Canadian researchers concluded that they have identified a 15 gene signature that is an independent prognostic marker in early stage non-small cell lung cancer (NSCLC) for identifying more selectively than stage, patients who may benefit from adjuvant chemotherapy.

The Study

Canadian researchers performed a genetic
analysis of frozen, banked tumour 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.  This was a follow-up analysis from the National Cancer Institute of Canada’s (NCIC) Clinical Trials
Group study JBR.10 and was conducted in collaboration with the U.S.
National Cancer Institute (NCI).  Of the 482 patients in the original study,
tumour 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 tumours from the patients who received adjuvant chemotherapy
as part of the JBR10 study were then tested to find the 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.  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

According to lead author Ming Tsao:

“Not all patients benefit from chemotherapy, and not all patients
require chemotherapy after surgery.  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.”

Source:  ASCO Abstract #7510