title: Can molecular imaging predict response to preoperative chemoradiation in patients with rectal cancer? A Fox Chase Cancer Center prospective experience.
abstract: This study was undertaken to correlate change in fluorine-18 fluorodeoxyglucose positron emission tomography ((18)FDG-PET) uptake with response to combined-modality neoadjuvant therapy in patients with locally advanced rectal cancer. Twenty patients (13 male; 7 female) underwent (18)FDG-PET scans before and 3 to 4 weeks after completion of chemoradiation before surgery. Staging by endoscopic ultrasound was T3/T4 (17/1); two patients were unable to undergo endorectal ultrasound. Fifteen patients had perirectal lymphadenopathy. Median radiation dose was 5,040 cGy (range, 4,500 to 5,500 cGy). All patients received continuous infusion 5-fluorouracil (or capecitabine) with radiation. Median pre- and post-chemoradiation standard uptake values were 9.4 (range, 3.6 to 37.0) and 3.05 (range, 0.5 to 8.2), respectively. Median percent standard uptake value decrease observed in the postchemoradiation PET scans was 71% (range, 7% to 95%). Six patients (30%) had pathologic complete response. Only two of six patients with postchemoradiation standard uptake values <or=2.5 had a complete pathologic response. The time from the end of radiation to surgery was marginally significant for predicting pathologic complete response (P = .12). Neoadjuvant combined-modality therapy resulted in decreased metabolic activity on PET. Because response to preoperative treatment predicts clinical outcome, the utility of midtreatment PET scans to guide treatment decisions should be further explored in larger clinical studies.
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA. andre.konski@fccc.edu
authors.forename: Andre
authors.initials: A
authors.lastname: Konski
authors.forename: John
authors.initials: J
authors.lastname: Hoffman
authors.forename: Elin
authors.initials: E
authors.lastname: Sigurdson
authors.forename: Oleh
authors.initials: O
authors.lastname: Haluszka
authors.forename: Paul
authors.initials: P
authors.lastname: Engstrom
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Cheng
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cohen
authors.forename: James C
authors.initials: JC
authors.lastname: Watson
authors.forename: Debra
authors.initials: D
authors.lastname: Eisenberg
authors.forename: Eileen
authors.initials: E
authors.lastname: McGarrity
authors.forename: Gary
authors.initials: G
authors.lastname: Freedman
authors.forename: Neal J
authors.initials: NJ
authors.lastname: Meropol
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000628:therapy*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000069287:Capecitabine; D003131:Combined Modality Therapy; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D005260:Female; D019788:Fluorodeoxyglucose F18; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D008297:Male; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011878:Radiotherapy; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*
chemical_list: D000970:Antineoplastic Agents; D003841:Deoxycytidine; D019788:Fluorodeoxyglucose F18; D000069287:Capecitabine; D005472:Fluorouracil