Anton J. Bilchik, M.D.
JWCI’s Gastrointestinal (GI) Research Program is a multidisciplinary collaboration to improve the diagnosis and treatment of the most common GI cancers, i.e., those occurring in the colon and rectum, pancreas, stomach, liver, and esophagus.
Ultrastaging gastrointestinal cancers
Distant metastasis of node-negative colorectal carcinoma may be explained by failure to detect occult nodal metastasis in the surgical specimen. This problem has been addressed by sentinel node biopsy, which targets a few tumor-draining nodes for focused analysis, thereby increasing the accuracy and decreasing the costs of pathologic examination. Although sentinel node biopsy does not decrease the extent of nodal resection in colorectal cancers, its use can improve nodal staging and identify patients likely to benefit from adjuvant chemotherapy. Dr. Bilchik is principal investigator of an NIH-funded multicenter trial to improve the staging of early colon cancer and the selection of candidates for postoperative chemotherapy. Better staging and selection not only will improve survival but also will avoid the toxicity and expense of chemotherapy for those patients who may be cured by surgery alone. There is considerable interest in this study because it is the only trial that combines surgery, pathology and genomics in colon cancer.
In addition to the presence and number of tumor-involved nodes, the number of nodes removed also appears to have prognostic significance. JWCI investigators have shown that resection of at least 15 nodes can prolong survival for patients with stage I, II or III colon cancer. These differences approximate results for adjuvant chemotherapy regimens.
Minimally invasive surgery
Under the leadership of Dr. Bilchik, JWCI clinical researchers are developing and refining minimally invasive techniques to perform complex gastrointestinal surgeries, particularly for patients with colon, liver and pancreatic cancers. Although surgical resection remains the first choice for treatment of hepatic and other GI malignancies, there have been profound changes in the techniques, instruments, and indications. JWCI surgical scientists are refining third-generation instruments that use radiofrequency or microwave energy for rapid thermal ablation of tumors. They are also expanding the indications for minimally invasive laparoscopic approaches to GI malignancies. The goal is to improve immediate quality of life as well as long-term disease-free survival. As a result, patients are fast-tracked, start eating almost immediately after surgery and are discharged home within a few days.
Extensive hepatectomy for primary or metastatic liver tumors must preserve enough hepatic function to avoid postoperative liver failure. JWCI surgeons have developed a canine model that uses a shunting procedure to preserve hepatic function after removal of 90% of the liver. If the efficacy of this technique can be validated in a larger preclinical study, it will have the potential for clinical translation to increase the indications for extensive resection in patients with advanced hepatic malignancy.
Under the mentorship of Dr. Bilchik, fellows in JWCI’s SSO-accredited surgical oncology training program are using SEER (Surveillance Epidemiology and End Results) and NCDB (National Cancer Data Base) to analyze quality measures, national treatment trends and outcomes in colorectal, gallbladder, pancreatic, and gastric cancers. In 2012, their longitudinal studies on colon cancer and gastric cancer won Merit Awards at the American Society of Clinical Oncology’s Gastrointestinal Cancers Symposium.
JWCI’s Department of Molecular Oncology is working with GI scientists to develop prognostic biomarkers for gastrointestinal cancers. In addition to biomarkers based on genetic aberrations, GI research teams are focusing on epigenetic alterations that can change a gene’s expression without altering its DNA sequence. For example, methylation of a gene appears to play a significant role in the development and progression of certain cancers. JWCI molecular scientists recently demonstrated that methylation changes in SPARC glycoprotein from stromal cells are linked to the recurrence of colorectal cancer.
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