title: Assessment of treatment response and recurrence in esophageal carcinoma based on tumor length and standardized uptake value on positron emission tomography-computed tomography.
abstract: BACKGROUND
  Previous studies demonstrated that a decrease of the standardized uptake value between pretreatment and posttreatment positron emission tomography (PET) scans can predict histopathologic treatment response in patients with esophageal cancer.
  
  
  METHODS
  Forty-seven patients who underwent PET-computed tomography (CT) scans before (scan 1) and after (scan 2) neoadjuvant chemoradiotherapy and during the follow-up period after surgery (scan 3) were included in this study. It was evaluated whether decrease of metabolic tumor length between scan 1 and scan 2 can predict histopathologic response to treatment. Moreover, the value of PET-CT was compared with PET in the assessment of tumor recurrence based on a visual analysis of scan 3. Reference standards for treatment response and recurrence were histopathology results.
  
  
  RESULTS
  The reduction of tumor length between before and after chemoradiotherapy scans (between scan 1 and scan 2) was a better predictor of histopathologic response and of time to recurrence than the decrease in standardized uptake value. The most accurate differentiation was achieved when using a cut-off value of 33% reduction of the initial tumor length. Using this threshold to define metabolic response, the sensitivity was 91% (19 of 21) and the specificity was 92% (24 of 26) for predicting histopathologic treatment response. Based on a visual analysis, PET-CT was more accurate than PET in the differentiation of tumor recurrence from posttreatment tissue changes. Integrated PET-CT achieved a sensitivity of 91% (48 of 53) and a specificity of 81% (30 of 37) in identifying sites of tumor recurrence, compared with 83% (44 of 53) and 65% (24 of 37) with PET.
  
  
  CONCLUSIONS
  Decrease of tumor length was shown to be a better predictor of treatment response and disease-free survival than decrease of standardized uptake value. Furthermore, PET-CT is more accurate in the evaluation of recurrence than PET.
authors.affiliation: Division of Abdominal and Interventional Radiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA. johannes.roedl@gmail.com
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Roedl
authors.forename: Mukesh G
authors.initials: MG
authors.lastname: Harisinghani
authors.forename: Rivka R
authors.initials: RR
authors.lastname: Colen
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Fischman
authors.forename: Michael A
authors.initials: MA
authors.lastname: Blake
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Mathisen
authors.forename: Peter R
authors.initials: PR
authors.lastname: Mueller
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003131:Combined Modality Therapy; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D016629:Esophagectomy / Q000379:methods; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011300:Preoperative Care; D016016:Proportional Hazards Models; D018714:Radiotherapy, Adjuvant; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden