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The study: Canadian researchers performed a genetic analysis of frozen, banked tumor samples from 133 patients with early-stage non-small cell lung cancer (NSCLC) to identify a set of genes that could predict whether a patient would benefit from adjuvant chemotherapy (treatment after surgery). This study is a follow-up analysis from the National Cancer Institute of Canada's Clinical Trials Group study JBR.10 and was conducted in collaboration with the U.S. National Cancer Institute. Of the 482 patients in the original study, tumor samples were available from 133 patients. Of these patients, 62 had not received adjuvant chemotherapy, and 71 patients received adjuvant chemotherapy.
The results: A set of 15 genes was first identified in the patients who had not received adjuvant chemotherapy. Some of these genes help control cancer cell growth and death or regulate other cancer-related genes. The researchers used this information to classify the tumor samples by risk of recurrence (chance that the cancer comes back after treatment) and found that 31 of the 62 patients had lung cancer with a high risk of recurrence, and 31 patients had lung cancer with a low risk of recurrence.
The tumors from the 71 patients who received adjuvant chemotherapy as part of the JBR.10 study were then tested to find the set of 15 genes that could predict the risk of recurrence. The patients predicted to have lung cancer with a high risk of recurrence experienced the most benefit from chemotherapy; they were 67% less likely to die from lung cancer than those who did not receive adjuvant chemotherapy. However, adjuvant chemotherapy did not lower the risk of death for patients predicted to have lung cancer with a low risk of recurrence because the risk of cancer recurrence for these patients was already low.
What this means for patients
“Not all patients benefit from chemotherapy, and not all patients require chemotherapy after surgery,” said lead author Ming Tsao, MD, Professor of Laboratory Medicine and Pathobiology at the University of Toronto, Canada. “Knowing that a patient may have a more aggressive cancer and that their chance of cure may be improved with adjuvant chemotherapy gives patients and their doctors a clearer picture of the need for treatment after surgery.” This test shows that in the future, doctors may be able to spare patients with low-risk cancer the side effects of chemotherapy and identify patients who could benefit from chemotherapy. These tests are currently only available through a clinical trial.
What to ask your doctor
- What is the type and stage of my lung cancer?
- What is the chance that the cancer will progress or recur?
- What are my treatment options? Am I a candidate for adjuvant chemotherapy?
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