External validation of a rectal cancer outcome prediction model with a cohort of patients treated with preoperative radiochemotherapy and deep regional hyperthermia

Int J Hyperthermia. 2018 Jun;34(4):455-460. doi: 10.1080/02656736.2017.1338364. Epub 2017 Jul 26.


Purpose: To validate a nomogram for the prediction of treatment outcomes after preoperative radiochemotherapy and surgery for locally advanced rectal cancer with a cohort of patients treated with additional deep regional hyperthermia.

Patients and methods: A total of 86 patients were treated with preoperative radiochemotherapy and deep regional hyperthermia at our institution. For every patient, the 5-year probability for death, distant metastases and local failure based on a previously published nomogram were calculated and patients were divided into three risk groups.

Results: Low-lying and clinically lymph node positive tumours were more frequent in the validation cohort. Five-year Kaplan-Meier estimates for overall survival (OS), distant metastases-free survival (DMFS) and local control (LC) were 87.3%, 79.9%, 95.8% (observed) and 75.5%, 71%, 90% (predicted), respectively. Discrimination between low- and high-risk groups was at a significant level for all endpoints. The c-index was 0.81 (OS), 0.67 (DMFS) and 0.92 (LC), respectively.

Conclusions: The nomogram showed reasonable performance when deep regional hyperthermia is incorporated into preoperative therapy. The higher than predicted rates seen for OS and DMFS in particular in the high-risk groups warrant further prospective validation and subsequent investigation of the underlying mechanisms.

Keywords: Predictive model; hyperthermia; nomogram; prognostic factors; radiochemotherapy; rectal cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Chemoradiotherapy*
  • Female
  • Humans
  • Hyperthermia, Induced*
  • Male
  • Middle Aged
  • Models, Theoretical*
  • Rectal Neoplasms / therapy*
  • Reproducibility of Results
  • Treatment Outcome