1987 to 1990, 40 asymptomatic patients were found to have an elevated PSA level 9 to 96 months after radical prostatectomy. The patients underwent transrectal needle aspiration biopsy of the urethrovesicle junction anastomosis (uvj); 28 patients had a positive biopsy and 12 patients had a negative biopsy. Delayed/salvage radiation therapy was administered to the pelvis (45 Gray [Gy]) and prostate bed (59.5 Gy), including the uvj. RESULTS: Twenty-four of 37 patients (65%) were free of clinical disease. In 10 patients (27%), the radiation therapy resulted in a durable decrease in the elevated PSA level below a detectable level for a minimum 5-year follow-up. Five patients were alive with clinical disease. Eight died of disease. Three patients were lost to follow-up. CONCLUSIONS: This experience shows that delayed/salvage radiation therapy to the pelvis (45 Gy) and prostate bed (59.5 Gy), even many years after radical prostatectomy for pathologic stage pB, pC, and pD1 carcinoma of the prostate, was well tolerated and provided freedom from clinical disease in 24 of 37 patients (65%), and a decrease in elevated PSA level in 10 patients (27%). Delayed/salvage radiation therapy appears to be beneficial for patients who had undergone radical prostatectomy only and then developed rising PSA levels during the follow-up period.

Anastomosis, Surgical↗
PubMed1996

The impact of radiation on early breast carcinoma survival. A Bayesian analysis.

BACKGROUND: A Bayesian statistical approach was used to examine the effect of local control on survival of patients with early breast carcinoma. METHODS: The effect of radiation on overall survival was examined in the four published randomized trials on conservation surgery with or without radiation: the Uppsala-Orebro, Canadian, NSABP-B06, and Milan III trials. Classical and Bayesian statistical approaches were used to evaluate the effect of sample size and follow-up on the results. RESULTS: Combined 5-year survival results of patients with negative lymph nodes and surgical margins in the Uppsala-Orebro, Canadian, and NSABP-B06 trials indicated a 79% probability of a positive benefit with the addition of radiation and a 9.6% relative reduction in the annual mortality rate in favor of the irradiated patients. For the same subgroup of patients in the NSABP-B06 trial, the probability of a positive benefit with radiation increased from 65% at 5 years to 87% at 10 years, and is reflected in the change of the relative reduction in annual mortality from 8.2% at 5 years to 17.5% at 10 years. For all patients who accepted randomized treatment in the NSABP-B06 trial, the probability of a positive survival benefit with radiation was 80%, 98%, and 91% at 5, 10, and 12 years, respectively, with corresponding relative reductions in the annual mortality rates of 12.8%, 20.5%, and 15.2%. CONCLUSIONS: The addition of radiation to lumpectomy offers a small but important survival advantage, even in patients with negative surgical margins and lymph nodes. Because locoregional control and breast preservation are significantly improved with radiation, even a small survival advantage substantiates the importance of radiation in the treatment of patients with early breast carcinoma.

Bayes Theorem↗
PubMed1996

Long-term follow-up of pathologic stage I large cell non-Hodgkin's lymphoma patients after primary radiotherapy.

The purpose of this study was to examine the long-term outcome of Stage I large-cell non-Hodgkin's lymphoma patients treated with primary radiotherapy and to assess the potential influence of these results on the development of future treatment protocols for non-Hodgkin's lymphoma. Between April 1970 and July 1983, 15 pathological Stage I and four pathological Stage II large cell lymphoma patients were treated with primary radiotherapy at the University of Minnesota Hospital and Clinics. This paper focuses on the long-term outcome of the 15 Stage I patients. As of March 1995, with a median survival of 171 months, five of the 15 Stage I patients are alive: four with no sign of lymphoma and one with recurrence and a secondary malignant neoplasm (SMN). Estimated 5- and 10- year recurrence-free survival rates are 86% and 78%, respectively. Overall survival at 5 years is 80% and at 10 years, 67%. Six patients developed SMNs, all of which were solid tumors. Ten of the 15 patients died: four from SMNs, three from non-Hodgkin's lymphoma, and three from other causes without recurrence (two died of cardiovascular disease and one of a pulmonary embolism). Deaths due to lymphoma in pathologic Stage I patients treated by radiotherapy alone have not changed significantly since our last report in 1985; however, deaths due to SMNs have increased. To provide optimal treatment for early non-Hodgkin's large-cell lymphoma, examination of the long-term treatment risks provides useful information for newer treatment regimens that do not yet have long-term treatment outcomes available.

Adult↗