For Stage II Colon Cancer, Oncotype DX Proves Cost-Saving
San Francisco, CA—For assessing prognosis in patients with stage II colon cancer, the 12-gene Oncotype DX Colon Cancer Assay increases quality-adjusted survival and is cost- saving, according to a new study reported at the 2013 Gastrointestinal Cancers Symposium.
“Patients with stage II, T3 colon cancer have an 88% cancer-specific survival rate at 5 years. The challenge remains to identify the individuals with a higher risk of recurrence for whom adjuvant chemotherapy would be considered and spare the remaining patients the toxicity and cost associated with chemotherapy,” said Steven R. Alberts, MD, MPH, Medical Director of the Clinical Research Office, Chair of Medical Oncology, Professor of Oncology, College of Medicine, and a consultant for the Division of Medical Oncology, Mayo Clinic Cancer Center, Rochester, MN.
The treatment decision-making process should take into account recurrence risk factors. The 12-gene assay has been clinically validated in patients with stage II colon cancer to predict the risk of recurrence after surgery, and has been shown to influence physicians’ recommendations in the adjuvant chemotherapy setting, Dr Alberts said.
The study assessed whether the use of the assay would improve outcomes while lowering medical costs for patients with stage II, T3, DNA mismatch repair–proficient (MMR-P) tumors. Patients with MMR-P tumors typically have worse outcomes than patients with mismatch repair–deficient tumors.
The data set came from a prospective trial of 141 patients that investigated clinicians’ actual adjuvant chemotherapy recommendations before and after the assay. The use of the assay frequently changed treatment recommendations. Although 48% of physicians recommended only observation before the assay (no chemotherapy), 70% recommended it after receiving the results.
Although 24% of physicians recommended 5-fluorouracil (FU) monotherapy before the assay, 13% recommended it after. Furthermore, although 28% of physicians recommended 5-FU plus oxaliplatin (Eloxatin) before the assay, only 17% would prescribe oxaliplatin after the assay.
Based on this study, adjuvant chemotherapy use would decrease from 52% to 30% with this assay; 11% of patients would receive a more intense chemotherapy option, and 33% of patients would receive a less intense option.
After evaluating how chemotherapy may reduce recurrences while increasing adverse events (AEs), the investigators concluded that there was
a net increase of 0.083 years in quality-adjusted survival.
Overall medical costs decreased by $4203 per patient on average with the assay, and the cost of managing AEs decreased by $3268 (Table).
The lifetime cost of treating with 5-FU plus oxaliplatin was significantly higher than with monotherapy, both in terms of the drug costs and the administration costs (+$28,242) and the cost of managing AEs ($17,689), Dr Alberts further noted.
The costs were most sensitive to change in the overall adjuvant chemotherapy use, the benefit of 5-FU monotherapy, and the cost of drugs for 5-FU plus oxaliplatin chemotherapy.
“Savings are expected to persist even if the cost of oxaliplatin decreases by greater than 75% due to generic substitution,” Dr Alberts predicted. “If the future cost of oxaliplatin is one fourth of the current cost, the use of the 12-gene assay saves on average $1108 per patient.”