In a recent study titled “Validation of the 12-Gene Colon Cancer Recurrence Score as a Predictor of Recurrence Risk in Stage II and III Rectal Cancer Patients”, published in the Journal of the National Cancer Institute, a team of researchers led by Dr. Cornelis J. H. van de Velde, Leiden University Medical Center, Netherlands, conducted a study to validate the 12-gene Recurrence Score assay in the prediction of recurrence risk in stage II and III rectal cancer patients from the Dutch Total Mesorectal Excision (TME) trial.
The Dutch TME trial took place between 1996 and 1999, and assessed the effect of short-term preoperative radiotherapy in combination with TME surgery compared with TME surgery alone in 1861 rectal cancer patients.
The results of this trial showed improved local recurrence rates in patients treated with preoperative radiotherapy and TME but no significant effect seen on distant recurrence and overall survival.
The 12-gene Recurrence Score assay (Genomic Health) was developed through the analysis of tumor gene expression data from 1,851 patients with resected colon cancer from four independent clinical trials, and serves as a predictor of recurrence risk in stage II and III colon cancer patients.
The main objective of the study was to confirm the validity of this assay in the TME-alone arm of the Dutch TME trial, a group of patients who received no pre- and postoperative therapy.
As such, researchers analyzed RNA from primary rectal tumor tissue from stage II and III patients randomized to TME surgery alone (who had no adjuvant treatment). Using real-time polymerase chain reaction (PCR), the team evaluated the recurrence score by looking at specific rectal cancer genes.
The results demonstrated that the recurrence score assay could predict risk of recurrence, risk of distant recurrence and rectal cancer-specific survival, especially in stage II patients, where the five-year incidence of recurrence ranged from 11.1% in the predefined low Recurrence Score group to 43.3% in the high Recurrence Score group.
The medical community has still not reached a conclusion on whether or not chemotherapy should be used as an adjuvant in rectal cancer, and alternative approaches that spare radiation and surgery are also being evaluated.
The results show that the use of the 12-gene Recurrence Score in clinical trials could help improve such efforts by allowing physicians to provide tailored treatment strategies to each individual patient.
Furthermore, as the authors state this assay is a “predictor of recurrence risk and cancer-specific survival in rectal cancer patients treated with surgery alone, suggesting a similar underlying biology in colon and rectal cancers”.
