prognostic value of diffusion mr imaging and clinical-pathologic factors in patients with rectal cancer

Background: apparent diffusion coefficient (adc) value measured from diffusion-weighted magnetic resonance (mr) images are highly correlated with pathological t or n stage, tumor differentiation grade, and extramural depth of tumor in patients with rectal cancer. objectives: to assess the prognostic value of diffusion mr imaging and clinical-pathologic risk factors in patients with rectal cancer. patients and methods: this retrospective study was approved by our institutional review board and written informed consent was waived. sixty-one consecutive patients with rectal cancer (41 men and 20 women; mean age, 64.5 ± 12.1 years; range, 32 - 86 years) underwent pelvic mr imaging. tumor adc value and clinical-pathologic risk factors were tested as possible risk factors for postoperative local recurrence or distant metastasis (lrdm) as well as disease-free survival outcome. results: of 62 tumors, 12 (19.4%) had postoperative lrdm (median follow-up 38.5 months). plasmatic ca19-9 level (p = 0.0027), pathological n stage (p = 0.0018), lymphatic invasion (p < 0.0001), and tumor adc value (p = 0.0076) were independently associated with postoperative ldrm. high plasmatic ca19-9 level (≥ 37 u/ml) (p = 0.010), ly2 (p = 0.020), ly3 (p < 0.0001), pathological n2 (p = 0.006), and low tumor adc value (< 0.996 × 10^-3 mm²/sec) (p = 0.0026) were associated with reduced disease-free survival. conclusion: preoperative tumor adc and plasmatic ca19-9 were significantly associated with postoperative lrdm and disease-free survival in rectal cancer.