Impact of FDG-PET for staging of oesophageal cancer.

BACKGROUND AND AIMS: Treatment of oesophageal cancer depends on staging and the general health of the patient. In stages I-II b, as well as in some stage III diseases, surgical resection remains the therapy of choice for cure, but a curative approach is not possible in stage IV. In our hospital we give preoperative radio-chemotherapy to all patients with an oesophageal cancer T>1, Nx, M0. Therefore, the main purpose of the clinical staging of oesophageal cancer is the exclusion of M1 and T4 disease with infiltration into the tracheobronchial system or the aorta. The aim of the investigation was the assessment of positron emission tomography for detection of M1 disease. PATIENTS/METHODS: Between 1998 and 2002, 84 patients with oesophageal cancer (64% squamous cell carcinoma and 36% adenocarcinoma) were enrolled into the study. Of these, 48.8% were operated on; 35.7% of the patients were not operated on, for oncological reasons, 7.1% for medical reasons, 3.6% chose not to be operated on, and, for unknown reasons, 4.8% were not operated on. RESULTS: Twenty-five patients had stage IV disease or additional, synchronous cancer of the head and neck ( n=2). As the only investigational procedure, positron emission tomography revealed M1 stage in 11 of 25 patients (44%). In 13/25 (52%) both computed tomography and positron emission tomography revealed stage IV disease. False positive results by positron emission tomography were observed in three patients. The sensitivity and specificity of positron emission tomography (PET) was 0.96 and 0.95, respectively. Most of the metastases detected by PET only, were localised within the neck, liver and bone. With regard to the 66 of 84 patients deemed medically fit for operation and without local infiltration into the tracheobronchial system (T4) PET as the only imaging procedure changed the therapeutic strategy in 11 of 66 (16.6%) patients with to M1 disease. CONCLUSION: Our results demonstrated clearly the impact of the PET scan for decision-making in patients with oesophageal carcinoma. PET should be performed prior to therapy with curative intention. However, addition of a computed tomography scan of the neck might reduce the rate of unexpected metastases detected by PET.

Effects of neoadjuvant radio-chemotherapy on 18F-FDG-PET in esophageal carcinoma.

AIM: To investigate whether results of [F-18]-fluorodeoxy-d-glucose (FDG) positron emission tomography (PET) of esophageal cancer (EC) before and after neoadjuvant radio-chemotherapy correlate with histopathology after esophageal resection. METHODS: Twenty consecutive patients with EC without distant metastases were examined twice with 18F-FDG-PET during primary staging and after neoadjuvant radio-chemotherapy. FDG standardised uptake values (SUV) were correlated with the histopathological findings (percentage of viable tumour cells, tumour regression grade 1-5). RESULTS: Regression analysis revealed a slight (not significant) positive correlation between SUV(pre) (R=0.41, p=0.08) and SUV(post) (R=0.37, p=0.11) and the percentage of viable tumour cells in the resectate. Although all patients showed a significant decrease in SUV after radio-chemotherapy (p < 0.01) the percentual decrease of the SUV after therapy (DeltaSUV%) did not significantly differ between the TRG-groups. In 12 of 20 patients (60%), therapy-induced esophagitis was detected in post-therapeutic PET images. CONCLUSION: In EC, a higher pre-therapeutic SUV might be correlated with a higher fraction of vital tumour cells remaining after radio-chemotherapy. Applying the neoadjuvant therapy protocol and the study design used in this examination, there is no correlation between decrease in SUV and histopathology.