title: Nodal tumor response according to the count of peripheral blood lymphocyte subpopulations during preoperative chemoradiotherapy in locally advanced rectal cancer.
abstract: OBJECTIVE
  The objective of this prospective study was to evaluate the relationship between the circulating lymphocyte subpopulation counts during preoperative chemoradiotherapy (CRT) and tumor response in locally advanced rectal cancer.
  
  
  METHODS
  From August 2015 to June 2016, 10 patients treated with preoperative CRT followed by surgery were enrolled. Patients received conventional fractionated radiotherapy (50.4 Gy) with fluorouracil-based chemotherapy. Surgical resection was performed at 4 to 8 weeks after the completion of preoperative CRT. The absolute blood lymphocyte subpopulation was obtained prior to and after 4 weeks of CRT. We analyzed the association between a tumor response and change in the lymphocyte subpopulation during CRT.
  
  
  RESULTS
  Among 10 patients, 2 (20%) had evidence of pathologic complete response. In 8 patients with clinically node positive, 4 (50%) had nodal tumor response. All lymphocyte subpopulation counts at 4 weeks after CRT were significantly lower than those observed during pretreatment (p < 0.01). A high decrease in natural killer (NK) cell, count during CRT (baseline cell count - cell count at 4 weeks) was associated with node down staging (p = 0.034).
  
  
  CONCLUSIONS
  Our results suggest that the change of lymphocyte subset to preoperative CRT may be a predictive factor for tumor response in rectal cancer.
authors.affiliation: Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Jaesung
authors.initials: J
authors.lastname: Heo
authors.affiliation: Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Young-Taek
authors.initials: YT
authors.lastname: Oh
authors.affiliation: Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: O Kyu
authors.initials: OK
authors.lastname: Noh
authors.affiliation: Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Mison
authors.initials: M
authors.lastname: Chun
authors.affiliation: Department of Pediatrics, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Jun-Eun
authors.initials: JE
authors.lastname: Park
authors.affiliation: Department of Laboratory Medicine, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Sung-Ran
authors.initials: SR
authors.lastname: Cho
keywords: Immunity; Lymphocytes; NK cells; Rectal neoplasms