title: A postoperative nomogram for local recurrence risk in extremity soft tissue sarcomas after limb-sparing surgery without adjuvant radiation.
abstract: OBJECTIVE
  To develop a nomogram based on clinicopathologic factors to quantify the risk of local recurrence (LR) after limb-sparing surgery without adjuvant radiation (RT).
  
  
  METHODS
  Review of our prospective sarcoma database identified 684 patients with primary, nonmetastatic, extremity STS treated with limb-sparing surgery alone between June 1982 and December 2006. No patient received adjuvant radiation or chemotherapy. Age, sex, grade, depth, size, site, margin status and histology were analyzed for prognostic significance with respect to local recurrence rates using Gray's test. Variables which were significant in univariate analysis at the 0.05 level were entered into a multivariate competing risk regression model. On the basis of the multivariate analysis, a nomogram for predicting the 3- and 5-year risk of LR was developed using R libraries cmprsk and QHScrnomo. Concordance index (C-index) was calculated to evaluate the discriminatory power of the prognostic model.
  
  
  RESULTS
  With a median follow-up of 58 months for censored patients (73 months for all patients), the overall 3- and 5-year actuarial local recurrence rates were 11% and 13%, respectively. Factors included in the nomogram were age (≤ 50 vs. >50), size (≤ 5 vs. >5 cm), margin status (negative vs. positive), grade (low vs. high), and histology (atypical lipomatous tumor/well differentiated liposarcoma vs. other). The STS nomogram predicted the local recurrence rate with a C-index of 0.73.
  
  
  CONCLUSIONS
  A nomogram for extremity STS that includes age, size, margin status, grade of tumor, and histology predicts the 3- and 5-year risk of local recurrence after limb-sparing surgery in the absence of adjuvant RT.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
authors.forename: Oren
authors.initials: O
authors.lastname: Cahlon
authors.forename: Murray F
authors.initials: MF
authors.lastname: Brennan
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Jia
authors.forename: Li-Xuan
authors.initials: LX
authors.lastname: Qin
authors.forename: Samuel
authors.initials: S
authors.lastname: Singer
authors.forename: Kaled M
authors.initials: KM
authors.lastname: Alektiar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005121:Extremities / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D049451:Nomograms; D011184:Postoperative Period; D012306:Risk; D012509:Sarcoma / Q000473:pathology* / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000601:surgery; D055815:Young Adult