Treatment for colorectal cancer should be based on genetic analysis
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《英国医生杂志》
Genetic analysis of colorectal cancers, rather than the current method of staging based on tumour anatomy and histology, would lead to better treatment regimes, a UK expert has proposed.
Patrick Johnston, director of the cancer research centre at Queen's University, Belfast, said he believed that this "paradigm shift" in classifying tumours would improve estimation of prognosis and targeting of treatment. Speaking at the National Cancer Research Institute's conference in Birmingham this week, Professor Johnston argued that genetic profiling of tumours would allow clinicians to identify which patients with the same stage of disease would go on to relapse early or late and which were likely to benefit from being given adjuvant chemotherapy.
The charity Colon Cancer Concern relaunched itself this week as Bowel Cancer UK, with an event outside St Paul's Cathedral, London
Credit: MARK THOMAS
The management of patients with potentially curative, early stage disease (stages II and III) would benefit particularly from better classification of tumours, Professor Johnston said. He explained that adjuvant chemotherapy is currently given to all patients at risk of relapse after primary surgical treatment but that only about a third of these patients derive any benefit from this treatment. "This exposes a large number of patients to chemotherapy that might be unnecessary," he pointed out. "At present, colorectal cancer is staged by the size of the tumour, the stage of the disease, and whether the disease has gone into the lymph nodes. This means that everybody at a certain stage gets treated. But for every 100 patients treated only 15 or 16 truly benefit."
It is now possible to profile gene expression in patients with colorectal cancer. High throughput genomic screening based on microarray technology allows rapid testing of the genetic profile of large numbers of tumour samples.
"By testing large numbers of tumours, we can determine patterns of gene expression that may allow us to prognosticate or to build a signature that tells us that a particular group of patients will do very well but another group of patients won't do so well," said Professor Johnston.
Recent research used gene expression profiling to define a set of prognostic genomic markers in patients with stage II colorectal cancer. A 23 gene signature profile accurately predicted outcome in 36 patients, with an overall accuracy of 78%—significantly higher than the most established prognostic factors currently in clinical practice ( Journal of Clinical Oncology 2004;22: 1564).
Professor Johnston called for further research but was confident that genetic profiling in colorectal cancer could be in clinical use within five years. "We are going to have to have some very significant international trials in relation to these concepts."(Claire Laurent)
Patrick Johnston, director of the cancer research centre at Queen's University, Belfast, said he believed that this "paradigm shift" in classifying tumours would improve estimation of prognosis and targeting of treatment. Speaking at the National Cancer Research Institute's conference in Birmingham this week, Professor Johnston argued that genetic profiling of tumours would allow clinicians to identify which patients with the same stage of disease would go on to relapse early or late and which were likely to benefit from being given adjuvant chemotherapy.
The charity Colon Cancer Concern relaunched itself this week as Bowel Cancer UK, with an event outside St Paul's Cathedral, London
Credit: MARK THOMAS
The management of patients with potentially curative, early stage disease (stages II and III) would benefit particularly from better classification of tumours, Professor Johnston said. He explained that adjuvant chemotherapy is currently given to all patients at risk of relapse after primary surgical treatment but that only about a third of these patients derive any benefit from this treatment. "This exposes a large number of patients to chemotherapy that might be unnecessary," he pointed out. "At present, colorectal cancer is staged by the size of the tumour, the stage of the disease, and whether the disease has gone into the lymph nodes. This means that everybody at a certain stage gets treated. But for every 100 patients treated only 15 or 16 truly benefit."
It is now possible to profile gene expression in patients with colorectal cancer. High throughput genomic screening based on microarray technology allows rapid testing of the genetic profile of large numbers of tumour samples.
"By testing large numbers of tumours, we can determine patterns of gene expression that may allow us to prognosticate or to build a signature that tells us that a particular group of patients will do very well but another group of patients won't do so well," said Professor Johnston.
Recent research used gene expression profiling to define a set of prognostic genomic markers in patients with stage II colorectal cancer. A 23 gene signature profile accurately predicted outcome in 36 patients, with an overall accuracy of 78%—significantly higher than the most established prognostic factors currently in clinical practice ( Journal of Clinical Oncology 2004;22: 1564).
Professor Johnston called for further research but was confident that genetic profiling in colorectal cancer could be in clinical use within five years. "We are going to have to have some very significant international trials in relation to these concepts."(Claire Laurent)