Microscopically Positive Margins for Primary Gastrointestinal Stromal Tumors: Analysis of Risk Factors and Tumor Recurrence - 21/06/12

Doi : 10.1016/j.jamcollsurg.2012.05.008

Martin D. McCarter, MD, FACS ^a,^⁎ , Cristina R. Antonescu, MD ^b, Karla V. Ballman, PhD ^e, Robert G. Maki, MD, PhD ^d, Peter W.T. Pisters, MD, FACS ^f, George D. Demetri, MD ^g, Charles D. Blanke, MD ^h, Margaret von Mehren, MD ⁱ, Murray F. Brennan, MD, FACS ^c, Linda McCall, MS ^j, David M. Ota, MD, FACS ^k, Ronald P. DeMatteo, MD, FACS ^c
American College of Surgeons Oncology Group (ACOSOG) Intergroup Adjuvant Gist Study Team^l
^a Department of Surgery, University of Colorado Denver School of Medicine, Aurora, CO
^b Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY
^c Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY
^d Department of Medicine, Mount Sinai School of Medicine, New York, NY
^e Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN
^f Department of Surgery, University of Texas MD Anderson Cancer Center, Houston, TX
^g Department of Medicine, Dana Farber Cancer Institute, Boston, MA
^h Department of Medicine, University of British Columbia and British Columbia Cancer Agency, Vancouver, BC, Canada
ⁱ Department of Medicine, Fox Chase Cancer Center, Philadelphia, PA
^j Duke Cancer Institute, Duke University, Durham, NC
^k Duke Clinical Research Institute, Duke University, Durham, NC
^l American College of Surgeons Oncology Group, Durham, NC

Correspondence address: Martin McCarter, MD, FACS, University of Colorado Denver, Department of Surgery, Division of GI, Tumor, and Endocrine Surgery, Academic Office One, MS C-313, 12631 E 17th Ave, Aurora, CO 80045

Résumé

Background

Little is known about the outcomes of patients with microscopically positive (R1) resections for primary gastrointestinal stromal tumors (GIST) because existing retrospective series contain small numbers of patients. The objective of this study was to analyze factors associated with R1 resection and assess the risk of recurrence with and without imatinib.

Study Design

We reviewed operative and pathology reports for 819 patients undergoing resection of primary GIST from the North American branch of the American College of Surgeons Oncology Group (ACOSOG) Z9000 and Z9001 clinical trials at 230 institutions testing adjuvant imatinib after resection of primary GIST. Patient, tumor, operative characteristics, factors associated with R1 resections, and disease status were analyzed.

Results

Seventy-two (8.8%) patients had an R1 resection and were followed for a median of 49 months. Factors associated with R1 resection included tumor size (≥10 cm), location (rectum), and tumor rupture. The risk of disease recurrence in R1 patients was driven largely by the presence of tumor rupture. There was no significant difference in recurrence-free survival for patients undergoing an R1 vs R0 resection of GIST with (hazard ratio [HR] 1.095, 95% CI 0.66, 1.82, p = 0.73) or without (HR 1.51, 95% CI 0.76, 2.99, p = 0.24) adjuvant imatinib.

Conclusions

Approximately 9% of 819 GIST patients had an R1 resection. Significant factors associated with R1 resection include tumor size ≥ 10 cm, location, and rupture. The difference in recurrence-free survival with or without imatinib therapy in those undergoing an R1 vs R0 resection was not statistically significant at a median follow-up of 4 years.

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Abbreviations and Acronyms : GIST, HR, R0 resection, R1 resection, R2 resection, RFS