Anthony Shields, MD, PhD, oncologist, Department of Oncology, Molecular Imaging and Diagnostics Program, Barbara Ann Karmanos Cancer Institute, discusses the standard of care in patients with newly diagnosed metastatic colorectal cancer (mCRC).

Several targeted therapies are under investigation, mainly in the second- and third-line setting, says Shields. Sequencing the number of available agents has become a challenge, especially for community oncologists, he adds. Moreover, it is unclear when to pull back on an agent. If a patient is started on a regimen like FOLFOXIRI and bevacizumab (Avastin), data suggest that patients are better served by pulling back on the drug after a few months and continuing on maintenance therapy. Determining when, and in whom this should be done, poses another challenge.

Therefore, patient personalization and preference should be used to determine the optimal approach. For example, a patient may express that they want to take a break from treatment after receiving a particularly challenging regimen. If their disease is under control and they have had a decent response, treatment cessation may be feasible. However, if the patient still has fairly active disease, maintenance might be the best option, concludes Shields.

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Dr. Shields on the Standard of Care in Newly Diagnosed mCRC

Anthony Shields, MD, PhD, oncologist, Department of Oncology, Molecular Imaging and Diagnostics Program, Barbara Ann Karmanos Cancer Institute, discusses the prevalence of genetic testing in colorectal cancer (CRC).

Genetic testing is done in virtually every patient now, Shields says. Even early-stage patients will be tested for mismatch repair proficiency. This may not change the way an oncologist treats a patient with early-stage CRC, but it certainly impacts the way the patient is monitored. At a minimum, patients with all stages of CRC should be tested for mismatch repair defects.

In stage IV disease, multi-gene panels are utilized for genetic testing. While these technologies are expensive, they are not dissimilar to the cost of 1 dose of standard therapy, Shields notes. It becomes worthwhile when a physician is able to identify whether a certain approach will or not work in a patient. While these gene panels are expanding, Shields expects full sequencing of DNA to be performed in the near future. Detectable alterations like 

 are extremely rare, but they can transform treatment for a patient.

Anthony Shields, MD, PhD, professor, Department of Oncology, Molecular Imaging and Diagnostics Program, Karmanos Cancer Institute, discusses the prevalence of genetic testing colorectal cancer.

Dr. Shields Discusses the Prevalence of Genetic Testing in CRC

Anthony Shields, MD, PhD, oncologist, Department of Oncology, Molecular Imaging and Diagnostics Program, Karmanos Cancer Institute, discusses patient selection criteria for adjuvant therapy in colorectal cancer (CRC).

Patients who are eligible for adjuvant therapy have an increased risk of recurrence, specifically patients with high-risk stage II disease or moderate- to high-risk patients with stage III disease. However, patients with small stage III tumors or limited lymph node involvement may not need adjuvant therapy, says Shields.

A patient’s risk status should be a major determinant in the optimal adjuvant therapy. Additionally, the added benefit of 3 versus 6 months of therapy and the specific regimens involved—namely, CAPOX or FOLFOX. Patient preference is another important factor, says Shields. In the community setting, some patients may only be given the chance to receive 6 months of FOLFOX, whereas evidence suggests 3 months of CAPOX may be superior. Moreover, CAPOX does not require a pump to be administered. However, Shields cautions that patients have to be compliant as physicians are reliant on patients to take the capecitabine pills at home.

Dr. Shields Discusses Patient Selection Criteria for Adjuvant Therapy in CRC

Anthony Shields, MD, PhD, oncologist, Department of Oncology, Molecular Imaging and Diagnostics Program, Karmanos Cancer Institute, discusses the challenge of identifying the optimal adjuvant therapy for the treatment of patients with colorectal cancer (CRC).

The big question that needs to be addressed in the field is whether patients need the standard 6-month regimen of either FOLFOX (5-fluorouracil plus leucovorin and oxaliplatin) or CAPOX (capecitabine and oxaliplatin). When physicians began giving adjuvant therapy with 5-FU chemotherapy alone, it was administered for 1 year until subsequent studies suggested that 6 months was adequate, Shields says. Other research suggested that infusional 5-FU could be given adequately for just 3 months.

Shields adds that there are data which propose that giving a more intensive 2-drug regimen—such as oxaliplatin and fluoropyrimidine&mdash;for 3 months may be sufficient. However, it is especially difficult to test this hypothesis; in order to prove the noninferiority of a shorter dosing schedule, thousands of patients must be enrolled in a clinical trial.

One international study organized in part by the late Daniel Sargent, PhD, of the Mayo Clinic, set out to determine what the optimal duration of adjuvant therapy is in patients with colon cancer. The study involved 6 different trials in 12 countries and around 13,000 patients and took 10 years to collect the data and follow-up, says Shields.

Anthony Shields, MD, PhD, oncologist, Department of Oncology, Molecular Imaging and Diagnostics Program, Karmanos Cancer Institute, discusses optimal adjuvant therapy for the treatment of patients with colorectal cancer.

Anthony Shields, MD, PhD

Articles

Dr. Shields on the Standard of Care in Newly Diagnosed mCRC

Dr. Shields Discusses the Prevalence of Genetic Testing in CRC

Dr. Shields Discusses Patient Selection Criteria for Adjuvant Therapy in CRC

Dr. Shields on Optimal Adjuvant Therapy for CRC