Re-irradiation for isolated neck recurrence in head and neck tumor: impact of rN category.

Unresectable, isolated lymph node recurrence after radiotherapy is rare but a candidate for re-irradiation. However, severe toxicity is anticipated. Therefore, this study aimed to explore the efficacy and toxicity of re-irradiation in isolated lymph node recurrence of head and neck lesions. We analyzed 46 patients who received re-irradiation for lymph node recurrence without local progression. The primary tumor sites included the oral cavity in 17 patients, the hypopharynx in 12, the oropharynx in seven, the larynx in three, the nasopharynx in two, and other sites. During a median follow-up time of 10 months, the median survival time was 10.6 months, and the 1-year overall survival rate was 45.5%. The 1-year local control and progression-free survival rates were 49.8% and 39.3%, respectively. According to univariate analysis, age (≥ 65 years), the interval between treatment (≥ 12 months), rN category (rN1), and gross tumor volume (GTV < 25 cm3) were predisposing factors for better survival. In the multivariate analysis, the rN category and interval were identified as statistically significant predictors. Late toxicity grade ≥ 3 occurred in four patients (8.6%). These were all Grade 5 carotid blowout syndrome, which associated with tumor invasion of the carotid artery and/ or high doses administration for the carotid artery. Small-volume rN1 tumor that recur after a longer interval is a feasible candidate for re-irradiation. However, strict patient selection and meticulous care for the carotid are required.

Reirradiation for local recurrence of oral, pharyngeal, and laryngeal cancers: a multi-institutional study.

This study aimed to examine the efficacy and toxicity of reirradiation in patients with locally recurrent oral, pharyngeal, and laryngeal cancers. We conducted a retrospective, multi-institutional analysis of 129 patients with previously irradiated cancer. The most frequent primary sites were the nasopharynx (43.4%), oral cavity (24.8%), and oropharynx (18.6%). With a median follow-up duration of 10.6 months, the median overall survival was 14.4 months and the 2-year overall survival rate was 40.6%. For each primary site, the 2-year overall survival rates were 32.1%, 34.6%, 30%, 60.8%, and 5.7% for the hypopharynx, oral cavity, larynx, nasopharynx, and oropharynx, respectively. Prognostic factors for overall survival were primary site (nasopharynx versus other sites) and gross tumor volume (GTV) (≤ 25 cm3 versus > 25 cm3). The 2-year local control rate was 41.2%. Twenty-four patients (18.6%) presented with grade ≥ 3 toxicities, including nine with hemorrhages that led to grade 5 toxicities in seven patients. All nine tumors that caused hemorrhage showed tumor encasement of the carotid ≥ 180 degrees and eight of nine tumors had larger GTV > 25 cm3. Reirradiation is a feasible treatment option for small local recurrence of oral, pharyngeal, and laryngeal cancers, with the requirement of a strict eligibility assessment for large tumors with carotid encasement.

Reirradiation for Rare Head and Neck Cancers: Orbit, Auditory Organ, and Salivary Glands.

We analyzed the efficacy and toxicity following reirradiation for locoregional recurrence of rare head and neck tumors. We retrospectively analyzed 17 patients who had received reirradiation for rare head and neck tumors. Primary tumor sites included nine ears (auditory organ), four salivary glands, and four orbits. The median follow-up time was 13.2 months for surviving patients. The median survival time was 12.6 months with one- and two-year survival rates of 53.1% and 44.3%, respectively. Nine out of 17 patients experienced local failure. The one- and two-year local control rates were 42.4% and 31.8%, respectively. The median survival times were 12.6, 5.3, and 11.0 months for orbit, auditory organ, and salivary glands, respectively. Three patients experienced grade 3 toxicity, including meningitis, brain necrosis, and facial nerve disorders. No grade ≥4 toxicities were observed. Reirradiation of rare head and neck tumors is feasible, with acceptable toxicity.

Reirradiation for Nasal Cavity or Paranasal Sinus Tumor-A Multi-Institutional Study.

We evaluated the efficacy and toxicity of reirradiation of nasal cavity or paranasal sinus tumors. We collected and analyzed multi-institutional data of reirradiation cases. Seventy-eight patients with nasal or paranasal sinus tumors underwent reirradiation. The median survival time was 20 months with a medial follow-up of 10.7 months. The 2-year local control and overall survival rates were 43% and 44%, respectively. Tumor volume (≤25 cm3), duration between previous radiotherapy and reirradiation (≤12 months), histology (squamous cell carcinoma), male sex, and lymph node involvement were predisposing factors for poor survival. Distant metastasis was observed in 20 patients (25.6%). Grade ≥ 3 adverse events were observed in 22% of the patients, including five grade 4 (8.6%) cases and one grade 5 (1.2%) case. Tumor location adjacent to the optic pathway was a significant predisposing factor for grade ≥3 visual toxicity. Reirradiation of nasal and paranasal sinus tumors is feasible and effective. However, adverse events, including disease-related toxicities, were significant. Prognostic factors emerge from this study to guide multidisciplinary approaches and clinical trial designs.

Effect of intratumoral abscess/necrosis on the outcome for head and neck cancer patients treated by hypofractionated stereotactic re-irradiation using CyberKnife®.

The aim of the present study was to elucidate the effect of intratumoral abscess/necrosis (AN) on the outcome of patients with recurrent head and neck cancer (HNC) treated by stereotactic radiotherapy. The records of 67 patients treated with CyberKnife® in four institutes between August 2000 and July 2010 were reviewed. The frequency of AN appeared to be increased in younger postoperative patients with large ulcerative tumors. The AN+ group exhibited a better initial response rate compared with the AN- group (64 vs. 33%, respectively; P=0.04). The 1-year local control rate was 51 and 75% in the AN+ and AN- groups, respectively (P=0.01), while the respective 1-year overall survival rates were 53 and and 71% (P=0.0004). A total of 21 patients (31%) experienced grade ≥3 toxicities, and carotid blowout syndrome (CBOS) was found in 11 patients, resulting in 8 deaths. A significantly larger proportion of patients in the AN+ group developed CBOS (8/18; 44%) compared with the AN- group (3/49; 6%) (P=0.001). Therefore, AN may be an important prognostic factor for patients with recurrent HNC, as well as a predictor of lethal toxicity due to CBOS.

Reirradiation for recurrent head and neck cancers using charged particle or photon radiotherapy.

OBJECTIVE: To examine the outcomes of reirradiation for recurrent head and neck cancers using different modalities. METHODS: This retrospective study included 26 patients who received charged particle radiotherapy (CP) and 150 who received photon radiotherapy (117 CyberKnife radiotherapy [CK] and 36 intensity-modulated radiotherapy [IMRT]). Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias. RESULTS: Higher prescribed doses were used in CP than photon radiotherapy. The 1­year overall survival (OS) rates were 67.9% for CP and 54.1% for photon radiotherapy (p = 0.15; 55% for CK and 51% for IMRT). In multivariate Cox regression, the significant prognostic factors for better survival were nasopharyngeal cancer, higher prescribed dose, and lower tumor volume. IPTW showed a statistically significant difference between CP and photon radiotherapy (p = 0.04). The local control rates for patients treated with CP and photon radiotherapy at 1 year were 66.9% (range 46.3-87.5%) and 67.1% (range 58.3-75.9%), respectively. A total of 48 patients (27%) experienced toxicity grade ≥3 (24% in the photon radiotherapy group and 46% in the CP group), including 17 patients with grade 5 toxicity. Multivariate analysis revealed that younger age and a larger planning target volume (PTV) were significant risk factors for grade 3 or worse toxicity. CONCLUSION: CP provided superior survival outcome compared to photon radiotherapy. Tumor volume, primary site (nasopharyngeal), and prescribed dose were identified as survival factors. Younger patients with a larger PTV experienced toxicity grade ≥3.

Comparison of Re-irradiation Outcomes for Charged Particle Radiotherapy and Robotic Stereotactic Radiotherapy Using CyberKnife for Recurrent Head and Neck Cancers: A Multi-institutional Matched-cohort Analysis.

AIM: To compare survival outcomes for charged particle radiotherapy (CP) and stereotactic body radiotherapy using CyberKnife (CK) in patients who had undergone re-irradiation for head and neck cancers. PATIENTS AND METHODS: We conducted a retrospective multi-institutional matched-cohort analysis on 25 patients treated with CP and 25 matched patients treated with CK according to three prognostic factors (nasopharyngeal cancer or not, interval between initial radiotherapy and re-irradiation, and planning target volume). RESULTS: CP was used more often to treat non-squamous cell cancer ((non-SCC): 52% vs. 0%) with a higher prescribed dose (median=57.6 Gy(RBE)/16 fractions) than CK (32 Gy/5 fractions). The local control rate (LC) for patients treated with CP was 71.2% at 1 year and that for patients treated with CK was 63.8% (p=0.24). The 1-year overall survival (OS) rates were 67.1% for CP and 36.3% for CK (p=0.0002), respectively. Non-SCC patients showed better OS rates at 1 year than SCC patients. In the SCC sub-group analysis, the 1-year LC, OS rates were 65%, 58.3% in the CP group and 64%, 36.3% in the CK group (p=0.81, p=0.02), respectively. A total of 16 patients (32%) experienced grade 3 or worse toxicities (24% in CK and 40% in CP, p=0.36), including six grade 5 toxicities. CONCLUSION: CP produced higher survival rates than CK, treated more non-SCC patients and used a higher prescribed dose. On the other hand, severe toxicities occurred in both groups, which, however, require further investigation.

Reirradiation using robotic image-guided stereotactic radiotherapy of recurrent head and neck cancer.

The purpose of this study was to examine the prognosis for patients with head and neck cancer after reirradiation using Cyberknife stereotactic body irradiation with special focus on mucosal ulceration. We conducted a retrospective multi-institutional review of 107 patients with previously irradiated head and neck cancer. The median follow-up time for all patients was 15 months, and the 2-year overall survival rate was 35%. Significant prognostic factors for overall survival were primary site (nasopharynx versus other sites), presence of ulceration, and PTV volume. Detailed analysis of ulceration showed a lower response rate (28%) in the ulceration (+) group than the ulceration (-) group (63%; P = 0.0045). The 2-year overall survival rates were 8% in the ulceration (+) group and 42.7% (P = 0.0001) in the ulceration (-) group, respectively. We recorded 22 severe toxicities, including 11 patients with carotid blow-out syndrome (CBOS), which was fatal in 9 patients. CBOS occurred in 6 patients with ulceration (6/25; 24%), and 5 patients experienced CBOS without ulceration (5/82; 6%; P=0.027). In conclusion, ulceration is an important prognostic factor, not only for adverse events but also for survival after reirradiation using CyberKnife.

Predictive value of skin invasion in recurrent head and neck cancer patients treated by hypofractionated stereotactic re-irradiation using a cyberknife.

BACKGROUND: This study aimed to elucidate the influence of skin invasion in patients with recurrent head and neck cancer treated with re-irradiation using stereotactic radiotherapy. MATERIALS: We reviewed 104 patients treated using CyberKnife in four institutions. RESULTS: Nine cases of skin invasion were recognized (8.6 %). Larger tumors tended to exhibit skin invasion. The skin invasion (+) group showed a lower response rate (0/9, 0 %) than the skin invasion (-) group (56/95, 59 %) (p = 0.002). The skin invasion (+) group showed lower local control (LC) and progression free survival (PFS) rates, both 0 % at 6 months, than the skin invasion (-) group, which had a LC of 69 % (p = 0.0001) and a PFS of 48 % at 1 year (p = 0.0157). Median survival time and one-year survival rates for the skin invasion (+) and (-) groups were 6.6 vs. 15.3 months and 14 % vs. 59 % (p = 0.0005), respectively. No patient with skin invasion survived more than 14.4 months. The percentage of patients who developed grade 3 or higher toxicity was 44 % in the skin invasion (+) group and 18 % in the skin invasion (-) group (p = 0.14). CONCLUSIONS: Skin invasion is an important predictor of poor prognosis in recurrent head and neck cancer after re-irradiation with stereotactic radiation therapy.

Carotid blowout syndrome in pharyngeal cancer patients treated by hypofractionated stereotactic re-irradiation using CyberKnife: A multi-institutional matched-cohort analysis.

BACKGROUND AND PURPOSE: Although reirradiation has attracted attention as a potential therapy for recurrent head and neck tumors with the advent of modern radiotherapy, severe rate toxicity such as carotid blowout syndrome (CBOS) limits its potential. The aim of this study was to identify the risk factors of CBOS after hypofractionated stereotactic radiotherapy (SBRT). METHODS AND PATIENTS: We conducted a matched-pair design examination of pharyngeal cancer patients treated by CyberKnife reirradiation in four institutes. Twelve cases with CBOS were observed per 60 cases without CBOS cases. Prognostic factors for CBOS were analyzed and a risk classification model was constructed. RESULTS: The median prescribed radiation dose was 30 Gy in 5 fractions with CyberKnife SBRT after 60 Gy/30 fractions of previous radiotherapy. The median duration between reirradiation and CBOS onset was 5 months (range, 0-69 months). CBOS cases showed a median survival time of 5.5 months compared to 22.8 months for non-CBOS cases (1-year survival rate, 36% vs.72%; p=0.003). Univariate analysis identified an angle of carotid invasion of >180°, the presence of ulceration, planning treatment volume, and irradiation to lymph node areas as statistically significant predisposing factors for CBOS. Only patients with carotid invasion of >180° developed CBOS (12/50, 24%), whereas no patient with tumor involvement less than a half semicircle around the carotid artery developed CBOS (0/22, 0%, p=0.03). Multivariate Cox hazard model analysis revealed that the presence of ulceration and irradiation to lymph nodes were statistically significant predisposing factors. Thus, we constructed a CBOS risk classification system: CBOS index=(summation of risk factors; carotid invasion >180°, presence of ulceration, lymph node area irradiation). This system sufficiently separated the risk groups. CONCLUSION: The presence of ulceration and lymph node irradiation are risk factors of CBOS. The CBOS index, including carotid invasion of >180°, is useful in classifying the risk factors and determining the indications for reirradiation.

Improvement in treatment results of glioblastoma over the last three decades and beneficial factors.

BACKGROUND: The purpose of this study is to elucidate the trend of glioblastoma outcome and scrutinize the factors contributing to better outcome over three decades. METHODS: Survival time and the influencing factors were retrospectively analyzed in 223 newly diagnosed primary glioblastoma patients during 1980-2010. Appraised factors included age, sex, tumor site, year of surgery, extent of resections, use of surgery supporting system, Karnofsky Performance Status (KPS), chemotherapy, conventional external beam radiotherapy (EBRT), and CyberKnife stereotactic radiotherapy (CK-SRT) use. RESULTS: The median survival time (MST) in all patients was 13.6 months. The MSTs for 4 periods were 9.8 (1980-1990), 13.7 (1991-2000), 12.9 (2001-2005), and 15.8 months (2006-2010), respectively (p=0.0047). Total resection, subtotal resection, partial resection, and biopsy had MSTs of 31.8, 13.9, 11.4, and 7.0 months, respectively (p<0.0001). Regarding chemotherapy, MSTs of the temozolomide base group and nimustine hydrochloride (ACNU) base group were 16.9 and 14.6 months, respectively, whereas the MST of patients without chemotherapy was only 9.8 months (p<0.0001). The MSTs for 40-Gy EBRT plus CK-SRT and 60-Gy EBRT were 19.1 and 10.7 months, respectively (p<0.0001). But in sub-selected patients, treated during 2001-2010, whose resection rate was total resection or subtotal resection, EBRT was completed and postoperative KPS was greater than or equal to 70, the MST with and without CK-SRT was 26.6 and 18.3 months, respectively (p=0.1529). According to the Cox proportional hazards model, degree of resection, KPS, ACNU use, temozolomide use, bevacizumab use, EBRT dose, and CK-SRT use were good prognostic factors. Use of neuronavigation and use of intraoperative magnetic resonance imaging were related to higher resection rate, but not determined as prognostic factors. CONCLUSIONS: We observed a gradual improvement in glioblastoma outcome, presumably because of improvements in therapeutic modalities for surgery, anticancer agents, and radiation, but the efficacy of CK-SRT remains unclear.

Hypofractionated stereotactic radiotherapy using CyberKnife as a boost treatment for head and neck cancer, a multi-institutional survey: impact of planning target volume.

AIM: To evaluate the role of hypofractionated stereotactic radiotherapy (hSRT) as a boost treatment for head and neck cancer. PATIENTS AND METHODS: We conducted a multi-institutional retrospective review for the outcome of boost irradiation using CyberKnife for head and neck cancer patients from the charts of four Institutes. Twenty-five patients were treated with hSRT boost for primary site with a median follow-up of 28 months. Treatment sites were 11 nasopharynx, 7 oropharynx, one hypopharynx, 3 nasal cavity or paranasal sinus and three oral cancers. All patients underwent preceding conventional radiotherapy of 35 to 72 Gy (median, 50 Gy) in 1.2- to 2 Gy-fractions. The dose and fractionation scheme of the Cyberknife SRT boost was individualized and the prescribed dose ranged from 12 Gy to 35 Gy in 1 to 5 fractions (median, 15 Gy in 3 fractions). RESULTS: There were 18 complete responses, 6 partial responses and one progressive disease, resulting in 96% (24/25) response rate. Local control (LC) rates at 2- and 5-years were 89% and 71%, respectively. Progression-free survival (PFS) and overall survival (OS) at 2- and 5-years were 70%/ 83% and 70%/ 70%, respectively. Planning target volume (PTV) at boost treatment planning and initial response were predisposing factors for PFS and OS. Patients with PTV ≤ 20 cm(3) showed better PFS (92%) and OS (100%) than those with a PTV > 20 cm(3) (PFS, 61% and OS, 47%). Good initial response predicts better outcome in LC, PFS and OS. CONCLUSION: The results of the present study showed potential benefits of the CyberKnife hSRT boost. Smaller PTV and good initial response predict good outcome.

Frequency, outcome and prognostic factors of carotid blowout syndrome after hypofractionated re-irradiation of head and neck cancer using CyberKnife: a multi-institutional study.

PURPOSE: Re-irradiation has attracted attention as a potential therapy for recurrent head and neck tumors. However, carotid blowout syndrome (CBS) has become a serious complication of re-irradiation because of the associated life-threatening toxicity. Determining of the characteristics of CBS is important. We conducted a multi-institutional study. METHODS AND PATIENTS: Head and neck carcinoma patients (n=381) were treated with 484 re-irradiation sessions at 7 Japanese CyberKnife institutions between 2000 and 2010. RESULTS: Of these, 32 (8.4%) developed CBS, which proved fatal that median survival time after CBS onset was 0.1 month, and the 1-year survival rate was 37.5%. The median duration between re-irradiation and CBS onset was 5 months (range, 0-69 months). Elder age, skin invasion, and necrosis/infection were identified as statistically significant risk factors after CBS by univariate analysis. The presence of skin invasion at the time of treatment found only in postoperative case, is identified as only statistically significant prognostic factor after CBS in multivariate analysis. The 1-year survival rate for the group without skin invasion was 42%, whereas no patient with skin invasion survived more than 4 months (0% at 1 year, p=0.0049). CONCLUSIONS: Careful attention should be paid to the occurrence of CBS if the tumor is located adjacent to the carotid artery. The presence of skin invasion at CBS onset is ominous sign of lethal consequences.

Reirradiation of head and neck cancer focusing on hypofractionated stereotactic body radiation therapy.

Reirradiation is a feasible option for patients who do not otherwise have treatment options available. Depending on the location and extent of the tumor, reirradiation may be accomplished with external beam radiotherapy, brachytherapy, radiosurgery, or intensity modulated radiation therapy (IMRT). Although there has been limited experience with hypofractionated stereotactic radiotherapy (hSRT), it may have the potential for curative or palliative treatment due to its advanced precision technology, particularly for limited small lesion. On the other hand, severe late adverse reactions are anticipated with reirradiation than with initial radiation therapy. The risk of severe late complications has been reported to be 20- 40% and is related to prior radiotherapy dose, primary site, retreatment radiotherapy dose, treatment volume, and technique. Early researchers have observed lethal bleeding in such patients up to a rate of 14%. Recently, similar rate of 10-15% was observed for fatal bleeding with use of modern hSRT like in case of carotid blowout syndrome. To determine the feasibility and efficacy of reirradiation using modern technology, we reviewed the pertinent literature. The potentially lethal side effects should be kept in mind when reirradiation by hSRT is considered for treatment, and efforts should be made to minimize the risk in any future investigations.

Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract.

BACKGROUND: To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. METHODS: We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma) including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans), were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. RESULTS: The median planning target volume (PTV) and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17-14.3 cm3) and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05-14.6 cm3) and 2.41 for meningioma. PTV volume was 10.1±1.74 cm3 for group 1 with a margin of 1-2 mm around the CTV (n=3) and 9.28±1.8 cm3 (p=0.51) for group 2 with no margin (n=7) in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1±3.26 cm3) than group 2 (6.91±0.7 cm3, p=0.03). All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation). However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan) in pituitary adenoma and 24.84 Gy (131% of the default plan) in meningioma to the optic nerve in the contours from different contouring. CONCLUSION: Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract.

Associations between liver (18)F fluoro-2-deoxy-D-glucose accumulation and various clinical parameters in a Japanese population: influence of the metabolic syndrome.

PURPOSE: Liver demonstrates a heterogeneous (18)F fluoro-2-deoxy-D: -glucose ((18)F-FDG) uptake pattern and sometimes shows an abnormally increased uptake even when there is no malignant tissue. The aim of this study was to evaluate the relationships of liver (18)F-FDG uptake as related to physical factors, fatty liver, blood glucose (BG), and other biochemical data. METHODS: (18)F-FDG positron emission tomography (PET) imaging was performed in 101 consecutive subjects for cancer screening. Multiple stepwise regression analysis was used to define the best predictors of the liver standardized uptake value (SUV) among height, weight, waist circumference, body mass index (BMI), systolic and diastolic blood pressure, BG and other biochemical data, i.e., aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, total cholesterol, high-density lipoprotein cholesterol, triglycerides, total protein, total bilirubin, and alkaline phosphatase. Furthermore, we evaluated the association between liver (18)F-FDG uptake and the metabolic syndrome. RESULTS: The independent factors for increased liver (18)F-FDG uptake (mean SUV > or = 2) were BMI (P < 0.0001), triglycerides (P = 0.0007), and high-density lipoprotein cholesterol (P = 0.0013). Other factors were not significantly associated with liver (18)F-FDG uptake. In addition, the liver (18)F-FDG uptake of metabolic syndrome subjects was significantly higher than that of a non-metabolic syndrome subjects. CONCLUSIONS: BMI was the strongest determinant of liver (18)F-FDG uptake, and the liver (18)F-FDG uptake of metabolic syndrome subjects was significantly higher than that of non-metabolic syndrome subjects. This result suggests that a subject with a high liver (18)F-FDG uptake should be screened for the metabolic syndrome.

Role of gastric distention with additional water in differentiating locally advanced gastric carcinomas from physiological uptake in the stomach on 18F-fluoro-2-deoxy-D-glucose PET.

PURPOSE: In this study, we investigated the role of gastric distention with additional water to determine whether it is beneficial for the differentiation of locally advanced gastric carcinomas from physiological 18F-fluoro-2-deoxy-D-glucose (FDG) uptake in the stomach and to characterize the FDG uptake of gastric carcinomas by relating it to the histopathological properties of the tumours. METHODS: Sixteen patients with locally advanced gastric carcinomas and 20 control patients were studied by FDG-PET. After whole-body PET imaging, the patients drank 400 ml of water and then spot imaging with additional water of the stomach was performed. The final diagnosis was determined from the results of surgery. The gastric areas were divided into the upper, middle, and lower parts. The degree of FDG uptake in the stomach was qualitatively evaluated by visual grading into three degrees. For quantitative analysis, the regional tumour uptake was measured by mean standardized uptake values using a region of interest technique. RESULTS: In visual analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET without additional water ingestion were 100, 50, 62, 100 and 72%, respectively, and those of PET with additional water ingestion were 88, 100, 100, 91 and 94%, respectively. Using spot imaging under the condition with additional water ingestion, four gastric carcinomas were depicted more clearly. CONCLUSION: Gastric distention as a result of patients drinking a glass of water is a simple and noninvasive method for improving the diagnostic accuracy of FDG-PET in patients with locally advanced gastric carcinoma.

An analysis of the physiological FDG uptake in the stomach with the water gastric distention method.

PURPOSE: Physiological FDG uptake in the stomach is a common phenomenon, especially noted at the cardia. Water intake just before scanning will result in gastric distention and thinning of the gastric wall, which in turn may lead to a reduction in the physiological uptake in the gastric wall. In the current study, we investigated whether gastric distention by water intake just before PET imaging reduces physiological FDG uptake in the stomach. METHODS: The patient population comprised 60 patients who underwent whole-body FDG-PET imaging for cancer screening following gastroscopy performed within the preceding week. All patients took 400 ml of water for hydration and were administered 185 MBq of FDG intravenously. The patients were randomly divided into two groups: a group with additional water intake (AW group; n = 30) and a group without additional water intake (NW group; n = 30). In the AW group, an additional 400 ml of water was given just before PET imaging. For quantitative analysis, the stomach was classified into three areas [upper (U), middle (M) and lower (L)], and the degree of FDG uptake in each area was evaluated using standardised uptake values (SUVs). RESULTS: In the NW group, the mean SUVs in the U, M and L areas were 2.41 +/- 0.75, 2.28 +/- 0.73 and 1.61 +/- 0.89, respectively, while in the AW group they were 1.82 +/- 0.66, 1.73 +/- 0.56 and 1.48 +/- 0.49, respectively, and 2.21 +/- 0.38 in the oesophago-gastric junction. The mean SUVs in the U and M areas in the AW group were significantly lower than those in the NW group (p < 0.05). CONCLUSION: Additional water intake just before PET imaging is an effective method for suppressing physiological FDG uptake in the stomach.