ENDOSCOPIC ULTRASOUND IN RESTAGING OF ESOPHAGEAL CANCER AFTER NEOADJUVANT CHEMORADIATION

Background: Endoscopic ultrasound (EUS) is established as the most acc urate method currently available for determining the depth of primary cancer invasion (T stage). Standard EUS criteria may not be accurate i n assessing depth of cancer invasion and nodal status after patients h ave received chemotherapy or radiotherapy. Methods: We conducted a pro spective study to determine whether EUS estimation of tumor size could be used to assess response to preoperative chemoradiation. Using EUS, TNM stage was assessed in 31 patients (22 men, 9 women; mean age 62 y ears) with cancer of esophagus or cardia (19 adenocarcinoma, 12 squamo us cell cancer) before initiation of combined radiation and 5-fluorour acil/ cisplatin (and/or carboplatinum) chemotherapy. The cross-section al area of the tumor in the transverse plane at the location where the tumor had maximal thickness was calculated to estimate tumor size. EU S staging and measurement of maximal cross-sectional area were repeate d at completion of chemoradiation just before surgery. Response to pre operative chemoradiation was defined as 50% reduction in maximal cross -sectional area. Surgical staging was compared between responders and nonresponders. Results: Eight patients who did not undergo surgery wer e excluded from analysis. EUST stage in the remaining 23 patients befo re therapy was as follows: 3 T2, 16 T3, and 4 T4. After chemoradiation , EUS T staging was changed in 6 patients (3 T4 downstaged to T3, 2 T3 downstaged to T2, and 1 T3 downstaged to T1). At surgical pathologica l examination, 3 patients had no residual tumor in the esophagus (T0), 5 had T1, 3 had T2, 10 had T3, and 2 had T4 tumors. EUS T staging acc uracy after adjuvant therapy was only 43%. Maximal cross-sectional are a decreased from a mean of 5.5 +/- 2.4 to 1.6 +/- 0.9 cm(2) in respond ers, whereas maximal cross-sectional area went from 7.0 +/- 3.0 to 5.4 +/- 2.2 cm(2) in nonresponders (p = 0.009). Ten of thirteen patients with at least a 50% reduction in maximal cross-sectional area (respond ers) had T0, T1, or T2 tumors at surgery, whereas 9 of 10 nonresponder s had T3 or T4 tumors at surgery (p = 0.001). Conclusions: (1) Standar d EUS staging criteria are not accurate after neoadjuvant chemoradiati on, (2) reduction in maximal cross-sectional area of tumor appears to be a more useful measure for assessing response of esophageal cancer t o preoperative chemoradiation, and (3) responders have an increased li kelihood of downstaging at surgery than nonresponders.