Patients With Gastric Cancer Who Respond Well to Chemo Before Surgery May Be Able to Skip Post-Operative Chemo

Patient sensitivity to chemotherapy prior to surgery could determine if a patient with gastric cancer needs to receive chemo after surgery.

For patients with gastric adenocarcinoma, responses to chemotherapy administered before surgery may provide enough information to help inform treatment decisions for after the surgery is complete.

The current standard of care for patients with locally advanced gastric cancer is to receive chemotherapy both before and after surgical removal of stomach tissue, said lead study author Dr. Lei Deng.

“When (patients learn) that they have cancer and it can be removed, a lot of time they are wanting to know (whether) they could have the surgery right away to take it out,” Deng, who is a second-year hematology-oncology fellow at Roswell Park Comprehensive Cancer Center in Buffalo, New York, said during an interview with CURE®. “But our study and other many other studies did show that preoperative chemotherapy can help them.”

The delivery of preoperative chemotherapy may prevent a patient’s disease from moving to a later stage that is harder to treat, he added. However, some patients may be able to be spared chemotherapy treatments after their disease has been resected, according to study findings.

The research, which was published in JAMA Network Open, assessed whether a tumor’s responsiveness to chemotherapy — known as chemosensitivity — could guide post-surgical treatment decisions for patients whose disease is sensitive or refractory to upfront chemotherapy.

Postoperative chemotherapy presents a challenge, as it has a completion rate of less than 50%, according to the study authors. Currently, regardless of whether a patient responds well to preoperative chemotherapy, they may receive the same regimen after surgery as tolerated.

“(If a) patient is really doing very well with chemotherapy before surgery, that we cannot even see any cancer cells left over, do they really need another course of chemotherapy, which can be really rough, and has a lot of toxicity? So, we tapped into the National Cancer database and tried to answer this question and found some interesting findings,” Deng explained.

The researchers used data from 2,382 newly diagnosed patients with gastric adenocarcinomas from 2006 to 2017, focusing on those with stage 2 or 3 disease who were treated with preoperative chemotherapy and surgical resection (with a curative goal), excluding radiotherapy. They sorted preoperative chemosensitivity into either very sensitive, sensitive or refractory.

Most patients had refractory disease (62%), while 31% had sensitive disease and 7% had very sensitive disease. Patients were less likely to receive post-operative chemotherapy if they were older, had comorbidities, had a longer time between chemotherapy initiation and surgery or had longer surgical hospitalization.

Postoperative chemotherapy was not associated with improved survival among all the patients. Those with refractory disease had the worst survival outcomes compared with the other two types.

For patients with chemotherapy-sensitive disease, postoperative chemotherapy resulted in longer survival, but not for those with very sensitive or refractory disease.

The study was retrospective — meaning the researchers analyzed existing data — so more research needs to be done, said Deng. However, he is confident in their findings.

“What I would say is that the chemotherapy before the surgery can have an effect on your cancer. And based on what we find during the surgery and what effect that chemotherapy has, it may provide some formation to help you make a decision about postoperative chemotherapy,” he said. “Should you use it or not use it or use it for how long? Although we don't have the definite answer yet, this is something that they can really discuss with their providers and have a joint decision (about).”

More research is underway at Roswell Park to see whether novel circulating biomarkers in the blood could assess chemosensitivity earlier on.

“Our hope is that if some patients have biomarker showing it's working, we will continue. But if in the middle, like after three or four weeks, we see that you probably don't see another promising sign, hopefully, in the future we can tell the patient, ‘Maybe that's enough for you, and we should just directly go to surgery,’” Deng said.

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