Association Between Very Small Tumor Size and Increased Cancer-Specific Mortality in Node-Positive Colon Cancer. Issue 3 (March 2016)

• Record Type: Journal Article
• Authors: Muralidhar, Vinayak; Nipp, Ryan D.; Ryan, David P.; Hong, Theodore S.; Nguyen, Paul L.; Wo, Jennifer Y.
• Is Part Of: Diseases of the colon & rectum. Volume 59:Issue 3(2016:Mar.)
• Publication Date: 2016-03
• Subjects: Colon cancer -- Lymph node metastasis -- Tumor size -- Personalized medicine; Colon (Anatomy) -- Diseases -- Periodicals; Rectum -- Diseases -- Periodicals; Colonic Diseases -- Periodicals; Colorectal Surgery -- Periodicals; 616.34
• DOI: 10.1097/DCR.0000000000000532
• Languages: English
• ISSNs: 0012-3706

Abstract

Abstract : BACKGROUND: Larger tumor size and lymph node involvement are traditionally associated with increased colon cancer-specific mortality. OBJECTIVE: We sought to determine whether patients with very small tumors associated with lymph node involvement are at paradoxically increased risk of colon cancer-specific mortality in comparison with those who have larger tumors and lymph node involvement. DESIGN: This is a retrospective cohort study using the Surveillance, Epidemiology, and End Results database. SETTING: Geographic areas included in one of the 18 Surveillance, Epidemiology, and End Results registries were used. PATIENTS: We identified 99, 594 patients with nonmetastatic colon adenocarcinoma treated with surgery between 1988 and 2001. MAIN OUTCOME MEASURES: The primary predictor variables were regional lymph node involvement and primary tumor size by longest dimension, grouped into the following predetermined strata: <5 mm, 5 to 19 mm, 20 to 39 mm, 40 to 59 mm, ≥ 60 mm. We used competing risks regression to determine differences in the risk of colon cancer-specific mortality between strata after controlling for T stage, tumor grade, age, year of diagnosis, race, and number of dissected lymph nodes. RESULTS: Median follow-up among censored patients was 12.9 years. We found a significant interaction between lymph node involvement and tumor size ( p < 0.05). Among those with node-negative disease, colon cancer-specific mortality increased monotonically with tumor size. In contrast, among those with node-positive disease, patients with the smallest tumors (<5 mm) were at increased risk of 10-year colon cancer-specific mortality compared with those with tumors sized 5 to 19 mm, 20 to 39 mm, 40 to 59 mm, and ≥60 mm (53.3% vs 30.1%, 37.5%, 39.2%, and 39.7%; adjusted hazard ratios, 1.63–2.24; p < 0.05 in all cases). LIMITATIONS: The main limitations are the retrospective design and information available in the study database. CONCLUSION: In the setting of lymph node involvement, very small tumor size may predict for increased colon cancer-specific mortality compared with larger tumors. Smaller tumors associated with lymph node involvement may represent more aggressive malignancies with a distinct biology that merits further investigation.