Biomedical subjects

Naoki Nakamura

Publications and source records attributed to Naoki Nakamura.

At least 19 recordsLinked to original sources

PubMed2006

A retrospective study of radiotherapy for spinal bone metastases from hepatocellular carcinoma (HCC).

OBJECTIVE: To evaluate the therapeutic effects of radiotherapy on spinal bone metastases from hepatocellular carcinoma (HCC). METHODS: A retrospective review was conducted on 24 ambulatory patients with spinal bone metastases from HCC treated by radiotherapy from 1995 to 2004. Ambulatory rate and local progression-free rate after radiotherapy were analyzed. Eight (33%) of 24 patients had radiographic spinal cord compression from the spinal bone metastases before the treatment. Two (8.3%) of the 24 patients had some spinal deficits before the treatment. Biological equivalent dose (BED) with alpha/beta ratios of 10 ranged from 39 to 50.7 Gy (median 44.8 Gy). RESULTS: The median observation period was 5.1 months ranging from 0.9 to 36.0 months. Among the 24 patients, five (21%) underwent salvage therapies, while of the remaining 19 patients four (21%) became nonambulatory by the last follow-up. The ambulatory rates at 3 months and 6 months were 85 and 63%, respectively. The local progression-free rates at 3 months and 6 months were 53 and 47%, respectively. CONCLUSIONS: Radiotherapy with a BED of 39-50.7 Gy (median 44.8 Gy) is not sufficiently effective for the patients with spinal bone metastases from HCC to prevent paralysis. Dose escalation with a highly precise radiation technique will need to be evaluated.

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PubMed2006

Relation between acute and late irradiation impairment of four basic tastes and irradiated tongue volume in patients with head-and-neck cancer.

PURPOSE: Taste loss is a major cause of morbidity in patients undergoing head-and-neck irradiation. The relationship between the time course and the degree of taste disorder was studied in both acute and late phases. METHODS AND MATERIALS: Taste ability was measured by the taste threshold for the four basic tastes using a filter paper disc method in patients before, during, and after radiotherapy. The subjects were divided into two groups. In Group A, the radiation fields included most of the tongue (n = 100), and in Group B the radiation fields did not include the tip of the tongue (n = 18). RESULTS: In Group A, there was a significant impairment of the threshold of all four basic tastes at 3 weeks after starting radiotherapy (RT), and this impairment remained at 8 weeks (p < 0.05). This was not seen in Group B. In Group A, there was no significant difference in the patterns of taste sensitivity change between the high-dose (>20 Gy) and low-dose (< or =20 Gy) groups. In the late phase, recovery of taste loss was seen in both groups since 4 months after completing RT. CONCLUSIONS: Unless the anterior part of the tongue was irradiated, taste loss was not observed during RT. When the anterior part of the tongue was irradiated, a difference by radiation dose was not observed in the taste loss pattern. Additionally, radiation-induced taste dysfunction appears to be a temporal effect.

Adult↗

PubMed2006

Treatment results of chemoradiation therapy for localized aggressive lymphomas: A retrospective 20-year study.

In this study we analyzed our cases of localized aggressive lymphoma treated in our institution during the last 20 years to compare the finding of this study with those of previous studies. Forty patients with Ann Arbor stage I-II aggressive lymphoma were treated with 3-6 cycles of a CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and radiation therapy (30 or 40 Gy with involved field). Between 1985 and 2003, 40 patients with stage I (N = 25) or stage II (N = 15) disease were treated. Chemotherapy mainly preceded radiotherapy, although the sequence of radiotherapy and chemotherapy was determined by individual physicians and patients' choice. Median and mean age was 50.5 and 48.6 years, respectively, at the time of diagnosis, with a male to female ratio of 19:21. Analyses were undertaken to determine (1) response to treatment according to age, international prognostic index (IPI), lactate dehydrogenase (LDH) value, serum interleukin 2 receptor (sIL-2R) value, cell type, stage, extent of maximum local disease, with or without mediastinal lymph nodes, number of sites, anatomic distribution, and irradiation dose, and (2) relapse patterns. Complete follow-up was obtained in all patients. The follow-up period of surviving 33 patients ranged from 24.7 to 180 months with a median of 69 and a mean of 72.7 months. A complete remission (CR) was achieved in 37 patients (93%). A study of relapse patterns after a CR showed that four patients had a first relapse within a radiation field and the other one patient had an extranodal distant relapse. Significant prognostic factors were not identified by multivariate analysis. Combined chemotherapy and radiation therapy is safe, highly effective, and probably curative for most patients with stage I-II aggressive lymphoma.

Adult↗

PubMed2006

Multi-institutional analysis of early squamous cell carcinoma of the hypopharynx treated with radical radiotherapy.

PURPOSE: To analyze the outcomes of patients with early hypopharyngeal cancer treated with radical radiotherapy (RT). METHODS AND MATERIALS: Ten institutions combined the data from 115 patients with Stage I-II hypopharyngeal squamous cell carcinoma treated with definitive RT between 1990 and 2001. The median patient age was 67 years; 99 patients were men and 16 were women. Of the 115 patients, 39 had Stage I and 76 had Stage II disease. Conventional fractionation was used in 98 patients and twice-daily RT in 17 patients; chemotherapy was combined with RT in 57 patients. The median follow-up period was 47 months. RESULTS: The overall and disease-specific 5-year survival rate for 95 patients without synchronous malignancies was 66.0% and 77.4%, respectively. The 5-year disease-specific survival rate by T stage was 95.8% for patients with T1 disease and 70.1% for patients with T2 disease (p=0.02). Of the 115 patients, local control with laryngeal voice preservation was achieved in 34 of 39 patients with T1 lesions, including 7 patients successfully salvaged, and in 56 of 76 patients with T2 lesions. Sixty-five patients (56.5%) had synchronous or metachronous cancers. Of the 115 patients, 19 died of hypopharyngeal cancer, 10 died of second primary cancers, and 14 died of other causes during the study and follow-up periods. CONCLUSIONS: Patients with early hypopharyngeal cancer tended to have a good prognosis after RT. However, second malignancies had an adverse effect on the overall outcomes of patients with early hypopharyngeal cancer.

Adult↗

PubMed2006

Taste dysfunction in patients receiving radiotherapy.

BACKGROUND: Taste loss is a major cause of morbidity in patients undergoing head and neck irradiation. METHODS: In a prospective study, 51 patients undergoing radical head and neck irradiation at the Tokyo University Hospital were assessed for taste loss. Taste ability was measured by the taste threshold for the four basic tastes (sweet, sour, salt, and bitter qualities) plus another taste of "umami" quality using a filter-paper-disc method in patients before, during, and after radiotherapy (RT). RESULTS: All tastes declined on the fifth week after the start of RT and improved on the 11th week. Anatomic pathologic analyses in rats revealed that taste buds diminished completely on the sixth day after irradiation of 15 Gy in a single fraction, and the appearance of taste buds returned almost to the preirradiation state on the 28th day. CONCLUSIONS: The main cause of taste disorder resulting from RT was believed to be a disappearance of taste buds and not damage to the taste nerves.

Adult↗

PubMed2006

Treatment planning and dosimetry of a multi-axis dynamic arc technique for prostate cancer: A comparison with IMRT.

PURPOSE: Intensity-modulated radiation therapy (IMRT) allows greater dose conformity to the tumor target. However, IMRT, especially static delivery, usually requires more time to deliver a dose fraction than conventional external beam radiotherapy (EBRT). The authors have been using a "two-axis dynamic arc therapy" (2A-DAT) technique for prostate cancer treatment to make a concave dose distribution to spare the rectum and bladder while working with limited time and human resources. The objectives of this study were to (1) clinically implement the 2A-DAT technique, (2) evaluate the dosimetry in comparison with IMRT, and (3) analyze the initial treatment outcome. MATERIALS AND METHODS: The 2A-DAT consists of two dynamic arc therapies (DATs) with half rotation around two isocenters each in two separate symmetrical rhombi. Treatment planning is forward and on a trial-and-error basis. Thirty-four patients received 2A-DAT with a median prescribed dose of 70 Gy. RESULTS: Although inferior in dose uniformity, the 2A-DAT provided equivalent sparing of normal structures to IMRT. Daily fraction delivery time for the 34 patients ranged from 6.4 to 9.6 minutes, with an average of 7.4 minutes. Five-year survival and five-year prostate specific autigen (PSA) failure-free survival were 89.3% and 79.5%, respectively. Three patients developed grade 2 proctitis. CONCLUSION: This technique is a possible alternative to IMRT in EBRT of prostate cancer.

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PubMed2006

Treatment results of preoperative concurrent chemoradiotherapy followed by surgery for stage III or IV esophageal squamous cell carcinoma.

PURPOSE: To evaluate the treatment outcome of preoperative neoadjuvant radiotherapy combined with chemotherapy (CTx) for 17 esophageal cancer patients. MATERIALS AND METHODS: Between 1992 and 2004, patients with locally advanced esophageal cancer (stage III or IV) before curative-intent surgery received radiotherapy (RT) combined with CTx (Cisplatin: 75 mg/m2, bolus infusion, and 5-fluorouracil (5-FU): 1,000 mg/m2/24 h, continuous infusion for 4 days) at a median total dose of 30 Gy (n=17). RESULTS: The median survival period was 13.8 months. The overall survival rates at 1, 2, and 3 years were 75%, 40%, and 20%, respectively. According to univariate analysis, no factor of worse prognosis was found. Pathological markedly (Grade 3) or moderately (Grade 2) effects were observed in 4 patients (24%) and 8 patients (47%), respectively. CONCLUSION: These results indicate that, although this regimen was effective in terms of pathological effect, it is unclear whether it made a contribution to the improvement of survival

Aged↗

PubMed2006

External beam radiotherapy to treat intra- and extra-hepatic dissemination of hepatocellular carcinoma after radiofrequency thermal ablation.

BACKGROUND: Radiofrequency ablation (RFA) is an alternative to percutaneous ethanol injection therapy (PEIT) for single non-surgical hepatocellular carcinoma. However, the risk of seeding along the needle track has been reported. METHODS: Seven patients presenting with neoplastic seeding after RFA or PEIT were treated with external beam radiotherapy using conventional fractionation. All patients underwent irradiation with a total dose in the range of 44-61 Gy (median and mode value: 50 Gy). RESULTS: An objective response to treatment was achieved in six of seven patients (86%). A complete response was obtained in two patients (29%). The median survival time was 14.7 months and the actuarial 1- and 2-year survivals were 67% and 50%, respectively. CONCLUSIONS: The response to treatment was relatively good without serious complications. Seeding from hepatocellular carcinoma is sensitive to external beam radiotherapy. It is useful in the treatment of these patients with 50 Gy in 25 fractions.

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PubMed2006

Small bowel perforation without tumor recurrence after radiotherapy for cervical carcinoma: report of seven cases.

AIM: We describe the clinical presentation, evaluation, management and outcome of patients experiencing small bowel perforation following radiation therapy for cervical cancer. METHODS AND MATERIALS: A database consisting of 95 Japanese women with stage 0-4 A cervix cancer treated between 1991 and 2004 contained seven patients (7.4%) with small bowel perforation. RESULTS: The median age at the time of perforation was 72.5 years (range 62-78). The median time from completion of radiotherapy to perforation was 6 months (range 2-58). Surgery (one small bowel resection and anastomosis with diversion; six small bowel resection and anastomosis) was performed immediately in all seven patients. One of seven patients died of small bowel perforation (i.e. mortality rate was 14%). Bowel adhesion was detected during the operation in only three cases (43%). Signs of peritonitis were absent in six cases (86%). Severe abdominal pain was seen in all seven patients. The perforation site was ileum in all seven cases. In all patients, pathological changes were compatible with postirradiation injury of the gastrointestinal tract. CONCLUSIONS: The presenting complaints of patients with bowel perforation following radiotherapy vary, and signs of peritonitis may be absent. Emergency physicians must be alert for these complications in patients who have been treated with radiotherapy.

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PubMed2005

Radiation therapy for portal venous invasion by hepatocellular carcinoma.

AIM: To clarify the efficacy and safety of three-dimensional conformal radiotherapy (3-D CRT) for this disease and to specify patient subgroups suitable for this treatment. METHODS: Fifty-two patients with HCC received PVI-targeted radiation therapy from January 1995 through December 2003. Portal venous invasion (PVI) was found in the second or lower order branches of the portal vein in 6 patients, in the first branch in 24 patients and in the main trunk in 22 patients. Child classifications of liver function before radiation therapy were A, B, and C for 19, 24 and 2 patients, respectively. All patients received three-dimensional conformal radiotherapy with a total dose ranging from 39 to 60 Gy (57.0 Gy in average). RESULTS: Overall survival rates at 1, 2, 3, 4, and 5 years were 45.1%, 25.3%, 15.2%, 10.1%, and 5.1%, respectively. Univariate analysis revealed that Child status, the number of tumor foci, tumor type, transcatheter arterial embolization (TAE) after radiation therapy were statistically significant prognostic factors. Multivariate analysis showed that the number of tumor foci and TAE after radiation therapy were statistically significant. CONCLUSION: The results of this study strongly suggest the efficacy of 3-D CRT as treatment for PVI in HCC. 3-D CRT is recommended in combination with post-radiation TAE for PVI of HCC with 5 tumor foci or less in the liver and with Child A liver function.

Adult↗

PubMed2005

Risk assessment of short-chain chlorinated paraffins in Japan based on the first market basket study and species sensitivity distributions.

The chemical risks of short-chain chlorinated paraffins (SCCPs) to human health and ecological species in Japan were assessed in this study. SCCPs are used as extreme pressure additives in metal-working fluids and flame retardant agents in plastic materials. The first market basket study with a high resolution gas chromatography and mass spectrometry with electron capture negative ionization is reported. Total daily food intakes for Japanese residents of different ages were estimated using Latin Hypercube simulations, and the highest 95th percentile intake is 6.8 x 10(2) ng/kg/day for a 1-year-old child. Based on the reported no-observed-adverse-effect-level (NOAEL) and the estimated exposure mainly from food, it was concluded thatSCCPs are not posing risks to humans in Japan. Ecological risks to aquatic and sediment organisms were estimated using species sensitivity distributions. The 95th percentiles of the distributions obtained by fitting several environmental SCCP concentration data of river water and sediment were 41.8 ng/L and 558 ng/g wet weight as the possible highest concentrations, respectively. No-observed-effect-concentrations (NOEC) were determined by calculating the fifth percentiles of a species sensitivity distribution, which were 2.2 microg/L for aquatic organisms and 1.7 to 13.5 mg/ kg wet weight for sediment organisms. While it is likely that there is no imminent environmental chemical risk for aquatic organisms at a regional level in Japan, this study concluded that a more detailed risk assessment is necessary for sediment organisms.

Animals↗

PubMed2005

Pathological changes after radiotherapy for primary pituitary carcinoma: a case report.

Pituitary carcinomas are extremely rare. The definition, diagnosis, therapy, and prognosis are controversial. So far, to our knowledge, there has been no report regarding pathological changes after radiotherapy for primary pituitary carcinoma. We reported a single case of a presumed prolactin staining pituitary carcinoma. We defined carcinoma by premorbid intracranial dissemination of the tumor. There were no proven extracranial metastases. The tumor was silent on PET scanning. The patient received external beam radiotherapy alone as primary therapy. Post-irradiation histology revealed that necrotic tissue made up approximately more than half. Tumor had viable cells. Probably approximately three-fifth of tumor cells were without alteration and approximately two-fifth were with degeneration. We confirmed that necrosis but no apoptosis were coexistent in the cells post irradiation for pituitary carcinoma.

Adenocarcinoma↗

PubMed2005

Comparison between conventional surgery and radiotherapy for FIGO stage I-II cervical carcinoma: a retrospective Japanese study.

PURPOSE: To compare treatment outcome results of conventional surgery vs. radiotherapy (RT) for carcinoma of the uterine cervix. MATERIALS AND METHODS: A retrospective analysis was conducted of 152 patients with uterine cervical cancer radically treated with surgery or high dose-rate intracavitary brachytherapy (HDR-ICBT) with or without external RT from June 1991 to May 2004. The median follow-up time was 43.5 months (range, 1.0-130.0 months). The median age was 53 years (range, 25-81 years). There were 13 patients (9%) in stage IA, 52 (34%) in stage IB, 24 (16%) in stage IIA, and 63 (41%) in stage IIB. The conventional surgery group included 115 patients (76%) who underwent hysterectomy with pelvic lymph node dissection. Of these, 72 (63%) received postoperative radiotherapy. Thirty-seven patients (24%) were assigned to the RT group. Of these, 14 (38%) received chemoradiotherapy. Three patients with stage I received ICBT-alone without external beam irradiation. RESULTS: The 5-year cause-specific survival (CSS) rates for surgery and RT were 79.9% and 82.3%, respectively; the difference between these two treatments was not statistically significant (P = 0.8524). The differences in the survival rates between the two treatments for each of the stage I or stage II patients were also not statistically significant (P = 0.8407 for stage I and P = 0.6418 for stage II). CONCLUSIONS: This retrospective study suggests that RT results in compatible survival with conventional surgery for patients with stage I-II cervical carcinoma.

Adenocarcinoma↗

PubMed2005

The experience of concurrent chemoradiation for Japanese patients with superficial esophageal squamous cell carcinoma: a retrospective study.

PURPOSE: To evaluate the treatment outcome of concurrent chemoradiation therapy (cCRT) for 13 clinically confirmed T1 esophageal cancer patients. METHODS: Between June 2000 and February 2004, patients with T1 esophageal cancer (tumor invading lamina propria or submucosa) received cCRT (50.4 Gy; CDDP: 75 mg/m2, day 1, bolus; 5-FU: 1000 mg/m2, days 1 to 4, continuous) (n = 13, T1 group). This treatment regimen was compared with the following 2 other groups treated during the same period: one was treated with radiation therapy alone for T1 disease (n = 5, RT-alone group); and the other group of patients consisted of those with T2 disease (tumor invading muscularis propria) who received the same cCRT regimen as the first T1 group (n = 9, T2 group). RESULTS: The overall survival rates at 1 and 3 years were in the T1 group, 75% and 75%; in the T2 group, 75% and 45% (P =0.2890); and in the RT-alone group, 60% and 40% (P = 0.2978). No treatment-related mortalities occurred in the T1 and RT-alone groups, but one patient in the T2 group died of radiation-induced pneumonitis. CONCLUSIONS: Although this study was not randomized, the results showed that cCRT is a safe and effective method for treating patients with superficial esophageal cancer.

Aged↗

PubMed2004

Malignant melanoma of nasal cavity: report of 16 Japanese patients.

BACKGROUND: Primary malignant melanoma of the nasal cavity is a rare disease that has a poor prognosis. There are significant racial differences in the incidence of melanomas in the nasal cavity. METHODS: Sixteen Japanese patients treated at the Hospital of Tokyo University were reviewed retrospectively. RESULTS: Fourteen patients were treated with surgery. Two patients received treatment with radiotherapy alone. Seven patients had microscopically negative surgical margins and seven patients had positive surgical margins. The 2- and 5-year actuarial survival rates for all patients were 63.6 and 31.8%, respectively. No statistically significant difference could be shown in the overall survival rate between patients with positive surgical margins and those with negative surgical margins. CONCLUSIONS: Clinical features of nasal melanoma in Japanese are not different from nasal melanoma in Caucasians. The negative surgical margins were not predictive of a better prognosis.

Aged↗

PubMed2003

Process and preliminary outcome of a patterns-of-care study of esophageal cancer in Japan: patients treated with surgery and radiotherapy.

PURPOSE: To evaluate the quality of radiotherapy (RT) in Japan, we have been carrying out a national survey through patterns-of-care studies (PCSs) since 1996. We present the preliminary results of surgery combined with RT with or without chemotherapy for thoracic esophageal cancer. METHODS AND MATERIALS: A Japanese PCS data format for esophageal cancer was established based on one used in the United States and including information used in the surgical registration system in Japan, so that the results in both countries could be compared. An independent panel of radiation oncologists surveyed randomly selected institutions and patients between September 1998 and March 2001. There were 767 esophageal cancer patients, of whom 220 had undergone preoperative or postoperative RT. RESULTS: The median age of the 220 patients was 62.3 years (range 31-89); of them, 88.1% were men. Pathologically, 218 patients (99.5%) had squamous cell carcinoma, predominantly located in the middle and lower thoracic esophagus, 41.7% of the patients had Stage III disease; they accounted for 52.6% of patients in nonacademic institutions and for 37.7% of those in academic institutions (p = 0.016). Sixty-nine patients received preoperative RT; of them, 60.9% received chemotherapy; 145 patients received postoperative RT with or without chemotherapy. The spinal cord of 23 (11.7%) of 196 patients was irradiated with >/=50 Gy. In academic institutions, extended radical "three-field" lymphatic dissection was performed for 72 (48.7%) of 148 patients; however, this sophisticated surgical procedure was done in only 13 (25.5%) of 51 patients in nonacademic settings (p = 0.004). In all large academic institutions (those treating >/=300 patients annually), >/=6 MV of photon energy was used; 30.5% of nonacademic institutes had linear accelerators of <6 MV photon (p = 0.001). No deviations occurred in the radiation dose (median 46 Gy), fractionations, or fields between the two types of institutions. Univariate analyses showed that the statistically significant prognostic factors affecting overall survival were stage (p = 0.001), extended radical "three-field" lymphatic dissection (p = 0.001), no residual tumor (p = 0.001), supraclavicular RT (p = 0.001), mediastinal RT (p = 0.025), Karnofsky performance status (p = 0.006) photon energy (p = 0.011), and stratification of the institutions (p = 0.001). Multivariate analysis showed that the type of institution (p = 0.045, risk ratio = 0.604), stage (p 0.029, risk ratio = 0.572), no residual tumor (p = 0.006, risk ratio = 0.487), photon energy (p = 0.043, risk ratio = 0.579), and use of chemotherapy (p = 0.012, risk ratio = 1.907) significantly affected overall survival. CONCLUSION: This PCS showed that in Japan important issues are present regarding RT for esophageal cancer that should be solved immediately, namely, treatment strategy, photon energy, and dose applied to the spinal cord. The PCS provided important information on how much improvement in structure and process would be required nationwide for RT of esophageal cancer.

Adult↗

PubMed2003

Optical sensor for carbon dioxide combining colorimetric change of a pH indicator and a reference luminescent dye.

A new optical CO(2) sensor based on the luminescence intensity change of the europium(III) complex tris(thenoyltrifluoroacetonato) europium(III) dihydrate ([Eu(tta)(3)]) caused by the absorption change of various pH indicators-thymol blue, phenol red, or cresol red-with CO(2) was developed and its CO(2) sensing properties were investigated. For all the CO(2) sensors using pH indicators the observed luminescence intensity from [Eu(tta)(3)] at 613 nm increased with increasing CO(2) concentration. The linear calibration method based on the plot of (I(100)-I(0))/(I-I(0)) versus the inverse of CO(2) concentration was suggested, where I(0) and I(100) were luminescence intensities at 613 nm of the CO(2) sensor film in 100% nitrogen and 100% gaseous CO(2). In all cases the plots showed good linearity and the correlation factors of the plots, r(2), were 0.991 for thymol blue, 0.990 for phenol red, and 0.998 for cresol red. The slopes of the plots (A/B) for thymol blue, phenol red, and cresol red were 2.2, 5.2, and 9.0%, respectively. The response times of the CO(2) sensor film were 4.0 s for thymol blue, 4.4 s for phenol red, and 8.8 s for cresol red for switching from nitrogen to CO(2), and the recovery times of films were 36 s for thymol blue, 39.2 s for phenol red, and 56.6 s for cresol red for switching from CO(2) to nitrogen. The signal changes were fully reversible and hysteresis was not observed during the measurements. The highly sensitive CO(2) sensor was developed using thymol blue as an indicator for the CO(2)-sensing probe.

Journal Article↗

PubMed2003

Usefulness of measuring plasma cytokines in oral and maxillofacial surgery.

We determined the intra- and postoperative plasma concentrations of cytokines (tumor necrosis factor [TNF]-Alpha, interleukin [IL]-1Beta, IL-6, and IL-8) in oral surgery patients with procedures ranging in duration from 20 to 375 min and investigated their relationship to the intensity of the surgical stress over time. No significant differences from baseline levels were observed in the levels of TNF-Alpha, IL-1Beta, and IL-8. By contrast, increased IL-6 levels were noted only on the first postoperative day, when they reached 1500% of the baseline level, after which they decreased to preoperative levels by the third postoperative day and tended to reflect the intensity of surgical stress.

Adult↗