The significance of fractionation regimens in radiation and combined hyperthermia using a murine fibrosarcoma

The significance of time-dose relationships in the use of local tumor hyperthermia (LTH) when combined with radiation (RAD) was studied in a murine fibrosarcoma. RAD, either alone or combined with LTH, was delivered in four equal fractions (total doses, 1.8 to 4.2 krad) separated by 1 to 4 days. LTH (43.1 C +/- .05 C for 15 minutes, water bath) was applied immediately after RAD. In this tumor system, RAD was most effective when delivered every 2nd or 3rd day, by a factor of 1.25 over the response achieved when the four fractions were delivered every 1 or 4 days. At all levels studied, RAD + LTH produced a superior tumor response compared to RAD alone. The ratio of the RAD + LTH/RAD doses to achieve an isobiological response ranged from 1.7 to 2.5. Most significant was the finding that the RAD + LTH treatment response was independent of the fractionation scheme used and more dependent on the total RAD dose delivered.

Radiation-induced soft-tissue and bone sarcoma

From the records of Memorial Hospital of the past 50 years, 47 cases with an established diagnosis of radiation-induced sarcoma were identified and divided into two groups: the first included 20 cases of soft-tissue sarcoma arising from irradiated tissues, and the second comprised 27 cases of bone sarcoma arising from normal bones in the irradiated field. Medians for the latent periods from irradiation to diagnosis of bone and soft-tissue sarcoma were 11 and 12, years, respectively. In bone sarcomas, the latent period was longer after larger radiation doses and children appeared to be more susceptible to cancer induction than adults. Criteria for establishing the diagnosis of radiation-induced sarcoma and the magnitude of the risk of bone sarcoma are discussed.

Multiple adjuvant therapy on a murine fibrosarcoma: actinomycin-D, X-irradiation and local tumor hyperthermia

The tumoricidal activities of single dose x-irradiation (RAD) and concomitant Actinomycin D (AMD) with or without local tumor hyperthermia (LTH) on an in vivo Methylcholanthreme-induced fibrosarcoma (Meth-A) are described. The addition of LTH enhanced the actions of AMD, RAD and AMD + RAD; the trimodality treatment was most effective. Based on delay of tumor growth, the radiation dose reduction factors for AMD + RAD + LTH compared to RAD; AMD + RAD + LTH, were approximately 2.8, 2.1, and 1.8, respectively. The shape of the curves suggests a further decrease in the ability of the tumor cell to repair sublethal damage with AMD + RAD + LTH. The clinical relevance is not determined.

Selective potentiation of hyperthermic killing of hypoxic cells by 5-thio-D-glucose

The modification of cell lethality at elevated temperatures by 5-thio-D-glucose, the nearest analog of D-glucose was studied with the use of HeLa cells in the presence or absence of oxygen. When the cells were exposed to temperatures ranging from 40.5-42 degrees for 0.5 to 4 hr in the presence of 5-thio-D-glucose (5 mM), there was a selective potentiation of hyperthermic killing of hypoxic cells. No enhanced killing of oxic cells by 5-thio-D-glucose was seen at these temperatures. These results indicate that glucose metabolism may be involved in influencing the heat sensitivity of hypoxic cells. The low toxicity of 5-thio-D-glucose and its specificity to hypoxic cells suggest that it may be a useful adjuvant to hyperthermic therapy.

Electron-beam therapy for mycosis fungoides

The lesions of mycosis fungoides are radiosensitive and because extensive areas of the body are usually involved, the treatment of choice is with the electron beam. Since 1971, a fractionation scheme of weekly doses for irradiation of the entire skin surface has been practiced with a 6 MeV linear accelerator that generates 3.5 MeV electrons. One hundred and five patients were treated in this way by delivering 400 rads once weekly for six consecutive weeks. All patitents enjoyed complete disappearance of the skin lesions at once. Of the 62 patients whom we were able to follow-up after electron-beam therapy, for periods ranging from one to nearly seven years (median, two years), the duration of remission was one-half to nearly five and a half years (median, one and one-half years). The treatment was well tolerated and no unusual skin reactions or hematopoietic depression occurred.

Combination hyperthermia and radiation therapy for cutaneous malignant melanoma

The clinical studies were carried out to evaluate whether radiation combined with hyperthermia would evoke better local tumor control than that achieved with radiation alone. Using an inductive method of radiofrequency heating at 27.12 MHz and radiation therapy, 37 lesions in 14 patients were treated with heat alone, radiation alone and heat in combination with radiation. In patients who completed the planned course of the combined therapy with an adequate follow-up period of more than six months, 16 out of 18 lesions (in 9 patients) had a complete response, whereas only 1 out of 8 lesions (in 5 patients) had a permanent regression after radiation alone. The amount of radiation dose necessary to achieve a satisfactory tumor control in combination with radiofrequency heating has been 3000 rad (300 rad X 10 in 4 weeks) to 3200 rad (400 rad X 8 in 4 weeks). Importance of the temperature measurements of both tumor and the adjacent normal tissue is discussed.

5-Thio-D-glucose selectively potentiates hyperthermic killing of hypoxic tumor cells

To investigate the mechanisms by which heat affects cancer cells, we used 5-thio-D-glucose, an inhibitor of glycolysis in HeLa S-3 cells, under aerobic and hypoxic conditions at temperatures ranging from 37 degrees to 43 degrees C. Drug alone or heat alone killed a minimum number of cells under aerobic or hypoxic conditions. Exposure to drug and hyperthermia selectively increased the number of cells killed under hypoxic conditions at temperatures as low as 40.5 degrees C but had little effect on cells incubated under aerobic conditions. These results suggest that the glycolytic pathways is a primary site of hyperthermic damage leading to cell death.

Socioeconomic differentials in selected causes of death

The areal approach utilized in mortality analysis for cities in the past is argued to be fruitful for suburban mortality analysis as well. Through factor analysis of four Census Tract indicators, weighted scores were computed and socioeconomic groups were constructed for each central city and each suburban area for three selected metropolitan areas: Birmingham, AL, Buffalo, NY, and Indianapolis, IN. Mortality rates from Heart Diseases, Malignant Neoplasms, and All Other Causes of death were found to be inversely associated with socioeconomic status in both the central cities and the suburban communities of these selected metropolitan areas. Evidence points to increasing socioeconomic differentials between 1960 and 1970 especially for males for the central cities and for suburban rings in spite of reductions in mortality during this period.

Epidural spinal cord compression from metastatic tumor: diagnosis and treatment

The clinical findings in 130 conseucutive cases of spinal cord compression by metastatic extradural tumors were analyzed. These 130 patients were combined with a previous survey of 105 patients to compare the effectiveness of radiation therapy (RT) alone with that of surgical decompression followed by RT. Ambulation after treatment was considered a successful outcome. The most common primary tumors producing spinal cord compression were (in order) breast, lung, prostate, and kidney. In 68% of these tumors the thoracic region was involved. Pain was the primary symptom of 96% of the patients, while motor or sensory deficits (or both) were found in 82% of them. Therapy consisted of surgery and RT in 65 patients and RT alone in 170 patients. There were no differences in outcome between those treated by surgery combined with RT and those managed by RT alone. Patients with radiosensitive tumors and those ambulatory at the onset of treatment benefited whether treated by surgery or by RT. Seventy-five percent of living patients who improved from treatment remained ambulatory at 6 months, and approximately 50% of living patients were ambulatory at 1 year. We conclude that RT without decompressive laminectomy is as effective as decompressive laminectomy in treating epidural spinal cord compression from systemic cancer.

Treatment of experimental spinal cord compression caused by extradural neoplasms

Epidural spinal cord compression was produced in rats by injection of Walker 256 carcinoma cell suspension anterior to the T-12 or T-13 vertebral body. The tumor grows through the intervertebral foramina to compress the spinal cord and produce paraplegia in 3 to 4 weeks. The effect of several treatments upon clinical signs was assessed. Dexamethasone caused a significant but transient improvement in neurological function. Radiation therapy likewise improved neurological function, and was more effective when given by a high-dose protracted course than when given either in a single dose or a low-dose protracted course. Laminectomy was not helpful in relieving neurological symptoms. Dimethyl sulfoxide did not relieve neurological symptoms. Cyclophosphamide was most effective in relieving neurological symptoms, and most of the animals that were treated with that drug when they were severely weak but still able to move their hind limbs recovered fully. Some animals that were totally paraplegic when treatment began recovered function after radiation therapy or cyclophosphamide treatment, but recovery was better if treatment was started when animals could still move their hind limbs. This animal model appears to be a useful way of studying the treatment of human spinal cord compression produced by epidural neoplasms.

Local tumor hyperthermia in combination with radiation therapy. 1. Malignant cutaneous lesions

There is increasing evidence that the use of hyperthermia alone or in conjunction with other modalities may improve the therapeutic effectiveness of treatment of cancer. The present clinical studies were carried out to evaluate the response of normal and tumor tissues in patients with various cutaneous malignant lesions to repeated courses of hyperthermia alone or in conjunction with radiation therapy. Thirty-six patients with malignant cutaneous lesions (mycosis fungoides, Kaposi sarcoma, malignant melanoma, lymphoma cutis, and other metastatic skin lesions) have been studied. The heating methods used were: 1) temperature regulated water bath immersion; and 2) radiofrequency inductive heating. The normal tissue effects of the combined treatments of radiation and hyperthermia do not appear to be greater than those treated with radiation alone. The initial tumor regression rates were faster in patients treated with radiation plus hyperthermia than in radiation alone, particularly in patients with Kaposi sarcoma and lymphoma cutis. Among ten locally recurrent patients, seven showed significant prolonged benefits achieved by the combined treatments as compared with the radiation therapy alone. Fractionated hyperthermia alone caused significant tumor regression in four out of five patients. Possible mechanisms leading to the improved results from the combined treatments are discussed.

Local tumor hyperthermia in combination with radiation therapy. 1. Malignant cutaneous lesions

There is increasing evidence that the use of hyperthermia alone or in conjunction with other modalities may improve the therapeutic effectiveness of treatment of cancer. The present clinical studies were carried out to evaluate the response of normal and tumor tissues in patients with various cutaneous malignant lesions to repeated courses of hyperthermia alone or in conjunction with radiation therapy. Thirty-six patients with malignant cutaneous lesions (mycosis fungoides, Kaposi sarcoma, malignant melanoma, lymphoma cutis, and other metastatic skin lesions) have been studied. The heating methods used were: 1) temperature regulated water bath immersion; and 2) radiofrequency inductive heating. The normal tissue effects of the combined treatments of radiation and hyperthermia do not appear to be greater than those treated with radiation alone. The initial tumor regression rates were faster in patients treated with radiation plus hyperthermia than in radiation alone, particularly in patients with Kaposi sarcoma and lymphoma cutis. Among ten locally recurrent patients, seven showed significant prolonged benefits achieved by the combined treatments as compared with the radiation therapy alone. Fractionated hyperthermia alone caused significant tumor regression in four out of five patients. Possible mechanisms leading to the improved results from the combined treatments are discussed.

Diaphragm pacing: histopathological changes in the phrenic nerve following long-term electrical stimulation

Phrenic nerves were obtained at autopsy from 7 patients with chronic ventilatory insufficiency. One or both nerves had been subjected to electrical stimulation to pace the diaphragm for about 2 months to 4 years. Sections of the nerves made from above, at the level of, and below the site of application of the cuff electrode were studied microscopically. In most specimens, focal areas of demyelination were seen ranging from severity from swelling and fragmentation of isolated fibers to focal myelin destruction with phagocytic activity and total removal of myelin with fibrosis. Some axone loss was seen. The fact that the nerves from 2 patients, each stimulated for about 2 years, showed no changes suggests that injury to the nerve was not caused by the electrical stimuli but rather was secondary to the technique of application and fixation of the cuff electrode to the nerve.

Locally recurrent carcinoma of the breast. Results of radiation therapy

Local and regional recurrences are frequent problems in breast cancer management. Radiation therapy is effective in producing long term remission. This study evaluates the results of radiation therapy of 215 patients with recurrent disease limited to the chest wall and/or regional lymph node areas. The local results showed complete control in 67% of cases (mean and median durations 32 months and 22 months, respectively), partial control in 24% of cases (mean and median 11 and 8 months, respectively) and no control in the remaining 9%. The radiation dose recommended for the treatment of recurrent mammary carcinoma is 5000 rads in 5 weeks for relatively small lesions. Supplementary local doses of 500-1000 rads in 1 week may be given to bulky lesions as necessary for residual disease. Although local relapse indicates a poor prognosis, it is by no means totally hopeless. Of 215 patients treated 44 (21%) survived 5 years and 10 (5%) survived 10 years following radiation therapy of recurrent disease. There were seven patients, or 3%, who were free of cancer at 5 to 15 years. Radiation therapy was valuable in controlling local lesions, and thus, in improving quality of survival, even in those patients who eventually died of metastatic disease.

Dose-time fractionation study in patients with mycosis fungoides and lymphoma cutis

Single and multiple dose-time fractionation schemes were investigated in patients with mycosis fungoides and lymphoma cutis. The single dose response shows that the disease-free interval is dose dependent. Remission rates are similar when the same total dose is given in either single treatments or multiple daily fractions. Weekly dose fractionation schemes are superior to daily regimes for lymphoma cutis. Changes in tumor volume reduction following single doses to lymphoma cutis indicate that the mean lethal dose (DO) is 90 rads and the extrapolation number (N) is less than 2. These findings are discussed in relation to the reoxygenation process and the cell cycle distribution of the tumor cell population.

Low energy radionuclides for permanent interstitial implantation

An analysis of 318 permanent implants was carried out in an attempt to establish the effectiveness of iodine 125 as compared with radon 222 and iridium 192; and to derive dose-response curves for iodine 125. Analysis of the clinical results obtained with iodine 125 in comparison with radon 222 and iridium 192 in selected anatomical sites demonstrated that iodine 125 has a higher therapeutic ratio than the other two radionuclides. A tumor control rate of at least 80% with iodine 125 implants might be expected after a good geometrical dose distribution, with a planned initial minimum tumor dose of at least 14,000 +/- 2,000 rads. Rapid tumor shrinkage ensures a more or less steady or even increased dose rate over a period of several weeks and improves the local tumor control. Tumors with a longer cell cycle are especially susceptible to irradiation with radionuclides of long half-lives.

The relationship between the time of fractionated and single doses of radiation and hyperthermia on the sensitization of an in vivo mouse tumor

The present study was undertaken to explore the relationship of the time interval between application of heat and irradiation on enhanced tumor cell sensitivity. Using the Ridgway osteogenic sarcoma grown in AKD2F1/J mice, local tumor hyperthermia (42.5 +/- .5 degrees C for 15 minutes) was applied at various time intervals before or after single or fractionated doses of x irradiation. Enhancement of tumor cell sensitivity by combined treatment with radiation and heat, as measured by delay in tumor growth, cure rates, and mean survival times was inversely proportional to the time interval between application of both modalities. The interactions associated with this increased sensitivity appear to be transitory, diminishing with time between treatments. Possible mechanisms of action for thermal sensitization may involve the reduction of oxygen dependence as well as a reduced recovery capacity of tumor cells.

The influence of dose fractionation on acute and late reactions in patients with postoperative rasiotherapy for carcinoma of the breast

The clinical courses of 418 patients with breast carcinoma who received postradical-mastectomy radiation therapy to the internal mammary and supraclavicular are were revied in order to determine the normal tissue tolerance with various time-dose fractionation radiation regimens. Four different dose fractionation schedules wereemplyed during the period 1958-1968 at Memorial Hospital: 4900 rads/10f/32d; 4410 rads/9f/30d; 5000 rads/13f/18d; and 4600 rads/20f/28d. There was no difference in the acute reaction or local recurrence rate of the tumor in the irradiated area among the four fractionation schemes, but the late effects were quite different. Patients who received 4900 rads in 10 fractions in 32 days had a 33% incidence of subcutaneous fibrosis.A similiar dose in 13 fractions in 21/2-3 weeks resulted in about 17% subcutaneous fibrosis. No significance of these clinical findings is discussed in relation to the various formulae currently being used to express time-dose equivalence.

Weekly total skin electron beam therapy for mycosis fungoides and other cutaneous lymphomata: further experience

Lymphomatous processes involving the skin can be managed effectively by total skin electron beam irradiation. A technique using weekly doses (400 rad for each of 6 successive weeks) has been employed in the therapy of 36 patients. Complete remission was obtained in all patients so treated. The median first disease-free interval for lymphoma cutis was 11 months and for mycosis fungoides 9 1/2 months

The radiosensitization of hypoxic tumor cells by hyperthermia

The influence of hyperthermia on the survival of irradiated oxic and hypoxic HeLa cells was determined. A significant reduction in OER was obtained for irradiated cells subsequently cultivated at 42-degrees C for two hours compared to irradiated cells cultivated at 37-degrees C. These results suggest that heating irradiated hypoxic cells is an effective means of reducing the oxygen dependence factor in radiation effects.

Iodine 125 source in interstitial tumor therapy. Clinical and biological considerations

Our clinical experience with interstitial tumor therapy is presented in 2 groups of patients: 98 patients with metastatic carcinoma in neck lymph nodes implanted with iodine 125, iridium 192 or radon 222 encapsulated sources, and 105 patients with primary unresectable lung tumors, which were implanted either with radon 222 or iodine 125 seeds. The local tumor control rates with iodine 125, radon 222 and iridium 192 were 78 per cent (38/49), 65 per cent (15/23) and 58 per cent (7/12), while the local complication rates were 17 per cent, 35 per cent and 43 per cent, respectively. An analysis of the tumor control rate as a function of the implanted tumor dose shows that the iodine 125 implants with a delivery of the minimal effective tumor dose of 16,000 rads have a higher therapeutic effect than either radon 222 or iridium 192. The results of the patients with unresectable lung tumors similarly show that the implants with iodine 125 sources are superior to those with radon 222. The advantages could stem from the better spatial dose distribution, and from radiobiologic considerations associated with low dose rates, continous irradiation, and possibly gains in RBE. There present clinical data clearly demonstrate that iodine 125 seeds have a higher therapeutic ratio than radon 222 seeds. There are, in addition, distinct physical advantages making iodine 125 an attractive substitute for radon 222 for the interstitial implantation of malignant tumors.

Thermal enhancement of the radiosensitivity using cultured normal and neoplastic cells

Cultures of normal tissue are relatively insensitive to heat, while malignant cells in culture are highly sensitive to thermal treatment. This differential thermal sensitivity is most pronounced when the cells of normal and neoplastic tissues are exposed to heat in their exponential growth phase. Dose survival curves of HeLa and 3T3 cells with and without postirradiation thermal treatment showed that the neoplastic HeLa line exhibited significant enhancement of radiosensitivity when the irradiated cells were exposed to elevated temperatures (42C. for 3 hours). Similar heat treatment of irradiated 3T3 fibroblasts did not appreciably enhance the radiation response. The potential significance of these findings for clinical radiotherapy is discussed.

Bartter's syndrome with possible hypothalamic dysfunction

A patient with Bartter’s Syndrome with hypernatremia, chronic low grade fever, fluctuating endocrine functions is presented. The fluetuating endocrine functions suggest a hypothalamic dysfunction. It appeared in this patient that the Bartter’s Syndrome and the changing endocrine functions co-existed rather than one being the causeof the other.