title: Neoadjuvant chemoradiation and duration of chemotherapy before surgical resection for pancreatic cancer: does time interval between radiotherapy and surgery matter?
abstract: BACKGROUND
  Neoadjuvant chemoradiation and chemotherapy provided for borderline or locally advanced, potentially resectable pancreatic adenocarcinoma improves resectability rates. Response to therapy is also an important prognostic factor. There are no data in the literature regarding optimal time interval or duration of chemotherapy after chemoradiation before surgery, and pathologic response rates. Using our database, we evaluated these relationships and the effect on overall and progression-free survival.
  
  
  METHODS
  We retrospectively analyzed the records of 83 patients who underwent neoadjuvant chemoradiation for locally advanced, potentially resectable, and borderline resectable pancreatic cancers before definitive resection. We divided patients into three groups according to time interval between completion of chemoradiation and resection: group A (0-10 weeks), group B (11-20 weeks), and group C (>20 weeks). After chemoradiation, patients underwent ongoing chemotherapy before resection. Pathologic response was defined as major (>95% fibrosis), partial (50-94% fibrosis), or minor (<50% fibrosis).
  
  
  RESULTS
  There were 56 patients in group A, 17 patients in group B, and 10 patients in group C. Patients in groups B and C were significantly more likely to experience a major response than group A (p < 0.013). Patients in group C had significantly increased median progression-free and overall survival (p < 0.05). Multivariable classification and regression tree analysis demonstrated pathologic response to be the only significant factor in overall survival.
  
  
  CONCLUSIONS
  Patients who underwent a prolonged time interval after neoadjuvant chemoradiation with ongoing chemotherapy were more likely to have an improved pathologic response at time of surgical resection, which was associated with improved median overall survival.
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA, kathryn.chen@gmail.com.
authors.forename: Kathryn T
authors.initials: KT
authors.lastname: Chen
authors.forename: Karthik
authors.initials: K
authors.lastname: Devarajan
authors.forename: Barton N
authors.initials: BN
authors.lastname: Milestone
authors.forename: Harry S
authors.initials: HS
authors.lastname: Cooper
authors.forename: Crystal
authors.initials: C
authors.lastname: Denlinger
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Cohen
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Meyer
authors.forename: John P
authors.initials: JP
authors.lastname: Hoffman
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000069287:Capecitabine; D059248:Chemoradiotherapy; D017024:Chemotherapy, Adjuvant; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000031:analogs & derivatives; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D011300:Preoperative Care; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors; D000093542:Gemcitabine
chemical_list: D003841:Deoxycytidine; D000069287:Capecitabine; D005472:Fluorouracil; D000093542:Gemcitabine