V. Chakravorty1,2, K. Mahendraraj1, R. S. Chamberlain1,2,3 1Saint Barnabas Medical Center,Department Of Surgery,Livingston, NJ, USA 2St. George’s University School Of Medicine,St. George’s, St. George’s, Grenada 3New Jersey Medical School,Department Of Surgery,Newark, NJ, USA
Introduction: Primary melanoma of the gastrointestinal tract (GIM) are exceedingly rare entities, with an overall incidence of ~0.47 cases per million. While outcomes for cutaneous melanomas have been extensively examined, clinical information related to GIM is scant and derived from small case series. This study examined a large cohort of GIM patients to determine demographic, clinical, and pathologic factors affecting outcomes.
Methods: Demographic and clinical data on 1,044 patients with GIM was abstracted from the SEER database (1973-2010) and analyzed using the Chi square test, t-test, and multivariate analysis. Kaplan-Meier analysis was used to compare long-term survival between groups.
Results: 1,044 cases of GIM were identified, involving the oropharynx in 307 patients (29.4%), esophagus in 48 (4.6%), stomach in 26 (2.5%), small bowel in 38 (3.6%), large bowel in 19 (1.8%), rectum in 250 (23.9%), and anal canal in 356 (34.1%). Overall, there were 569 women (54.5%) and 475 men (45.5%; female-to-male ratio 1.2:1, p<0.001) with an overall mean age of 68+15 years. GIM was most common in Caucasians (73.7%, p<0.001) often presenting with localized (40.1%, p<0.001), poorly differentiated (68.1%, p=0.01) tumors measuring 2-4cm (34.5%, p<0.001), with uncommon lymphatic spread (37.9%, p<0.001). Mean survival for GIM was 3.8+0.3 years with longest survival seen among oropharyngeal GIMs (5.4+0.6 years, p<0.005) and shortest in gastric GIMs (0.7+0.2 years, p<0.005). Overall and cancer-specific mortality for GIM were 80.3% and 72.6%, respectively, (p=0.01). Surgical resection was the most common GIM therapy (64.8%, p<0.001), followed by surgery and radiotherapy (15.8%, p<0.001). Survival was greatest with combination surgical and radiotherapy was used (4.4+0.8 years, p<0.001) compared to surgical resection only (4+0.3 years, p<0.001). Multivariate analysis identified regional (OR 1.9, CI 1.1-3.1) or distant disease (OR 4.5, CI 2.3-8.8), lymph node positivity (OR 4.5, CI 1.7-9.8), and age >60 (OR 6.2, CI 2.4-15) as independently associated with increased mortality for GIM (p<0.005). Specific site of disease was not associated with increased mortality.
Conclusion: GIM is a rare malignancy that occurs in all parts of the GI tract with the highest incidence in the oropharyngeal and anorectal regions. GIMs are more common in Caucasian women in the seventh decade of life. The majority of GIMs are localized, often poorly differentiated, with gastric GIM having the worst prognosis. Advanced age, stage and lymph node positivity are associated with increased mortality. Surgical resection with or without radiotherapy confers a significant survival advantage, and is standard therapy for all GIM patients with resectable disease.
