Presurgical Chemo May Not Improve Disease Control in Colon Cancer

It’s important for patients with locally advanced colon cancer to speak with a doctor about “the best avenues of treatment,” an expert told CURE®. This is particularly true as a recent study showed that a presurgical chemotherapy regimen did not improve certain outcomes.

In a phase 3 trial called OPTICAL, 744 patients with locally advanced colon cancer either received preoperative (neoadjuvant) chemotherapy or surgery. In one treatment arm, patients received four or six cycles of preoperative chemotherapy regimens, the study stated. Patients in the second treatment arm first received surgery and then a post-surgical (adjuvant) chemotherapy chosen by the doctor.

“When it comes to surgical outcomes, compared with neoadjuvant versus adjuvant therapy, the surgical outcomes are the same,” said Dr. Christopher Cann. “They all ended up having adequate resections (surgical removal) [and] there were no excessive complications from those that had chemotherapy before.”

Cann is an assistant professor in the gastrointestinal cancer program at Fox Chase Cancer Center in Philadelphia.

Differences Between Neoadjuvant and Adjuvant Treatment in Colon Cancer

These two treatment options should not affect them negatively regarding toxicity or surgical outcomes, Cann added.

He explained that it “comes down to understanding [these outcomes] with your provider, [and] what the best avenue of treatment would be, whether chemotherapy comes in the beginning or after surgery. That’s the discussion that has to be had between [patients and doctors].”

“[The findings of this trial] are important for a few reasons,” Cann said. “What the study found was that when giving neoadjuvant — or therapy before surgery —patients had a decrease in the staging of the cancer. So, less lymph node involvement [and] decreasing in the size of the cancer that was shown.”

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Standard-of-care (traditional treatment) for locally advanced colon cancer was surgery first, then three to six months of chemotherapy, Cann said.

“[Standard-of-care] has been proven to provide long-term benefits for these patients to improve not only overall survival, but we’re decreasing the risk of recurrence of this cancer,” he explained.

Overall survival is defined as the time from diagnosis or the start of treatment when patients are alive, but still have cancer, according to the National Cancer Institute.

Additionally, patients within the neoadjuvant therapy group within the study were not able to finish their treatment, Cann noted.

“They ended up stopping short for various reasons. We may not have a full understanding of how many benefits a full course of this chemotherapy would really provide,” he said.

Cann explained that patients in the trial were not of a population that typically benefited from the type of chemotherapy they received.

“Other components of this are that they included patients that we know do not often benefit from what we call cytotoxic chemotherapy,” he said. Cann stated that the type of chemotherapy used in the trial is for patients with microsatellite instability cancers.

“Essentially, these tumors don’t have the ability to repair themselves as normal colon cancers do, so immunotherapy often provides benefits in [patients without microsatellite instability],” he defined.

Disease-Free Survival Rates for Colon Cancer Treatments

Regarding the two treatment options within the trial, the researchers determined differences between disease-free survival (DFS).

DFS is the time after treatment when patients stop showing signs or symptoms of cancer, the National Cancer Institute states.

Cann noted the trial researchers were unable to determine whether presurgical chemotherapy was better than standard of care regarding DFS.

According to the study, patients who received chemotherapy before surgery had a three-year DFS of 82.1%. Researchers reported that the rate of DFS in patients who received chemotherapy after surgery was 77.5%.

“That means the study treatment group had about a 25% lower risk of disease recurrence, compared to the standard-of-care,” Cann said. “However, the statistics did not say that it’s statistically significant.

“So how do we use that information? What it shows us from at least the pathologic response (shrinkage or disappearance of tumors) in the sense that we have a decrease in size, decrease in staging and the decision-making for whether we provide chemotherapy before surgery or just after surgery.”

Cann emphasized patients speaking with their doctors about treatment options beforehand. This is specifically because the DFS did not show a significant difference between the standard of care and neoadjuvant chemotherapy.

“The biggest thing is having open conversations with your provider. Patients having an understanding of the medical literature and what new trials have come out is so important,” Cann said. “We can have an educated conversation between the patient and the provider to say, ‘Would this be an option for me going forward, but this provides me benefit?’ And there can be an active discussion so that the patient has the best outcome possible. Then, the relationship can really be built between the patient and the provider.”

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