Early metabolic response evaluation by fluorine-18 fluorodeoxyglucose positron emission tomography allows in vivo testing of chemosensitivity in gastric cancer: long-term results of a prospective study.

PURPOSE: We prospectively evaluated the predictive value of positron emission tomography using fluorine-18 fluorodeoxyglucose (FDG-PET) for in vivo testing of chemosensitivity in locally advanced gastric cancer using an a priori definition of metabolic response (a decrease of >35% of the standard uptake value). The goal of the study was the definition of biologically different groups of patients prior to or early during induction therapy, with special emphasis on FDG non-avid tumors. EXPERIMENTAL DESIGN: Based on our data, which was published in 2003, at least 36 patients with metabolic response or FDG non-avid tumors had to be recruited for an analysis of the group of FDG non-avid tumors with sufficient statistical power. Seventy-one patients (32 metabolic nonresponders, 17 metabolic responders, and 22 patients with FDG non-avid tumors) underwent FDG-PET at baseline. In FDG-avid tumors, FDG-PET was repeated 14 days after the initiation of chemotherapy. RESULTS: Metabolic responders (17 of 49) showed a high histopathologic response rate (69%) and a favorable prognosis (median survival not reached), whereas metabolic nonresponders (32 of 49) had a poor prognosis (median survival, 24.1 months) and showed a histopathologic response in 17%. The histopathologic response rate (24%) for FDG-PET non-avid patients showed no significant difference compared with FDG-avid nonresponders (P=0.72). Survival of FDG non-avid patients was 36.7 months (not significantly different from FDG-avid nonresponders, 24.1 months, P=0.46). CONCLUSION: In locally advanced gastric cancer, three different metabolic groups exist. Response and survival was predicted by PET in FDG-avid tumors. Metabolic response assessment was not possible in FDG non-avid tumors; however, due to unfavorable outcome, therapy modification might also be considered in FDG non-avid tumors.     

Reduction of glucose metabolic activity is more accurate than change in size at predicting histopathologic response to neoadjuvant therapy in high-grade soft-tissue sarcomas

PURPOSE: Change in tumor size as classified by Response Evaluation Criteria in Solid Tumors poorly correlates with histopathologic response to neoadjuvant therapy in patients with soft-tissue sarcomas. The aim of this study was to prospectively evaluate whether positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) allows for a more accurate evaluation of histopathologic response. EXPERIMENTAL DESIGN: From January 2005 to January 2007, 42 patients with resectable biopsy-proven high-grade soft-tissue sarcoma underwent a FDG-PET/computed tomography scan before and after neoadjuvant treatment. Relative changes in tumor FDG uptake and size from the baseline to the follow-up scan were calculated, and their accuracy for assessment of histopathologic response was compared by receiver operating characteristic curve analysis. Histopathologic response was defined as > or =95% tumor necrosis. RESULTS: In histopathologic responders (n = 8; 19%), reduction in tumor FDG uptake was significantly greater than in nonresponders (P < 0.001), whereas no significant differences were found for tumor size (P = 0.24). The area under the receiver operating characteristic curve for metabolic changes was 0.93, but only 0.60 for size changes (P = 0.004). Using a 60% decrease in tumor FDG uptake as a threshold resulted in a sensitivity of 100% and a specificity of 71% for assessment of histopathologic response, whereas Response Evaluation Criteria in Solid Tumors showed a sensitivity of 25% and a specificity of 100%. CONCLUSION: Quantitative FDG-PET was significantly more accurate than size-based criteria at assessing histopathologic response to neoadjuvant therapy. FDG-PET should be considered as a modality to monitor treatment response in patients with high-grade soft-tissue sarcoma.     

Tumor response and survival predicted by post-therapy FDG-PET/CT in anal cancer

PURPOSE: To evaluate the response to therapy for anal carcinoma using post-therapy imaging with positron emission tomography (PET)/computed tomography and F-18 fluorodeoxyglucose (FDG) and to compare the metabolic response with patient outcome. PATIENTS AND METHODS: This was a prospective cohort study of 53 consecutive patients with anal cancer. All patients underwent pre- and post-treatment whole-body FDG-PET/computed tomography. Patients had been treated with external beam radiotherapy and concurrent chemotherapy. Whole-body FDG-PET was performed 0.9-5.4 months (mean, 2.1) after therapy completion. RESULTS: The post-therapy PET scan did not show any abnormal FDG uptake (complete metabolic response) in 44 patients. Persistent abnormal FDG uptake (partial metabolic response) was found in the anal tumor in 9 patients. The 2-year cause-specific survival rate was 94% for patients with a complete vs. 39% for patients with a partial metabolic response in the anal tumor (p = 0.0008). The 2-year progression-free survival rate was 95% for patients with a complete vs. 22% for patients with a partial metabolic response in the anal tumor (p < 0.0001). A Cox proportional hazards model of survival outcome indicated that a complete metabolic response was the most significant predictor of progression-free survival in our patient population (p = 0.0003). CONCLUSIONS: A partial metabolic response in the anal tumor as determined by post-therapy FDG-PET is predictive of significantly decreased progression-free and cause-specific survival after chemoradiotherapy for anal cancer.     

Time course of tumor metabolic activity during chemoradiotherapy of esophageal squamous cell carcinoma and response to treatment.

PURPOSE: To evaluate the time course of therapy-induced changes in tumor glucose use during chemoradiotherapy of esophageal squamous cell carcinoma (ESCC) and to correlate the reduction of metabolic activity with histopathologic tumor response and patient survival. PATIENTS AND METHODS: Thirty-eight patients with histologically proven intrathoracic ESCC (cT3, cN0/+, cM0) scheduled to undergo a 4-week course of preoperative simultaneous chemoradiotherapy followed by esophagectomy were included. Patients underwent positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) before therapy (n = 38), after 2 weeks of initiation of therapy (n = 27), and preoperatively (3 to 4 weeks after chemoradiotherapy; n = 38). Tumor metabolic activity was quantitatively assessed by standardized uptake values (SUVs). Results Mean tumor FDG uptake before therapy was 9.3 +/- 2.8 SUV and decreased to 5.7 +/- 1.9 SUV 14 days after initiation of chemoradiotherapy (-38% +/- 18%; P <.0001). The preoperative scan showed an additional decrease of metabolic activity to 3.3 +/- 1.1 SUV (P <.0001). In histopathologic responders (< 10% viable cells in the resected specimen), the decrease in SUV from baseline to day 14 was 44% +/- 15%, whereas it was only 21% +/- 14% in nonresponders (P =.0055). Metabolic changes at this time point were also correlated with patient survival (P =.011). In the preoperative scan, tumor metabolic activity had decreased by 70% +/- 11% in histopathologic responders and 51% +/- 21% in histopathologic nonresponders. CONCLUSION: Changes in tumor metabolic activity after 14 days of preoperative chemoradiotherapy are significantly correlated with tumor response and patient survival. This suggests that FDG-PET might be used to identify nonresponders early during neoadjuvant chemoradiotherapy, allowing for early modifications of the treatment protocol.     

Positron emission tomography in non-small-cell lung cancer: prediction of response to chemotherapy by quantitative assessment of glucose use.

PURPOSE: To prospectively evaluate the use of positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) to predict response to chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients with stage IIIB or IV NSCLC scheduled to undergo platinum-based chemotherapy were eligible for this study. Patients were studied by FDG-PET before and after the first cycle of therapy. Based on previous studies, a reduction of tumor FDG uptake by more than 20% as assessed by standardized uptake values (SUV) was used as a criterion for a metabolic response. Furthermore, changes in tumor SUVs were compared with changes in FDG net-influx constants (Ki) and tumor/muscle ratios (t/m). RESULTS: Fifty-seven patients were included in the study. There was a close correlation between metabolic response and best response to therapy according to Response Evaluation Criteria in Solid Tumors (P <.0001; sensitivity and specificity for prediction of best response, 95% and 74%, respectively). Median time to progression and overall survival were significantly longer for metabolic responders than for metabolic nonresponders (163 v 54 days and 252 days v 151 days, respectively). Similar results were obtained when Ki was used to assess tumor glucose use, whereas changes in t/m showed considerable overlap between responding and nonresponding tumors. CONCLUSION: In NSCLC, reduction of metabolic activity after one cycle of chemotherapy is closely correlated with final outcome of therapy. Using metabolic response as an end point may shorten the duration of phase II studies evaluating new cytotoxic drugs and may decrease the morbidity and costs of therapy in nonresponding patients.     

The new credo: induction chemotherapy in locally advanced gastric cancer: consequences for surgical strategies

Perioperative chemotherapy in stage II and stage III gastric cancer is now accepted as a standard of care in the Western world. Two randomized phase III studies have shown improved survival for patients with induction chemotherapy followed by surgery compared with surgery alone. It is generally accepted that patients who respond to induction therapy have a significantly improved survival compared with that in nonresponding patients. Unfortunately no prospectively tested markers predicting response and/or prognosis are available for clinical practice. In adenocarcinomas of the esophagogastric junction (AEG), fluorodeoxyglucose-positron emission tomography (FDG-PET) prospectively was established as a surrogate predicting response and prognosis. The MUNICON (Metabolic response evalUatioN for Individualisation of neoadjuvant Chemotherapy in oesOphageal and oesophagogastric adeNocarcinoma) I study confirmed prospectively the usefulness of early metabolic response evaluation and showed the feasibility of a PET-guided treatment algorithm. These findings are an important step forward in the tailoring of multimodal treatment in accordance with tumor biology. In gastric cancer, we have analyzed FDG-PET in a prospective study. In gastric cancer the issue is more complicated, because about 30% of gastric cancers cannot be visualized with sufficient contrast for quantification. Insufficient FDG uptake is mostly associated with diffuse-type gastric cancer with signet ring cells and mucinous content. In FDG-avid patients, FDG-PET can be used for response evaluation, comparable to that in AEG. The prognosis of FDG-nonavid patients is similar to that in metabolic nonresponders. The addition of new tracers such as fluorothymidine may increase the sensitivity of PET in the future. Treatment concepts such as immediate resection after only 2 weeks of induction therapy with or without adjuvant treatment could be considered in metabolic nonresponders, or modified chemotherapy regimens, possibly including biologically targeted drugs, could be considered in those with FDG-nonavid tumors. Presented in part at the 7th International Gastric Cancer Congress, Sao Paulo, Brazil, 2007     

Prediction of response to neoadjuvant chemotherapy by sequential F-18-fluorodeoxyglucose positron emission tomography in patients with advanced-stage ovarian cancer.

PURPOSE: The aim of this study was to evaluate sequential F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) to predict patient outcome after the first and third cycle of neoadjuvant chemotherapy in advanced-stage (International Federation of Gynecology and Obstetrics stages IIIC and IV) ovarian cancer. PATIENTS AND METHODS: Thirty-three patients received three cycles of carboplatin-based chemotherapy, followed by cytoreductive surgery. Quantitative FDG-PET of the abdomen and pelvis was acquired before treatment and after the first and third cycle of chemotherapy. Changes in tumoral FDG uptake, expressed as standardized uptake values (SUV), were compared with clinical and histopathologic response; overall survival served as a reference. RESULTS: A significant correlation was observed between FDG-PET metabolic response after the first (P = .008) and third (P = .005) cycle of chemotherapy and overall survival. By using a threshold for decrease in SUV from baseline of 20% after the first cycle, median overall survival was 38.3 months in metabolic responders compared with 23.1 months in metabolic nonresponders. At a threshold of 55% decrease in SUV after the third cycle median overall survival was 38.9 months in metabolic responders compared with 19.7 months in nonresponders. There was no correlation between clinical response criteria (P = .7) or CA125 response criteria (P = .5) and overall survival. There was only a weak correlation (P = .09) between histopathologic response criteria and overall survival. CONCLUSION: Sequential FDG-PET predicted patient outcome as early as after the first cycle of neoadjuvant chemotherapy and was more accurate than clinical or histopathologic response criteria including changes in tumor marker CA125. FDG-PET appears to be a promising tool for early prediction of response to chemotherapy.     

Imaging of esophageal and gastric cancer

The three major aims of imaging in esophageal and gastric cancer are to distinguish between locoregional and systemic disease (M stage), to determine local tumor extension (T and N stages), and to assess response to chemotherapy or chemoradiotherapy. Depending on the applied standard of reference, the sensitivity of computed tomography (CT) for detection of distant metastases ranges between less than 50% to greater than 90%. In esophageal cancer, positron emission tomography with the glucose analog fluorodeoxyglucose (FDG-PET) has been shown to detect metastatic disease in approximately 20% of the patients who were considered to have only locoregional disease with CT. In clinical studies, endoscopic ultrasound (EUS) has been shown to differentiate between tumor stages T1/T2 and stages T3/T4 with an accuracy of more than 90%. Accuracy of EUS for differentiating individual tumor stages in routine clinical use has been reported to be markedly lower. Assessment of tumor response by FDG-PET has been shown to correlate with histopathologic tumor regression and patient survival. Furthermore, quantitative measurements of tumor FDG uptake may predict histopathologic tumor response and patient outcome as early as 2 weeks after initiation of preoperative chemotherapy.     

Monitoring of response to pre-operative chemoradiation in combination with hyperthermia in oesophageal cancer by FDG-PET.

PURPOSE: To evaluate the use of positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) to assess early response to pre-operative chemoradiation therapy in combination with external locoregional hyperthermia in patients with oesophageal cancer by correlating the reduction of metabolic activity with histopathologic response. MATERIAL AND METHODS: Twenty-six patients with histopathologically proven intra-thoracic oesophageal cancer (with < or =2 cm gastric involvement), scheduled to undergo a 5-week course of pre-operative chemoradiation therapy and hyperthermia, were included. FDG-PET was performed before (n = 26) and 2 weeks after initiation of therapy (n = 17). FDG uptake was quantitatively assessed by standardized uptake values. RESULTS: After neoadjuvant therapy, 24 of the 26 patients underwent surgery. In 16 patients changes in FDG uptake were correlated to histopathologic response. In these patients, histopathologic evaluation revealed less than 10% viable tumour cells in eight patients (responders) and more than 10% viable tumour cells in eight patients (non-responders). In responders, FDG uptake decreased by a median -44% (-75 to 2); in non-responders, it decreased by a median of -15% (-46 to 40). At a threshold of 31% decrease of FDG uptake compared with baseline, sensitivity to detect response was 75%, with a corresponding specificity of 75%. The positive and negative predictive values were both 75%. CONCLUSION: FDG-PET is a promising tool for early response monitoring in patients undergoing chemoradiation therapy in combination with hyperthermia.     

Prediction of response to preoperative chemotherapy in adenocarcinomas of the esophagogastric junction by metabolic imaging.

PURPOSE: Preoperative chemotherapy in patients with gastroesophageal cancer is hampered by the lack of reliable predictors of tumor response. This study evaluates whether positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) may predict response early in the course of therapy. PATIENTS AND METHODS: Forty consecutive patients with locally advanced adenocarcinomas of the esophagogastric junction were studied by FDG-PET at baseline and 14 days after initiation of cisplatin-based polychemotherapy. Clinical response (reduction of tumor length and wall thickness by > 50%) was evaluated after 3 months of therapy using endoscopy and standard imaging techniques. Patients with potentially resectable tumors underwent surgery, and tumor regression was assessed histopathologically. RESULTS: The reduction of tumor FDG uptake (mean +/- 1 SD) after 14 days of therapy was significantly different between responding (-54% +/- 17%) and nonresponding tumors (-15% +/- 21%). Optimal differentiation was achieved by a cutoff value of 35% reduction of initial FDG uptake. Applying this cutoff value as a criterion for a metabolic response predicted clinical response with a sensitivity and specificity of 93% (14 of 15 patients) and 95% (21 of 22), respectively. Histopathologically complete or subtotal tumor regression was achieved in 53% (eight of 15) of the patients with a metabolic response but only in 5% (one of 22) of the patients without a metabolic response. Patients without a metabolic response were also characterized by significantly shorter time to progression/recurrence (P =.01) and shorter overall survival (P =.04). CONCLUSION: PET imaging may differentiate responding and nonresponding tumors early in the course of therapy. By avoiding ineffective and potentially harmful treatment, this may markedly facilitate the use of preoperative therapy, especially in patients with potentially resectable tumors.     

Use of positron emission tomography in localized extremity soft tissue sarcoma treated with neoadjuvant chemotherapy

BACKGROUND: Patients with high-grade soft tissue sarcomas are at high risk of developing local disease recurrence and metastatic disease. [F-18]-fluorodeoxy-D-glucose (FDG) positron emission tomography (PET) scans are hypothesized to detect histopathologic response to therapy and to predict risk of tumor progression in patients with various malignancies. Serial FDG-PET scans were taken to determine the correlation between FDG uptake and patient outcomes in patients receiving multimodality treatment of extremity sarcomas. METHODS: Forty-six patients with high-grade localized sarcomas were studied. The maximum standardized uptake values (SUVmax) of tumors were measured before receipt of neoadjuvant chemotherapy and again before surgery. Resected specimens were examined for residual viable tumor. Patients were followed up at least annually for evidence of local and distant recurrence of disease and survival. RESULTS: Patients with a baseline tumor SUVmax >/= 6 and < 40% decrease in FDG uptake were at high risk of systemic disease recurrence estimated to be 90% at 4 years from the time of initial diagnosis. Patients whose tumors had a >/= 40% decline in the SUVmax in response to chemotherapy were at a significantly lower risk of recurrent disease and death after complete resection and adjuvant radiotherapy. CONCLUSIONS: The FDG-PET scan was found to be a useful method with which to predict the outcomes of patients with high-grade extremity soft tissue sarcomas treated with chemotherapy. The pretreatment tumor SUVmax and change in SUVmax after neoadjuvant chemotherapy independently identified patients at high risk of tumor recurrence. The FDG-PET scan showed promise as a tool to identify the patients with sarcoma who are most likely to benefit from chemotherapy.     

18FDG-PET评价局部晚期和晚期非小细胞肺癌化疗的客观疗效

 目的 前瞻性地探索18-氟脱氧葡萄糖-正电子发射计算机断层扫描（18FDG-PET）的SUV值标准与实体瘤疗效评价标准（RECIST）标准评价非小细胞肺癌（NSCLC）化疗的客观疗效是否具有一致性。方法 初治不可切除的局部晚期和晚期NSCLC患者前瞻性入组，行两周期含铂双药方案全身化疗。按RECIST标准和SUV值标准（2个周期化疗后SUV值下降大于30 %）互为盲法分别评价肿瘤客观疗效。用配对计数资料的χ2检验和κ系数检验比较18FDG-PET代谢缓解与RECIST标准的客观疗效是否具有一致性（SPSS13.0）。结果 不可切除的局部晚期8例，晚期35例。18FDG-PET代谢缓解与按RECIST标准评价的疗效具有明显的一致性（P＜0.001）。18FDG-PET评价NSCLC化疗客观疗效的敏感性、特异性、准确性、阳性预测值和阴性预测值分别是94 %、70 %、80 %、67 %和95 %。结论 18FDG-PET可以评价局部晚期和晚期NSCLC化疗的客观疗效。     

Monitoring of response to pre-operative chemoradiation in combination with hyperthermia in oesophageal cancer by FDG-PET

Purpose: To evaluate the use of positron emission tomography using ¹⁸F-fluorodeoxyglucose (FDG-PET) to assess early response to pre-operative chemoradiation therapy in combination with external locoregional hyperthermia in patients with oesophageal cancer by correlating the reduction of metabolic activity with histopathologic response. Material and methods: Twenty-six patients with histopathologically proven intra-thoracic oesophageal cancer (with ≤2?cm gastric involvement), scheduled to undergo a 5-week course of pre-operative chemoradiation therapy and hyperthermia, were included. FDG-PET was performed before (n?=?26) and 2 weeks after initiation of therapy (n?=?17). FDG uptake was quantitatively assessed by standardized uptake values. Results: After neoadjuvant therapy, 24 of the 26 patients underwent surgery. In 16 patients changes in FDG uptake were correlated to histopathologic response. In these patients, histopathologic evaluation revealed less than 10% viable tumour cells in eight patients (responders) and more than 10% viable tumour cells in eight patients (non-responders). In responders, FDG uptake decreased by a median ?44% (?75 to 2); in non-responders, it decreased by a median of ?15% (?46 to 40). At a threshold of 31% decrease of FDG uptake compared with baseline, sensitivity to detect response was 75%, with a corresponding specificity of 75%. The positive and negative predictive values were both 75%. Conclusion: FDG-PET is a promising tool for early response monitoring in patients undergoing chemoradiation therapy in combination with hyperthermia.     

Posttherapy surveillance monitoring of cervical cancer by FDG-PET

PURPOSE: To evaluate the effect of irradiation and chemotherapy for carcinoma of the uterine cervix on posttreatment tumor uptake of the glucose analog (18)F-fluorodeoxyglucose (FDG) imaged by positron emission tomography (PET) and to assess the utility of FDG-PET for surveillance monitoring. MATERIALS AND METHODS: This was a retrospective review of 76 patients with a new diagnosis of carcinoma of the uterine cervix who underwent pre- and posttreatment whole-body FDG-PET. Posttreatment FDG-PET was performed 2.4-10.4 months (median 4.2) after irradiation completion. RESULTS: After treatment, persistent abnormal FDG uptake in the cervix was found in 18% (14 of 76), in the pelvic lymph nodes in 16% (9 of 55), in the paraaortic lymph nodes in 45% (5 of 11), and in the supraclavicular lymph nodes in 75% (3 of 4). Eleven patients developed new sites of increased FDG uptake. In relation to the findings on posttreatment PET, the 2-year progression-free survival rate was 86% for patients with no abnormal FDG uptake at any site and 40% for those with persistent abnormal uptake; there were no survivors at 2 years among patients who developed new sites of abnormal FDG uptake (p <0.0001). A multivariate analysis of prognostic factors demonstrated that any posttreatment abnormal FDG uptake (persistent or new) was the most significant prognostic factor (p <0.0001) for death from cervical carcinoma. CONCLUSIONS: FDG-PET is a valuable tool to evaluate the response of primary cervical carcinoma and lymph node metastasis to treatment and for the surveillance of patients after initial therapy.     

~（18）FDG-PET显像对胃肠道肿瘤化疗反应的监测

目的探讨18-氟脱氧葡萄糖-正电子发射计算机断层扫描（18FDG-PET）的早期代谢疗效与RECIST标准评价的胃肠道肿瘤化疗最佳客观疗效的关系,评价其在化疗反应监测中的临床价值。方法不可切除的局部晚期和晚期胃肠道肿瘤患者入组,行全身化疗。按RECIST标准和SUV值标准（2疗程化疗后SUV值下降〉30%）分别评价肿瘤客观疗效。用计数资料的χ2检验和相关分析检验比较2疗程后18FDG-PET代谢缓解与RECIST标准的最佳客观疗效是否具有一致性（SPSS10.0）。结果不可切除的局部晚期胃肠道肿瘤3例,晚期胃肠道肿瘤27例。18FDG-PET代谢缓解与按RECIST标准评价的最佳客观疗效具有明显的一致性（P=0.004）。18FDG-PET预测胃肠道肿瘤化疗最佳客观疗效的敏感性、特异性、阳性预测值和阴性预测值分别是91.7%、66.7%、64.7%和92.3%。结论 18FDG-PET可以预测局部晚期和晚期胃肠道肿瘤化疗的最佳客观疗效,在化疗反应监测中具有一定的临床价值。     

Positron emission tomography using [(18)F]Fluorodeoxyglucose for monitoring primary chemotherapy in breast cancer.

PURPOSE: To address the role of positron emission tomography (PET) using [(18)F]fluorodeoxyglucose (FDG) to monitor primary (neoadjuvant) chemotherapy in patients with locally advanced breast cancer. PATIENTS AND METHODS: Quantification of regional FDG uptake of the breast acquired after the first and second courses of chemotherapy was compared with the baseline scan in 22 patients with a total of 24 breast carcinomas. To evaluate the predictive value of PET imaging, histopathologic response after completion of chemotherapy classified as gross residual disease (GRD) or minimal residual disease (MRD) served as the gold standard. RESULTS: Significant differences in tracer uptake between nonresponding tumors (GRD) and responding lesions (MRD) were observed (P <.05) as early as after the first course of chemotherapy. Tracer uptake showed little change in tumors with GRD found later in pathologic analysis but decreased sharply to the background level in most tumors with MRD. After the first course, all responders were correctly identified (sensitivity 100%, specificity 85%) by a standardized uptake value decrease below 55% of the baseline scan. At this threshold, histopathologic response could be predicted with an accuracy of 88% and 91% after the first and second courses of therapy, respectively. CONCLUSION: This study demonstrates that in patients with advanced breast cancer undergoing primary chemotherapy, FDG-PET differentiates responders from nonresponders early in the course of therapy. This may help improve patient management by avoiding ineffective chemotherapy and supporting the decision to continue dose-intensive preoperative chemotherapy in responding patients.     

2-Fluoro-2-deoxy-D-glucose positron emission tomography imaging is predictive of pathologic response and survival after preoperative chemoradiation in patients with esophageal carcinoma

BACKGROUND: The current study was performed to assess the value of 2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) in predicting the pathologic response and survival of patients with esophageal carcinoma treated with preoperative chemoradiation (CRT) and tumor resection. Preliminary reports suggest that FDG-PET may be predictive of the response of esophageal carcinoma patients to preoperative CRT. METHODS: Eighty-three patients with resectable esophageal carcinoma who underwent preoperative CRT and FDG-PET and tumor resection were evaluated for pathologic response to CRT, percent residual tumor, and survival. RESULTS: The majority of patients in the current study were men (74 of 83 patients; 89%). Most tumors were adenocarcinomas (73 of 83 tumors; 88%) and clinical (EUS)T3/4 (69 tumors; 83%) or N1 (46 tumors; 55%). FDG-PET after preoperative CRT identified pathologic responders but failed to rule out microscopic residual tumor in 13 of 73 cases (18%). Pathologic response was found to correlate with the post-CRT FDG-PET standardized uptake value (SUV) (P = 0.03) and a post-CRT FDG-PET SUV of or 4 was found to be the only preoperative factor to correlate with decreased survival (2-year survival rate of 33% vs. 60%; P = 0.01). On univariate Cox regression analysis, only post-CRT FDG-PET was found to be correlated with post-CRT survival (P = 0.04). CONCLUSIONS: Post-CRT FDG-PET was found to be predictive of pathologic response and survival in patients with esophageal carcinoma who undergo preoperative CRT. Esophagectomy should still be considered even if the post-CRT FDG-PET scan is normal because microscopic residual disease cannot be ruled out.     

A case of gastric gastrointestinal stromal tumor operated after low-dose chemotherapy with imatinib mesylate

A 76-year-old man was admitted to our hospital because of tarry motions. Endoscopic findings showed an ulcer on a large submucosal tumor in the stomach. Abodminal CT scan showed a protruding lesion of approximately 13 cm at the lumen of the gastric body. FDG-PET imaging revealed FDG uptake in the gastric body and abdominal cavity. We diagnosed it as GIST with peritoneal dissemination clinically, and treatment with 300 mg of imatinib mesylate was started in December 2006. The main tumor was reduced(reduction rate of 27%)and FDG-PET imaging revealed a decrease in FDG uptake in the main tumor and all disseminated tumors after 5 months of treatment. However, the drug was discontinued for arthritis(grade 3). Partial gastrectomy with sampling peritoneal nodules was performed in June 2007. The present case suggests that low-dose chemotherapy with imatinib mesylate may be useful as a preoperative therapy for a minimal surgery.     

Recent chemotherapy reduces the sensitivity of [18F]fluorodeoxyglucose positron emission tomography in the detection of colorectal metastases.

PURPOSE: [18F]2-fluoro-2-deoxyglucose (FDG) -positron emission tomography (PET) has become a useful tool in the assessment of patients with colorectal cancer. Patients often undergo chemotherapy as treatment for primary or metastatic colorectal malignancy. Because cytotoxic chemotherapy may decrease the cellular metabolic activity of tumor, we assessed the effects of chemotherapy on PET imaging. PATIENTS AND METHODS: This is a prospective study examining detection of hepatic colorectal metastases by FDG-PET as related to use of chemotherapy. Pathologic analysis of the liver resection specimens was used as gold standard. RESULTS: There was significantly decreased tumor FDG uptake (as measured by the maximal standardized uptake value) in patients treated preoperatively with chemotherapy, resulting in less efficient detection of cancerous lesions. One biologic basis of this change in accuracy of PET was a significant decrease in the activity of the key glycolytic enzyme hexokinase in tumors from patients treated with chemotherapy. CONCLUSION: These results indicate that FDG-PET scanning should be interpreted in the context of concurrent cytotoxic therapy. FDG-PET scanning results may also be useful in assessment of response to such cytotoxic therapies.     

Posttherapy [18F] fluorodeoxyglucose positron emission tomography in carcinoma of the cervix: response and outcome.

PURPOSE: The aim of this study was to evaluate response to therapy using posttherapy molecular imaging with [(18)F] fluorodeoxyglucose (FDG), and to compare the response with patient outcome. PATIENTS AND METHODS: This was a retrospective medical record review of 152 patients with carcinoma of the cervix. All patients underwent a pre- and posttreatment whole-body positron emission tomography (PET) imaging scan with FDG. Patients were treated with external irradiation and intracavitary brachytherapy, and most received concurrent weekly cisplatin. Posttherapy whole-body FDG-PET was performed 1 to 12 months (mean, 3 months) after completion of treatment. RESULTS: The posttherapy PET did not show any abnormal FDG uptake in 114 patients, and their 5-year cause-specific survival estimate was 80%. There was persistent (in the irradiated region) abnormal FDG uptake in the cervix or lymph nodes in 20 patients. Their 5-year cause-specific survival estimate was 32%. New anatomic sites (in unirradiated regions) of abnormal FDG uptake were present in 18 patients, and none were alive at 5 years. A Cox proportional hazards model of survival outcome indicated that any abnormal posttherapy FDG uptake (persistent or new) was the most significant prognostic factor for developing metastatic disease and death from cervical cancer when compared with pretreatment- and treatment-related prognostic factors (P <.0001). CONCLUSION: Posttherapy abnormal FDG uptake (persistent or new) as detected by whole-body PET measures tumor response and might be predictive of tumor recurrence and death from cervical cancer. Prospective validation of these results is warranted.