Irving A. Lerch

Intentions and outcomes in the radiotherapeutic management of epidemic Kaposi's sarcoma

The indications for and outcome of radiotherapy for 226 epidemic Kaposis sarcomas are reported. The overall likelihood of obtaining complete regression of tumor masses was 68%, although residual purple pigmentation remained in 20%. Local recurrence developed in 9%. The indications for treatment were not equally represented. Palliation of pain or improvement of the patients appearance were the most common indications for treatment. Kaposis sarcoma lesions do not all behave in a like manner. Best fit log-linear models of associations among the variables were derived. They demonstrated that the combination of treatment intention, anatomic site, and Karnofsky score predicted the short-term and long-term tumor response. The intention of treatment was closely linked to the anatomic site of treatment and in concert directly influenced outcome. The hosts Karnofsky score was an independent predictive factor, but had less impact on outcome than did site or intention. Our data demonstrate that case selection can markedly alter the observed response rate of epidemic Kaposis sarcoma to radiotherapy. This finding should be considered in future analyses of trials that test the efficacy of treatment for this disease.

Analysis of multiple prognostic factors in patients with stage IB cervical cancer: Age as a major determinant

To evaluate the prognostic importance of age in patients with Stage IB cervical cancer we reviewed the results of 131 patients treated between 1974 and 1985. Patients ranged in age from 25 to 87 (mean 48) and were followed for a median of 65 months. One hundred twenty-five patients had complete follow-up information for survival analysis. Patients were divided into two groups; Group A comprising 43 patients less than or equal to age 40 and Group B comprising 88 patients greater than age 40. Both Group A and Group B patients were comparable with respect to all covariables studied. The 5-year actuarial survival for the 125 patients studied was 80%, whereas that for Group A (42 patients) and Group B (83 patients) was 54% and 91%, respectively (p = .0001). The 5-year survival for 100 surgical patients was 79% and that for Group A (36 patients) and Group B (64 patients) was 53% and 90%, respectively (p = .0001). The 5-year survival for 25 patients treated with curative RT was 65% and that for Group A (six patients) and Group B (19 patients) was 42% and 90%, respectively (p = .005). Eighteen patients were treated with adjuvant RT following surgery and their 5-year survival was 69% with three out of nine Group A and nine out of nine Group B patients alive at 65 months (p = .004). In 18 patients with pelvic nodal involvement, the 5-year survival was 48% compared to 84% in patients with negative nodes (p = .007). The difference in survival at 5 years between Group A (nine patients) and Group B (nine patients) with positive nodes was 25% and 75%, respectively. Finally, there was an increase in both local and distant failure in Group A patients. Our data illustrate that age has a profound influence on survival in women with Stage IB cervical cancer independent of potentially confounding variables.

The prognostic significance of residual pigmentation following radiotherapy of epidemic Kaposi's sarcoma.

The response to radiotherapy of epidemic Kaposis sarcoma (EKS) is unusual in that irradiated regions are frequently left with a persistent purple stain, reminiscent of the color of the original tumor, but with no tumor mass. To date there are no published data to indicate whether the persistence of pigmentation can be predicted beforehand or if it has any prognostic import. We reviewed the response to treatment of 118 EKS lesions that were irradiated at New York University (NYU) Medical Center between 1981 and 1986. A total of 86 responded to treatment by complete clearance of the mass. Of these, 29 left residual purple pigmentation within the treatment portal, while 57 did not. Complete response (CR; without residual pigmentation) occurred more often in patients who had higher Karnofsky scores at the time of treatment. However, in terms of ultimate local control or survival, there were no differences between patients whose lesions cleared completely v those in whom pigmentation remained. We conclude that persistent pigmentation represents only a benign remnant of irradiated EKS and has no prognostic import.

Radiofrequency hyperthermia: The design of coil transducers for local heating

Simple and complex coils have been designed and built for use as radiofrequency transducers for local and regional hyperthermia. The heating from such coils is produced by currents generated in the dielectric by the electromagnetic field radiated from the coil elements. The heating rate profile, as a function of phantom depth, is dependent upon the size and geometry of the coil, its proximity to the dielectric, and the transducer current. Since the fields of simple pancake coils are inhomogeneous, either complex geometries or some method of smoothing is required. A simple solution is to move the coil over the region to be heated or to use multiple applicators. However, many satisfactory heating patterns have been derived for stationary coils designed to heat well-defined subcutaneous volumes to a depth of 3-5 cm. Thermometry studies in static saline-gelatin phantoms demonstrate extensive heating ranges and flexibility since the coils couple with the dielectric through air.

Patient immobilization with a low-temperature splint/brace material.

The authors describe a low-temperature plastic which is useful for the construction of immobilizing devices where beam orientation is critical.

Long‐term use of an isotope check source for verification of ion chamber calibration

A radioactive check source is recommended for operational and constancy checks of dosimetry systems used for the calibration of therapeutic x-ray generators, including linear accelerators. Eight years of data have been analyzed for two ion chambers (and their associated electrometers) irradiated at fixed geometry in such a device. These dosimetry systems have also been calibrated every 2 years at a single Accredited Dosimetry Calibration Laboratory. Our analysis suggests that when a check source is used, and the results are consistent, the interval between formal calibrations can be lengthened.

Adjustable compensators for whole-brain irradiation.

A compensator for use in irradiating the whole brain with parellel opposed lateral fields was made from a stack of thin tempered aluminum plates. This configuration gives a wide latitude of degrees of compensation and can accommodate a broad range of head sizes. Dosimetry studies indicate that overcompensation may be desirable to reduce the dose to the mid-coronal plane of the skull and scalp without seriously affecting the dose uniformity in the treatment volume.

Development of optical process for accessing three-dimensional patient topology.

A commercial optical system developed by Solid Photography, Inc., has been used to generate precise paraffin--polyethylene tissue compensators. A program with the objective of constructing a medical facility has been undertaken to access patient topology for treatment planning, tissue-compensator fabrication, and patient positioning verification on the treatment table. Currently, patients are taken to a specially equipped studio where a series of microprocessor-controlled reticles are projected on the surface to be analyzed and photographs are taken automatically for computer processing. The topology data then drives a machine tool to sculpt the tissue compensators and may be transmitted via acoustic-coupled terminals to a treatment-planning computer at the Medical Center. The tissue compensators have been found to conform accurately to patient contours. At present, data bases can be generated to accommodate volumes of approximately 70,000 cm3.

Electronic communications and collaboration: the emerging model for computer aided communications in science and medicine

Abstract In the industrial northern hemisphere, the advent of computer-aided communications (CAC) and office automation has provided physicians and scientists with the tools to quickly and accurately obtain information, computer resources, communications, and administrative support. Databases such as those offered by the National Library of Medicine and commercial vendors, once available only through librarian services, are now routinely accessed by individuals, greatly increasing the rapidity and accuracy of literature searches. Formal computer networks such as ARPANET and the emerging university system, BITNET, are being supplemented by a spectrum of host facilities available at reasonable cost via packet-switching utilities. This has greatly facilitated the exchange of information and data among and between individuals and institutions in North America and Western Europe. The enhanced sophistication and declining cost of mid- and micro-hardware and software, has led to the emergence of local, regional, and national networking and sharing of facilities. The promise for the future is that of a global network of interconnected communities provided that certain intractable technical and fiscal problems can be solved.

Assessment of the irradiated brain by quantitative computerized tomography scan analysis—II. Application in studies of the necrotic and edematous braint

Abstract In this second part of a 2 part report, the authors present clinical application of the methods developed in Part I, a quantitative analysis of brain parenchyma and ventricular volume. Part II presents computerized tomography (CT) studies and histogram analyses of a patient with cerebral edema and 2 patients with autopsy proven radiation necrosis. Preliminary data from CT number frequency distributions for normal, edematous and necrotic brain suggest that while reversible and irreversible changes in brain tissue may not be separable on evaluation of brain parenchyma alone, quantitative analysis of CT numbers for cerebrospinal fluid in large numbers of patients may provide the basis for differentiating degrees of radiation damage.