My Colon Cancer
A 77 year old white male was seen in and evaluated in the Sarasota/Manatee area for colon cancer.
The patient underwent hemicolectomy and was found to have a poorly differentiated adenocarcinoma with 15 of 23 lymph nodes removed at the time of surgery positive for cancer. Preoperative CT scan of the abdomen/pelvis was negative.
“WITH SO MANY DIFFERENT CHEMOTHERAPY DRUGS AVAILABLE FOR MY CANCER— HOW DO I KNOW WHICH ONE WILL WORK?”
Upon presentation to the Cancer Center of Sarasota Manatee a CT PET was ordered. This demonstrated the presence of stage IV disease with at least 8 metastatic sites noted in the abdominal pelvic area that were missed on CT scan. Molecular profiling of the patient’s cancer was ordered on the cell block with results as follows
EGFR (high expression), KRAS (Wild type, no mutation), BRAF (Wild type, no mutation), ERCC1 (high expression), TS (low expression), VEGFR2 (high expression)
[tabs tab1=”Diagnosis” tab2=”Significant Findings” tab3=”Pharmacology” tab4=”Management” tab5=”Comments”]
[tab num=1]The patient at the time of his initial visit with us was thought to have Stage III disease. Further evaluation by CT PET demonstrated the presence of Stage IV disease.[/tab]
[tab num=2]The patient has a good performance status and desires aggressive therapy.[/tab]
[tab num=3]The use of molecular profiling or pharmacogenomic testing greatly influenced the management of this patient. The combination of high EGFR, lack of mutation of BRAF and KRAS suggested that the patient would benefit from Erbitux. Additionally the high expression of VEGFR2 indicated that Avastin would also be beneficial. Most importantly, the high expression of ERCC1 suggests a resistance to Oxaliplatin, a drug very commonly used to treat advanced stage colorectal cancer.[/tab]
[tab num=4]This patient was started on treatment with 5FU Leucovorin, CPT-11 (Camptosar), Erbitux, and Avastin.[/tab]
[tab num=5]In very basic terms molecular pharmacogenomics allows us to evaluate molecular markers that can predict response or resistance of a tumor to a particular pharmaceutical agent. In some cases molecular pharmacogenomics can also predict potential increased risk of toxicity of a particular drug. Pharmacogenomics in some cases can indicate the precise agents that would be most likely to help treat a patient’s cancer. Conversely, it can also help treating physicians avoid drugs which have little likelihood of helping the patient. This is extremely important when treating cancer pa-tients due to the high toxicity and cost of chemotherapy and biologic agents.
* In this particular case the patient was not exposed to Oxaliplatin, a common treatment for advanced stage colorectal cancer. This drug can cost the average patient in excess of $5000 per month for 2 doses of treatment. It is also associated with a great deal of toxicity, in particular neurotoxicity which is not reversible in many cases.[/tab]