Post-treatment Standardized Uptake Value Research Articles

Role of F-18 FDG PET/CT in Predicting Response to Neoadjuvant Chemotherapy in Invasive Ductal Breast Cancer.

The role of baseline and post-treatment standardized uptake value (SUVmax) values in predicting pathological response in patients with breast cancer after neoadjuvant chemotherapy (NAC). Thirty patients with invasive ductal breast cancer were included in this retrospective study. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) examinations were performed before and after NAC. Pretreatment SUVmax (SUVmax I), post-treatment SUVmax (SUVmax II) and ΔSUVmax values of primary breast cancer were obtained. Breast tumor pathology preparations were examined for the evaluation of tumor response according to the Miller and Payne classification. Patients were grouped as responding to treatment (pCR) and unresponsive to treatment (nonpCR). In all analyses, p<0.05 was considered statistically significant. The mean age of the 30 patients included in the study was 51.2±11.98 years. In the study-defined grouping, 13 patients (43.3%) were nonresponders and 17 patients (56.7%) were responders. ΔSUVmax was significantly greater in the responders group compared to the nonresponders group, while SUVmax II was lower (p = 0.001 and p = 0.004, respectively). There was no significant difference between the responders and nonresponders in terms of age, tumor diameter, and SUVmax I values. Multivariate logistic regression analysis showed ΔSUVmax to be the only independent predictive factor for pCR. F-18 FDG PET/CT was an effective method in evaluating the treatment response after NAC in breast cancer, and ΔSUVmax and post-treatment SUVmax can be used to predict the response of the primary tumor to treatment.

Impact on Radiological and Pathological Response with Neoadjuvant Chemoradiation and Its Effect on Survival in Squamous Cell Carcinoma of Thoracic Esophagus.

Neoadjuvant chemoradiation (NCRT) has been shown to improve survival in patients with locally advanced esophageal squamous cell carcinoma (SCC). The aim of the present study was to evaluate the role of 18-FDG PET-CT in predicting pathological response to NCRT. We assessed 70 patients of esophageal SCC who underwent NCRT and were evaluated with baseline and post chemoradiation 18F-FDG PET-CT scan. Receiver operating characteristic (ROC) curve was generated by analyzing the sensitivity and specificity of different cut-off points for defining a positive test and their ability to predict pathological complete response. Univariate and multivariate analysis were performed using log-rank and Cox proportional hazards models, and survival curves were estimated using the Kaplan-Meier method. Radiological and pathological complete response was achieved in 44.3% (n=31) and 34.3% (n=24) patients, respectively. Using ROC curves, post-treatment standardized uptake value (SUV) max [3.25, area under curve (AUC) 0.752] and % change in SUVmax cut-off value (72.32%, AUC 0.705) was used to predict pathological response. Significant associations between pathological response in primary tumor and post chemotherapy/radiotherapy SUVmax values (p=0.016), % change in SUVmax (p=0.006), radiological response in primary (p=0.006), and grade of dysphagia at presentation (p=0.041) were observed. Mean overall survival and relapse free survival was 83 and 58%, respectively at 34months. 18F-FDG PET-CT can be used to predict pathological response to NCRT in locally advanced SCC.

Prognostic significance of (18)FDG PET/CT in colorectal cancer patients with liver metastases: a meta-analysis.

BackgroundThe role of 18-fluorodeoxyglucose positron emission tomography CT (18FDG PET/CT), as a prognostic factor for survival in colorectal cancer patients with liver metastases, is still controversial. We sought to perform a meta-analysis of the literature to address this issue.MethodsA systematic literature search was performed to identify the studies that associated 18FDG PET/CT to clinical survival outcomes of patients with liver metastases. Methodological qualities of the included studies were also assessed. The summarized hazard ratio (HR) was estimated by using fixed- or random-effect model according to heterogeneity between trails.ResultsBy analyzing a total of 867 patients from 15 studies, we found that PET/CT for metabolic response to the therapy was capable of predicting event-free survival (EFS) and overall survival (OS) with statistical significance, and the HR was 0.45 (95 % confidence interval [CI], 0.26–0.78) and 0.36 (95 % CI, 0.18–0.71), respectively. Furthermore, pre-treatment 18FDG PET/CT with high standardized uptake value (SUV) was also significantly associated with poorer OS HR, 1.24; (95 % CI, 1.06–1.45). However, we did not find a statistically significant effect of post-treatment SUV for predicting OS HR, 1.68; (95 % CI, 0.63–4.52).ConclusionsThe present meta-analysis confirms that 18FDG PET/CT is a useful tool to help predict survival outcomes in patients with liver metastases.Electronic supplementary materialThe online version of this article (doi:10.1186/s40644-015-0055-z) contains supplementary material, which is available to authorized users.

Regional Lymph Node Uptake of [18F]Fluorodeoxyglucose After Definitive Chemoradiation Therapy Predicts Local-Regional Failure of Locally Advanced Non-Small Cell Lung Cancer: Results of ACRIN 6668/RTOG 0235

The American College of Radiology Imaging Network (ACRIN) 6668/Radiation Therapy Oncology Group (RTOG) 0235 study demonstrated that standardized uptake values (SUV) on post-treatment [(18)F]fluorodeoxyglucose-positron emission tomography (FDG-PET) correlated with survival in locally advanced non-small cell lung cancer (NSCLC). This secondary analysis determined whether SUV of regional lymph nodes (RLNs) on post-treatment FDG-PET correlated with patient outcomes. Included for analysis were patients treated with concurrent chemoradiation therapy, using radiation doses ≥60 Gy, with identifiable FDG-avid RLNs (distinct from primary tumor) on pretreatment FDG-PET, and post-treatment FDG-PET data. ACRIN core laboratory SUV measurements were used. Event time was calculated from the date of post-treatment FDG-PET. Local-regional failure was defined as failure within the treated RT volume and reported by the treating institution. Statistical analyses included Wilcoxon signed rank test, Kaplan-Meier curves (log rank test), and Cox proportional hazards regression modeling. Of 234 trial-eligible patients, 139 (59%) had uptake in both primary tumor and RLNs on pretreatment FDG-PET and had SUV data from post-treatment FDG-PET. Maximum SUV was greater for primary tumor than for RLNs before treatment (P<.001) but not different post-treatment (P=.320). Post-treatment SUV of RLNs was not associated with overall survival. However, elevated post-treatment SUV of RLNs, both the absolute value and the percentage of residual activity compared to the pretreatment SUV were associated with inferior local-regional control (P<.001). High residual metabolic activity in RLNs on post-treatment FDG-PET is associated with worse local-regional control. Based on these data, future trials evaluating a radiation therapy boost should consider inclusion of both primary tumor and FDG-avid RLNs in the boost volume to maximize local-regional control.

PET Scans as a Predictive Marker of Survival in Advanced Colorectal Cancer

BackgroundThe clinical utility of fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan in predicting the outcome of patients with metastatic colorectal cancer (mCRC) has not been well studied. We hypothesized that standardized uptake value (SUV) in FDG-PET scans after treatment predicts outcomes among patients with mCRC. Patients and MethodsWe retrospectively reviewed mCRC patients who had FDG-PET scans before their treatment and measured their SUV on follow-up imaging at the Karmanos Cancer Institute. Primary end points of time to progression (TTP) and overall survival (OS) were compared in 2 groups: follow-up (posttreatment) SUV of 0 versus > 0. ResultsThe study population consisted of 44 patients (median age of 58.1 years). Forty (91%) of the patients were treated first-line, 34 (77%) received an oxaliplatin-based regimen, and 7 (16%) received an irinotecan-based regimen. Thirty-four (77%) patients received concurrent bevacizumab. Median pretreatment SUV was 9.2 (range, 1.7-46.3), and median posttreatment SUV (in n = 41) was 4.0 (range, 0-14). The median percent change in SUV was −68.5% (range, −9.2% to −100%). The median time interval between scans was 2.6 months. There was no statistically significant difference noted between metabolic responders and nonresponders with regard to TTP and OS. However, patients with a posttreatment SUV of 0 had significantly longer OS than those with posttreatment SUV of > 0 (median, 42 vs. 25.2 months, respectively), and slightly longer TTP (median, 8.2 vs. 6.9 months, respectively). ConclusionSystemic therapy significantly decreased SUV on follow-up PET scans in advanced colorectal cancer patients. Absence of FDG uptake on follow-up PET scans was associated with markedly longer OS and slightly longer TTP.

PET scan as a prognostic marker in advanced colorectal cancer.

442 Background: Clinical utility and ability to prognosticate using FDG-PET scan in metastatic colorectal cancer (mCRC) has not been well studied in previous literature. We hypothesized that standardized uptake value (SUV) in post treatment FDG-PET predicts clinical outcomes. Methods: We retrospectively reviewed mCRC patients who had pre and post treatment FDG - PET scans during 2005-2012 at Karmanos Cancer Institute. Primary end points of time to progression (TTP) and overall survival (OS) were compared between the two groups (follow up SUV = 0 vs. SUV &gt; 0) using log-rank testing. Results: Study population consisted of 44 patients (median age of 58.1 years). Forty (91%) of these patients were treated first line and 34 (77 %) received an Oxaliplatin based regimen. Forty-one patients had both pre- and a post-treatment SUV. The 12 patients with post treatment SUV= 0 and the 29 patients with post-treatment SUV &gt; 0 had median OS of 42 and 25.2 months, respectively; they had median TTP of 8.2 and 6.9 months, respectively. The patients with post treatment SUV= 0 had significantly longer OS (p = 0.0310) and weakly significantly longer TTP (p = 0.0628) compared to the patients with post-treatment SUV &gt; 0. Conclusions: Systemic therapy decreased SUV on follow-up PET scans in the study population. Absence of FDG uptake on follow up PET scan was associated with longer OS and was suggestive of longer TTP in patients with metastatic colorectal cancer.

Prediction of Survival by [18F]Fluorodeoxyglucose Positron Emission Tomography in Patients With Locally Advanced Non–Small-Cell Lung Cancer Undergoing Definitive Chemoradiation Therapy: Results of the ACRIN 6668/RTOG 0235 Trial

In this prospective National Cancer Institute-funded American College of Radiology Imaging Network/Radiation Therapy Oncology Group cooperative group trial, we hypothesized that standardized uptake value (SUV) on post-treatment [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) correlates with survival in stage III non-small-cell lung cancer (NSCLC). Patients received conventional concurrent platinum-based chemoradiotherapy without surgery; postradiotherapy consolidation chemotherapy was allowed. Post-treatment FDG-PET was performed at approximately 14 weeks after radiotherapy. SUVs were analyzed both as peak SUV (SUVpeak) and maximum SUV (SUVmax; both institutional and central review readings), with institutional SUVpeak as the primary end point. Relationships between the continuous and categorical (cutoff) SUVs and survival were analyzed using Cox proportional hazards multivariate models. Of 250 enrolled patients (226 were evaluable for pretreatment SUV), 173 patients were evaluable for post-treatment SUV analyses. The 2-year survival rate for the entire population was 42.5%. Pretreatment SUVpeak and SUVmax (mean, 10.3 and 13.1, respectively) were not associated with survival. Mean post-treatment SUVpeak and SUVmax were 3.2 and 4.0, respectively. Post-treatment SUVpeak was associated with survival in a continuous variable model (hazard ratio, 1.087; 95% CI, 1.014 to 1.166; P = .020). When analyzed as a prespecified binary value (≤ v > 3.5), there was no association with survival. However, in exploratory analyses, significant results for survival were found using an SUVpeak cutoff of 5.0 (P = .041) or 7.0 (P < .001). All results were similar when SUVmax was used in univariate and multivariate models in place of SUVpeak. Higher post-treatment tumor SUV (SUVpeak or SUVmax) is associated with worse survival in stage III NSCLC, although a clear cutoff value for routine clinical use as a prognostic factor is uncertain at this time.

Factors associated with local-regional failure after definitive chemoradiation for locally advanced esophageal cancer.

e14669 Background: Esophageal cancer is often treated with a trimodality approach (chemotherapy and radiation followed by surgery). However a significant proportion of such patients achieve a clinical complete response (cCR) following chemoradiation alone. We retrospectively analyzed patients who reached cCR after definitive chemoradiation for locally advanced esophageal cancer to identify clinical predictors of local disease recurrence. Methods: We identified 141 patients who obtained initial cCR after definitive chemoradiation for esophageal cancer from January 2002 through January 2009. The initial response to treatment was assessed by endoscopic evaluation and biopsy results, with cCR defined as having no evidence of disease present. Patterns of failure were categorized as in-field (within the planned treatment volume [PTV]), outside the radiation treatment field, or both. Results: At a median follow-up of 22 months (range 6-87 months), 77 patients (55%) had experienced disease recurrence. Most first failures (32, or 23%) were outside the radiation field, followed by 30 (21%) within the field and 15 (11%) were both. In multivariate analysis, in-field failure after cCR was associated with a post-treatment standardized uptake value (SUV) on positron emission tomography of &gt;3.5 (odds ratio [OR] 4.93, p=0.022), squamous histology (OR 0.07, p=0.010), and borderline for T3/T4 disease (OR 10.25, p=0.055). All failures, in-field and out-of-field, correlated with T3/T4 disease (OR 11.61, p=0.015), N1 disease (OR 5.07, p=0.010), pretreatment SUV &gt;10 (OR 4.00, p=0.048), and post-treatment SUV &gt;3.5 (OR 3.59, p=0.052). Conclusions: Clinical characteristics can be used to predict failure patterns after definitive chemoradiation. Such risk-assessment strategies can help individualize therapy.

Predicting Pathological Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer Using 18FDG-PET/CT

Pathologic complete response (pCR) after neoadjuvant chemoradiation (CRT) has been observed in 15-30% of patients with locally advanced rectal cancer (LARC). The objective of this study was to determine whether PET/CT can predict pCR and disease-free survival in patients receiving CRT with LARC. This is a retrospective review of patients with EUS-staged T3-T4, N+rectal tumors treated with CRT, who underwent pre/post-treatment PET/CT from 2002-2009. All patients were treated with CRT and surgical resection. Standardized uptake value (SUV) of each tumor was recorded. Logistic regression was used to analyze the association of pre-CRT SUV, post-CRT SUV, %SUV change, and time between CRT and surgery, compared with pCR. Kaplan-Meier estimation evaluated significant predictors of survival. Seventy patients (age 62 years; 42M:28F) with preoperative stage T3 (n=61) and T4 (n=9) underwent pre- and post-CRT PET/CT followed by surgery. The pCR rate was 26%. Median pre-CRT SUV was 10.8, whereas the median post-CRT SUV was 4 (P=0.001). Patients with pCR had a lower median post-CRT SUV compared with those without (2.7 vs. 4.5, P=0.01). Median SUV decrease was 63% (7.5-95.5%) and predicted pCR (P=0.002). Patients with a pCR had a greater time interval between CRT and surgery (median, 58 vs. 50 days) than those without (P=0.02). Patients with post-CRT SUV<4 had a lower recurrence compared with those without (P=0.03). Patients with SUV decrease≥63% had improved overall survival at median follow-up of 40 months than those without (P=0.006). PET/CT can predict response to CRT in patients with LARC. Posttreatment SUV, %SUV decrease, and greater time from CRT to surgery correlate with pCR. Post-CRT, SUV<4, and SUV decrease≥63% were predictive of recurrence-free and overall survival.

Early prediction of local control in head and neck cancer after chemoradiotherapy by FDG-PET

To determine the utility of 2-deoxy-2-[F]fluoro-D-glucose positron emission tomography (FDG-PET) for assessment of early locoregional clinical outcome of chemoradiotherapy for head and neck squamous cell carcinomas (HNSCCs). From July 2002 to July 2008, a total of 35 patients with HNSCCs underwent FDG-PET before and between 4 and 7 weeks (median: 5 weeks) after the end of concurrent chemoradiotherapy. FDG uptake of primary sites and metastatic lymph nodes was measured as standardized uptake values (SUVs) and was analyzed in relation to local control. Visual inspection showed a sensitivity of 88.2% and a negative predictive value of 93.1%, but the positive predictive value was only 37.5%. Setting a posttreatment SUV of 3.0 and percentage change of 60 as cut-off values, positive predictive value increased to 81.3% and overall accuracy increased to 89.9% using the combined analysis of these two parameters. The local control rate was not associated with T, the N category, or the tumor node metastasis stage. In contrast, combined analysis of the posttreatment SUV and the percentage change in SUV was a useful indicator of locoregional control. In particular, combined evaluation of SUVs was very effective for assessment of therapeutic effects with reference to metastatic lymph nodes. Early follow-up with FDG-PET is thus considered helpful further in choosing optimal therapy and for making an accurate prognosis.

18f-fluorodeoxyglucose-positron emission tomography (FDG-PET) as a predictive biomarker in metastatic colorectal cancer (mCRC).

e14120 Background:Information on the prognostic and predictive role of FDG-PET in the management of patients (pts) with mCRC is limited. The growing complexity of current therapies and the increasing number of agents to be tested in this disease warrants better understanding of the role of FDG-PET in earlier treatment decisions. Methods: Consecutive pts with 2 or more serial FDG-PET scans at baseline and during the treatment course were studied. Tumor standardized uptake value (SUV) and its percentage change (%DSUV) were each studied for their potential association with time to progression (TTP) via univariate Cox models to estimate the hazard ratio (HR) for progression. Results: 31 pts (median age 58.4 yrs) with mCRC were studied. 87% of pts were treated in the first line setting. 48% had received prior adjuvant therapy. 61%, 22% and 13% received oxaliplatin based, irinotecan based, and fluropyrimidine only regimens, respectively. 84% received concurrent bevacizumab. Median pretreatment SUV was 9.0 (range 1.7-46.0); median post treatment SUV was 4.0 (range 0 - 13.5); median %DSUV was -70.7 (range -10% to -100%). Median interval between scans was 3.0 months. 9 (29%) patients had no tumor uptake on post treatment scans. 55% and 39% of pts had partial response and stable disease (RECIST criteria), respectively. Median TTP was 11.9 months (90% CI: 9.9–13.7 mos), with a median follow-up time for progression of 15.4 months. The HRs for baseline SUV and %DSUV were 1.009 (90% CI: 0.978–1.040, p = 0.635) and 1.014 (90% CI: 1.002–1.026, p = 0.049), respectively. Among the 20 pts with inter-scan interval < 4 months, the median TTP of pts with posttreatment SUV = 0 was 9.7 months vs. 6.6 months for pts with post-treatment SUV > 0. TTP duration did not differ significantly (p = 0.085). Conclusions: Systemic therapy substantially decreased the SUV on follow up PET scans in pts treated for mCRC. However, no significant association was seen between either baseline SUV or %DSUV and TTP. Further work is needed to optimize and standardize evaluation of tumor response in mCRC patients with FDG- PET. No significant financial relationships to disclose.

18F]-Fluorodeoxyglucose-Positron Emission Tomography for the Assessment of Histopathologic Response and Prognosis After Completion of Neoadjuvant Chemoradiation in Esophageal Cancer

To evaluate the potential of [(18)F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) after the completion of neoadjuvant chemoradiation for the assessment of histopathologic response and prognosis in the multimodality treatment of patients with esophageal cancer. Combined chemoradiation with and without surgery are widely accepted treatment options for patients with locally advanced esophageal cancer. Evidence suggests that patients with response to chemoradiation have no additional benefit from surgery compared with definitive chemoradiation. However, there is still a great lack in noninvasive markers for response assessment in patients with esophageal cancer undergoing multimodality treatment. Interestingly, recent studies imply that FDG-PET significantly correlates with histopathologic response and survival in patients with esophageal cancer undergoing neoadjuvant chemotherapy followed by surgical resection. Study patients were recruited from a prospective clinical observation trial on neoadjuvant chemoradiation for esophageal cancer between 1997 and 2006. The study included 119 (98 men, 21 women; median age, 59.4 years; squamous cell cancer: 66; adenocarcinoma: 53) patients with locally advanced esophageal cancer (cT2- 4, N(x), M(0)). All patients received neoadjuvant chemoradiation (cisplatin, 5-FU, 36 Gy) and subsequently underwent transthoracic en bloc esophagectomy. Histomorphologic regression was defined as major histopathologic response when resected specimens contained less than 10% vital residual tumor cells (major response: 47 patients [39.5%]; minor response: 72 patients [60.5%]). FDG-PET was performed before and 2 to 3 weeks after the end of chemoradiation with assessment of the intratumoral FDG-uptake (pretreatment standardized uptake value; post-treatment standardized uptake value; percentage change). These variables were correlated with histopathologic response and survival. Major histomorphologic response was confirmed as an important prognostic factor (P = 0.005; log-rank test). Neoadjuvant chemoradiation led to a significant reduction of intratumoral FDG-uptake (P = 0.0001). A nonsignificant association was seen between major responders and FDG-PET results (P = 0.056). However, the receiver operating characteristic analysis could not identify a standardized uptake value threshold with a relevant predictive value for histomorphologic response. No significant association between metabolic imaging and prognosis was found. FDG-PET seems not to be an imaging system that effectively characterizes the groups of major and minor response as well as survival in patients with esophageal cancer after multimodality treatment.

18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) as a prognostic and predictive biomarker in metastatic colorectal cancer (mCRC)

e15037 Background: Information on the prognostic and predictive role of FDG-PET in the management of patients (pts) with mCRC is limited. The growing complexity of current therapies and the increasing number of agents to be tested in this disease warrants better understanding of the role of FDG-PET in earlier treatment decisions. Methods: Consecutive pts with 2 or more serial FDG-PET scans at baseline and during the treatment course were studied. Tumor standardized uptake value (SUV) and its percentage change (%ΔSUV) were each studied for their potential association with time to progression (TTP) via univariate Cox models to estimate the hazard ratio (HR) for progression. Results: 27 pts (median age 58.2 yrs) with mCRC were studied. 85% of pts were treated in the first line setting. 44% had received prior adjuvant therapy. 63%, 26% and 11% received oxaliplatin based, irinotecan based and fluropyrimidine only regimens, respectively. 85% received concurrent bevacizumab. Median pretreatment SUV was 9.0 (range 1.7 - 46.0); Median post treatment SUV was 3.4 (0–13.5); median %ΔSUV was -77.2 (range -10% to -100%). Mean interval between scans was 4.1 months. Ten (37%) patients had no tumor uptake on post treatment scans. 56% and 37% of pts had partial response and stable disease (RECIST criteria), respectively. Median TTP was 13.0 months (90% CI: 10.9 - 16.3 mos), with a median follow-up time for progression of 7.8 months. The HRs for baseline SUV and %ΔSUV were 0.972 (90% CI: 0.901 - 1.048, p=0.534) and 1.018 (90% CI: 1.003 - 1.033, p=0.049), respectively. The median TTP of patients whose post-treatment SUV reached zero was 13.8 months vs. 10.9 months (p=0.17) for pts whose post-treatment SUV did not reach zero. Conclusions: Systemic therapy significantly decreased the SUV on follow up PET scans in pts treated for mCRC. However, no significant association was seen between either baseline SUV or %ΔSUV and TTP. There may be a very weak statistical association of decreasing SUV with decreasing risk of progression. Further work is needed to optimize and standardize evaluation of tumor response in mCRC patients with FDG-PET. No significant financial relationships to disclose.

Preliminary study of carbon-11 methionine PET in the evaluation of early response to therapy in advanced breast cancer

Breast cancer is one of the principal oncological challenges in the Western world. Currently, there are only a few reliable predictive methods for monitoring treatment. We investigated the ability of carbon-11 methionine ("11C-MET) positron emission tomography (PET) to evaluate early response to therapy in advanced breast cancer. Thirteen patients with metastases in the lungs/pleura, lymph nodes, soft tissue, or bones entered a MET PET study both before and after the first cycle of polychemotherapy (n=4), or after the first month of therapy with hormones (n=5), or low dose weekly cytostatics (n=3). One patient underwent three PET studies: before hormonal therapy, after 1 month of hormonal therapy, and after the first cycle of polychemotherapy (total, 27 studies). MET accumulation in the metastatic sites was measured as standardized uptake values (SUVs), and the pretreatment and post-treatment SUVs were compared with each other and the clinical follow-up data. A total of 26 different metastatic sites were investigated in 13 patients. All metastases were visible by MET PET except one superficially spreading local skin recurrence, probably because of respiratory movements. Five new metastatic sites were detected. After therapy the SUVs decreased significantly (30-54%; P < 0.05) in all six responding metastatic sites, whereas the SUVs of nonresponding metastases decreased somewhat (11-130/%; n=4), remained stable (+/- 8%; n=10), or increased (13-23%; n=4) (P=NS). The SUVs of two nonresponding metastatic sites decreased clearly. Physiological MET uptake in the salivary glands, the myocardium, and the bone marrow did not disturb the image interpretation. MET PET may be useful in assessing the early response to therapy in advanced breast cancer.

Use of Molecular Imaging to Predict Clinical Outcome in Patients With Rectal Cancer After Preoperative Chemotherapy and Radiation

To correlate changes in 2-deoxy-2-[18F]fluoro-d-glucose (18-FDG) positron emission tomography (PET) (18-FDG-PET) uptake with response and disease-free survival with combined modality neoadjuvant therapy in patients with locally advanced rectal cancer. Charts were reviewed for consecutive patients with ultrasound-staged T3x to T4Nx or TxN1 rectal adenocarcinoma who underwent preoperative chemoradiation therapy at Fox Chase Cancer Center (FCCC) or Robert H. Lurie Comprehensive Cancer Center of Northwestern University with 18-FDG-PET scanning before and after combined-modality neoadjuvant chemoradiation therapy . The maximum standardized uptake value (SUV) was measured from the tumor before and 3 to 4 weeks after completion of chemoradiation therapy preoperatively. Logistic regression was used to analyze the association of pretreatment SUV, posttreatment SUV, and % SUV decrease on pathologic complete response (pCR), and a Cox model was fitted to analyze disease-free survival. A total of 53 patients (FCCC, n = 41, RLCCC, n = 12) underwent pre- and postchemoradiation PET scanning between September 2000 and June 2006. The pCR rate was 31%. Univariate analysis revealed that % SUV decrease showed a marginally trend in predicting pCR (p = 0.08). In the multivariable analysis, posttreatment SUV was shown a predictor of pCR (p = 0.07), but the test results did not reach statistical significance. None of the investigated variables were predictive of disease-free survival. A trend was observed for % SUV decrease and posttreatment SUV predicting pCR in patients with rectal cancer treated with preoperative chemoradiation therapy. Further prospective study with a larger sample size is warranted to better characterize the role of 18-FDG-PET for response prediction in patients with rectal cancer.

Correlation of Molecular Response as Measured by 18-FDG Positron Emission Tomography With Outcome After Chemoradiotherapy in Patients with Esophageal Carcinoma

To determine whether 18-fluorodeoxyglucose positron emission tomography (PET) computed tomography scans predict the pathologic complete response and disease-free and overall survival in patients with esophageal carcinoma undergoing definitive or preoperative chemoradiotherapy. The records of patients with esophageal carcinoma presenting for definitive or preoperative treatment and undergoing pre- and post-treatment 18-fluorodeoxyglucose PET-computed tomography scans were retrospectively reviewed. The histologic type, T stage, and nodal status were the variables investigated to determine a relationship with the baseline standardized uptake value (SUV) of the primary tumor at diagnosis. We also attempted to determine whether a relationship exists between the percent decrease in SUV and a pathologic complete response, overall and disease-free survival. A total of 81 patients, 14 women and 67 men, underwent 18-fluorodeoxyglucose PET-computed tomography scanning before treatment and 63 also had post-treatment scans. T stage and tumor location predicted in univariate, but not multivariate, analysis for the initial SUV. Of the patients with a postchemoradiotherapy SUV of <2.5, 66% had tumor in the surgical specimen and 64% of patients had positive lymph nodes at surgery that were not imaged on the postchemoradiotherapy PET scan. A trend existed for post-treatment SUV and the days from radiotherapy to surgery to predict for a pathologic complete response (p = 0.09 and p = 0.08, respectively). The post-treatment SUV predicted for disease-free survival in the definitive chemoradiotherapy group (p = 0.01). A correlation was found between the depth of tumor invasion and the baseline SUV. The post-treatment SUV predicted for disease-free survival in the definitive chemoradiotherapy group. Caution should be exercised in using post-treatment PET scans to determine the necessity for surgical resection.

Assessment of response to treatment of unresectable liver tumours with 90Y microspheres: Value of FDG PET versus computed tomography

Selective internal radiation therapy (SIRT) with SIR spheres (90Y microspheres) is a treatment option for liver tumours in patients in whom other therapies are inappropriate or have failed. This study aims to assess the value of FDG PET in assessing the response to SIRT as compared to computed tomography (CT). Twenty-one patients (11 F, 10 M; age range 40-75 years, mean, 58 years) received SIR spheres at the Hammersmith Hospital. One patient received two treatments. Most patients had colorectal metastases (n=10), while the others (n=11) had liver metastasis from different primaries. The mean administered dose was 1.9 GBq (range, 1.2-2.5 GBq). Follow-up was done with FDG PET and CT at 6 weeks, and 6-monthly thereafter. Pre-therapy and post-therapy CT and PET scans were assessed visually (RECIST criteria for CT) and semi-quantitative for PET using the standardized uptake value (SUV). Eighty-six percent of patients showed decreased PET activity at 6 weeks while only 13% showed a partial response in the size of tumour on CT scan. The mean pre-treatment SUV was 12.2+/-3.7 and the mean post-treatment SUV was 9.3+/-3.7 (P=0.01). CT imaging showed progressive disease in 27% patients and stable liver disease in 60% patients. Based on FDG PET results one patient had surgery for down-staged tumour. FDG PET imaging is more sensitive than CT in the assessment of early response to SIR spheres, allowing clinicians to proceed with further therapeutic options.

Detection of local residual tumor after laryngeal cancer treatment using FDG-PET

Fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is sometimes used as a means of follow-up after diagnosis and treatment of cancers of the head and neck region. The present study was undertaken to evaluate the ability of FDG-PET to detect local residual tumor after treatment of laryngeal cancer. Thirty-six patients with laryngeal cancer underwent FDG-PET before and after initial treatment. Of these patients, 20 received FDG-PET before treatment and 28 received it after treatment. The relationship between standardized uptake values (SUV) and the presence or absence of local residual tumor was investigated by setting the cut-off value of the SUV using the receiver operating characteristics (ROC) curve. When the pre-treatment SUV threshold for laryngeal cancer was set at 7.20, the detection of local residual tumor after treatment using FDG-PET had a sensitivity of 77.78%, specificity of 81.82%, false positive rate of 18.18%, false negative rate of 22.22%, accuracy of 80% and a p value of 0.02. When the post-treatment SUV threshold for the larynx was set at 3.35, the test had a sensitivity of 93.75%, specificity of 91.67%, false positive rate of 8.33%, false negative rate of 6.25%, accuracy of 92.86% and a p value of 0.0001. FDG-PET was found to be useful for determining the presence of local residual tumor after treatment of laryngeal cancer.