FDG-PET in the prediction of pathologic response after neoadjuvant chemoradiotherapy in locally advanced, resectable esophageal cancer

Symptomatic cardiac toxicity is predicted by dosimetric and patient factors rather than changes in 18F-FDG PET determination of myocardial activity after chemoradiotherapy for esophageal cancer

PURPOSE

To determine factors associated with symptomatic cardiac toxicity in patients with esophageal cancer treated with chemoradiotherapy.

MATERIAL AND METHODS

We retrospectively evaluated 102 patients treated with chemoradiotherapy for locally advanced esophageal cancer. Our primary endpoint was symptomatic cardiac toxicity. Radiation dosimetry, patient demographic factors, and myocardial changes seen on (18)F-FDG PET were correlated with subsequent cardiac toxicity. Cardiac toxicity measured by RTOG and CTCAE v3.0 criteria was identified by chart review.

RESULTS

During the follow up period, 12 patients were identified with treatment related cardiac toxicity, 6 of which were symptomatic. The mean heart V20 (79.7% vs. 67.2%, p=0.05), V30 (75.8% vs. 61.9%, p=0.04), and V40 (69.2% vs. 53.8%, p=0.03) were significantly higher in patients with symptomatic cardiac toxicity than those without. We found the threshold for symptomatic cardiac toxicity to be a V20, V30 and V40 above 70%, 65% and 60%, respectively. There was no correlation between change myocardial SUV on PET and cardiac toxicity, however, a greater proportion of women suffered symptomatic cardiac toxicity compared to men (p=0.005).

CONCLUSIONS

A correlation did not exist between percent change in myocardial SUV and cardiac toxicity. Patients with symptomatic cardiac toxicity received significantly greater mean V20, 30 and 40 values to the heart compared to asymptomatic patients. These data need validation in a larger independent data set.

Metabolic response at repeat PET/CT predicts pathological response to neoadjuvant chemotherapy in oesophageal cancer

OBJECTIVES

Reports have suggested that a reduction in tumour 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) examination during or after neoadjuvant chemotherapy may predict pathological response in oesophageal cancer. Our aim was to determine whether metabolic response predicts pathological response to a standardised neoadjuvant chemotherapy regimen within a prospective clinical trial.

METHODS

Consecutive patients staged with potentially curable oesophageal cancer who underwent treatment within a non-randomised clinical trial were included. A standardised chemotherapy regimen (two cycles of oxaliplatin and 5-fluorouracil) was used. PET/CT was performed before chemotherapy and repeated 24-28 days after the start of cycle 2.

RESULTS

Forty-eight subjects were included: mean age 65 years; 37 male. Using the median percentage reduction in SUV(max) (42%) to define metabolic response, pathological response was seen in 71% of metabolic responders (17/24) compared with 33% of non-responders (8/24; P = 0.009, sensitivity 68%, specificity 70%). Pathological response was seen in 81% of subjects with a complete metabolic response (13/16) compared with 38% of those with a less than complete response (12/32; P = 0.0042, sensitivity 52%, specificity 87%). There was no significant histology-based effect.

CONCLUSIONS

There was a significant association between metabolic response and pathological response; however, accuracy in predicting pathological response was relatively low.

Esophageal carcinoma advances in treatment results for locally advanced disease: review

The treatment results of patients with locally advanced esophageal carcinomas have evolved since the publication of the first trial of concurrent mitomycin C and 5-fluorouracil with radiotherapy (RT) in 1983. Subsequent studies refined and improved on the concurrent chemotherapy (chemo) with administration of cisplatin and 5-fluorouracil infusion (PF). Chemo (PF) before surgery improved overall survival (OS) in those patients in most of the randomized trials and in meta-analyses. Two courses of PF concurrent with irradiation followed by additional two courses of PF were superior to RT alone without surgery for both groups. Concurrent chemoradiotherapy followed by surgery was found to have statistically improved OS as compared with surgery only in randomized trials and meta-analyses. In most of these studies, it was found that those patients with pathologic complete response to the initial treatment(s) did better than those who had no improvement at all. Current treatment outcome for these diseases is disappointing; newer strategies including induction chemo with the optimal combination, proper dosage of each drug, and proper number of courses before concurrent chemoradiotherapy; improvement in RT; and immunotherapy with or without subsequent surgery are exciting and definitely need to be investigated in prospective randomized trial(s).

Outcomes of patients with esophageal cancer staged with [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG-PET): can postchemoradiotherapy FDG-PET predict the utility of resection?

PURPOSE

To determine whether [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) can delineate patients with esophageal cancer who may not benefit from esophagectomy after chemoradiotherapy.

PATIENTS AND METHODS

We reviewed records of 163 patients with histologically confirmed stage I to IVA esophageal cancer receiving chemoradiotherapy with or without resection with curative intent. All patients received surgical evaluation. Initial and postchemoradiotherapy FDG-PET scans and prognostic/treatment variables were analyzed. FDG-PET complete response (PET-CR) after chemoradiotherapy was defined as standardized uptake value ≤ 3.

RESULTS

Eighty-eight patients received trimodality therapy and 75 received chemoradiotherapy. Surgery was deferred primarily due to medical inoperability or unresectable/metastatic disease after chemoradiotherapy. A total of 105 patients were evaluable for postchemoradiotherapy FDG-PET response. Thirty-one percent achieved a PET-CR. PET-CR predicted for improved outcomes for chemoradiotherapy (2-year overall survival, 71% v 11%, P < .01; 2-year freedom from local failure [LFF], 75% v 28%, P < .01), but not trimodality therapy. On multivariate analysis of patients treated with chemoradiotherapy, PET-CR is the strongest independent prognostic variable (survival hazard ratio [HR], 9.82, P < .01; LFF HR, 14.13, P < .01). PET-CR predicted for improved outcomes regardless of histology, although patients with adenocarcinoma achieved a PET-CR less often.

CONCLUSION

Patients treated with trimodality therapy found no benefit with PET-CR, likely because FDG-PET residual disease was resected. Definitive chemoradiotherapy patients achieving PET-CR had excellent outcomes equivalent to trimodality therapy despite poorer baseline characteristics. Patients who achieve a PET-CR may not benefit from added resection given their excellent outcomes without resection. These results should be validated in a prospective trial of FDG-PET-directed therapy for esophageal cancer.

Added value of baseline 18F-FDG uptake in serial 18F-FDG PET for evaluation of response of solid extracerebral tumors to systemic cytotoxic neoadjuvant treatment: a meta-analysis

The purpose of this study was to test the hypothesis that the level of baseline (18)F-FDG uptake in the primary tumor adds value to its relative change in (18)F-FDG uptake in serial PET scans in predicting the histopathologic response to systemic cytotoxic neoadjuvant treatment of patients with solid extracerebral tumors.

METHODS

We performed a literature search from January 1995 through November 2008 using PubMed and Embase. Two reviewers independently selected eligible studies for possible inclusion in the meta-analysis by reviewing titles and abstracts. Inclusion criteria were at least 10 patients, (18)F-FDG PET before and after therapy, (18)F-FDG PET performed with the intention of monitoring the response of solid extracerebral tumors in humans to cytotoxic neoadjuvant systemic therapy, attenuation-corrected (18)F-FDG PET studies, and studies presenting individual patient data (PET results and histopathologic reference test after treatment). Multilevel logistic regression was used to assess the effect of relative change of (18)F-FDG uptake ([baseline - end]/baseline) and baseline (18)F-FDG uptake value with type of tumor and type of treatment as level 1 covariates.

RESULTS

Nineteen studies (all observational; a total of 438 patients [median, 23 patients per study; range, 10-40]) were included, aiming at the accuracy of PET versus histopathology. To quantify PET, maximum standardized uptake value (SUV) was used in 6 studies, mean SUV in 7, SUV (subtype unclear) in 1, tumor-to-background ratio in 3, and dose uptake ratio in 1. The average overall histopathologic response rate was 0.47 (median, 0.50), ranging from 0.17 to 0.88. The relative change in (18)F-FDG uptake was the strongest indicator (P < 0.0001) for tumor response. Baseline (18)F-FDG was not significantly associated as a main factor; however, a significant interaction of baseline uptake and relative change after therapy was observed (P < 0.001).

CONCLUSION

Relative change in (18)F-FDG uptake was the strongest indicator for tumor response, but the level of baseline (18)F-FDG uptake in the primary tumor provided additional information about prediction of response to therapy. These data corroborate and extend the need for standardization, quality assurance, and control of PET studies quantifying (18)F-FDG in oncologic treatment monitoring.

Prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer with use of 18F FDG PET: a systematic review

PURPOSE

To systematically review the accuracy of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) positron emission tomography (PET) in the prediction of tumor response to neoadjuvant therapy in patients with esophageal cancer.

MATERIALS AND METHODS

The MEDLINE and EMBASE databases were systematically searched for relevant studies. Methodologic quality of the included studies was assessed. Sensitivities and specificities of (18)F FDG PET in individual studies were calculated and underwent meta-analysis with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. A chi(2) test was performed to test for heterogeneity (defined as P < .10). Potential sources for heterogeneity were explored by assessing whether certain covariates significantly (P < .05) influenced the relative diagnostic odds ratio.

RESULTS

Twenty reports, comprising a total of 849 patients with esophageal cancer, were included. Overall, the studies were of moderate methodologic quality. Sensitivity and specificity of (18)F FDG PET ranged from 33% to 100% and from 30% to 100%, respectively, with pooled estimates of 67% (95% confidence interval: 62%, 72%) and 68% (95% confidence interval: 64%, 73%), respectively. The area under the sROC curve was 0.7815. There was significant heterogeneity in both the sensitivity and specificity of the included studies (P < .0001). Spearman rho between the logit of sensitivity and the logit of 1-specificity was 0.086 (P = .719), which suggested that there was no threshold effect. Studies performed outside of the United States and studies of higher methodologic quality yielded significantly higher overall accuracy.

CONCLUSION

On the basis of current evidence, (18)F FDG PET should not yet be used in routine clinical practice to guide neoadjuvant therapy decisions in patients with esophageal cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091324/-/DC1.

Assessment of response to neoadjuvant therapy in esophageal cancer: an updated systematic review of diagnostic accuracy of endoscopic ultrasonography and fluorodeoxyglucose positron emission tomography

For assessing response to neoadjuvant therapy in patients with esophageal cancer, both endoscopic ultrasonography (EUS) and fluorodeoxyglucose positron emission tomography (FDG-PET) are commonly used, and despite few controlled trials, it is not known if one imaging modality is superior to the other. Also, relative diagnostic accuracy of early (during the course of neoadjuvant therapy) and FDG-PET after completion of neoadjuvant therapy has not been reviewed. The aim of this study was to perform a systematic review of published information to compare diagnostic accuracy of EUS and FDG-PET in this setting. A search of the MEDLINE, EMBASE, and Cochrane databases was performed along with a manual search of cross-references of eligible articles. Data on the accuracy of the imaging modalities were compared by constructing summary receiver-operating characteristic curves. Seven studies with EUS and 15 with FDG-PET were included in the final analysis (N= 966). The sensitivity of EUS and FDG-PET ranged from 20 to 100% and 42 to 100%, respectively. The specificity ranged from 36 to 100% and 27 to 100%, respectively. The areas under the curve were 0.86 (95% confidence interval [CI]: 0.77-0.96) for EUS and 0.80 (95% CI: 0.72-0.89) for FDG PET (P= 0.37). The maximum joint sensitivity and specificity (Q* index) values for EUS and FDG-PET were 0.79 (95% CI: 0.70-0.88) and 0.74 (95% CI: 0.66-0.81), respectively (P= 0.38). There was no difference in accuracy between early FDG-PET and FDG-PET after completion of neoadjuvant therapy. EUS and FDG-PET have similar overall diagnostic accuracy for assessment of response to neoadjuvant therapy in patients with esophageal cancer.

Trends in the management of esophageal carcinoma based on provider volume: treatment practices of 618 esophageal surgeons

Controversy exists regarding optimal treatment practices for esophageal cancer. Esophagectomy has received focus as one of the index procedures for both hospital and surgical quality despite a relative paucity of controlled trials to define best practices. A survey was created to determine the degree of heterogeneity in the treatment of esophageal cancer among a diverse group of surgeons and to use high-volume (HV) (>/=15 cases/year) and low-volume (LV) (<15 cases/year) designations to discern specific differences in the management of esophageal cancer from the surgeon's perspective. Based on society rosters, surgeons (n = 4000) in the USA and 15 countries were contacted via mail and queried regarding their treatment practices for esophageal cancer using a 50-item survey instrument addressing demographics, utilization of neoadjuvant chemoradiotherapy, and choice of surgical approach for esophageal resection and palliation. There were 618 esophageal surgeons among respondents (n = 1447), of which 77 (12.5%) were considered HV. The majority of HV surgeons (87%) practiced in an academic setting and had cardiothoracic training, while most LV surgeons were general surgeons in private practice (52.3%). Both HV and LV surgeons favored the hand-sewn cervical anastomosis and the stomach conduit. Minimally invasive esophagectomy is performed more frequently by HV surgeons when compared with LV surgeons (P = 0.045). Most HV surgeons use neoadjuvant therapy for patients with nodal involvement, while LV surgeons are more likely to leave the decision to the oncologist. With a few notable exceptions, substantial heterogeneity exists among surgeons' management strategies for esophageal cancer, particularly when grouped and analyzed by case volume. These results highlight the need for controlled trials to determine best practices in the treatment of this complex patient population.

Early response evaluation and prediction in neoadjuvant-treated patients with esophageal cancer

Since the introduction of multimodal therapy regimens, the prognosis of esophageal cancer has improved. There is undoubtedly true for patients with surgically resected tumors in the case of a response to neoadjuvant chemotherapy or chemoradiation. Important conclusions can be drawn from this regarding the indication for perioperative therapies, the radicality of surgery, or the surgical indications. Thus, most of the current research in this field is aimed at the early identification of this subset of patients, at the beginning of, or even before, neoadjuvant treatment. Conventional staging tools have failed to predict responses to neoadjuvant therapy. However, molecular imaging methods, e.g. positron emission tomography (PET)-scans, have shown promising results in the early selection of responders and non-responders during the course of neoadjuvant therapy, allowing physicians to alter the treatment plan accordingly. Even more desirable is the identification of potential responders before the start of neoadjuvant therapy. Preliminary molecular data on biopsy specimens demonstrate the possibility of early response prediction in these patients. We present the current knowledge on response evaluation and prediction in esophageal cancer and draw conclusions for future clinical practice and studies in this review.

2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography/computed tomography imaging evaluation of esophageal cancer

We evaluated the clinical utility of 2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) on the precise localization of pathologic foci and exclusion of normal variants in the imaging evaluation of patients with esophageal carcinoma. Combined PET/CT scans were performed in 60 patients (50 males, 10 females, age range 47-84 years) with history of esophageal carcinoma either at the time of initial diagnosis (group I, n=14) or for surveillance and/or detection of recurrent and metastatic disease (group II, n=46). Prior treatments included esophagectomy with gastric pull-up (n=23), surgery and chemotherapy (n=3), surgery and chemoradiation therapy (n=10), chemotherapy alone (n=5), radiation therapy alone (n=2), and chemoradiation without surgery (n=3). Diagnostic validation was by tissue sampling in three patients and clinical/radiological follow-up for up to 1.5 years in the remaining patients. In group I, discordant abnormalities were noted in seven patients. PET demonstrated hypermetabolism in normal-size lymph nodes on CT in three patients that were considered likely true positive in view of concurrent existence of other adjacent enlarged hypermetabolic lymph nodes in the same nodal basin. Hypometabolic incidental CT abnormalities of up to 1-cm lung nodules were noted in three patients and pleural effusion in one patient, which were considered true negative in view of no change on follow-up PET/CT studies. In group II, both PET and CT showed concordant abnormalities in 23 patients. The precise image fusion of hypermetabolism in a liver lesion allowed a diagnostic CT-guided biopsy in one patient. PET demonstrated true positive hypermetabolic abnormalities in four patients that localized to structures, which were normal by noncontrast CT criteria, and true negative in one patient with hepatic fatty deposits. PET showed decline in metabolic activity of the primary lesion in one patient after chemotherapy, while the corresponding CT abnormality remained unchanged. PET/CT image fusion provided relevant complementary diagnostic information in 14 patients with discordant findings (23% of total) that resulted in biopsy in three cases, institution of chemotherapy in four cases, and a wait-and-watch strategy in seven cases. In conclusion, our findings add to the current body of literature that suggests that FDG-PET/CT scanning may improve the imaging evaluation of patients with esophageal cancer by providing complementary structural-metabolic information. In particular, our findings support the notion that PET/CT may be the most appropriate imaging modality in the evaluation of patients of esophageal cancer that may impact patient management.

Positron emission tomography for monitoring response to neoadjuvant therapy in patients with oesophageal and gastro-oesophageal junction carcinoma

AIMS

The aim of this review is to consolidate our knowledge on an important and rapidly expanding area of expertise. Numerous methods for predicting response (in terms of pathological response and survival) to neoadjuvant therapy (chemotherapy/chemo-radiotherapy) in oesophageal and junctional cancers have been proposed. This review concerns itself only with the use of positron emission tomography for such a purpose. At present there are no standardised criteria amongst PET trials as to what determines a response according to PET, what is the optimal time to perform PET in relation to the timing of neoadjuvant therapy, and what is the ideal method of quantifying PET tracer uptake.

METHODS

An electronic search was performed of PubMed, Ovid and Embase websites to identify studies, in the English language, using the search terms: PET; oesophageal; oesophago-gastric; survival; cancer; response; chemotherapy and chemo-radiotherapy. The reference lists were searched manually to identify further relevant studies.

RESULTS

Twenty-two studies were identified, all using (18)FDG as the tracer, using PET to predict response in terms of pathological response and survival following neoadjuvant therapy (chemotherapy/chemo-radiotherapy). PET had a varying degree of success in predicting both pathological response and survival outcomes, with only one study using PET to influence management decisions.

CONCLUSIONS

PET seems a promising technique, but large-scale conclusions are hindered by small study numbers, lack of criteria as to what constitutes a response and markedly differing PET imaging times. A large randomised trial concerning a homogeneous group of patients and tumours is required before PET might be used to influence management.

Correlations between selected tumor markers and fluorodeoxyglucose maximal standardized uptake values in esophageal cancer

OBJECTIVE

Esophageal cancer tumor biology is best assessed clinically by 2-[18F]fluoro-2-deoxy-d-glucose (FDG)-PET. Both FDG-PET maximal positron emission tomography (PET) standardized uptake values (SUVmax) and selected tumor markers have been shown to correlate with stage, nodal disease, and survival in esophageal cancer. Interestingly, there is limited data examining the relationship between FDG-PET SUVmax and expression of these tumor markers in esophageal cancer. The purpose of this study was to determine the correlation of tumor markers with FDG-PET SUVmax in esophageal cancer.

METHODS

FDG-PET SUVmax was calculated in 67 patients with esophageal cancer of which 59 (88%) had adenocarcinoma. Neoadjuvant radiotherapy and/or chemotherapy were administered to 42% (28/67) of patients. Esophageal tumor tissue and surrounding normal tissue was obtained and tissue microarrays were created. Immunohistochemical analysis was performed for five known esophageal cancer tumor markers (GLUT-1, p53, cyclin D1, epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF)). Assessment of each tumor marker was made by two independent, blinded pathologists using common grading criteria of intensity and percentage of cells stained. A p value <0.05 was considered significant.

RESULTS

There were 55 men (82%) and 12 women (18%) with a median age of 63 years (range 40-83). Pathologic staging included stage I (n=29, 43%), stage II (n=19, 28%), stage III disease (n=18, 27%), and stage IV disease (n=1, 2%). PET SUVmax correlated with T stage (p=0.001). In patients undergoing surgery without induction therapy, increasing SUVmax values correlated with increased expression of GLUT-1 transporter (p=0.01). There was no correlation between SUVmax and EGFR, cyclin D1, VEGF, or p53 expression in primary tumor.

CONCLUSIONS

FDG-PET SUVmax correlates with an increased expression of GLUT-1 transporter in esophageal cancer specimens not subjected to induction therapy. No significant difference in tumor marker expression was noted between patients undergoing induction therapy or surgery alone except p53 expression decreased in primary tumors following induction therapy. Failure of SUVmax values to correlate with known prognostic esophageal cancer tumor markers suggests that FDG-PET may have limited clinical utility in assessing response to therapies targeting these markers.

[Use of PET for staging, treatment evaluation, and follow-up in esophageal cancers]

FDG-(18F) PET can now be usually included in the treatment strategy of esophageal cancers for the pretreatment staging in operable tumours or for the diagnosis of recurrence. PET is also a good tool in conformal radiation therapy for improving the target coverage to treat the metabolic target volume or the biological target volume. Furthermore, PET seems to be interesting for evaluation of tumour response and could modify the treatment strategy after neoadjuvant chemotherapy or concurrent chemotherapy and radiation therapy. New radiotracers could allow advances in biological and molecular tumour delineation and contribute to change in treatment strategy based on functional and biological imaging.

Lack of fludeoxyglucose F 18 uptake in posttreatment positron emission tomography as a significant predictor of survival after subsequent surgery in multimodality treatment for patients with locally advanced esophageal squamous cell carcinoma

OBJECTIVE

Patients with advanced esophageal squamous cell carcinoma receive neoadjuvant chemotherapy or chemoradiotherapy to improve survival, but benefits are observed only in those with histologic response. Positron emission tomography with fludeoxyglucose F 18 (INN fludeoxyglucose [(18)F]) detects accumulation of glucose analog in viable cancer cells. This study investigated the usefulness of positron emission tomography with fludeoxyglucose F 18 in assessment of response of advanced esophageal squamous cell carcinoma to neoadjuvant treatment to establish new criteria to predict postoperative long-term survival.

METHODS

Fifty patients with locally advanced esophageal squamous cell carcinoma who received neoadjuvant therapy (chemotherapy 35, chemoradiotherapy 15) underwent positron emission tomography with fludeoxyglucose F 18 before surgical resection in evaluation of posttreatment maximum standardized uptake value, residual tumor size (maximum square area of longitudinal axis), histologic response, and postoperative survival.

RESULTS

After treatment, uptake was not noted in 21 patients (posttreatment maximum standardized uptake value < 2.5, negative) but was detected in 29 (> or = 2.5, positive). Residual tumor size ranged from 0 to 54.0 mm(2) for negative results and 55.0 to 676.0 mm(2) for positive, clearly distinguishing histologic major response from nonresponse. The negative group demonstrated significantly higher 5-year cause-specific survival (67.7%) and lower hematogenous recurrence (4.8%) than the 36.5% and 37.0% values in the positive group, (P < .0042 and P = .0083, respectively). Univariate Cox regression analyses identified posttreatment maximum standardized uptake value (cutoff 2.5) as the only preoperative prognostic factor (P = .0071).

CONCLUSION

Posttreatment positron emission tomography with fludeoxyglucose F 18 reliably predicted histologic response and postoperative survival in advanced esophageal squamous cell carcinoma. This tool could potentially be used to tailor optimal treatment according to individual responses.

Correlation of PET/CT findings and histopathology after neoadjuvant therapy in non-small cell lung cancer

OBJECTIVES

Prediction of histopathological response with PET/CT scans after neoadjuvant chemoradiotherapy is limited by confounding factors which have been evaluated in this analysis.

METHODS

(18)F-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT findings [standard uptake value (SUV), residual tumor volume] were correlated with histopathological parameters of the resection specimens (tumor cell density, necrosis, scar, macrophage infiltration) in patients with locally advanced non-small cell lung cancer (stage IIIA/IIIB) after neoadjuvant induction chemotherapy (platinum-based doublet) and concurrent chemoradiotherapy (cisplatin/vinorelbine/45 Gy).

RESULTS

Sixty patients [40 male/20 female, median age 56 years (34-78)] completed induction therapy, 46 patients (stage IIIA/IIIB: 16/30; squamous cell carcinoma 41%, adenocarcinoma 48%, large cell carcinoma 11%) were resected. Pathologic complete response of the primary tumor was observed in 19 patients (41%) with a broad range of SUV(mean) (0.4-9.8, mean 3.0) after neoadjuvant therapy. A high rate of histopathological complete remissions (44%) was observed in tumors with a postinduction SUV >2.5 and volumes larger than the median (7.9 cm(3)) before resection. SUV(mean) was positively correlated with the macrophage score (r = 0.39, p = 0.007) and tumor cell density (r = 0.32, p = 0.03).

CONCLUSIONS

These observations suggest that postinduction FDG uptake should be interpreted with caution in larger residual tumor volumes, since high SUV levels may be due to macrophage infiltration and not viable tumor tissue.

Positron emission tomography and pathological evidence of response to neoadjuvant therapy in adenocarcinoma of the esophagus

Our aim was to determine if fluorodeoxyglucose positron emission tomography (FDG-PET) could be correlated with a pathological response in patients with esophageal adenocarcinoma receiving neoadjuvant chemotherapy and/or chemoradiation therapy. Patients with resectable, histologically proven adenocarcinoma of the esophagus were entered in the study. Preoperative chemotherapy comprised two cycles of cisplatin and 5-fluorouracil. Radiation therapy commenced with the second cycle on day 22. FDG-PET images were obtained pre-treatment and on completion of intended neo-adjuvant treatment. Quantification was achieved by the calculation of both standardized uptake values (SUV) and tumor/liver ratios (TLR). Evidence of histopathological response was identified according to the Mandard tumor regression scoring system. There were 45 patients, 22 receiving neoadjuvant chemotherapy and 23 chemoradiation therapy. Forty patients underwent surgical resection. Seven patients (16%) had a histopathological response. The mean percentage change in SUV in the histological responders group was -56.8% (SD 29) and in the non-responders -27.8% (SD 32.1) (P = 0.035). The mean percentage change in TLR was -49.1% (SD 44.8) in the responders and in the non-responders -27.3% (SD 31.3) (P = 0.128). There was no difference between the two methods of assessment, however there was less variation with SUV. There was no correlation between the FDG-PET response and the histopathological response. Presently an FDG-PET scan performed 3-6 weeks after neoadjuvant therapy for adenocarcinoma of the esophagus should not be used as a marker of the potential result of the treatment. The optimal timing of a second FDG-PET remains unclear.

The evaluation of esophageal adenocarcinoma using dynamic contrast-enhanced magnetic resonance imaging

Although neoadjuvant chemoradiation eradicates esophageal adenocarcinoma in a substantial proportion of patients, conventional imaging techniques cannot accurately detect this response. Dynamic contrast-enhanced magnetic resonance imaging is an emerging approach that may be well suited to fill this role. This pilot study evaluates the ability of this method to discriminate adenocarcinoma from normal esophageal tissue. Patients with esophageal adenocarcinoma and control subjects underwent scanning. Patients treated with neoadjuvant therapy underwent pre- and postchemoradiation scans. Parameters were extracted for each pixel were Ktrans (equilibrium rate for transfer of contrast reagent across the vascular wall), ve (volume fraction of interstitial space), and taui (mean intracellular water lifetime). Five esophageal adenocarcinoma patients and two tumor-free control subjects underwent scanning. The mean Ktrans value was 5.7 times greater in esophageal adenocarcinoma, and taui is 2.0 times smaller, than in the control subjects. Ktrans decreased by 11.4-fold after chemoradiation. Parametric maps qualitatively demonstrate a difference in Ktrans. DCE MRI of the esophagus is feasible. Ktrans, a parameter that has demonstrated discriminative ability in other malignancies, also shows promise in differentiating esophageal adenocarcinoma from benign tissue. The determination of Ktrans represents an in vivo assay for endothelial permeability and thus may serve as a quantitative measure of response to induction chemoradiation.

PET/CT and hepatic radiation injury in esophageal cancer patients

This paper evaluates the imaging appearance of radiation injury in the liver on positron emission tomography (PET)/computed tomography (CT) in patients with distal esophageal cancer who underwent pre-operative chemoradiation therapy. Twenty-six patients with distal esophageal cancer who received chemoradiotherapy before esophagectomy were included. All patients had baseline and follow-up PET/CT. Fluorodeoxyglucose (FDG) uptake in both left and right lobes of the liver was evaluated. CT findings suggesting radiation damage were documented. Abnormal FDG uptake in the liver was observed in 5 (19%) patients after therapy. These abnormalities were in the left lobe (12%) and right lobe (12%) of the liver. In the irradiated left lobe, FDG uptake increased focally greater than 50% over baseline in two patients (54% and 133%); in one of these patients, biopsy confirmed radiation injury. In the non-irradiated right lobe, standard uptake values (SUV) increased diffusely in two different patients. In one patient, SUV decreased by at least 50% in both the right and left lobes. In the remaining patients, there were no significant changes in FDG uptake. Atrophy and attenuation changes of irradiated liver on CT were found in 15 (58%) patients. In patients receiving chemoradiotherapy, PET/CT may identify metabolic abnormalities in irradiated liver. Such abnormalities should be correlated with other imaging, clinical and laboratory findings to avoid confusion with hepatic metastases.

FDG-PET/CT tumor segmentation-derived indices of metabolic activity to assess response to neoadjuvant therapy and progression-free survival in esophageal cancer: correlation with histopathology results

PURPOSE

To evaluate the diagnostic and prognostic abilities of PET tumor segmentation-derived indices of metabolic activity for the assessment of response to neoadjuvant chemoradiotherapy and progression-free survival in patients with esophageal cancer.

METHODS

Twenty-five patients with histologically confirmed esophageal cancer were retrospectively evaluated. The patients underwent PET-CT imaging before and after completion of neoadjuvant therapy. Images were evaluated visually and quantitatively with a three-dimensional threshold-based region-growing program, which calculates SUVm, SUVa of the entire tumor, metabolic tumor length (Lm) and volume (Vm) before and after therapy (SUVm1, SUVm2, SUVa1, SUVa2, Lm1, Lm2, Vm1, and Vm2, respectively). Percentage changes in these metabolic variables before and after therapy were also calculated (%SUVm, %SUVa, %Lm, %Vm, respectively).

RESULTS

SUVm1 (P = 0.018), SUVa1 (P = 0.019), Lm1 (P = 0.016), and Vm1 (P = 0.016) correlated with T-status. Advanced stage tumors (T3 + T4) had significantly higher glucose metabolism, metabolic length, and volume. Moreover, Lm1 >47.4 mm and Vm1 >29 cm3 were the best predictors of the level of tumor invasiveness. SUVm1 >12.7 and SUVa1 >5.9 could differentiate patients with positive lymph nodes from those without at presentation. %SUVa >32.3% and the SUVa1 >5.5 proved to be reliable predictors of pathologic response. SUVa2 >3.55 and SUVm2 >4.35 were the best predictors of disease progression during follow-up, with the latter having the best prognostic value.

CONCLUSIONS

This study showed that FDG-PET tumor segmentation-derived indices of metabolic activity play a definite role in the evaluation of response to neoadjuvant chemoradiotherapy and progression-free survival in patients with esophageal cancer.

Evaluation of respiratory-induced target motion for esophageal tumors at the gastroesophageal junction

PURPOSE

To quantify the internal motion margin requirements for radiotherapy of tumors near the gastroesophageal junction (GEJ).

METHODS AND MATERIALS

Four-dimensional computed tomography (4DCT) scans were obtained for 25 patients with primary tumors located near the GEJ. The gross tumor volume (GTV) was manually contoured on the exhale-phase image from the 4DCT image set. A deformable image registration method was used to automatically propagate the contours to other phases of the 4DCT images. To quantify target motion, we measured the displacement of the GTV centroid and the variations in the target boundary and volume. Internal margins were calculated in the lateral (RL), anterior-posterior (AP), and superior-inferior (SI) directions.

RESULTS

The mean+/-standard deviation peak-to-peak GTV centroid motion was 0.39+/-0.27cm (range, 0.04-1.09cm) in the RL, 0.38+/-0.23cm (range, 0.10-0.94cm) in the AP, and 0.87+/-0.47cm (range, 0.43-2.63cm) in the SI directions, respectively. On average, the internal target volume was 72% (range, 9-172%) larger than the GTV defined on a single-phase CT image. Variations in tumor boundaries due to tissue motion and deformation suggested asymmetric margins: 1.0cm left [toward the stomach], 0.8cm right, 1.1cm anterior, 0.6cm posterior, 1.0cm superior (toward the distal esophagus), and 1.6cm inferior (toward the stomach).

CONCLUSION

Because tumors near the GEJ are subject to a marked but asymmetric amount of respiratory-induced intrafractional tumor motion, the use of asymmetric internal margins may be beneficial.

Predicting the response of localised oesophageal cancer to neo-adjuvant chemoradiation

BACKGROUND

A complete pathological response to neo-adjuvant chemo-radiation for oesophageal cancer is associated with favourable survival. However, such a benefit is seen in the minority. If one could identify, at diagnosis, those patients who were unlikely to respond unnecessary toxicity could be avoided and alternative treatment can be considered. The aim of this review was to highlight predictive markers currently assessed and evaluate their clinical utility.

METHODS

A systematic search of Pubmed and Google Scholar was performed using the following keywords; "neo-adjuvant", "oesophageal", "trimodality", "chemotherapy", "radiotherapy", "chemoradiation" and "predict". The original manuscripts were sourced for further articles of relevance.

RESULTS

Conventional indices including tumour stage and grade seem unable to predict histological response. Immuno-histochemical markers have been extensively studied, but none has made its way into routine clinical practice. Global gene expression from fresh pre-treatment tissue using cDNA microarray has only recently been assessed, but shows considerable promise. Molecular imaging using FDG-PET seems to be able to predict response after neo-adjuvant chemoradiation has finished, but there is a paucity of data when such imaging is performed earlier.

CONCLUSION

Currently there are no clinically useful predictors of response based on standard pathological assessment and immunohistochemistry. Genomics, proteomics and molecular imaging may hold promise.

Positron emission tomographic scanning predicts survival after induction chemotherapy for esophageal carcinoma

BACKGROUND

The ability to accurately predict clinical and pathological response and survival in patients undergoing preoperative chemotherapy may have a significant impact on treatment strategy for esophageal carcinoma. This study assessed the predictive accuracy of clinical response (CR) and positron emission tomography (PET) scanning in determining pathological downstaging and disease free survival (DFS) after chemotherapy.

METHODS

This is a retrospective review of patients who underwent chemotherapy prior to complete surgical resection for esophageal carcinoma between 1999 and 2005. Clinical response was correlated with pathological downstaging and survival. For PET scanning, the percent reduction in maxSUV after induction therapy was determined and we identified the optimal threshold of percent reduction in maxSUV for predicting clinical response and pathological downstaging.

RESULTS

Sixty-two patients (52 men, median age 62.3) were evaluated. Thirty-nine patients (62.9%) had either a partial (n = 32) or complete clinical response (n = 7) to induction therapy. The sensitivity, specificity, positive, and negative predictive value of an objective clinical response in predicting downstaging in T and (or) N were 85.7%, 55.9%, 61.5%, and 82.6%, respectively. There was no difference in DFS between responders and nonresponders. The PET sensitivity, specificity, positive, and negative predictive values for predicting pathologic downstaging were 77.8%, 52.9%, 56.8%, and 75%, respectively. Thirty-seven patients (59.7%) had a 50% or greater reduction in the maxSUV of their primary tumor and had a significant improvement in DFS compared with patients with a less than 50% reduction in maxSUV (median DFS time: 35.5 months vs 17.9 months, respectively, p = 0.03). Significantly, 11 patients had a 100% reduction in maxSUV despite the presence of residual tumor.

CONCLUSIONS

Complete response and PET appear equivalent in predicting pathological downstaging. However, a 50% reduction in the maxSUV after induction therapy is more significantly associated with improved DFS than CR or pathological downstaging. Additionally, a complete absence of PET signal cannot be equated with a complete pathological response.

Value of complete metabolic response by 18F-fluorodeoxyglucose-positron emission tomography in oesophageal cancer for prediction of pathologic response and survival after preoperative chemoradiotherapy

We aimed to assess the ability of (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan to predict pathologic complete response (CR) and survival in patients with oesophageal cancer treated with preoperative chemoradiotherapy (CRT). The study cohort consisted of 62 consecutive patients with operable oesophageal cancer who were treated with preoperative CRT followed by oesophagectomy. Endoscopy, computed tomography (CT) and PET were performed before and after CRT. Of the 62 patients, 56 (90%) patients responded to preoperative CRT. FDG-PET-determined complete metabolic response (CMR) was achieved by 33 patients (54.1%), whereas pathologic CR was achieved by 28 patients (45.2%). Compared with endoscopic biopsy or CT scan, CMR by FDG-PET showed the highest correlation with pathologic CR (concordance, 71%). At a median follow-up of 19.3 months (range, 3.9-57.1 months), median overall survival (OS) was not reached in patients with CMR compared to 22.4 months in patients who did not achieve CMR. Median disease free survival (DFS) was not reached in patients with CMR compared to 17.4 months in patients who did not achieve CMR. By multivariate analysis, CMR by FDG-PET was significantly associated with better DFS and OS (P=0.006, P=0.033, respectively). The variables associated with pre-CRT PET scan were not predictive of survival. In conclusion, CMR by FDG-PET has a significant correlation with pathologic CR and can predict the long-term outcome in oesophageal cancer patients undergoing CRT. Although surgery is standard treatment for respectable oesophageal cancer, currently even in patients with CMR, the addition of (18)F-FDG-PET could be used to select the patient subgroup not requiring surgery.

Correlation of molecular response as measured by 18-FDG positron emission tomography with outcome after chemoradiotherapy in patients with esophageal carcinoma

PURPOSE

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.

METHODS AND MATERIALS

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.

RESULTS

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).

CONCLUSIONS

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.

The utility of positron emission tomography in staging of potentially operable carcinoma of the thoracic esophagus: results of the American College of Surgeons Oncology Group Z0060 trial

OBJECTIVES

The American College of Surgeons Oncology Group trial Z0060 is a prospective multi-institutional trial with a primary objective to evaluate whether positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) detects evidence of metastastic disease that precludes esophagectomy in patients with esophageal cancer who are surgical candidates after routine staging.

METHODS

Patients with resectable, biopsy-proven carcinoma were enrolled after computed tomography of chest and abdomen demonstrated no evidence of metastasis. FDG-PET was performed according to specified standards. FDG-PET findings suggesting metastases required confirmation and patients without metastases on PET were expected to proceed to surgery.

RESULTS

A total of 262 patients were registered. Of these, 199 were deemed eligible and of these, 189 patients were evaluable. Seventy-three patients were ineligible or unevaluable. Reasons for ineligibility included nonresectable disease by routine staging (39), missing or outdated staging procedures (12), PET technical protocol violations (10), no cancer (4), pre-PET induction therapy (3), claustrophobia (1), and other causes (4). There were 145 (78%) patients who went on to have surgery, 42 (22%) who did not, and 2 patients for whom the surgical status was not determined. The reasons for no resection included the following: M1 disease found by PET and confirmed (9), M1 disease found by PET and not confirmed (2), M1 disease at exploration not found by PET (7), decline or death before surgery (10), patient refusal of surgery (7), unresectable local tumor at exploration (5), and extensive N1 disease precluding operation (2). Eight (4.2%) patients undergoing resection had a recurrence in the first 6 months.

CONCLUSIONS

Although 22% of eligible patients did not undergo esophagectomy, FDG-PET after standard clinical staging for esophageal carcinoma identified confirmed M1b disease in at least 4.8% (95% confidence interval: 2.2%-8.9%) of patients before resection. Unconfirmed PET evidence of M1 disease and regional adenopathy (N1 disease) led to definitive nonsurgical or induction therapy in additional patients.

The role of integrated computed tomography positron-emission tomography in esophageal cancer: staging and assessment of therapeutic response

Computed tomography (CT) and endoscopy/endoscopic ultrasonography are usually performed to initially stage patients with esophageal cancer, to determine primary tumor response, and to detect nodal and distant metastases after preoperative therapy. Positron-emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose and integrated CT-PET are useful in the initial staging of patients with esophageal cancer as well as in the prediction of pathologic response, disease-free interval, and overall survival after preoperative therapy. Importantly, integrated CT-PET imaging decreases the number of futile attempts at surgical resection, mainly because of the detection of occult distant metastases. The following sections review the use of integrated CT-PET imaging in determining the T, N, and M descriptors of the American Joint Commission on Cancer's 2002 guidelines for pathologic and clinical staging at initial diagnosis and after chemoradiation therapy in those patients being considered for surgical resection.

Considerations in Treatment Planning for Esophageal Cancer

Radiation therapy is an important component of the multidisciplinary management of esophageal cancer. In this article, we review the current approaches to achieving the desired dose to the esophagus and regional lymph nodes, with an emphasis on the dose constraints to adjacent normal structures, particularly the heart and lungs. The application of newer technologies such as positron-emission tomography/computed tomography scanning and intensity-modulated radiation therapy is also explored.

Evolving role of (18)F-fluorodeoxyglucose positron emission tomography in the management of esophageal carcinoma

Positron emission tomography (PTE) and PET/CT imaging with (18)F-fluorodeoxyglucose are metabolic imaging modalities that depict tissues based on their level of glucose uptake. PET provides useful information in the primary staging of disease. PET performance in detecting locoregional nodal metastases is limited; however, it is the most accurate single noninvasive modality for detecting distant metastases. It is the imaging modality of choice for whole-body scanning in high-risk patients or patients who have clinically suspected recurrence, and is particularly helpful in determining which patients are the best candidates for surgical cure.

PET: other thoracic malignancies

The vast majority of esophageal cancers are fluorodeoxyglucose (FDG) avid; the primary use for positron emission tomography (PET) in patients with esophageal cancer is in the detection of distant metastases, because known distant metastatic disease precludes surgical resection. High standardized uptake values (SUVs) may be predictive of poor prognosis. PET findings may be used to assess therapy response and evaluate for esophageal tumor recurrence after treatment. PET findings may be non-specific in different types of thymic lesions, although thymic carcinomas tend to be extremely FDG avid. PET can be helpful in detecting distant spread from invasive thymomas and thymic carcinomas. Similarly, PET may be used to assess the extent of disease in patients with malignant pleural mesothelioma, thereby facilitating optimal therapy approaches.

Gastrointestinal tract malignancies and positron emission tomography: an overview

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is highly accurate in restaging colorectal cancer, esophageal cancer, and gastrointestinal stromal tumors. Overall, it compares favorably with anatomical imaging in the evaluation of tumor recurrence because metabolic abnormalities usually precede a structural change. Initial staging of these malignancies with PET is best used in patients with locally advanced disease who may benefit from curative resection if distant metastases are not found. It also appears to have great potential in predicting histopathologic response to neoadjuvant therapy and in monitoring the success of radiofrequency ablation and (90)Y microspheres radioembolization soon after intervention. FDG-PET can be used in other gastrointestinal malignancies as a prognostic tool and to detect distant disease but its role has not yet been well defined.

Epidermal growth factor receptor as a predictor of tumor downstaging in locally advanced rectal cancer patients treated with preoperative chemoradiotherapy

PURPOSE

To examine retrospectively whether levels of epidermal growth factor receptor (EGFR) expression can predict tumor downstaging after preoperative chemoradiotherapy in patients with locally advanced rectal cancer.

METHODS AND MATERIALS

A total of 183 patients with rectal cancer (cT3-T4 or N+) were enrolled in this study. Preoperative chemoradiotherapy consisted of 50.4 Gy of pelvic radiation with concurrent 5-fluorouracil and leucovorin bolus intravenous chemotherapy in 94 patients or oral capecitabine and leucovorin in 89 patients. EGFR expression in pretreatment paraffin-embedded tumor biopsy specimens was assessed by immunohistochemistry. EGFR expression was determined from the intensity and extent of staining. Tumor downstaging was defined as a reduction of at least one T-stage level.

RESULTS

Tumor downstaging occurred in 97 patients (53%), and the tumors showed a pathologic complete response in 27 patients (15%). Positive EGFR expression was observed in 140 (76%) of 183 patients. EGFR expression levels were low in 113 patients (62%) and high in 70 patients (38%). On logistic regression analysis, the significant predictive factor for increased tumor downstaging was a low level of EGFR expression and preoperative chemotherapy using oral capecitabine (odds ratio, 0.437; p = 0.012 vs. odds ratio, 3.235; p < 0.001, respectively).

CONCLUSION

A high level of EGFR expression may be a significant predictive molecular marker for decreased tumor downstaging after preoperative chemoradiotherapy in locally advanced rectal cancer.

Diagnosis and therapy in advanced cancer of the esophagus and the gastroesophageal junction

PURPOSE OF REVIEW

The aim of this article is to discuss recent developments in the diagnosis and treatment with curative option of advanced cancer of the esophagus and gastroesophageal junction.

RECENT FINDINGS

Recent data indicate improvement of clinical staging accuracy by multi-slice computer tomography, endoscopic ultrasound with fine needle aspiration and positron emission tomography, the latter gaining growing impact as a prognostic indicator. When combined with extended lymphadenectomy primary surgery offers 5-year survivals between 25 and 35% for stage III disease. Results of induction therapy remain conflicting. While the most recent meta-analysis favored induction chemoradiotherapy, a subsequent randomized trial failed to confirm this conclusion. A growing interest in adjuvant chemoradiotherapy is stimulated by promising results from a recent pilot study. Trials investigating definitive chemoradiotherapy indicate a high incidence of locoregional recurrence. The emerging understanding of the molecular pathways that govern neoplastic events are under intense investigation. Results of pilot clinical studies on targeted therapy are expected shortly.

SUMMARY

Refinements in staging offer incremental increase of accuracy, the impact of positron emission tomography becoming increasingly important. In locally advanced disease, the debate on the added value of multimodality therapy remains unsolved as primary surgery combined with extended lymphadenectomy offers equal results. New drugs in particular in combination with targeted therapy may offer better perspectives in the near future.

Esophageal Cancer: The Role of Integrated CT-PET in Initial Staging and Response Assessment After Preoperative Therapy

Esophageal cancer, an uncommon neoplasm, has been increasing in incidence over the past few decades. Optimal management of patients is determined by the stage of disease at presentation, patient performance status, and location of the primary cancer. Recently, there has been increasing use of multimodality therapy in suitable candidates that employs preoperative chemotherapy and/or radiation followed by surgical resection. This evolving treatment strategy together with the substantial morbidity and mortality associated with esophagectomy makes appropriate patient selection critical. Computed tomography (CT) and endoscopy/endoscopic ultrasonography are usually carried out to initially stage patients with esophageal cancer, to determine primary tumor response, and to detect nodal and distant metastases after preoperative therapy. Positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose and integrated CT-PET are useful in the initial staging of patients with esophageal cancer and in the prediction of pathologic response, disease-free interval, and overall survival after preoperative therapy. Importantly, integrated CT-PET imaging decreases the number of futile attempts at surgical resection, mainly because of the detection of occult distant metastases. The following sections review the use of integrated CT-PET imaging in determining the T, N, and M descriptors of the American Joint Commission on Cancer's 2002 guidelines for pathologic and clinical staging at initial diagnosis and after chemoradiation therapy in those patients being considered for surgical resection.