An applicator for intraluminal afterloading irradiation using ¹⁹²Iridium thin wires was devised and applied to 17 patients with lung cancer which had endobronchial residual tumor after external radiation therapy. Prescribed therapy was completed in 72 courses except one. No residual cancer was found in the treated airway of any of the 17 patients, but three patients had regrowth of the disease in the extrabronchial, region and/or untreated airway. No particular complication has so far been found during the intraluminal irradiation therapy nor until now, May in 1990. Characteristics of this applicator are:(1) it can be inserted selectively into an upper bronchus or a peripheral one, (2) radiation source can be put at the central part of bronchus to give an uniform dose distribution over the bronchial wall as wings are provided at the top of the applicator that contains the radiation source and serve as a spacer, (3) the soft silicon material of the applicator does not injure the bronchial mucosa. We conclude that this method is very useful for patients with early hilar lung cancer which cannot be subjected to sufficient external radiation therapy because of low pulmonary function or poor performance status.

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Selective deletion of radiosensitive suppressor T cells by low dose total body irradiation (TBI) is believed to be part of the mechanism of anti-tumor effect of this irradiation. Recently, with the concept of “Radiation Hormesis” being introduced by T. D. Luckey, new experimental data and hypotheses have been reported. It is possible that adaptive feedback control singnals are stimulated to upregulate stem cells and proliferative populations in response to cell injury and cell death induced by low dose irradiation as described by Fabricant and Makinodan. Two-color analyses of peripheral blood lymphocytes using flowcytometry in 9 patients with non-Hodgkin's lymphoma, who received low dose total body irradiation (TBI) or half body irradiation (HBI), were performed to look at the influence of low dose irradiation on lymphocytes and its anti-tumor effects. The results of the present study are: significant increase in the proportion of helper T, helper-inducer T, and active helper/inducer T cells; slight increase of cytotoxic T cells; and decrease of suppressor-inducer T and suppressor T cells. Since low dose TBI preceded the other treatments such as primary site irradiation and multiple agent chemotherapy in three cases, the antitumor effect of TBI was able to be investigated. All three patients showed at least partial responses, especially in case 7 (stage III) where almost all tumors disappeared after only TBI. In patients without pretreatment, the extent of bone marrow suppression of two or three times per week TBI using 0.1 Gy as a dose/fraction and 1.5 Gy as a total dose was not as serious and seemed to pose no problem clinically. The results of the present study support the ideas presented by Fabricant and Makinodan, where the proportion of the helper T cells would increase in response to low dose irradiation as homeostatic adaptation of lymphoid tissue.

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A useful three-dimensional system using CT has been developed for treatment planning. We have elaborated this research in cooperation with Toshiba company. Clinically this system is especially useful for complicated cases in which the target volume is adjacent to dose limited normal organs. Providing 3-dimensionally reconstructed images, named CTS images (CT simulator images), the radiation fields are based on these images. This system enables us to make full use of CT information and to do accurate 3-dimensional treatment planning with no further cost for special hardware. It is expected that this simple and inexpensive system will be widely used by many radiotherapists.

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Thirty-two previously untreated patients suffering from superior sulcus Pancoast tumors of the lung were treated with fast neutron beams (30Me V d-Be) between 1975 and 1988 at the NIRS. A high irradiation dose (average dose: TDF 113) was administered with a large field to cover subclinical deposits utilizing a shrinking field technique. Local control of the tumor mass was observed in 44% of the patients, greatly improving chances for prolonged survival. Median survival was 21.1 months for patients with local control versus 10.4 months for those with local failure. The relative five-year survival rate was 20% for the total (n=32), 34% for stage III A (n=12), 15% for stage III B (n=16) and 0% for stage IV (n=4). Radiation therapy achieved pain relief for 62.5% of patients. Radiation myelopathy developed in one long-surviving patient, but complications from radiation were, otherwise, mild to moderate

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Movement of the target volume during the exposure to radiation results in decreased accuracy in radiotherapy. We carried out the quantitative evaluation of the movement of the diaphragm during the radiation therapy. Seventy seven patients, who received radiation therapy for lung cancer from December 1988 to February 1990 at the Osaka-prefectural Habikino Hospital, were studied. The movement was recorded with a sonoprinter at the time of treatment planning for radiotherapy, and the length of movement was evaluated at 6 points on the diaphragm. In a study of 402 points in 77 patients, the average movement was 12 mm, and the maximum movement was 40 mm. At the 17% of the points, the movement exceeded 20 mm. The largest movement was observed at the outer point of the right lung. Movement was greater in men than in women. Performance status was not related to the degree of movement. We concluded that in chest and abdominal irradiation, movement caused by respiration is not negligible, and synchronized radiotherapy should be developed in the future.

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This is a retrospective analysis of 56 patients with carcinoma of the cervical (Ce) and upper thoracic (Iu) esophagus treated by radiotherapy (>=50 Gy). Complete response rates were 29% in Ce cancer, 18% in Iu cancer and 14% in Ce+Iu cancer. Five-year cause specific survival rates by Kaplan-Meier method were 27% in Ce cancer, 4% in Iu cancer and 0% in Ce+Iu cancer. Two-year local tumor control was obtained in 5 Ce, 4 Iu and 1 Ce+Iu cancer. Anterior-posterior portal treatment was used for 3 of the above 10 patients, a four field technique was used for two, and rotation, double wedge, wedge pair, right-left lateral portal and oblique portal were used for one patient each. There was no significant correlation between treatment method and local tumor control. Side effects after treatment were pneumonitis (2 patients) and radiation myelopathy (1). Wedge and compensating filter were used for 11 patients. Further investigation of dose and compensation is necessary for Ce and Iu cancer.

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Radio and thermal sensitization effects on in vitro cultured mammalian cells of (-)-(R)-2-aminomethylpyrrolidine (1, 1-cyclobutanedicarboxylato) platinuth (II) monohydrate (DWA2114R) were investigated. Radiosensitization by DWA2114R was more pronounced in hypoxic cells than in aerobic cells. Dose modifying factors (DMF) in hypoxic V 79 cells was about 1.3 at 100μM and 300μM DWA2114R during gamma-ray irradiation. DMF in aerobic cells was 1.06 at 300μM. At elevated temperature, the cytotoxicity of DWA2114R was enhanced in FM 3 A cells. DMF for cell killing at 10μM DWA2114R was 5.77 at 42°C, 1.71 at 43°C and 1.59 at 44°C. The activation energy in the presence of DWA2114R between 42°C and 44°C was comparable to that in the absence of drug between 43 and 44°C. Enhanced cytotoxicity of DWA2114R depended on the sequence of drug and heat. Enhanced killing was observed when the drug was administered either during or immediately after heat. Present results suggest that the combined DWA2114R and heat or radiation may improve the therapeutic ratio in thermal-or radio-chemotherapy.

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