Canadian Cancer Society-funded researchers discovering ways to personalize cancer treatments

01 September 2010

September 2010 – Researchers funded by the Canadian Cancer Society are identifying ways to refine treatments for some of the most difficult cancers and improve the quality of life of patients living with these cancers.

In the Sept. 7 edition of the Journal of Clinical Oncology, research findings point to potential new personalized treatments for medulloblastoma, a malignant form of childhood brain cancer, and lung cancer, the leading cause of cancer death in Canada for both men and women.

“These findings are very promising because they could lead to cancer therapies that are tailored precisely to the genetic make-up of a specific tumour in a specific patient,” says Dr Christine Williams, director of research, Canadian Cancer Society Research Institute. “Ultimately, this type of research is crucial in helping us to identify the right treatment at the right time for the right person.”

Researchers discover new types of childhood brain cancer

A study led by Dr Michael Taylor has discovered that medulloblastoma, the most common malignant form of childhood brain cancer is not one but four different diseases, each with its own molecular composition and clinical characteristics. These findings could lead to more personalized, targeted treatments for children.

Dr Taylor, a pediatric brain surgeon at Toronto’s Hospital for Sick Children, led a team of international researchers who studied more than 100 medulloblastoma tumour samples and identified four different sub-types of the disease, some more severe than others. In their study, the researchers used the combined power of new genomic (the study of the collective genetic material in an organism) and bioinformatics (the use of computer science to solve a biological problem) techniques. The improved understanding of medulloblastoma could lead to more precise treatments and prevent over-treatment with radiation, which can lead to long-lasting side effects, including damage to brain structure.

Previously, medulloblastoma was thought of as one disease and patients were treated as such. Dr Taylor’s findings could lead to more personalized, targeted treatments and would ensure that the best treatment is given for each form of the disease.

Study zeroes in on those who can benefit most from lung cancer treatment

A research team led by Dr Ming-Sound Tsao has, for the first time, identified a set of genes that can predict whether patients with early-stage non-small cell lung cancer (NSCLC) will benefit from adjuvant chemotherapy (additional treatment after surgery to prevent disease recurrence).

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.

The study is a follow-up analysis from an earlier lung cancer clinical trial led by the NCIC Clinical Trials Group. Dr Tsao, a researcher at Toronto’s Princess Margaret Hospital, led a research team that used tumour samples from 133 patients who participated in the study. They first identified a characteristic 15-gene expression pattern in patients who had not received adjuvant chemotherapy and used this information to accurately predict which patients would have a high or low risk of cancer recurrence.

They also found that the patients predicted to be at high risk of lung cancer recurrence experienced the most benefit from adjuvant chemotherapy. These patients were 67% less likely to die from lung cancer than those high-risk patients who did not receive adjuvant chemotherapy. In contrast, they showed that lung cancer patients with a low risk of recurrence did not benefit from adjuvant chemotherapy, and could potentially be spared unnecessary treatment side-effects. With this prognostic genetic test, clinicians will be able to classify individual patients, and provide them with the treatment most appropriate and effective for their disease.

The original clinical trial upon which this study was based found that a brief course of chemotherapy after surgery increased survival of patients with NSCLC by 15% after 5 years. Prior to this finding, surgery was the only treatment available to these patients and the tumour often recurred outside the lung within a few years. The finding was named one of the top advances in cancer research in 2005 by the American Society of Clinical Oncology. The NCIC Clinical Trials Group receives core funding from the Canadian Cancer Society.