Assistant Professor, Department of Gastrointestinal Medical Oncology
This past weekend, experts in gastrointestinal malignancies gathered to review interval advances in the field at the ASCO Gastrointestinal Cancer Symposium. Of the studies presented, three are worth noting that are likely to change the standard therapies or provide exciting research opportunities.
Treatment for neuroendocrine tumors has made recent advances, exemplified by a study reported at the meeting for the oral tyrosine kinase inhibitor sunitinib. Pancreatic neuroendocrine tumor (PNET) is one of the most common subtypes of an uncommon tumor. PNETs traditionally have been treated variably with somatostatin analogs, interferon or cytotoxic chemotherapy, although several recent studies have demonstrated promising molecularly targeted treatment approaches.
Traditional pancreatic cancers have been difficult to treat and very few advances have been made in the field over the past few years. Recent data has suggested that the insulin-like growth factor receptor (IGFR) pathway may be a promising candidate for treatment of many cancers, including pancreatic cancer based on limited laboratory studies.
Importantly, Dr. Javle and his colleagues are concurrently collecting important information to understand how the tumor is responding on a molecular level to the novel therapies. This combination of concurrent molecular studies and novel study design was praised by the expert discussant at the meeting as an optimal model for future studies in pancreatic cancer.
Significant effort has been focused on new techniques to detect and prevent colon cancer. One recent advance was presented by K.P. Raj, M.D., on the role of polyamines in colon cancer development.
A large chemoprevention study of DFMO and sulindac had previously shown a 70% reduction in new precancerous lesions. In this study, 375 patients with prior precancerous lesions were randomized to DFMO/sulindac or placebo, with all patients obtaining normal screening colonoscopies. DFMO and sulindac inhibit new synthesis of polyamines in the body, among other potential mechanisms of actions. Dr. Raj analyzed the dietary intake of polyamines in patients on this study to determine the role for the dietary forms of polyamine in cancer formation.
These results demonstrated that patients who reported high dietary intake of polyamines had larger and more advanced colon polyps prior to starting the study. For patients with lower reported dietary intake of polyamine, treatment with DFMO and sulindac resulted in a 94% reduction in advanced cancers. In contrast, in patients with high dietary intake of polyamines, there was no benefit seen with the chemoprevention. Further studies are needed to understand this finding, but it suggests that in high-risk patients, chemoprevention may only be beneficial with appropriate dietary modifications.
Collectively, these findings reiterate the active ongoing research in gastrointestinal malignancies, while highlighting areas where significant improvements are needed in our ability to detect, diagnosis and treat gastrointestinal cancers.