George J. Chang, MD, MS, FACS, FASCRS
George J. Chang, MD, MS, FACS, FASCRS, of the Department of Surgical Oncology at The University of MD Anderson Cancer Center, told The ASCO Post that although adjuvant therapy in stage II disease has been shown to improve outcomes in patients with certain high-risk features, “the benefits are relatively small in absolute terms.” Nevertheless, said Dr. Chang, proof of benefit with the addition of oxaliplatin in stage III disease had led many people to try to figure out other poor prognostic features.
According to Dr. Chang, infiltrating tumor border configuration has been described in the literature for a while, and it’s also been shown to be associated with a poor prognosis. One of the challenges with this feature, however, is interobserver variation, he said. Although the study authors found infiltrating tumor border configuration in 45% patients with stage II disease, other reports have observed this phenotype in up to 70% of patients.
Under Debate
“It may be a more common feature than we recognize, which could contribute to some of the controversy with respect to whether this should be included or not [in cancer staging models],” said Dr. Chang. “The AJCC [American Joint Committee on Cancer] is always undergoing revision, and this is something that probably should be revitalized in the discussion.”
According to Dr. Chang, it’s possible that patients with infiltrating tumor border configuration should be considered for adjuvant therapy, but there may also be a combination of factors that are important. Before this approach is implemented in routine practice, he said, it should be determined how often tumor infiltrating phenotype is associated with other recognized high-risk features such as lymphatic invasion, tumor deposits, or perineural invasion.
“If this phenotype colocalizes frequently with other high-risk features, it would be additive in thinking about how this would be implemented,” he explained. “In other words, maybe we’re capturing a lot of these patients already in our risk stratification. It would be interesting to see the outcomes of patients who have a tumor-infiltrating phenotype alone and not those other high-risk features.”
Search Continues for Better Treatment Indicators
Ultimately, this topic is worth further investigation, said Dr. Chang. He noted that the ongoing phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer is one example of research seeking better indicators for treatment of stage II disease.1
“Chemotherapy is not benign, so we need to figure out a better way to identify patients,” Dr. Chang concluded. “We are continuing to learn about the right ways to make treatment decisions, and this work certainly is contributory.”
DISCLOSURE: Dr. Chang has served as a consultant or advisor to Medicaroid and MORE Health and has received research funding from Agendia.
REFERENCE
1. Morris VK, Yothers G, Kopetz S, et al: NRG-GI005 (COBRA): Phase II/III study of circulating tumor DNA as a predictive biomarker in adjuvant chemotherapy in patients with stage II colon cancer. 2020 Gastrointestinal Cancers Symposium. Abstract TPS261. Presented January 25, 2020.
