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I Tsukiyama

Publications and source records attributed to I Tsukiyama.

At least 19 recordsLinked to original sources
PubMed2001

Simultaneous intraluminal thermobrachytherapy: an in vitro study.

A multi-institutional study on simultaneous intraluminal thermobrachytherapy (SITB) for advanced esophageal cancer was conducted in Japan. In this study, brachytherapy was administered by a small radioactive source stepping through a catheter in the esophagus, and hyperthermia was also applied by an endoesophageal coil. However, experimental or clinical findings on the spatial distribution of its antitumor effects around the esophagus are not available. Therefore, we developed an in vitro model of SITB using a high-dose-rate iridium-192 stepping source and two human cancer cell lines (WiDr and A549), and determined the spatial distribution of the antitumor effects. According to this model, the antitumor effects steeply decreased as the source-cell distance increased when cells of both cell lines were irradiated with 5 Gy without heat. When WiDr cells, a more resistant cell line to radiation and heat, were simultaneously irradiated and heated for 30 min at 44 degrees C, the effects decreased much less steeply as the distance increased. For A549 cells, a more sensitive cell line, irradiation with hyperthermia even at 42 degrees C made the decrease in the effects smaller. The largest antitumor effects can be expected at 5 - 10 mm beneath the esophageal mucosa, where the endoesophageal coil can heat tissues most effectively. SITB can induce larger antitumor effects than brachytherapy alone, especially in submucosal disease, which would favor treatment of advanced cancer.

Brachytherapy↗
PubMed1999

Radiation therapy for roentogenographically occult lung cancer by external beam irradiation and endobronchial high dose rate brachytherapy.

PURPOSE: We investigated the clinical usefulness of radiation therapy by external beam irradiation and endobronchial brachytherapy for the treatment of roentogenographically occult lung cancer. PATIENTS AND METHODS: From 1995 to 1996, five patients were treated with radiation therapy. We analyzed their treatment outcomes. The follow-up period varied from 3.0 to 3.8 years or until death. External beam radiation (40 Gy/20 fractions/4 weeks) was delivered to the tumor site alone, and not prophylactically given to the mediastinum. Endobronchial brachytherapy using high dose rate iridium (Ir)-192 was concurrently administered principally to a total dose of 18 Gy on the bronchial mucosa in three weekly fractions of 6 Gy each. RESULTS: Complete remission was obtained in all patients. Two patients died of intercurrent diseases at 12 and 21 months without any evidence of recurrence. The disease has been also controlled in the other three cases. With the above doses, three small tumors < 1 cm were controlled without adverse effect. In two tumors, the dose reference points were set 2-7 mm beneath the mucosa, and larger doses were administered by brachytherapy. An applicator acting as a spacer was not used in these cases. The tumors were controlled, although the irradiated bronchi showed severe stenosis in 6 months following the treatment. However, the patients were asymptomatic and did not need further intervention. CONCLUSION: External beam irradiation combined with endobronchial brachytherapy was useful for the treatment of roentogenographically occult lung cancer as an alternative to surgery. Further investigation is needed to determine the optimal doses of radiation therapy.

Aged↗
PubMed1999

Uniformity of biological effect in high-dose rate stepping source brachytherapy: an in vitro study.

In brachytherapy with a high dose rate of iridium-192, to make a flat isodose surface that covers a target volume, the dwell times of the single stepping source are computer adjusted. However, the dose rates of the irradiation vary with the positions in the volume. To examine this effect, we developed an in vitro model of stepping source brachytherapy with a 20 cm long target volume, and determined the uniformity of the biological effect in the volume on two human cancer cell lines (WiDr and A549) plated on a multi-well plate. When the source-cell distance was 10 mm, D1 (radiation dose for 1% survival) was similar in seven positions among the target volume for both cell lines. In contrast, at the 3 mm source-cell distance for one of the two cell lines (A549), D1 in the centre of the volume was significantly higher than at the periphery, suggesting a milder antitumour effect in the centre. Considering the possible decreased effect in the centre of the target volume, where most cancers clinically exhibit their maximum tumour volume, a minimum increase in radiation dose in the centre may be clinically reasonable, especially when dose reference points are set close to the source.

Adenocarcinoma↗
PubMed1999

Endobronchial brachytherapy for recurrent thymoma showing endobronchial polypoid growth.

The authors report a case of recurrent thymoma displaying endobronchial polypoid growth. Initially, the patient had invasive thymoma with intracaval growth into the right atrium. He was treated with multimodality therapy consisting of chemotherapy, surgical resection, and radiotherapy (50.4 Gy). Both 3 years and 6 years after the initial treatment, the tumor recurred outside the reconstructed superior vena cava. The patient was treated with repeated radiotherapy (50.4 Gy and 40 Gy), and remission was achieved. Eight years after the first therapy, an endobronchial polypoid lesion was detected in the right upper lobe bronchus and was histologically found to be thymoma. Endobronchial high-dose rate brachytherapy (20 Gy at 3 mm/5 fractions) was carried out for palliation because the recurrent tumor occurred outside of the superior vena cava area, which had been reirradiated. After the treatment, the endobronchial tumor shrunk remarkably in size without adverse effects. No tumor regrowth has been noted after a follow-up of 10 months.

Aged↗
PubMed1993

Linac-based small-field radiotherapy for brain tumors.

Small-field radiotherapy based on a 6-MeV linac and a conventional head mold is investigated as an alternative to radiosurgery with stereotactic frames. The system requires no additional device and allows fractionated treatment. The dose distributions obtained are comparable to those reported with a Gamma Unit. Overall positioning errors are within 2 mm. Using this approach, seven patients with brain tumors who could not have been treated otherwise, underwent fractionated radiotherapy with total accumulated doses ranging from 70 to 108 Gy. The treatment was tolerated well with no acute toxicity or adverse effect encountered during the follow-up period of 8-14 months. All of the patients remained free from disease progression in the treated volumes. Although the follow-up is brief, the preliminary results suggest that this is a simple and inexpensive but effective system for the treatment of small intracranial malignancies.

Brain Neoplasms↗
PubMed1992

[Histological and biological evaluation of preoperative radiotherapy on T1N0 breast carcinoma].

In order to clarify the role of radiotherapy in breast preserving surgery for early breast cancer, histological and biological effects of preoperative radiation were evaluated. Thirty-five T1N0 patients were treated by preoperative radiotherapy with beta-tron, cumulative doses of which were ranging from 25 Gy (5 Gy x 5) to 40 Gy (8 Gy x 5) and underwent subsequent modified radical mastectomy 2 or 3 weeks after the termination of radiotherapy. Clinical tumor shrinkage more than 50% was observed in 25 out of 35 cases (71%) but did not directly correlate with histological effects. Radiotherapy was basically ineffective within 25-30 Gy, whereas histological effects more than Grade 2 were gained in 8 out of 25 patients (32%), who had received 40 Gy or more. In the preoperative radiation group, there were more ER(+), PgR(+) and histologically well-differentiated cases than in the non-radiated stage I patients. Mitotic figures were also significantly reduced after radiotherapy, whereas the expression of c-erB-2 protein was unchanged between these two groups. Our data indicate the various radiosensitivity of breast cancer cells and the indication of hormone therapy for the conservative treatment of breast carcinoma.

Adult↗
PubMed1991

Stage I-II carcinoma of the anterior two-thirds of the tongue treated with different modalities: a retrospective analysis of 244 patients.

Treatment results of 244 patients with stage I-II cancer of the mobile tongue were analyzed according to the modalities employed (implantation, surgery, cryosurgery and intraoral irradiation). Overall local control rates at three years were 90 +/- 3% for implant, 89 +/- 7% for cryosurgery, and 84 +/- 9% for surgery. Local control rates in stage II patients treated with intraoral electron irradiation, however, were only 50 +/- 13%. Five-year survival rates were 72 +/- 3% with no significant differences observed in patients with either stage I or stage II regardless of treatment modality. Sixty percent (29/48) of the patients with local recurrences were salvaged by the second treatment. Since the local control and survival achieved by these modalities were similar, with the exception of patients with stage II treated by intraoral electron irradiation, we recommend interstitial implantation with iridium, intraoral electron irradiation or surgery for patients with T1 tumors, and iridium implantation or surgery for patients with T2 tumors. For those with superficial lesions measuring 5 mm or less in thickness, cryosurgery is being offered as an alternative. The patient can choose the treatment modality taking into account his/her age, sex and profession.

Combined Modality Therapy↗
PubMed1991

Radiotherapy of T1 glottic cancer with 6 MeV X rays.

We treated 154 patients with T1 glottic carcinoma with 6 MeV X rays through 16 cm2 parallel-opposing open fields on a free set-up delivering a median dose of 67 Gy in 6 2/3 weeks. Observed and relative 5-year survival rates for all patients were 87% and 100%, respectively. The local control rate at 5 years was 89%. Of 18 patients who clinically had local recurrence, 17 were salvaged by a secondary treatment. There were no complications requiring medical or surgical attention. A tendency toward increasing local control rates with increasing total doses was observed in the range between 57.5 Gy and 72.5. No significant correlation was found between local control rates and field size, daily dose, or the technique used. A tendency toward a lower local control rate was noted for patients whose anterior commissures were grossly involved; however, it is not known if this could be attributed to the use of 6 MeV X rays. The results are comparable to those obtained with 60Co as reported in the literature. It is concluded that 6 MeV X rays on a free set-up delivering 65-70 Gy in 6 1/2-7 weeks can be used satisfactorily for the treatment of early glottic carcinoma.

Adult↗
PubMed1990

[Radiotherapy for endobronchially invading recurrence of esophageal cancer after resective surgery].

Sixty-eight patients with endobronchially invading recurrence of esophageal cancer after resective surgery were treated with radiotherapy from 1966 to 1988. The mean interval between resective surgery and diagnosis of recurrence was 11.1 months, that was significantly shortened in a3 group. The dose of radiation for recurrence ranged from 2 to 70.3 Gy, with a mean dose of 42.6 Gy. The mean survival time after treatment of recurrence was 4.9 months. The dose of radiation was found to have a positive correlation with survival time. The cause of death was bleeding in 20 patients, and respiratory failure in 36. High dose of radiation was thought to induce high incidence of bleeding. The results indicated that external beam radiotherapy with conventional fractionation was not so much effective for the recurrence.

Adult↗
PubMed1990

Dose equivalence for high-dose-rate to low-dose-rate intracavitary irradiation in the treatment of cancer of the uterine cervix.

By comparing the incidence of major radiation injury, we estimated doses clinically equivalent for high-dose-rate (HDR) to conventional low-dose-rate (LDR) intracavitary irradiation in patients with Stages IIb and IIIb cancer of the uterine cervix. We reviewed a total of 300 patients who were treated with external beam therapy to the pelvis (50 Gy in 5 weeks) followed either by low-dose-rate (253 patients) or high-dose-rate (47 patients) intracavitary treatment. The high-dose-rate intracavitary treatment was given 5 Gy per session to point A, 4 fractions in 2 weeks, with a total dose of 20 Gy. The low-dose-rate treatment was given with one or two application(s) delivering 11-52 Gy to the point A. The local control rates were similar in both groups. The incidence of major radiation injury requiring surgical intervention were 5.1% (13/253) and 4.3% (2/47) for low-dose-rate and high-dose-rate groups, respectively. The 4.3% incidence corresponded to 29.8 Gy with low-dose-rate irradiation, thus, it was concluded that the clinically equivalent dose for high-dose-rate irradiation was approximately 2/3 (20/29.8) of the dose used in low-dose-rate therapy.

Aged↗
PubMed1990

Carcinoma of the uterine cervix treated by irradiation alone. Results of treatment at the National Cancer Center, Tokyo.

Six hundred and twelve patients with previously untreated invasive carcinoma of the uterine cervix were treated by irradiation alone at the National Cancer Hospital from 1972 to 1983. The number of patients was 7, 39, 43, 127, 15, 319, 28 and 34 in stages IA, IB, IIA, IIB, IIIA, IIIB, IVA and IVB respectively. Low-dose-rate intracavitary irradiation with or without external irradiation was used in 383 patients, high-dose-rate intracavitary irradiation with or without external irradiation in 130, external irradiation alone in 98, and external irradiation combined with radon-222 seed implantation in one patient. Five-year-survival rates were 85, 65, 57, 41, 14 11% for stages IB, IIA, IIB, IIIB, IVA, and IVB respectively. The rate of complications was rather high in the present series, and so we have been investigating whether it is possible to reduce the dose. Low-dose-rate intracavitary irradiation has been replaced by high-dose-rate irradiation by using a remotely controlled afterloading system.

Adult↗
PubMed1990

[Control of aftereffects due to intraoperative radiotherapy].

In cases of treating a pancreatic cancer, an aneurysm and thrombus of the abdominal aorta, necrosis of the vertebral body, and damage to the peripheral nerves can be caused by intraoperative radiotherapy (IORT). These aftereffects have been observed in tests conducted in experimental animal reported by Colorado State University. Similarly, our clinical experiences have led us to set safety guidelines to prevent damage due to IORT. The safety level of a radiation dose for IORT alone is limited to 30 Gy, and for IORT combined with external beam radiotherapy, from 20 Gy (IORT) plus 50 Gy (EBRT). Using these parameters, among 58 cases of a pancreatic tumor treated by IORT, only one case subsequently developed a pseudoaneurysm at the stump of splenic artery.

Adult↗
PubMed1988

High-dose-rate intracavitary irradiation in the treatment of carcinoma of the uterine cervix: early experience with 84 patients.

Eighty-four patients with previously untreated invasive carcinoma of the uterine cervix were treated by high-dose-rate intracavitary irradiation using a remotely controlled afterloading system (Ralstron) with or without external irradiation at the National Cancer Center Hospital, Tokyo, between 1977 and 1981. Survival rates and local control rates were comparable to those for 372 patients treated by low-dose-rate intracavitary irradiation with or without external irradiation from 1972 to 1981 at the hospital. The incidence of major complications was 5.1 and 2.4% for the patients treated by low-dose-rate intracavitary irradiation and by high-dose-rate irradiation, respectively. The results are comparable to those reported by other institutions. We have abandoned the conventional low-dose-rate intracavitary irradiation with the impression that the high-dose-rate remotely controlled afterloading system is a good alternative to the conventional one.

Adult↗
PubMed1988

Hyperthermic therapy of deep seated tumors: comparison of the heating efficiencies of an annular array applicator and a capacitively coupled radiofrequency system.

Among 82 cases of deep seated tumors treated by hyperthermia with an annular array applicator (AA) and/or a capacitively coupled 8 mHz system (CCS) combined with radiation therapy, 13 cases were treated by both devices. The efficiencies of tumor heating were compared in terms of the time required to attain 42 degrees C, the duration of heating time and the thermal dose as determined by a biological iso-effect formula for equivalent minutes at 42.5 degrees C. Temperature profiles and percent of temperature levels greater than 42 degrees C were better in the cases treated by the AA, but higher thermal doses were obtained with the CCS because longer treatment times were tolerated with the CCS than with the AA. Methods are necessary to prevent excess elevation of body temperature in the case of the AA, and to reduce superficial pain where the applicators contact the skin in the case of the CCS.

Adult↗
PubMed1988

Radiation therapy for advanced gastric cancer.

A retrospective study of 75 patients with advanced inoperable gastric cancers, referred to the National Cancer Center Hospital between 1962 and 1982, was performed. According to the Borrmann classification based on X ray findings, Type 1 was found in 3 patients, Type 2 in 5, Type 3 in 40, and Type 4 in 15. Twelve patients could not be classified. The histological type was papillary adenocarcinoma in 7 patients, tubular adenocarcinoma in 23, mucinous carcinoma in 6, poorly differentiated adenocarcinoma in 14, signet ring cell carcinoma in 12 and others in 13. The site of remote metastasis in 19 patients was Virchow's lymph node in 8 patients, Douglas pouch in 3, liver and lung in 2 each and others in 4. All patients were treated by a either telecobalt 60 unit or a linear accelerator using 6 Mv photon and the total dose to primary lesion was 4000 cGy in 5 weeks to 7000 cGy in 8-9 weeks. Complete response (CR) was achieved in 6 patients or 8.0%, partial response (PR) in 46 or 61.3%, and no change (NC) in 23 or 30.7%. The response rate based on the sum of CR and PR was about 70%. The 50% survival period in months was 26.5, 7.3, and 3.2, respectively for patients with CR, PR, and NC. For the response of advanced gastric cancer to chemotherapy in the National Cancer Center Hospital, the combined use of UFT and Mitomycin C gave the highest rate, 46%. As for as local response is concerned, the response rate to radiation was 70%, a better result than that of chemotherapy alone.

Adenocarcinoma↗
PubMed1988

[Hyperthermia in bone and soft tissue tumors].

Local response of hyperthermia for soft tissue and bone tumors was investigated. Ten tumors were superficial tumors and 16 were deep seated tumors; 9 tumors were malignant fibrous histiocytoma, 5 were liposarcoma, 4 were neurogenic and 3 were myogenic sarcoma. The other five tumors were an angiosarcoma, a malignant mesenchymoma, an Ewing's sarcoma, a chordoma and an osteosarcoma. Some 23 tumors were heated in combination with radiation therapy, and 3 were combined with arterial infusion of ADR. Four of 10 superficial tumors disappeared (CR), and, 2 of 10 signified PR. Only one of 16 deep seated tumors showed CR, 3 were PR and 12 showed no response. But 4 of 12 tumors without regression in tumor volume indicated coagulation necrosis owing to histological examinations, and 5 of 12 were regarded as the same response from hypodensity area with CT examination after hyperthermia. Local response rate of of superficial tumors was 60% and that of deep-seated tumors was 81.4%.

Bone Neoplasms↗