Adjuvant therapy in small intestinal leiomyosarcoma: A comparative analysis of outcomes.

Abstract

e23556 Background: Leiomyosarcoma of the small intestine is a rare gastrointestinal cancer that has been sparsely studied compared to other intraabdominal cancers. It is a malignant tumor of smooth muscle and typically grows into the subserosal layer of the small intestine. This progression of growth away from the lumen often delays presentation until the disease has progressed significantly. Although surgical resection remains the mainstay of treatment, adjuvant treatment such as chemotherapy, radiation therapy, and combined chemo-radiation therapy continue to have use clinically. However, a comprehensive analysis comparing the efficacy of these different therapies for is lacking. This study aims to address this gap by evaluating the differences among these treatment modalities. Methods: The National Cancer Database (NCDB) was used to identify patients diagnosed with Leiomyosarcoma from 2004 to 2019 using the histology code 8890 as assigned by the Commission on Cancer Accreditation program. Kaplan-Meier, ANOVA Chi-Square, and Cox Proportional Hazards tests were performed. Data was analyzed using SPSS version 27 and statistical significance was set at α = 0.05. Results: In a sample size of 81 patients diagnosed with small intestine leiomyosarcoma, 66 (81.5%) patients received adjuvant chemotherapy (AC), 8 (9.9%) patients received adjuvant radiation therapy (AR), and 7 (8.6%) patients received adjuvant combined chemotherapy and radiation. AC patients had a shorter mean survival time (34.7 months) than AR patients (79.1 months) (p<.03). AR patients were more likely to have no comorbidities (p<0.009) and interestingly less likely to receive care at Academic/Research program (p<0.035). There were no significant differences found between the adjuvant treatment groups in terms of age at diagnosis, tumor size, and positive regional lymph nodes. Although not statistically significant, there was a small difference in patients with no residual tumor on surgical margins being more likely to have received AC versus adjuvant AR (p<.111). Conclusions: This study demonstrates that among adjuvant therapies for the treatment of leiomyosarcoma of the small intestine, radiation therapy is associated with the longest mean survival time. This finding may be influenced by many factors, including the preference for chemotherapy over radiation in patients with comorbidities and the lack of standardized guidelines for the use of adjuvant therapy in this cancer. Therefore, further research is needed to better understand the true causes behind the disparity.