Navigating Drug Resistance in Post-Surgery Colorectal Cancer Treatment

Q: Navigating Drug Resistance in Post-Surgery Colorectal Cancer Treatment

Hello： 1. I am not your attending physician and cannot provide answers to your questions. 2. What is often not mentioned in online advertisements and promotional content is that it requires a significant amount of money, and it is completely outside of the Nat

Colorectal cancer resistance to treatment

After my family member's surgery for colorectal cancer, they had a KRAS mutation and underwent all lines of chemotherapy.
The first-line treatment was the most effective, but the tumor only shrank initially and then showed no further changes.
However, the CEA levels remained under control within normal limits until we had to switch medications due to the lack of insurance coverage, after which the CEA levels began to rise.
The doctor agreed to my request to return to the first-line treatment out-of-pocket, but mentioned that the oral medication is less effective and suggested using an injectable instead.
The doctor also expressed that he didn't think the efficacy of the cancer treatment was particularly good.
There may be a plan to combine first and second-line chemotherapy drugs.
Question 1: The second-line medication has been used alone before with poor results; is it still worth using again?
Question 2: I am concerned about running out of medication in the future, so I suggested out-of-pocket genetic testing through blood samples, but the doctor felt it wouldn't be helpful, stating that we already know the results we need.
The tissue sample from two years ago during surgery was tested, and after prolonged chemotherapy, wouldn't there be changes? If the mutations are no longer present, wouldn't that provide an additional target for treatment? Is this line of thinking correct? The doctor mentioned that blood tests and tissue tumor tests are not quite the same.
If the patient develops resistance and there are no available medications, shouldn't we be able to pay for genetic testing to help guide treatment options? Are there any concerns regarding this? If the doctor disagrees with my testing, would he not accept the results if I had them done externally?

Xiao Wu, 70~79 year old female. Ask Date: 2022/09/10

Dr. Chen Yunfang reply Oncology

Hello:
1.
I am not your attending physician and cannot provide answers to your questions.

2.
What is often not mentioned in online advertisements and promotional content is that it requires a significant amount of money, and it is completely outside of the National Health Insurance coverage.
There are no standard fees, as each institution sets its own prices, but the basic cost for testing can be over a hundred thousand NTD.
If, unfortunately, a genetic mutation is detected that corresponds to a targeted therapy, it is usually extremely expensive, with out-of-pocket costs ranging from 100,000 to over 300,000 NTD per month.
The critical point is that after spending a large amount of money, the question of how long one can live is uncertain (online promotional content often presents this in a very favorable light, as pharmaceutical companies pay for advertisements).
Therefore, the concern is about your financial capability—can you afford to spend several million NTD? And the effectiveness is not guaranteed.
Thank you.

Reply Date: 2022/09/10

More Info

Navigating drug resistance in post-surgery colorectal cancer treatment can be a complex and challenging journey, especially when dealing with mutations like KRAS and the limitations of available therapies. Your situation highlights several important considerations regarding treatment options, drug resistance, and the potential for genetic testing.

Question 1: Is it worth using second-line drugs that have previously shown poor efficacy?
In the context of cancer treatment, particularly with colorectal cancer, the effectiveness of second-line therapies can vary significantly from patient to patient. While it is true that some second-line drugs may not have shown substantial efficacy in previous treatments, there are instances where reintroducing these drugs can yield different results. This variability can be attributed to several factors, including changes in the tumor microenvironment, the potential for altered drug metabolism, and the emergence of new mutations that may affect drug sensitivity.
However, it is crucial to have a thorough discussion with your oncologist about the rationale for reusing these drugs. They may have insights into the specific characteristics of your cancer and how it has responded to treatments in the past. If the oncologist believes that there is a chance of benefit, they may recommend a trial of the second-line drug, possibly in combination with other agents to enhance efficacy.

Question 2: Should I pursue genetic testing to identify potential new targets for therapy?
Genetic testing can be a valuable tool in the management of cancer, particularly for identifying actionable mutations that can guide targeted therapies. In your case, the concern about whether the tumor's genetic profile has changed since the initial surgery is valid. Tumors can evolve over time, and new mutations may arise that were not present in the original biopsy.
While your oncologist may feel that the standard tests have already provided sufficient information, pursuing additional genetic testing, particularly through liquid biopsies, can offer insights into the current state of the tumor. Liquid biopsies analyze circulating tumor DNA (ctDNA) in the blood and can detect mutations that may not be present in the original tissue sample. This information can help identify new targets for therapy, especially if the tumor has developed resistance to previous treatments.

If your oncologist is hesitant about the utility of additional genetic testing, it may be beneficial to seek a second opinion from another specialist or a multidisciplinary team that focuses on precision medicine. They may have different perspectives on the value of genetic testing in your specific case.

Concerns about drug availability and resistance:
It is understandable to be concerned about the availability of effective treatments as resistance develops. The landscape of cancer treatment is continually evolving, with new therapies and combinations being explored. If you find that your current oncologist is not receptive to your concerns about genetic testing or exploring alternative therapies, it may be worthwhile to seek a second opinion from a cancer center that specializes in colorectal cancer and drug resistance.

In summary, navigating drug resistance in colorectal cancer requires a collaborative approach with your healthcare team. Open communication about treatment options, the potential for reusing second-line drugs, and the value of genetic testing is essential. Your active involvement in your treatment plan can lead to better outcomes and a more personalized approach to your care. Always advocate for your health and seek the information and support you need to make informed decisions about your treatment options.

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