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why precision medicine matters

when we talk about mutations, this represents a very small amount of cancer patients – in colorectal cancer for example, mutations in NTRK, MSI-h/dMMR, and BRAF are considered rare [1%, 15%, 9% respectively].

however, this actually represents respectively- 1.500, 22.500, and 13.500 of the canadians living with colorectal cancer.

targeted therapies for these mutations is a new optional approach that has successfully prolonged overall survival, improved quality of life and outcomes for mCRC patients. providing molecularly targeted therapies that are easily administered with minimal side effects, and permit patients to carry on normal lives is fundamental for basic and high quality care in canada.

while mutations are found in a small percentage of people diagnosed with colorectal cancer, the importance of testing is highlighted by this small group of people, who represent a subtype of cancer patients who are more likely to respond to targeted therapies.

this is true for colorectal cancer patients as much as for patients who present with other types of cancers where mutations have been identified and include lung, breast, gynecological cancers, melanomas, bladder and gastric cancers – just to name a few.

we understand that cancers, even those originating in the same place [eg. breast] are unique from one person to the next- the same is true for blood cancers, which can be more heterogenous and present with more genomic alterations.

in canada in 2021, according to CCS, it is estimated that 11,100 people will be diagnosed with non hodgkin lymphoma [NHL]. diffuse large B-cell lymphoma [DLBCL] is the most common subtype of NHL in canada and constitutes 30-40% of all NHLs – so, according to our CCS statistics this means that in 2021, 3330-4440 people who get diagnosed with NHL will present with DLBCL.

although it represents a curable disease, less than half of the patients are cured with conventional chemotherapy. this highly variable outcome is a reflection of the heterogeneity of the tumour, with different genetic abnormalities and responses to therapy. molecular profiling in DLBCL provides value for diagnostic purposes but also predictive to identify therapeutic targets with clinical benefit for patients.

the expression of CD10, BCL6, and MUM1 can be used as biomarkers that subdivide diffuse large B-cell lymphoma [DLBLC] into molecular subtypes. MYC rearrangements are detected in 5%–10% of DLBCL. in a quarter of cases with MYC rearrangements, a second hit chromosomal aberration involving BCL2 or BCL6 can be found. MYC, BCL2 and BCL6 rearrangements are potential predictive biomarkers for R-CHOP for about 20 -30% of patients with double hit features.

while Mutations in the TP53 gene are the most common mutations in DLBCL and are found in up to 20% they are predictive of poor response to R-CHOP.

CDKN2A deletions are detected in up to 35% of patients with DLBCL and indicate possible chemoresistance.

and because we know that a precision medicine approach means looking at a tumour by its molecular characteristic versus its location, this means that the small population of BRAF+ patients in colorectal, added to the melanoma patients, and lung patients – suddenly our small population isn’t so small anymore.

however, in order to move to this type of personalized care we need a system that is ready to implement precision medicine, including genomic testing for patients consistently and adequately across provinces, across hospitals and across communities, whether they are rural or cosmopolitan centres.

to learn more about biomarkers in colorectal cancer visit

to learn more about DLBCL visit

to learn more about precision medicine and precision medicine awareness month visit and make sure to follow the cancer collaborative, Colorectal Cancer Canada and Lymphoma Canada throughout november and throughout the year.


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