Effect of hyperthermia combined with external radiation therapy in primary non-small cell lung cancer with direct bony invasion

PURPOSE

Local control in lung cancer directly invading the bone is extremely poor. Effects of regional hyperthermia combined with conventional external beam radiation therapy were evaluated.

MATERIALS AND METHODS

Thirteen patients with non-small lung cancer (NSCLC) with direct bony invasion were treated with hyperthermia plus irradiation (hyperthermia group). The treatment outcome was compared with the historical treatment results in 13 patients treated with external radiation therapy alone (radiation alone group). In patients with no distant metastasis, radiation therapy at a total dose of 60-70 Gy was administered to both groups. Hyperthermia was performed for 45-60 min immediately after irradiation for two-four sessions with radiofrequency capacitive heating devices.

RESULTS

For primary response, 10 of the 13 tumours responded to the treatment (3 CR, 7 PR) in the hyperthermia group, whereas seven tumours responded (1 CR, 6 PR) in the radiation alone group. The 2-year local recurrence-free survival rate for clinical M(0) patients in the hyperthermia group and that in the radiation alone group were 76.1 and 16.9%, respectively. Three patients died of distant metastases within 2 years in the hyperthermia group, but two out of three tumours histologically disappeared, even in the autopsy examination. The 2-year overall survival rate for clinical M(0) patients in the hyperthermia group and that in the radiation alone group were 44.4 and 15.4%, respectively. No severe pulmonary complication was observed in either group.

CONCLUSIONS

Regional hyperthermia combined with conventional irradiation could be a tool to improve local control in patients with NSCLC deeply invading the chest wall.

Analysis of recurrence of squamous cell carcinoma of the uterine cervix after definitive radiation therapy alone: patterns of recurrence, latent periods, and prognosis

PURPOSE

A retrospective analysis was performed with emphasis on the patterns of recurrence, latent period, and prognosis in patients with cervical squamous cell carcinoma of the uterus treated with definitive radiation therapy alone. Late recurrence, which was observed more than 5 years after the initial radiation therapy, was finally focused on and discussed.

MATERIALS AND METHODS

Between 1976 and 1994, 256 patients with squamous cell carcinoma of the uterine cervix without hematogenous metastasis were treated with definitive radiation therapy alone. The patients were staged as follows according to the FIGO classification: 26 in Stage I, 56 in Stage II, 124 in Stage III, 28 in Stage IVa, and 22 in Stage IVb. All the patients were treated with external beam irradiation and low-dose-rate intracavitary brachytherapy.

RESULTS

A total of 74 patients had recurrence. The recurrence appeared in 67 cases (90.5%) within 5 years. Metastasis to para-aortic and/or supraclavicular nodes developed later than other types of recurrence. Among patients with lymphogenous metastasis, there were more 5-year survivors after recurrence than with other types of recurrence. Patients with early recurrence, within 2 years of the initial therapy, had a worse prognosis than those with recurrence more than 2 years after treatment. Seven patients (2.7%) in all developed late recurrence more than 5 years after the treatment. The first site of recurrence was an abdominal para-aortic or supraclavicular node in all patients, excluding one patient who developed intrapelvic lymph node metastasis. Six patients had pelvic node metastasis detected with lymphangiography at the initial treatment. Median survival after late recurrence was 16.0 months. Two of 7 patients survived more than 3 years after secondary radiation therapy, and the remainder died of recurrent disease.

CONCLUSION

Patients with para-aortic and/or supraclavicular node metastasis that developed late after the initial treatment are more likely to survive due to secondary radiation therapy. Careful follow-up is emphasized for long-term survivors.

Hyperthermia-induced apoptosis in two rat yolk sac tumor cell lines with different radiothermosensitivity in vitro

We investigated cell susceptibility to hyperthermia-induced apoptosis in two rat yolk sac tumor cell lines (RYSTs) and attempted to correlate this with the known potentially relevant molecular determinants of apoptosis, p53 protein status, Bcl-2 family of proteins and heat shock proteins (Hsp). Parent cell line, NMT-1 (carrying wild-type p53 gene) was radiosensitive but thermoresistant compared to the variant cell line, NMT-1R (mutated type p53), which was isolated from NMT-1 by repeated radiation exposure. Induction of apoptosis by hyperthermia at 43 degrees C was morphologically detected in both RYSTs using hematoxylin and eosin, and TUNEL staining and additionally confirmed by DNA ladder formation (the cleavage of DNA into oligonucleosomal fragments). Western blot analysis showed an increase in expression of p53, p21WAF1/CIP1, Hsp70 proteins in both cell lines after heat-shock at 43 degrees C for 30 min. Hsp90 expression increased in NMT-1 but was not affected by heating in NMT-1R cells, whereas hyperthermia exerted no effect on the endogenous expression of Bax. Bcl-2 protein could not be detected in either RYST. These results suggest that hyperthermia induced apoptosis in both NMT-1 and NMT-1R and apoptosis in RYSTs may be independent of p53-dependent signaling pathway.

High-dose radiation therapy for elderly patients with inoperable or unresectable non-small cell lung cancer

PURPOSE

To evaluate definitive radiation therapy delivering doses in excess of 60 Gy for elderly patients aged 75 years or over with non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

The treatment results for 97 patients aged 75 years or older (mean age 78 years; elderly group) with inoperable or unresectable NSCLC were retrospectively analyzed and compared with those for 206 patients younger than 75 year old (mean age 64 years; younger group). The elderly patients were classified into two groups; 67 patients aged 75-79 years (the elderly A) and 30 patients aged 80 years or older (the elderly B). Most of all patients were treated with a total dose of 60 Gy or more in 2 Gy daily standard fractionation.

RESULTS

The overall 2 and 5 year survival rates were 32 and 13% for the elderly A group, and 28 and 4% for the elderly B group, respectively, compared with 36 and 12% for the younger group. There was not a statistically significant difference in survival rates among three groups. In stage I-II NSCLC patients there was also no significant difference in survival curves among the three groups. In patients with stage III disease, however, the survival curve of the elderly B was inferior to those of the younger group and the elderly A group, although the difference was not statistically significant. After the treatment the deterioration rate of the performance status was only 5% in the younger group and 8% in the elderly group. Only three younger and two elderly patients died of late pulmonary insufficiency associated with high-dose irradiation to the proximal bronchus. No other treatment-related event was observed except for mild acceptable acute complications in the elderly groups.

CONCLUSIONS

Definitive radiation therapy is recommended to the elderly aged 75 years or older with inoperable or unresectable NSCLC, especially early stage disease, as an acceptable choice of treatment.

Small cell lung cancer with a brain metastasis controlled for 5 years: a case report

We report a case of small cell lung cancer whose initial presentation was a solitary brain metastasis. On chest radiography the primary tumor was unclear and only detected by bronchofiberscopy. A small single pulmonary metastasis was noted in the right lower lobe. Subtotal resection and external irradiation were applied to the brain tumor and external irradiation was applied to the lung. Concurrently one course of systemic chemotherapy was administered. The tumors in the brain and lung had disappeared by the end of the treatment. The patient has been alive and well for 5 years without recurrence.

Clinical application of low dose-rate brachytherapy combined with simultaneous mild temperature hyperthermia

BACKGROUND

Recent biological research has shown that mild temperature hyperthermia (MTH) around 41 degrees C simultaneously combined with low dose-rate irradiation (LDRI) is an effective treatment modality for cancer. The aim of the study was to assess the clinical usefulness of a combination of MTH and simultaneous low dose-rate brachytherapy.

MATERIALS AND METHODS

Seven superficial and 8 deep-seated tumors were included in this protocol. Two tumors had no previous treatment and the remainder were recurrent tumors which had arisen from previously treated sites. The average major diameters of superficial and deep tumors were 8.6 and 7.0 cm, respectively. The average values for Tmin in superficial and deep tumors were 41.5 and 40.7 degrees C, respectively. Brachytherapy was delivered by 137Cs and/or 192Ir LDRI sources.

RESULTS

For superficial tumors, six of the seven tumors responded to the treatment (4 achieved CR, 2 PR, 1 NC) and four tumors did not recur within the follow-up period of 5-15 months. All of the deep tumors responded and 5 achieved CR, 3 PR. Four tumors recurred 4-17 months after the treatment and the remainder showed no local recurrence within the follow-up period of 4-31 months.

CONCLUSION

MTH simultaneously combined with LDRI was an effective method for treating progressive and bulky tumors with a previous treatment history.

[Radiation therapy for head and neck cancer]

Radiation therapy is the first choice of treatment for most of the early squamous cell carcinoma of the head and neck. Conventional radiotherapy however, contributes to the high local control rates only for carcinoma of the glottic larynx and the nasopharynx. Squamous cell carcinoma of the other sites cannot be sterilized easily only by external beam radiation therapy alone. Chemoradiotherapy, conformal three-dimensional radiotherapy and multi-daily fractionation are introduced clinically to improve local control and/or survival for radioresistant tumor. In this review, consensus report of radiation therapy for carcinoma of the larynx and pharynx, which was reached an agreement in JASTRO meeting in 1998, is introduced. The role of radiation therapy in the management of head and neck cancer in present and near future is also discussed.

Biological cell survival mapping for radiofrequency intracavitary hyperthermia combined with simultaneous high dose-rate intracavitary irradiation

We examined the best way to combine recently developed radiofrequency intracavitary hyperthermia with simultaneous high dose-rate intracavitary brachytherapy in an original experimental model. Temperature distribution was measured with an experimental phantom which was immersed in a water bath with the temperature controlled at 37 degrees C. Radiation dose distribution was calculated with a treatment-planning computer. Cell survival was measured by colony assay with HeLa-TG cells in vitro. Radiation dose response at 1 - 7 Gy and time response with hyperthermia in the range of 40 - 46 degrees C were estimated. Radiation dose-response curves in simultaneous treatment with hyperthermia for 30 min at 37 to 46 degrees C were estimated and the surviving fractions in combined treatment were plotted against temperature. For intracavitary radiation alone, cell survival rates increased with increasing distance from the source. For intracavitary hyperthermia alone, the maximum temperature was observed at a depth of 13 mm from the surface of the applicator under suitable treatment conditions. Homogeneous cell killing from the surface of the applicator to a tumor depth of 13 mm was observed under a specific treatment condition. Our experimental model is useful for evaluating the best simultaneous combined treatment.

The effects of p53 status and human papillomavirus infection on the clinical outcome of patients with stage IIIB cervical carcinoma treated with radiation therapy alone

BACKGROUND

It has been suggested that the p53 tumor suppressor gene regulates the radiosensitivity in human malignancies after irradiation; however, in cervical carcinoma, the role of the p53 gene is still unclear because of inactivation of functional p53 by infection with human papillomavirus (HPV). The objective of this study was to clarify the effects of p53 status and HPV infection on the clinical outcome of patients with cervical carcinoma after undergoing radiation therapy.

METHODS

Fifty-two patients with International Federation of Gynecology and Obstetrics Stage IIIB squamous cell carcinoma of the cervix who received radiation therapy alone were reviewed. The combination of external beam irradiation therapy and three sessions of intracavity brachytherapy irradiation was performed for all patients. Genomic DNA extracted from paraffin embedded tissues was examined for HPV types 16, 18 and 33 by the polymerase chain reaction (PCR) method and for p53 status by PCR-single-strand conformation polymorphism (PCR-SSCP) technique. The effects of HPV infection, p53 status, and other parameters on clinical outcome were investigated by univariate analysis.

RESULTS

HPV-DNA was detected in 40 patients (76.9%), and 14 patients (26.9%) had mutations of the p53 gene in the study. There was a significant correlation between the existence of HPV and p53 status (P < 0.001). Mutations of the p53 gene were detected in 6 of 12 patients (50%) who had local recurrent tumors, whereas p53 were wild type in 32 of 40 patients (80%) who achieved local control. The p53 mutation had a significant correlations with local tumor recurrence. Furthermore, p53 status caused statistical significant differences in the curves of the recurrence free survival rate and local control rate as determined by the log rank test (P = 0.02 and P = 0.03, respectively). Conversely, no obvious correlation with any clinical outcome for patients with cervical carcinoma was found concerning HPV infection.

CONCLUSIONS

It is possible that the p53 gene may be used as a predictive factor in radiation therapy for patients with Stage IIIB squamous cell carcinoma of the cervix.

Intraoperative radiotherapy and bypass surgery for unresectable pancreatic cancer

BACKGROUND/AIMS

Conflicting results have been reported concerning the usefulness of radiotherapy for unresectable pancreatic cancer. We evaluated the clinical efficacy of intraoperative radiotherapy and/or external beam radiotherapy in combination with bypass surgery.

METHODOLOGY

Twenty-six patients with unresectable pancreatic cancer (16 in Stage II-III and 10 in Stage IV) were treated with intraoperative radiotherapy plus external beam radiotherapy (16 patients) or intraoperative radiotherapy alone (10 patients). The dose of intraoperative radiotherapy was either 25 or 30 Gy and the external beam radiotherapy dose was 31-60 Gy. The feasibility and clinical outcome were analyzed.

RESULTS

The median survival time for Stage II-III and Stage IV were 11.5 and 6.5 months, respectively. The difference between Stage II-III and Stage IV in survival patterns was statistically significant (P < 0.05). For Stage II-III patients, the survival curves between the groups of intraoperative radiotherapy plus external beam radiotherapy and intraoperative radiotherapy alone were not significantly different, and only performance status was a significant factor in the prognosis (P < 0.05). Gastrointestinal bleeding was noted in 8%, but did not occur in the patients treated with an external beam radiotherapy dose less than 50 Gy. Palliative radiation was successfully performed to relieve pain, jaundice and appetite-loss and to shorten the hospital stay.

CONCLUSIONS

The combination therapy with intraoperative radiotherapy and bypass surgery is considered to be tolerable and effective for unresectable pancreatic cancer, and also may improve the quality of life of the patients.

[Study on evaluation method of patient dose in diagnostic radiology required for introducing the guidance level: investigation of entrance surface dose of patient using direct measurement by TLD]

Using direct measurement, we investigated entrance surface doses of patients for routine radiographs in attempt to develop evaluation methods of patient dose in order to establish the guidance level in Japan. To date, patient doses have been evaluated by calculations based on radiographic conditions, or model experiments using phantoms. Their patient doses are then evaluated based on several assumptions. Direct measurement of patient dose is difficult to perform in many patients due to its time requirement, level of expertise required and difficulty in providing an explanation of the procedure to the patient. However, such direct measurement is essential since it incorporates all aspects of radiography from the radiographic equipment used, to the actual conditions of each patient without assumption. In this study, we examined the (1) need for introducing the guidance level, (2) controversial points in the calculation method for patient dose evaluation, (3) evaluation accuracy required for introducing the guidance level, and (4) necessity for a standardized method.

[Recent advances of radiation therapy for non-small cell lung cancer]

Radiation therapy(RT) has been frequently used for patients with inoperable or unresectable non-small cell lung cancer(NSCLC). In our series of NSCLC patients without progression of disease at the end of two years after RT, the majority of squamous cell carcinoma patients were alive well after 5 years from RT. On the other hand, half of adenocarcinoma patients had distant failures later. The recent data have indicated that the prognosis for selected favorable patients with unresectable disease will be improved by systemic chemotherapy combined with RT. Furthermore recent innovations in RT have shown promise in the treatment of NSCLC, especially squamous cell carcinoma. For future improvement of the treatment results of NSCLC, it is important that the role of RT be established.

Caffeine enhanced radiosensitivity of rat tumor cells with a mutant-type p53 by inducing apoptosis in a p53-independent manner

The radiosensitizing effects of caffeine on two rat yolk sac tumor cell lines with a different p53 status were investigated. A reduction of radiation-induced G(2) arrest was caused by caffeine at a concentration of 2 mM in both cell lines. The reduction of survival was observed in a combination of radiation and 2 mM caffeine only in a lower radiation dose range, but not in a higher dose range in NMT-1 with a wild type p53. Radiosensitization of caffeine was recognized even in a higher dose range for cells with a mutant-type p53. Apoptosis, which was not prominent after irradiation alone or caffeine treatment alone, was induced by irradiation in combination with caffeine in cells with a mutant-type p53 through a p53-independent pathway.

Radiation therapy for elderly patient with squamous cell carcinoma of the uterine cervix

OBJECTIVE

The purpose of this study was to profile cervical squamous cell carcinoma in elderly patients undergoing radiation therapy and to study the treatment outcome and side effects of therapy.

MATERIALS AND METHODS

A retrospective analysis was carried out from the records of 380 patients with squamous cell carcinoma of the uterine cervix who had been given radiation therapy between 1970 and 1994. The patients were divided into three age groups: under 70 years (youngest group; n = 215), 70 to 79 years (intermediate group; n = 124), and 80 years or older (oldest group; n = 41). Radiation therapy was performed by a combination of external beam therapy and three brachytherapy fractions using low-dose-rate sources.

RESULTS

The 5-year overall survival rates in the youngest, intermediate, and oldest groups were 58, 50, and 33%, respectively, while cause-specific survival rates were 68, 70, and 65%, respectively. For the patients with stage III, the 5-year overall survival rates in the youngest, intermediate, and oldest groups were 59, 48, and 36%, respectively, while cause-specific survival rates were 72, 70, and 70%, respectively. There was no statistical significance in the 5-year intrapelvic recurrence rates among the three groups. Grade 3 or 4 complications occurred in 6.5% of the youngest, 11.3% of the intermediate, and 7.3% of the oldest groups.

CONCLUSION

Radiation therapy with external beam combined with three fractions of low-dose-rate brachytherapy proved both highly effective and safe for senior patients with cervical squamous cell carcinoma.

Experimental study of the effects on apoptosis of docetaxel alone and in combination with irradiation

The effects of docetaxel alone and in combination with irradiation were experimentally investigated in terms of induction of apoptosis. A human ependymoblastoma was transplanted into nude mice, and they were intravenously injected with docetaxel, followed or preceded by irradiation with a single dose of 2 Gy. Apoptosis was less common in the docetaxel-alone group than in the irradiation-alone group. When administration of docetaxel was followed by irradiation, apoptosis was equal to or less common than in the irradiation-alone group. Apoptosis was most common in the irradiation-followed-by-docetaxel group. The incidence of mitosis was lower in the irradiation-alone group and the irradiation-followed-by-docetaxel group than in the docetaxel-alone group and the docetaxel-followed-by-irradiation group. The combined effect of irradiation and docetaxel appears to be useful in inducing apoptosis, but the sequence of irradiation and docetaxel is important.

Comparison of effects of doxorubicin and radiation on p53-dependent apoptosis in vivo

The effects of doxorubicin and radiation on apoptosis, p53 expression, and tumor growth in human tumor xenografts were investigated. Human ependymoblastoma (NNE), primitive neuroectodermal tumor (YKP), glioblastoma (KYG) and small cell lung carcinoma (GLS) that are all transplantable to nude mice were treated with doxorubicin (8 mg/kg) or radiation (1 Gy). The histological study was performed by using TUNEL and p53 staining. Cytotoxic effects of doxorubicin and radiation were compared with no-treatment group by the growth curves and apoptotic index of tumor to each treatment. In NNE with wild-type p53, doxorubicin induced growth delay of tumors (tumor volume doubling time; 13.7+/-3.3 days in control group vs 30.4+/-1.5 days in doxorubicin group), but no growth delay of tumors in KYG and GLS with mutant type p53. While radiation-induced apoptosis appeared most frequently at 6 h after irradiation, doxorubicin-induced apoptosis had a tendency to appear later. Furthermore, although the frequency of doxorubicin-induced apoptosis was lower than that of apoptosis by 1 Gy irradiation, apoptotic cells appeared for many hours after the treatment. Doxorubicin-induced apoptosis may be correlated with p53 phenotype because apoptosis was induced only in tumor with wild-type p53, but it appeared less frequently and later than radiation-induced apoptosis.

Induction of p53-dependent apoptosis in vivo by nedaplatin and ionizing radiation

p53 protein expression, apoptosis and growth delay induced by nedaplatin, a novel platinum compound, were investigated in vivo, and compared with those induced by ionizing radiation. A human ependymoblastoma with wild-type p53 was transplanted subcutaneously to the thighs of nude mice. The incidences of p53 protein-positive cells and apoptosis in tumors increased following exposure to ionizing radiation. In tumors treated with nedaplatin, they also increased, but the incidences of p53 protein-positive cells and apoptosis induced by 32 mg/kg nedaplatin, 1/2 LD50, were lower than those induced by 1 Gy irradiation. However, growth-delay assay showed no significant difference between the efficacy of 32 mg/kg nedaplatin and that of 1 Gy irradiation. These results suggest that the main antineoplastic activity caused by nedaplatin may be mediated through different mechanisms than those of the p53-dependent early apoptosis.

Experimental induction of apoptosis by a combination of etoposide and radiation treatment

The present study was undertaken to investigate cell death (particularly apoptosis) induced by etoposide, radiation, and both, and to examine p53 protein expression in relation to cell death. Nude mice transplanted with a human tumor (ependymoblastoma) were treated with etoposide (5-40 mg/kg) or 1-2 Gy X-ray irradiation or both. The tumor was excised at different points after treatment, and tumor tissue specimens were used to check for apoptosis and p53 protein expression by TUNEL, p53 protein staining, etc. Induction of p53-dependent apoptosis was observed in the etoposide treatment group, the X-ray irradiation group, and the combined (etoposide + X-ray irradiation) group. Etoposide 10 mg/kg was found to be approximately equivalent to 1 Gy X-ray irradiation in ability to induce apoptosis. When etoposide treatment was combined with X-ray irradiation at intervals of 3-6 hours, an approximately additive effect was observed.

Potentially lethal damage repair and its inhibitory effect of caffeine in two yolk sac tumor cell lines with different radiosensitivities

PURPOSE

In order to investigate the role of potentially lethal damage repair (PLDR) in cellular radiosensitivity, PLDR and its inhibitory effect by caffeine was examined. In addition, cell cycle distribution was also examined.

MATERIALS AND METHODS

Two rat yolk sac tumor cell lines, NMT-1 and NMT-1R, with different radiosensitivities in vitro were used. The capacity for PLDR was examined using confluent-phase cells, and evaluated by calculating the recovery ratio. Inhibitory effect of caffeine on PLDR was examined with doses of 1, 5 and 10 mM.

RESULTS

The capacity of PLDR in two cell lines reflected radiosensitivity. The recovery ratio after irradiation of 5 Gy was 2.8 in the radiosensitive NMT-1 and 5.2 in the radioresistant NMT-1R, and recovery reached its peak level at 6 h in both cell lines. The degree of inhibition of PLDR was weaker in NMT-1R than that in NMT-1 at the same dose level, and was correlated with reduction of G2-arrested cells by caffeine.

CONCLUSIONS

The results of this study suggest that the capacity of PLDR may be one of the determinant factors for radiosensitivity in the two cell lines used, and the inhibitory effect of caffeine on PLDR was in part attributable to the modification of the cell cycle progression.

Limited field irradiation for medically inoperable patients with peripheral stage I non-small cell lung cancer

The outcome of limited field irradiation for medically inoperable patients with peripheral stage I non-small cell lung cancer (NSCLC) was analyzed to discuss the elective irradiation of regional lymph nodes. From 1976 through 1994, 36 patients with peripheral stage I NSCLC were treated with definitive radiation therapy (RT) alone at Gunma University hospital. The total dose ranged from 60 to 81 Gy with a 2 Gy-daily standard fractionation, although only one patient received 48 Gy. Ten patients received elective irradiation of the regional lymph nodes with a total dose of 40 Gy or more. The overall response rate was 97% with 31% complete responses. The overall survival rates at 3 and 5 years were 42 and 23%, and disease-specific survival rates were 56 and 39% at 3 and 5 years, respectively. In 26 patients without the elective regional irradiation, disease-specific survival rates at 3 and 5 years were 53 and 40%, respectively, whereas they were 64 and 39% in 10 patients with the regional nodal irradiation. The cumulative 5-year local progression rate was 28%, and the overall progression rate was 60% at 5 years. Four patients had a local recurrence as the only site of initial tumor progression. Combined local and regional progression was seen in two patients, and one patient had a local recurrence in combination with distant metastasis. Twelve patients had distant failure without evidence of local or regional progression. Only one patient without regional nodal irradiation developed an isolated regional failure. No patient had serious complications related to RT. High-dose limited field RT is justified for medically inoperable patients with peripheral stage I NSCLC. The regional nodal irradiation can be omitted in these pulmonary compromised patients because of the low regional relapse rate. Dose-escalation by a conformal RT with a small target volume can be expected to provide a better local control rate and better survival.

Effect of paclitaxel pretreatment on radiation-induced p53-dependent apoptosis

The aim of this study was to investigate the effect of paclitaxel on radiation-induced p53-dependent apoptosis. A human ependymoblastoma transplanted to nude mice was used. They were treated with paclitaxel (40 mg/kg), irradiation (2 Gy), or a combination of both. Apoptosis was markedly increased in the irradiation group. p53 protein expression was well correlated with the frequency of radiation-induced apoptosis. There was only a slight increase in apoptosis in the paclitaxel group, with little p53 protein expression. In the combination group, the frequency of apoptosis varied with the time intervals, and the group irradiated 12 h after paclitaxel administration showed much less apoptosis than the irradiation group. The Ki-67 labeling index in the paclitaxel group was always higher than before administration. The present study indicates that p53-dependent apoptosis was frequently induced in the human tumor in vivo by irradiation, but not by paclitaxel alone. When combined with irradiation, the timing affected the frequency of apoptosis and the degree of p53 protein expression.

Apoptosis and appearance of Trp53-positive micronuclei in murine tumors with different radioresponses in vivo

The purpose of this paper is to determine the relationship between the response to radiation and the appearance of apoptosis and micronuclei with Trp53 protein in murine tumors after irradiation. Two murine tumors, EL4, which was derived from a mouse lymphoma, and FM3A, which was derived from a mouse mammary carcinoma, were locally irradiated with 15 Gy and sections were stained with H&E and an anti-Trp53 antibody. The response to radiation was greater in EL4 tumors than in FM3A tumors. The frequency of apoptotic cells in EL4 tumors was 6.1 +/- 1.2% at time zero, reached a peak of 36.3 +/- 3. 8% at 6 h, and then decreased with time through 72 h to 2.5 +/- 1.5% after 15 Gy irradiation. In FM3A tumors, no apoptotic cells were detected at 0, 1, 3, 6 or 24 h after exposure. At 48 and 72 h, the frequency was only 3.0 +/- 0.6% and 1.3 +/- 0.3%. Apoptotic cells increased significantly at 3, 6 and 24 h after irradiation in EL4 tumors (P < 0.008) and at 48 and 72 h in FM3A tumors (P < 0.006). The frequency of Trp53-positive cells was 17.9 +/- 2.2 and 15.2 +/- 2.3% at time zero in EL4 and FM3A tumors, respectively, increased to 74.5 +/- 4.5% in EL4 cells (P = 0.001), and increased to 33.9 +/- 1. 1% in FM3A cells (P = 0.005) 1 h after irradiation. Trp53-positive micronuclei appeared in cells in both tumors from 24 to 72 h after irradiation. The frequency of Trp53-positive micronuclei was 3.8 +/- 0.5 and 13.5 +/- 1.3% at 24 h in EL4 and FM3A tumors, respectively, and gradually decreased by 72 h. After exposure to 15 Gy, Trp53-positive micronuclei increased significantly in FM3A tumors compared to EL4 tumors at both 24 and 48 h (P < 0.02). The frequency of these micronuclei increased with increasing dose in FM3A tumors, and the difference between these percentages after 3 Gy and after 5, 10 and 15 Gy was significant (P < 0.02). Many apoptotic cells were observed in the radiosensitive EL4 tumor after irradiation. Death by apoptosis may be related to an early response to radiation in these tumors. The appearance of micronuclei may be an important mechanism of cell death in FM3A tumors in which no apoptosis was induced.

Giant cell tumor of the thoracic spine simulating mediastinal neoplasm

A case of giant cell tumor of the thoracic spine simulating mediastinal neoplasm was identified on plain films, CT scans, MR images, and with scintigraphy. CT showed a hypervascular soft-tissue mass with shell-like calcification in the right upper mediastinum. MR imaging showed a collapse of the T1 vertebral body and a mass extending to the mediastinum. The mass had a low signal on T1-weighted MR images and a predominantly high signal on T2-weighted images with heterogeneity. Technetium-99m methylene diphosphonate bone scintigraphy showed intense uptake in both the T1 and marginal parts of the mediastinal mass. There was no accumulation of gallium-67 citrate, but 18-fluorine fluorodeoxyglucose positron emission tomography showed marked uptake. The variation in these imaging findings played an important role in the differential diagnosis of this uncommon mediastinal mass.

In vivo study of radiosensitizing effect of hypoxic cell radiosensitizer PR-350 on a human small cell lung cancer

PURPOSE

The purpose of this study was to clarify the utility of 1-(1',3',4'-Trihydroxy-2'-Butoxy) Methyl-2-Nitroimidazol (PR-350) as a hypoxic cell radiosensitizer in an in vivo human tumor. We examined the effect of PR-350 on the changes of tumor volume and microscopic features following irradiation.

METHODS AND MATERIALS

Tissue from a human small-cell lung cancer was transplanted to 136 nude mice. They were given 200 mg/kg of PR-350, as a hypoxic cell radiosensitizer, or saline, for the control. One hundred mice were used to evaluate the effect of PR-350 on tumor volume after irradiation, and the other mice were used for histological study: hematoxylin and eosin staining, immunohistochemistry (Ki-67 and p53), TUNEL staining, and electromicroscopy.

RESULTS

Respective 10, 15, and 20 Gy irradiation groups showed some tendency of a sensitizing effect of PR-350, compared with the saline group. A statistically significant difference was observed between PR-350- and saline-treated groups with 15 Gy of irradiation (p < 0.05). Apoptotic cells counts were slightly increased in both PR-350 and saline groups at 6 h after 15 Gy of irradiation. Massive necrotic areas were noted in both groups at 72 h after irradiation. p53 was intensely positive in most tumor cells with or without irradiation. However, no significant difference was found between PR-350 and saline groups in these microscopic features.

CONCLUSION

PR-350 was an effective hypoxic cell radiosensitizer for a human small cell lung cancer in vivo, in which necrotic change was dominant following irradiation.

Is radiosensitive cell line cross-sensitive to heat?: Effect of heat on two rat yolk sac tumor cell lines with different radiosensitivity

The differences between two rat yolk sac tumor cell lines, which are of the same origin but differ in their response to irradiation, in thermal sensitivity and development of thermotolerance were investigated. A radiosensitive cell line NMT-1 is consistently less heat sensitive than the radioresistant cell line NMT-1R. The thermotolerances in NMT-1 and in NMT-1R preheated at 43 degrees C for 30 min, respectively, reached peaks at 6 h and at 12 h, but did not completely disappear at 48 h. Thermotolerance with a good correlation between both cell lines with HSP70 accumulation was observed in a different time course after a primary heating.

Analysis of 57 nonagenarian cancer patients treated by radical radiotherapy: a survey of eight institutions

BACKGROUND

As the human society grows more aged, it is considered important to elucidate factors essential in applying radical radiotherapy (RT) to the elderly, with ages as high as 90 years and greater.

METHODS

A retrospective survey was conducted for patients 90 years of age or older who received radiotherapy with radical intent in eight leading institutions in Japan from 1990 through 1995.

RESULTS

Fifty-seven nonagenarian patients were studied. Their ages ranged up to 98 (median 91) and there was a strong female preponderance (M/F: 16/41). The distribution by site was as follows: head and neck, 16; skin and adnexae, 11; uterine cervix, 7; esophagus, 6. The prevailing histopathological diagnosis was squamous cell carcinoma (34), followed by adenocarcinomas (8). The highest age at RT was 98 years [female, skin cancer, died of senility 2.5 years after treatment, with no evidence of disease (NED)] and the longest survivor is 102 years old (female, glottic cancer T2, age at RT 93, alive NED for 8 years, uses wheel-chair). The rate of completion of treatment was 75% (43/57), if the treatment field was limited to the gross primary tumor volume only and if the cumulative dose was above 80% of the tolerable adult dose. Familial escort was necessary for most of the patients in completing the day-to-day RT.

CONCLUSION

Radiotherapy is feasible with radical intent even in the elderly, if the treatment field is limited to the gross primary tumor volume only, if the cumulative dose is above 80% of the tolerable adult dose and if familial support is adequate.

Interaction between low dose-rate irradiation, mild hyperthermia and low-dose caffeine in a human lung cancer cell line

PURPOSE

To investigate cell killing by means of low dose-rate irradiation (LDRI) combined with concurrent mild hyperthermia and to determine the effect of low-dose caffeine on this combination treatment.

MATERIALS AND METHODS

Human lung adenocarcinoma cells, LK87, were treated with LDRI (50 cGy/h) in combination with mild hyperthermia at 41 degrees C and low-dose caffeine (1 mM). Cell survival was estimated by clonogenic assay. Flow-cytometry was performed with PI staining using FACScan. Heat-shock protein (HSP72/73) was measured by the Western blotting method. All treatments were simultaneously performed for up to 48 h (24 Gy).

RESULTS

LDRI cytotoxicities were enhanced by hyperthermia at 41 degrees C. D0 calculated from the dose-response curve for LDRI combined with 41 degrees C was 3.46 Gy whereas it was 6.55 Gy for LDRI alone. The survival curve for LDRI +41 degrees C demonstrated no chronic thermotolerance up to 48 h. For LDRI + simultaneous low-dose caffeine, cell killing was also enhanced, where D0 was 3.38 Gy at 37 degrees C. Radiosensitization caused by caffeine was enhanced by combination with simultaneous mild hyperthermia at 41 degrees C, where D0=1.78 Gy. Cell cycle analysis demonstrated remarkable G2 and mild G1 arrest for LDRI alone, but only G1 arrest was observed for LDRI combined with 41 degrees C and for LDRI combined with caffeine. Strong and early G1 arrest was observed in the treatment with LDRI + caffeine at 41 degrees C. The amount of HSP72/73 in the combination of LDRI with caffeine at 41 degrees C was less than that at 41 degrees C alone.

CONCLUSION

LDRI cytotoxicity was enhanced by non-lethal hyperthermia. Low dose caffeine produced further cell killing in the combination of LDRI with mild hyperthermia.

Cancer in patients aged 90 years or older: radiation therapy

PURPOSE

To investigate the clinical efficacy of radiation therapy for cancer in patients aged 90 years or older.

MATERIALS AND METHODS

Cancer cases in 32 patients (11 men, 21 women) aged 90 years or older who underwent radiation therapy in 1970-1997 were retrospectively analyzed. The mean patient age was 92.2 years, with a range of 90-98 years. Head and neck cancer (n = 14 [44%]) and skin cancer (n = 6 [19%]) were the most common.

RESULTS

Eleven (79%) of the 14 patients with head and neck cancer were treated with curative intent. Radiation response without any severe complication was observed in nine (90%) of the 10 patients with head and neck cancer treated with curative intent who finished treatment. The median survival time was 8 months (range, 3-55 months) in the 10 patients with head and neck cancer who completed treatment with curative intent. Complete response was achieved in all of the patients with skin cancer without any major sequelae. Complete response was also observed in all three of the patients with non-Hodgkin lymphoma, but two patients treated with adjuvant chemotherapy died of drug-induced pneumonitis. Palliation was achieved in all nine of the patients treated with palliative intent.

CONCLUSION

Age of 90 years or older is not a limiting factor for radiation therapy.

p53 mutation decreased radiosensitivity in rat yolk sac tumor cell lines

PURPOSE

We reported that two established rat yolk sac tumor cell lines differ in their radiosensitivity by 1.7 fold, and the variation is most likely manifested by the differences seen in their apoptotic response. We investigated the relationship between radiosensitivity and p53 in these cell lines.

METHODS AND MATERIALS

We assessed the status of p53 in cell lines by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequence analysis, and also analyzed protein expression of p53, p21, and bax as a function of time after irradiation to determine the signal transduction for p53 by immunoblotting.

RESULTS

A band shift was observed only in exon 7 for the radioresistant NMT-1R cells and no band shift was detected for the radiosensitive NMT-1 cells. A band shift was confirmed also at the mRNA level. Exon 7 of p53 DNA showed a three base substitution of DNA at codon 267 to 268. Expression of p53, p21, and bax proteins in NMT-1R cells did not change after 10 Gy irradiation; however, in NMT-1 cells, the expression of these proteins was increased from 1-12 h after irradiation.

CONCLUSION

A loss of p53 function by radiation-induced mutation of p53 decreased the radiosensitivity in these cell lines.

Stereotactic radiotherapy for locally recurrent nasopharyngeal carcinoma

OBJECTIVE

To determine the efficacy of stereotactic radiotherapy (SRT) in the treatment of recurrent nasopharyngeal carcinoma.

STUDY DESIGN

A retrospective review of the outcome of SRT for patients with recurrent nasopharyngeal carcinomas following definitive conventional radiation therapy.

METHODS

Five patients were treated with daily static multiportal irradiation. Two Gy was administered with eight isocentric portals in a single plane 5 days a week, and the plane was changed for every 20 to 30 Gy. Of these patients, three had poorly differentiated squamous cell carcinoma. Tumor sizes ranged from 1 to 15 cm3, with a median size 3.2 cm3. Median follow-up time from SRT was 34 months (range, 4-61 mo).

RESULTS

Four of five recurrent tumors responded well and achieved complete regression. Three patients have survived without evidence of local recurrence with a median follow-up time of 34 months. Marginal recurrence was observed at the posterosuperior wall in a patient with adenoid cystic carcinoma at 30 months after SRT. One patient who received SRT after the two complete courses of radiation therapy died 6 months after SRT as a result of rupture of a branch of the left carotid artery, but autopsy revealed no local residual tumor.

CONCLUSIONS

Stereotactic radiotherapy with isocentric multiportals in one plane, which is changed at every 20 to 30 Gy, can provide local control with acceptable toxicity in patients with recurrent nasopharyngeal carcinoma, but increased clinical experience and longer follow-up will be necessary to evaluate the overall role of this technique in nasopharyngeal carcinoma.

Modification of tumor-associated antigen (CEA) expression of human lung cancer cells by irradiation, either alone or in combination with interferon-gamma

The effect of irradiation either alone or in combination with cytokine (IFN-gamma) on the expression of carcinoembryonic antigen (CEA) on the surface of the human lung cancer cell line, GLL-1, was studied in vitro. The results demonstrated that CEA expression on GLL- 1 cells increased after irradiation with a single dose of 10 Gy. In a time-course study the peak of CEA expression was observed at the 4th day after irradiation. The relative CEA expression on the 1st to 5th day after irradiation were 1.2, 1.2, 1.2, 1.4 and 1.3, respectively. Irradiation in combination with IFN-gamma showed an additional effect on the expression of CEA. A 1.7 fold increase in CEA expression was detected. A cell cycle study showed that the change in the relative CEA expression of the G1 cell fraction was similar to that of all cell fractions. The relative CEA expression of GLL-1 cells treated by irradiation in combination with IFN-gamma in the G1 cell fraction was much higher than those treated differently.

Surgical margin and breast recurrence after breast-conserving therapy

A total of 161 patients with clinical stage I and II breast cancer received breast-conserving therapy between August 1991 and December 1997, and local recurrence occurred in five patients. The actuarial local control 5 years after breast-conserving surgery was 96.6%. We studied microscopic surgical margins of resected specimens in patients with breast-conserving surgery to determine whether the surgical margin was a risk factor for local recurrence in the conserved breast. Microscopic margins were negative in 125 (78%) of 161 patients and positive in 36 (22%). There were no differences between patients with positive surgical margins and those with negative surgical margins in age at operation, tumor size, clinical stage, lymph node status, estrogen receptor status, or distance from tumor to nipple. Local control was significantly better in the surgical margin-negative patients than in the surgical margin-positive patients. We conclude that microscopic surgical margin is a risk factor for local recurrence in the conserved breast.

Nasopharyngeal cancer with neck recurrence at 8 years and a lung metastasis at 15 years after the first definitive radiotherapy: a case report

We report a patient with nasopharyngeal cancer with long-term follow-up of more than 16 years after the first course of radiotherapy in 1981. He developed a lung metastasis in 1996 after having a second course of radiotherapy for neck recurrence in 1989. The patient was a 42-year-old man with a nasopharyngeal tumor and a fixed upper neck metastasis (T1N1M0), which was treated with definitive radiotherapy. He manifested regional recurrence, at the margin of the radiation portal, with an 8 year disease-free interval, which was treated successfully by definitive re-irradiation. He developed a solitary lung metastasis, which was treated by video-assisted thoracoscopic lung resection, 7 years disease-free after the second course of radiotherapy. For 20 months after the removal of the lung metastasis he has been generally well without any signs of recurrence of sequelae. This case indicates the efficacy of definitive re-irradiation for regional recurrence and the necessity for long-term observation after radiation therapy for nasopharyngeal cancer.

31P NMR spectroscopy can predict the optimum interval between fractionated irradiation doses

This study was performed to clarify whether changes in the metabolites observed by phosphorous-31 magnetic resonance spectroscopy (31P-MRS) could indicate an optimum interval between two doses of radiation in a murine tumor model. Murine mammary carcinoma cells, FM3A, were irradiated 7 days after transplantation with a single 5 Gy dose without anesthesia. 31P spectra were measured with a spectrometer up to 30 days. The beta-ATP/Pi and PCr/Pi values were calculated from the peak area of each spectrum. In a fractionation experiment, two fractions of irradiation at a 5 Gy per fraction were given at 0, 1, 2, 3 and 6 day intervals. Tumor growth delay was also scored to determine the fractionated radiation effect. In the control group, beta-ATP/Pi and PCr/Pi decreased with tumor growth. In the single irradiation group, the tumor did not grow up to day 6, and an initial rise and subsequent decrease in beta-ATP/Pi and PCr/Pi were observed. Maximum beta-ATP/Pi and PCr/Pi were observed on day 2 after irradiation. In a fractionation experiment, the greatest growth delay was observed in the two day interval group, in which maximum beta-ATP/Pi and PCr/Pi were demonstrated in 31P-MRS. Our results suggested that changes in the metabolites observed by 31P-MRS could be useful indicators for determining the fractionation schedule in radiation therapy.

Consistency of variables in PCS and JASTRO great area database

PURPOSE

To examine whether the Patterns of Care Study (PCS) reflects the data for the major areas in Japan, the consistency of variables in the PCS and in the major area database of the Japanese Society for Therapeutic Radiology and Oncology (JASTRO) were compared.

METHODS AND PATIENTS

Patients with esophageal or uterine cervical cancer were sampled from the PCS and JASTRO databases. From the JASTRO database, 147 patients with esophageal cancer and 95 patients with uterine cervical cancer were selected according to the eligibility criteria for the PCS. From the PCS, 455 esophageal and 432 uterine cervical cancer patients were surveyed. Six items for esophageal cancer and five items for uterine cervical cancer were selected for a comparative analysis of PCS and JASTRO databases.

RESULTS

Esophageal cancer: Age (p=.0777), combination of radiation and surgery (p=.2136), and energy of the external beam (p=.6400) were consistent for PCS and JASTRO. However, the dose of the external beam for the non-surgery group showed inconsistency (p=.0467). Uterine cervical cancer: Age (p=.6301) and clinical stage (p=.8555) were consistent for the two sets of data. However, the energy of the external beam (p<.0001), dose rate of brachytherapy (p<.0001), and brachytherapy utilization by clinical stage (p<.0001) showed inconsistencies.

CONCLUSION

It appears possible that the JASTRO major area database could not account for all patients' backgrounds and factors and that both surveys might have an imbalance in the stratification of institutions including differences in equipment and staffing patterns.

Malignant neuroendocrine tumor presenting a huge mediastinal mass controlled with radiation therapy

A case of malignant neuroendocrine tumor presenting a huge mediastinal mass controlled with radiation therapy is reported. A thoracotomy was performed on a 57-year-old male and a mass was found to invade the trachea, main bronchus, and left atrium. The tumor was unresectable. Subsequently, cisplatin was administered, but the tumor grew in size and radiation therapy was recommended. The tumor responded well to thoracic irradiation (56 Gy) and disappeared. Three months later, lymph nodes metastases were noted in the retrocrural and upper abdominal paraaortic regions, but these were controlled again with palliative irradiation. Without further treatment, he survived free of disease for over 5 years. Specimens obtained during the thoracotomy showed that the tumor consisted mainly of small round cells with a rosette formation. Immunohistochemically the tumor was positive to NSE and slightly positive to keratin, but negative to LCA, L26, UCLH-1, EMA, Leu7, and chromogranin, suggesting a malignant tumor derived from neuroendocrine tissue.

Radiation therapy and concurrent daily intra-arterial infusion of low-dose cisplatin following alteration of pelvic blood flow for invasive bladder cancer: a preliminary report

Concurrent intra-arterial infusion chemotherapy and radiation therapy following alteration of pelvic blood flow was performed in 15 patients with invasive bladder cancer (T2: 2, T3a: 4, T3b: 5, T4: 4). Infusion chemotherapy consisted of a daily low-dose of cisplatin with a dose range of 7 to 9 mg per patient. Of the 15 patients, 11 achieved complete response (73%) and other had partial response. Four of those with CR developed recurrence (local recurrence in three and distant metastasis in one patient). Cause specific and disease-free survival at 3-years were 56% and 49.9%, respectively, and the bladder preservation rate at 3-year was 47%. Toxic reactions related to the treatment was of a reasonable level, and cisplatin-induced renal dysfunction was not experienced, even in the patients with poor renal function, although transient neutropenia and thrombocytopenia occurred in all patients at the latter stage of the treatment. This treatment modality is considered to be effective and feasible even in patients with locally advanced disease and/or those unsuited for cisplatin-based systemic chemotherapy.

Does AK-2123 (Senazole) have sensitizing effects on radiation, cisplatin and hyperthermia under aerobic conditions in vitro?

We investigated the sensitizing effects of AK-2123 (Senazole) on the interaction of radiation, cisplatin and hyperthermia under aerobic conditions in the rat yolk sac cell line NMT-1R in vitro. The effects were assessed by clonogenic assay. A cytotoxic effect of AK-2123 after 24 hours exposure was observed as a function of the dose. For NMT-1R cells, the ID70 of AK-2123 was 400 micrograms/ml for 24 hours exposure, which was employed for subsequent combined treatments. Although a statistically significant increase in the G1 cell fraction was observed after AK-2123 treatment with a dose of ID70 (p = 0.02) no enhancing effect of AK-2123 on radiation, cisplatin or heat response curves was detected under aerobic conditions in vitro.

The prognostic significance of immunohistochemically detected p53 protein expression in non-small cell lung cancer treated with radiation therapy

The prognostic significance of nuclear p53 protein expression in survival and local control was investigated immunohistochemically in 36 patients with inoperable or unresectable non-small cell lung cancer who were treated with radiation therapy (RT). Formalin-fixed, paraffin-embedded sections obtained by bronchoscopy were used to examine the expression of nuclear p53 protein with immunohistochemistry. In 25 cases (69%), p53 protein expression was detected. There was no relation between p53 expression and other pretreatment characteristics. Response to RT was found in all p-53 negative cases versus 72% in p53-positive cases (p < 0.05). The 2-year survival rate for p53-negative cases was 51% with a median survival time of 21 months. The corresponding rate for p53-positive cases was 31% with a median survival time of 9 months. This difference, however, did not reach a statistically significant level because of the small sample size. In conclusion, the results of this study suggest that p53 protein expression may be of predictive value on response to RT in non-small cell lung cancer.

Effect of radiation on the expression of E-cadherin and alpha-catenin and invasive capacity in human lung cancer cell line in vitro

PURPOSE

To investigate the effect of radiation on E-cadherin and alpha-catenin expression in a human lung cancer cell line, and also evaluate invasive capacity in the membrane invasion culture system using the Boyden Chamber.

MATERIALS AND METHODS

The immunoblot and immunofluorescence analyses were performed using the human lung cancer cell line A549 to examine altered expression of E-cadherin and alpha-catenin after irradiation. We also compared invasive capacity of untreated cells with that of irradiated cells.

RESULTS

Immunoblot analysis revealed that the expression of E-cadherin increased after irradiation. In a time-course analysis, the expression was increased 6 h after irradiation with 10 Gy and reached its peak level at 24 h, being 2.3 times the control value, whereas expression at 1 and 3 h after irradiation was almost equivalent to that of the control. A slight increase in expression was observed after irradiation of 2 Gy and the expression reached peak levels after 5 Gy. After fractionated irradiation, the increase in expression of both E-cadherin and alpha-catenin was observed, and the alteration of alpha-catenin was more prominent than that after a single irradiation of the same total dose. In the immunofluorescence study for E-cadherin antibody analyzed by confocal laser scanning microscopy, increased intensity in irradiated cells produced as a nondisrupted and continuous line at cell-cell contact sites. In an invasive assay, the number of migrated cells in irradiated cells after a dose of 5 and 10 Gy was reduced significantly compared to untreated cells.

CONCLUSION

The results indicate that irradiation of A549 increased the expression of E-cadherin, possibly preserving their functional property.

Early radiation effects in highly apoptotic murine lymphoma xenografts monitored by 31P magnetic resonance spectroscopy

PURPOSE

Phosphorus-31 magnetic resonance spectra (31P-MRS) were obtained from highly apoptotic murine lymphoma xenografts before and up to 24 hr following graded doses of radiation ranging from 2 to 30 Gy. Radiation-induced apoptosis was also estimated up to 24 hr by scoring apoptotic cells in tumor tissue.

METHODS AND MATERIALS

Highly apoptotic murine lymphoma cells, EL4, were subcutaneously transplanted into C57/BL mice. At 7 days after transplantation, radiation was given to the tumor with a single dose at 3, 10, and 30 Gy. The beta-ATP/Pi, PME/Pi, and beta-ATP/PME values were calculated from the peak area of each spectrum. Radiation-induced apoptosis was scored with counting apoptotic cells on hematoxylin and eosin stained specimens (% apoptosis).

RESULTS

The values of % apoptosis 4, 8, and 24 hr after radiation were 21.8, 19.6, and 4.6% at 3 Gy, 35.1, 25.6, and 14.8% at 10 Gy, 38.4, 38.0, and 30.6% at 30 Gy, respectively (cf. 4.4% in control). There was no correlation between early change in beta-ATP/Pi and % apoptosis at 4 hr after radiation when most of the apoptosis occurred. An early decrease in PME/Pi was observed at 4 hr after radiation dose at 30 Gy. For each dose, the values of beta-ATP/Pi 24 hr after radiation were inversely related to radiation dose.

CONCLUSION

The increase in beta-ATP/Pi observed by 31P-MRS was linked to the degree of histological recovery from radiation-induced apoptosis.

Clinical FDG-PET in diagnosis and evaluation of radiation response of patients with nasopharyngeal tumor

BACKGROUND

We investigated the utility of clinical FDG-PET in patients with nasopharyngeal tumor treated by radiotherapy, retrospectively.

MATERIALS AND METHODS

Fifteen patients with known or suspected nasopharyngeal tumors underwent FDG-PET. PET images were evaluated with visual interpretation qualitatively. Semiquantitative analysis was also performed on the metabolic ratios (MRs).

RESULTS

The sensitivity and specificity of FDG-PET based on visual inspection were 92.9% (13/14) and 83.3% (10/12), respectively. There was a statistically significant difference between histological types in the mean MR. MR was significantly decreased by radiotherapy in patients with poorly differentiated squamous cell carcinoma. PET scans obtained 1-3 months after radiotherapy indicated decreased levels of FDG uptake in all tumors but one scan did not accurately reflect the status of the disease.

CONCLUSION

These results are encouraging as to the clinical usefulness of FDG-PET for evaluating radiation effects in patients with nasopharyngeal tumor.

Cytotoxic enhancement of low dose-rate irradiation in human lung cancer cells by mild hyperthermia

PURPOSE

The aim of this study was to investigate the cell killing induced by low dose-rate irradiation (LDRI) simultaneously combined with long duration mild hyperthermia in LK87 human lung cancer cells. Cell cycle alteration due to this combined treatment was also observed.

MATERIALS AND METHODS

Human lung adenocarcinoma cells, LK87, were treated with concurrent LDRI (50 cGy/hr) and mild hyperthermia (38 to 42 degrees C). Cell survival was estimated by clonogenic assay. Flow cytometry was performed with FACScan. The treatments were simultaneously performed for up to 48 hr (24 Gy).

RESULTS

Survival curves of mild hyperthermia alone revealed development of chronic thermotolerance up to 48 hr, whereas LDRI plus hyperthermia caused an exponential decrease in survival. The LDRI cytotoxicities were enhanced by mild hyperthermia over a non-lethal temperature range. The Do values calculated from dose response curves at 37, 38, 39, 40, 41 41.5 and 42 degrees C were 6.55, 5.25, 4.24, 3.99, 3.46, 1.83 and 0.70 Gy, respectively. Cell cycle analysis demonstrated a remarkable G2 and a mild G1 block for LDRI alone, but only a G1 block was observed for LDRI combined with 41 degrees C hyperthermia.

CONCLUSION

The LDRI cytotoxicity was enhanced by long duration mild temperature hyperthermia. The suppression of chronic thermotolerance was considered to be a mechanism involved in this sensitization.