~(18)F-FDG PET/CT在行结肠癌检查时发现同时性重复癌的价值

目的探讨18氟-氟脱氧葡萄糖(18F-FDG)PET/CT用于检查结肠癌时发现同时性重复癌的价值。方法回顾性分析232例经病理证实结肠癌病人的18F-FDG PET/CT影像资料和临床病理结果,采用卡方检验比较18F-FDG PET/CT结果与病理结果并行kappa系数一致性检验,分析PET/CT显像的诊断效能。结果 232例病理证实的结肠癌病人中,56例病理证实为重复癌。18F-FDG PET/CT诊断真阳性53例,假阳性4例,其中2例经肠镜病理证实分别为息肉和管状腺瘤(癌前病变),1例病理证实为甲状腺腺瘤,1例为肺炎性假瘤。假阴性3例,其中1例为胃窦部印戒细胞癌,1例为肾透明细胞癌,另1例18F-FDG PET/CT显像为高代谢,诊断为结肠癌肝转移,结果病理证实为结肠癌+原发性肝癌。18F-FDG PET/CT诊断重复癌的敏感度为94.64%,特异度为97.58%,准确度为96.83%,阳性预测值92.98%,阴性预测值98.17%。与病理诊断结果比较,两者间差异无统计学意义(P≈1.000),而且两者间一致性良好(κ=0.917,P=0.000)。结论应用18F-FDG PET/CT进行结肠癌检查时可以有效发现同时性重复癌。     

Performance profile of FDG-PET and PET/CT for cancer screening on the basis of a Japanese Nationwide Survey

Objective The aim of this study is to survey the situation of ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening in Japan and to describe its performance profile. Methods “FDG-PET for cancer screening” was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. We sent questionnaires regarding FDG-PET cancer screening to 99 facilities in which FDG-PET tests were performed during the fiscal year 2005. Replies were obtained from 68 of the 99 facilities, of which 46 facilities performed FDG-PET cancer screening. The total number of subjects who underwent FDG-PET cancer screening was 50 558. From 38 of 46 facilities, reliable results of thorough examinations were obtained for the subjects who were positive by FDG-PET and/or one or more of the combined screening tests was performed and were referred for further evaluation. The total number of subjects in these 38 facilities amounted to 43 996. Results A total of 50 558 healthy subjects underwent FDG-PET (including PET/CT) scanning with or without other tests for cancer screening in 46 PET centers during the fiscal year of 2005 in Japan. Thorough examination was indicated for 9.8% of the cases as a result of positive findings suggesting possible cancer. On analyzing 43 996 cases from 38 PET centers from which detailed information was obtained, 500 cases of cancers (1.14%) were found, of which 0.90% were PET positive and 0.24% were PET negative, resulting in the relative sensitivity of PET being 79.0%. Cancers of the thyroid, colon/rectum, lung, and breast were most frequently found (107, 102, 79, and 35 cases, respectively) with high PET sensitivity (88%, 90%, 80%, and 92%). PET showed an overall positive predictive value of 29.0%. PET/CT had a better detection rate, sensitivity, and positive predictive value than dedicated PET (P < 0.01). Conclusions We were able to clarify the performance profile of “FDG-PET for cancer screening” on the basis of a Japanese nationwide survey. The number of facilities possessing PET is increasing steadily, highlighting the necessity of evaluating the usefulness of “FDG-PET cancer screening” as soon as possible by undertaking long-term investigations of large series of subjects.     

Evaluation of whole-body cancer screening using <Superscript>18</Superscript>F-2-deoxy-2-fluoro-<Emphasis Type="SmallCaps">d</Emphasis>-glucose positron emission tomography: a preliminary report

OBJECTIVE: (18)F-2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) is a promising screening modality targeting whole body. However, the validity of PET cancer screening remains to be assessed. Even the screening accuracy for whole-body screening using FDG-PET has not been evaluated. In this study, we investigated the screening accuracy of PET cancer screening. METHODS: A total of 2911 asymptomatic participants (1629 men and 1282 women, mean age 59.79 years) underwent both FDG-PET and other thorough examinations for multiple organs (gastrofiberscopy, total colonofiberscopy or barium enema, low-dose thin section computed tomography and sputum cytology, abdominal ultrasonography, an assay of prostate-specific antigen, mammography, mammary ultrasonography, Pap smear for the uterine cervix, and magnetic resonance imaging for the endometrium and ovaries) between February 2004 and January 2005, and followed sufficiently. The detection rate, sensitivity, specificity, and positive predictive value of FDG-PET were calculated using cancer data obtained from all examinations along with a 1 year follow-up. RESULTS: From among 2911 participants FDG-PET found 28 cancers, 129 cancers were PET negative. PET-positive cancers comprised seven colorectal cancers, four lung cancers, four thyroid cancers, three breast cancers, two gastric cancers, two prostate cancers, two small intestinal sarcomas (gastrointestinal stromal tumors), one malignant lymphoma, one head and neck malignancy (nasopharyngeal carcinoid tumor), one thymoma, and one hepatocellular carcinoma. PET-negative cancers included 22 gastric cancers and 20 prostate cancers that were essentially difficult to detect using FDG-PET. The overall detection rate, sensitivity, specificity, and positive predictive value were estimated to be 0.96%, 17.83%, 95.15%, and 11.20%, respectively. CONCLUSIONS: FDG-PET can detect a variety of cancers at an early stage as part of a whole-body screening modality. The detection rate of PET cancer screening was higher than that of other screening modalities, which had already shown evidence of efficacy. However, the sensitivity of PET cancer screening was lower than that of other thorough examinations performed at our institute. FDG-PET has some limitations, and cancer screening using only FDG-PET is likely to miss some cancers.     

The current status of an FDG-PET cancer screening program in Japan, based on a 4-year (2006–2009) nationwide survey

Objective

The aim of this study was to survey the 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program conducted in Japan.

Methods

The “FDG-PET cancer screening program” included both FDG-PET and positron emission tomography with computed tomography (PET/CT) with or without other combined screening tests that were performed for cancer screening in asymptomatic subjects. A total of 155,456 subjects who underwent the FDG-PET cancer screening program during 2006–2009 were analyzed.

Results

Of the 155,456 subjects, positive findings suggesting possible cancer were noted in 16,955 (10.9 %). The number of cases with detected cancer was 1,912 (1.23 % of the total screened cases, annual range 1.14–1.30 %). Of the 1,912 cases of detected cancer, positive findings on FDG-PET were present in 1,491 cases (0.96 % of the total number of screened cases). According to the results of further examinations, the true positive rate for subjects with suggested possible cancer (positive predictive value) was 32.3 % with FDG-PET. Cancers of the colon/rectum, thyroid, lung, and breast were most frequently found (396, 353, 319, and 163 cases, respectively) with high PET sensitivity (85.9, 90.7, 86.8, 84.0 %, respectively). Prostate cancer and gastric cancer (165 and 124 cases, respectively) had low PET sensitivity (37.0 and 37.9 %, respectively). The Union for International Cancer Control (UICC) clinical stage of cancer found with the FDG-PET cancer screening program was mainly Stage I.

Conclusions

The FDG-PET screening program in Japan has detected a variety of cancers at an early stage. However, several cancers were found in repeated FDG-PET cancer screening program, indicating the limitation of a one-time FDG-PET cancer screening program. The value of the FDG-PET cancer screening program is left to the judgment of individuals with regard to its potentials and limitations.     

Performance profile of FDG-PET and PET/CT for cancer screening based on a Japanese nationwide survey

A total of 50,558 healthy subjects underwent an FDG-PET (including PET/CT) scan with or without combination of other tests for cancer screening in 46 PET centers during fiscal year of 2005 in Japan. Thorough examination was indicated for 9.8% of the cases due to positive findings suggesting possible cancer. On analyzing 43,996 cases from 38 PET centers, where detailed information was obtained, 500 cases of cancers (1.14%) were found, of which 0.90% was PET positive and 0.24% was PET negative, resulting in the relative sensitivity of PET being 79.0%. Cancers of thyroid, colon/rectum, lung and breast were most frequently found (107, 102, 79, 35 cases, respectively) with high PET sensitivity (88%, 90%, 80%, 92%). PET showed an overall positive predictive value of 29.0%. PET/CT had better detection rate, sensitivity, and positive predictive value than dedicated PET (p<0.01).     

Detection of colorectal cancer and adenomas by FDG-PET cancer screening program: results based on a nationwide Japanese survey

Purpose

The aim of this study was to analyze the detection rate for CRC and adenomas for asymptomatic subjects in Japan by FDG-PET cancer screening program carried out between 2006 and 2009.

Methods

The “FDG-PET cancer screening program” included both PET and positron emission tomography with computed tomography (PET/CT) with or without other screening tests. A total of 154,783 asymptomatic subjects underwent FDG-PET cancer screening program; we analyzed the 1,808 cases with findings from any detection method that indicated suspected CRC.

Results

Among the 1,808 cases, the number of cases verified as CRC and adenoma was 394 and 679, respectively. The sensitivity and positive predictive value (PPV) of FDG-PET were 86.0 and 31.7 % for CRC, and 63.6 and 63.8 % for CRC and adenoma. The sensitivity and PPV of fecal occult blood test (FOBT) for CRC were lower than those of FDG-PET, but higher for adenoma. Therefore, FDG-PET and FOBT were complementary for screening for CRC, and CRC and adenoma. The majority of CRC detected by the FDG-PET imaging was UICC stage 0 or I, however, detection of smaller or less invasive cancer was limited.

Conclusion

The FDG-PET screening program in Japan has detected CRC at an early stage and adenomas as premalignant lesions. A combination of FDG-PET and FOBT yields the best results if the intent is to detect either CRC or adenoma. However, it is absolutely clear that an FDG-PET cancer screening program cannot detect all colon lesions.     

18F-FDG PET/CT在胃癌中的临床应用进展

胃癌是全球范围内最常见的恶性肿瘤之一。18F-氟脱氧葡萄糖（FDG）PET/CT在胃癌中的应用既有优点又有局限性。胃癌原发灶对18F-FDG的摄取与癌症分期、组织学分型和肿瘤大小密切相关。早期胃癌18F-FDG摄取阳性预示着内镜黏膜下剥离术的不可治愈性。进展期胃癌的最大标准化摄取值（SUV_max）在肠型与印戒细胞癌（SRC）或弥漫型胃癌间的差异显著,SRC的SUV_max与患者的总生存时间和无病生存时间呈负相关。18F-FDG PET/CT对区域淋巴结转移的诊断灵敏度较低,但其特异度很高,区域淋巴结对18F-FDG摄取呈阳性是预后不良的指征。18F-FDG PET/CT可检出隐匿的远处转移（7.2%~10.0%）,其中大部分（4.7%~8.8%）使用腹腔镜也不能检出。常规性应用18F-FDG PET/CT并联合腹腔镜检查对明确胃癌分期的意义重大。因此,笔者就18F-FDG PET/CT在胃癌中的临床应用进展进行综述。     

FDG PET as a procedure for detecting simultaneous tumours in head and neck cancer patients

AIM: The presence of simultaneous primary tumours in other regions affects the prognosis and management decisions of head and neck cancer patients. Therefore, early detection of these tumours is necessary. Recent improvements in positron emission tomography (PET) have made it possible to examine the patient's whole body. The present study was undertaken to evaluate the clinical contribution of whole-body PET using fluorodeoxyglucose (FDG) for head and neck cancer patients. METHODS: Fifty-three consecutive patients with previously untreated head and neck cancer were examined. Whole-body FDG PET imaging was performed at 1 h after injection of (18)F-FDG. A 3-D acquisition was undertaken and iterative reconstruction was performed. The final diagnosis of simultaneous primary tumour was established by histological findings or clinical follow-up. RESULTS: Of 53 patients, six (11%) had evidence of simultaneous primary tumour. In five of these six patients, simultaneous primary tumours (two gastric cancer; one colon cancer; one pancreatic cancer; one thyroid cancer) were found by FDG PET. One more patient was found to have prostate cancer on the basis of blood test but this was not detected by FDG PET. In none of the remaining 47 patients, were additional simultaneous primary tumours found by FDG PET or any of the other routine examinations or during follow-up. CONCLUSIONS: The results of this study show a high rate of simultaneous primary tumour in patients with primary head and neck cancer. FDG PET appears to be a promising imaging modality for the detection of simultaneous tumours in head and neck cancer patients.     

The detection rates and tumor clinical/pathological stages of whole-body FDG-PET cancer screening

OBJECTIVE: FDG-PET has been used for cancer screening, mainly in East-Asia, and cancers are found not infrequently. However, their stages have not been clarified. We examined the detection rates of various cancers using whole-body PET for the screening of cancers in asymptomatic individuals, focusing on their clinical and pathological stages. METHODS: Whole-body PET was obtained as a part of our cancer screening program among 3,426 healthy subjects. All subjects participated in a course of PET examination in conjunction with conventional examinations including a medical questionnaire, tumor markers, immunological fecal occult blood test, neck and abdominal ultrasonography and whole body computed tomography. A diagnosis and staging was obtained by an analysis of the pathological findings or by an analysis of the clinical follow-up data. RESULTS: Malignant tumors were discovered in 65 lesions found in 3,426 participants (1.90%). The PET findings were true-positive in 46 of the 65 cancer cases. The cancers were found in the following organs: the colon 14; thyroid gland 10; stomach 7; lung 5; liver 3; breast 2; and one each in the kidney, gallbladder, esophagus, pancreas and retroperitoneum. The stages were as follows: stage 0 5, stage I 17, stage II 10, stage III 7, and stage IV 6. One was an unknown primary. There were 19 false-negative findings (0.6%) on PET. Six cancers (0.18%) were missed in our screening program. CONCLUSIONS: PET imaging has the potential to detect a wide variety of cancers at potentially curative stages. Most PET-negative cancers are early stage cancers, and thus can be detected using other conventional examinations such as endoscopy.     

Diagnostic performance of FDG PET/CT for surveillance in asymptomatic gastric cancer patients after curative surgical resection

Purpose

The present study evaluated the diagnostic performance of 2-[¹⁸F] fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) for surveillance in asymptomatic gastric cancer patients after curative surgical resection.

Methods

We retrospectively recruited 190 gastric cancer patients (115 early gastric cancer patients and 75 advanced gastric cancer patients) who underwent 1-year (91 patients) or 2-year (99 patients) postoperative FDG PET/CT surveillance, along with a routine follow-up program, after curative surgical resection. All enrolled patients were asymptomatic and showed no recurrence on follow-up examinations performed before PET/CT surveillance. All PET/CT images were visually assessed and all abnormal findings on follow-up examinations including FDG PET/CT were confirmed with histopathological diagnosis or clinical follow-up.

Results

During follow-up, 19 patients (10.0 %) developed recurrence. FDG PET/CT showed abnormal findings in 37 patients (19.5 %). Among them, 16 patients (8.4 %) were diagnosed as cancer recurrence. Of 153 patients without abnormal findings on PET/CT, three patients were false-negative and diagnosed as recurrence on other follow-up examinations. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET/CT were 84.2 %, 87.7 %, 43.2 %, and 98.0 %, respectively. Among 115 early gastric cancer patients, PET/CT detected recurrence in four patients (3.5 %) and one patient with local recurrence. Among 75 advanced gastric cancer patients, PET/CT detected recurrence in 12 patients (16.0 %), excluding two patients experiencing peritoneal recurrence. In addition, FDG PET/CT detected secondary primary cancer in six (3.2 %) out of all the patients.

Conclusions

Post-operative FDG PET/CT surveillance showed good diagnostic ability for detecting recurrence in gastric cancer patients. FDG PET/CT could be a useful follow-up modality for gastric cancer patients, especially those with advanced gastric cancer. However, further careful evaluation is needed because of false-positive findings on PET/CT.

     

Gastric distension by ingesting food is useful in the evaluation of primary gastric cancer by FDG PET

Gastric carcinoma is the second leading cause of cancer-related death worldwide. Detection and surgical resection of gastric cancer in the early stage provides the only hope for improved survival in patients with gastric cancer. Positron emission tomography (PET) with F-18 2-deoxy-2-fluoro-D-glucose (FDG) has been shown to be essential in the evaluation of a variety of malignancies. However, conventional FDG PET has limited value for detecting a primary tumor of the stomach, mostly because of the relatively high levels of physiological uptake by the contracted stomach. We report 3 cases of primary gastric carcinomas detected successfully by FDG PET after the ingestion of food. The PET images of the stomach after ingesting food were compared with the routine fasting-state whole-body PET images for each patient. When the stomach was distended by food, the malignant lesions were more discernible. These cases indicate that gastric distension by ingesting food may be a simple method that can help to detect a primary gastric malignancy by FDG PET.     

Analysis of various malignant neoplasms detected by FDG-PET cancer screening program: based on a Japanese Nationwide Survey

Objective

The most distinctive feature of FDG-PET cancer screening program is the ability to find various kinds of malignant neoplasms in a single test. The aim of this survey is to clarify the range and frequency of various malignant neoplasms detected by FDG-PET cancer screening performed in Japan.

Methods

“FDG-PET cancer screening” was defined as FDG-PET or positron emission tomography and computed tomography (PET/CT) scan with or without other tests performed for cancer screening of healthy subjects. This survey was based on a questionnaire regarding FDG-PET cancer screening. We analyzed the situation of 9 less frequently found malignant neoplasms including malignant lymphoma, malignancy of head and neck, esophagus, hepatobiliary and gallbladder, pancreas, kidney, cervical and uterine, ovary, and bladder.

Results

The detailed information of subjects with the suspected 9 kinds of malignant neoplasms mentioned above in the FDG-PET cancer screening program was studied in a total of 1,219 cases from 212 facilities. A statistical significance between PET/CT and PET was found in relative sensitivity and PPV for renal cell cancer. Malignant lymphoma was frequently of indolent type, suspected head and neck cancers had many false-positive results, and pancreatic cancer detected in this program was often in the advanced stage even in asymptomatic subjects. The recommendation of combined screening modality to PET or PET/CT was as follows: gastric endoscopy for assessing early esophageal cancer; abdominal ultrasound for screening hepatobiliary and gallbladder cancer; pelvic magnetic resonance imaging for assessing gynecological and pelvic cancers; and the CA125 blood test for screening ovarian cancer. Delayed image was helpful depending on the type of suspected malignant neoplasm.

Conclusion

We analyzed various types of malignant neoplasms detected by the FDG-PET cancer screening program and presented recommended combination of examinations to cover FDG-PET and PET/CT.     

PET and cancer screening

Various carcinomas are discovered incidentally during FDG PET study. This points to the potential use of PET as a cancer screening modality. Our experience using three PET scanners showed that PET can be performed in many individuals, and a wide variety of carcinomas can be detected at potentially curable stages. PET screening targets various organs that conventional organ-specific screening tests cannot cover. PET used simultaneously with conventional tests can prevent the overlooking of cancer, reduce false-positive results, and assist in the interpretation of CT and MR images. Thus, PET can play a supportive role when used with conventional screening tests. To reduce false-positive and false-negative results in PET screening, however, experienced PET oncologists who can differentiate between distinct physiological FDG uptake and faint abnormal FDG uptake are needed. In Japan, more than half of the PET facilities offer PET examinations for cancer screening of asymptomatic persons. Not a few individuals pay for sophisticated cancer screenings. Guidelines concerning the use of PET for cancer screening were issued by the Japanese Society of Nuclear Medicine in 2004. The guidelines provide for maintenance of study quality and warn of overselling PET screening. It is unclear how much PET contributes to sophisticated cancer screening. Data are lacking as to whether mortality is reduced by PET screening. Scientific evidence should be presented demonstrating the value of PET in cancer screening.     

Lymph node staging of gastric cancer using (18)F-FDG PET: a comparison study with CT.

This study was performed to compare (18)F-FDG PET with CT for the evaluation of primary tumors and lymph node metastases in gastric cancer. METHODS: Eighty-one patients (28 women and 53 men; mean age, 56.6 y; age range; 32-82 y) who had undergone radical (n = 74) or palliative (n = 7) gastrectomy and lymph node dissection for the management of gastric cancer were included. Preoperative (18)F-FDG PET and CT were reviewed retrospectively for primary tumors of the stomach and lymph node metastases. Any increased (18)F-FDG uptake exceeding that of the adjacent normal gastric wall was considered positive for the primary tumor. Lymph nodes were classified into 3 groups based on their anatomic sites. Because perigastric lymph nodes (N1) were often not clearly differentiated from primary tumors, N1 lymph node metastases were determined when possible. Lymph nodes were considered positive or negative on the basis of the group as a whole. Final conclusions for primary tumors and lymph node metastases were based on histopathologic specimens in all patients. RESULTS: There were 17 patients with early gastric cancer (EGC) and 64 patients with advanced gastric cancer (AGC). For primary tumors, both PET and CT showed a sensitivity of 47% (8/17) for EGC and 98% (63/64) for AGC. The sensitivity of CT for N1 disease was significantly higher than that of PET. (18)F-FDG PET had a sensitivity, specificity, and accuracy of 34% (11/32), 96% (47/49), and 72% (58/81), respectively, for N2 metastases, whereas the corresponding CT values were 44% (14/32), 86% (42/49), and 69% (56/81). For N3 metastases, PET and CT had the same sensitivity, specificity, and accuracy: 50% (3/6), 99% (74/75), and 95% (77/81), respectively. Overall, the sensitivity, specificity, and accuracy of (18)F-FDG PET were not significantly different from those of CT for primary tumors or for N2 and N3 metastases. CONCLUSION: (18)F-FDG PET is as accurate as CT for the detection of primary tumors of either EGC or AGC. The low sensitivities of PET and CT were insufficient to allow decision making on the extent of lymphadenectomy. In contrast, the high specificity of PET for N disease appeared valuable, and the presence of N disease on PET may have a clinically significant impact on the choice of initial therapy.     

Improved detection of breast cancer on FDG-PET cancer screening using breast positioning device

Objective The aim of this study was to investigate the detection rate of breast cancer by positron emission tomography cancer screening using a breast positioning device. Methods Between January 2004 and January 2006, 1,498 healthy asymptomatic individuals underwent cancer screening by fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) at our institution; 660 of 1498 asymptomatic healthy women underwent breast PET imaging in the prone position using the breast positioning device to examine the mammary glands in addition to whole-body PET imaging. All subjects that showed abnormal ¹⁸F-FDG uptake in the mammary glands were referred for further examination or surgery at our institution or a local hospital. Our data were compared with the histopathological findings or findings of other imaging modalities in our institution and replies from the doctors at another hospital. Results Of the 660 participants, 7 (1.06%) were found to have breast cancers at a curable stage. All the seven cancers were detected by breast PET imaging, but only five of these were detected by whole-body PET imaging; the other two were detected by breast PET imaging using the breast positioning device. Conclusions In cancer screening, prone breast imaging using a positioning device may help to improve the detection rate of breast cancer. However, overall cancer including mammography and ultrasonography screening should be performed to investigate the false-negative cases and reduce false-positive cases. The effectiveness of prone breast PET imaging in cancer screening should be investigated using a much larger number of cases in the near future.     

Semiquantitative in vitro binding assay of indium-111-labeled monoclonal antibodies to human cancer and normal tissues

We have developed a simple in vitro method for the semiquantitative assessment of the radiolabeled antibody binding to cancer and normal tissues. Indium-111-labeled F(ab')2 fragments of 17-1A and 19-9 monoclonal antibodies with well-characterized specificity for gastrointestinal cancer demonstrated similar binding properties between cultured cancer cells and membrane fractions of homogenates prepared from tumor tissues. All of the 17 colon cancer specimens and seven (64%) of 11 gastric cancer specimens obtained by surgery showed positive binding with 17-1A. Specific binding of 19-9 was observed in 9 (53%) colon cancers and 4 (36%) gastric cancers. However, some normal colon tissues were also positive with 111In-labeled 17-1A. Relative levels of CA 19-9 antigen expression, determined by the binding with radiolabeled antibodies, correlated with percent positive cells determined by the immunohistochemical assays. Furthermore, membrane fractions could be cryopreserved without losing antibody-binding activity. These results indicate that this assay can be used for testing the immunoreactivity of radiolabeled anti-tumor antibodies and in vitro binding properties to cancer and normal tissues.     

Performance profile of a FDG-PET cancer screening program for detecting gastric cancer: results from a nationwide Japanese survey

Purpose

It has been reported that gastric cancer is the sixth most common cancer found during the ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program, which is defined as cancer screening of asymptomatic subjects using FDG-PET(/CT) (in combination with other screening tests or not). The aim of this study was to analyze the detection rate and the effectiveness of the FDG-PET cancer screening program at detecting gastric cancer between 2006 and 2009 in Japan.

Materials and methods

A total of 153,775 asymptomatic subjects (92,255 men, 61,520 women) between 30 and 80 years old underwent the FDG-PET cancer screening program. Of these, we analyzed 790 cases with findings of possible gastric cancer in any screening test.

Results

The number of cases who were verified to have gastric cancer was 124. Among these, only 47 cases were detected by FDG-PET, which resulted in a relative sensitivity of 37.9 % and a positive predictive value of 33.6 %. The relative sensitivity of FDG-PET was much lower than those of gastric endoscopy and the serum pepsinogen test.

Conclusion

The FDG-PET screening program in Japan detected some cases of early-stage gastric cancer, but this was not achieved using FDG-PET alone but in combination with gastric endoscopy. Gastric endoscopy should be included in FDG-PET cancer screening programs to screen for gastric cancer.     

A preliminary report of breast cancer screening by positron emission mammography

Objective

Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) and PET/computed tomography (PET/CT) have had a considerable impact on the detection of various malignancies. PET and PET/CT are minimally invasive methods that can provide whole-body imaging at one time. Therefore, an FDG-PET cancer screening program has been widely used in Japan. However, the breast cancer detection rate of FDG-PET cancer screening is relatively low. Therefore, FDG-PET screening is not recommended for breast cancer screening. Positron emission mammography (PEM) is a high-resolution molecular breast imaging technology. PEM can detect small breast cancers that cannot be detected on PET or PET/CT images due to limited spatial resolution. We have performed opportunistic breast cancer screening using PEM since 2011. To the best of our knowledge, this is the first report regarding PEM breast cancer screening.

Methods

This study enrolled 265 women. PEM images were analyzed by agreement of 2 experienced nuclear medicine physicians. The readers were given information from medical interview sheet. US findings were interpreted holistically. The number of participants, patient recall rate, further examination rate, and cancer detection rate by year were calculated.

Results

The overall recall rate was 8.3 %; the work-up examination rate was 77.3 %, and cancer detection rate was 2.3 %. The positive predictive value of PEM was 27.3 %. Six cancers were found by PEM screening. Five were invasive cancers and one was ductal carcinoma in situ. Histological tumor sizes were reported in three cases: 0.7, 1.2, and 2 cm.

Conclusion

PEM screening appears to have potential for breast cancer screening.

     

Assessment of lymph node metastases using 18F-FDG PET in patients with advanced gastric cancer

Purpose The aim of this study was to assess the diagnostic accuracy of ¹⁸F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) with respect to lymph node (LN) metastasis in patients with advanced gastric cancer, and to ascertain the factors that affect this accuracy.Methods Seventy-three patients with advanced gastric cancer, verified in all cases by endoscopic biopsy, were enrolled in this prospective study. We conducted FDG PET and other routine preoperative studies, including abdominal computed tomography (CT). Patients underwent either curative-intent gastrectomy and lymphadenectomy (n=67) or exploratory laparotomy. The Japanese system for the classification of gastric cancer was used for LN assessment.Results FDG PET was able to detect primary lesions in 70 of the 73 cases. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value of FDG PET for LN metastasis were 40%, 95%, 91% and 56%, respectively. Signet-ring cell carcinoma was associated with the lowest sensitivity (15%), whereas other cell types could be detected with moderate sensitivity (30–71%) and high specificity (93–100%). According to multiple logistic regression, the standardised uptake value for primary tumours was the only independent variable to be significantly related to sensitivity for LN metastasis (p=0.02, odds ratio=1.14). CT was superior to PET in terms of sensitivity (p<0.0001), and PET was superior to CT in terms of specificity (p<0.0001) and PPV (p=0.05).Conclusion FDG PET exhibits good specificity for LN staging of gastric cancer, and FDG uptake in the primary tumour is significantly related to the accuracy of FDG PET. Despite some clear limitations, FDG PET proved useful in the LN staging of FDG-avid gastric cancer.Seok-Ki Kim and Keon Wook Kang contributed equally to this paper.     

Accuracy of FDG-PET in Gastric Cancer. Preliminary Experience

OBJECTIVE: Currently available imaging modalities, including CT, ultrasound, and MRI are unsatisfactory in the detection of metastatic gastric cancer, especially lymph node metastases and peritoneal spread. The aim of this study is to evaluate FDG-PET in the diagnosis of primary as well as metastatic gastric cancer.METHOD: All patients (18M/5F; mean age 62, range 33-81) with gastric cancer referred for FDG-PET scan from 1/1/97 to 3/20/98 were studied. PET images of the neck, chest, and abdomen were acquired using a dedicated whole body scanner. A final diagnosis was reached in 21 patients by histology, surgical findings, or clinical follow-up.RESULTS: All but 1 primary tumor (12 out of 13) and both cases with local recurrence showed a high degree of FDG uptake, with mean SUV of 8.9 (range 4.8-17.6). The one false negative (FN) occurred in a poorly controlled diabetic with blood sugar of >400 at the time of study. Six cases with prior gastrectomy were true negative (TN) in the region of the stomach. This translates to a sensitivity of 93%, specificity of 100%, and accuracy of 95% for the primary site. In contrast, for intra-abdominal lymph node (LN) stations PET was true positive (TP) in 2, FN in 7, false positive (FP) in 1, and TN in 32, yielding a sensitivity of 22% and accuracy of 81%. PET detected only 2 out of 9 perigastric lymph node metastases. For the 8 patients in this series who had documented M1 disease, PET detected two with liver metastasis, one with colon metastasis, and one with submandibular LN. However, four cases of peritoneal spread were missed.CONCLUSION: FDG-PET is highly sensitive in detecting the primary lesion in gastric cancer and shows promise in the detection of liver and extra-abdominal metastasis. However, PET appears limited in the detection of perigastric lymphadenopathy as distinct from the primary tumor and in assessing peritoneal spread. Our preliminary assessment suggests that staging of gastric cancer with FDG-PET scanning is relatively effective at detecting distant metastatic disease and will complement standard staging methods such as laparoscopy, which are more effective at staging local nodal spread and peritoneal disease.