The Combination of Neoadjuvant Therapy and Surgical Resection: A Safe and Effective Treatment for Rectal Gastrointestinal Stromal Tumors

Gastrointestinal Stromal Tumours (GIST) of the Rectum: A Systematic Review and Meta-Analysis

Background: Rectal gastrointestinal stromal tumours (GISTs) have many treatment options, but uncertainty remains regarding the best treatment regimen for this rare pathology. The aim of this review is to assess the optimal management approach including timing of chemotherapy. Methods: PubMed, EMBASE, and Cochrane databases were searched for relevant articles comparing the impact of radical vs. local excision, and neoadjuvant vs. adjuvant therapy had on outcomes in the management of rectal GISTs. We specifically evaluated the influence that the aforementioned factors had on margins, recurrence, overall survival, 5-year disease-free survival, and hospital length of stay. Results: Twenty-eight studies met our predefined criteria and were included in our study, twelve of which were included in the quantitative synthesis. When comparing neoadjuvant versus adjuvant chemotherapy, our meta-analysis noted no significance in terms of margin negativity (R0) (odds ratio [OR] 2.01, 95% confidence interval [CI], 0.7−5.79, p = 0.20) or recurrence rates (OR 0.22, 95% CI, 0.02−1.91, p = 0.17). However, there was a difference in overall 5-year survival in favour of neoadjuvant therapy (OR 3.19, 95% CI, 1.37−7.40, * p = 0.007). Comparing local excision versus radical excision, our meta-analysis observed no significance in terms of overall 5-year survival (OR1.31, 95% CI, 0.81−2.12, p = 0.26), recurrence (OR 0.67, 95% CI, 0.40−1.13, p = 0.12), or 5-year disease-free survival (OR 1.10, 95% CI, 0.55−2.19, p = 0.80). There was a difference in length of hospital stay with a reduced mean length of stay in local excision group (mean difference [MD] 6.74 days less in the LE group; 95% CI, −6.92−−6.56, * p =< 0.00001) as well as a difference in R0 rates in favour of radical resection (OR 0.68, 95% CI, 0.47−0.99, * p = 0.05). Conclusion: Neoadjuvant chemotherapy is associated with improved overall 5-year survival, while local excision is associated with reduced mean length of hospital stay. Further large-volume, prospective studies are required to further define the optimal treatment regimen in this complex pathology.

Efficacy and safety of neoadjuvant imatinib therapy for patients with locally advanced rectal gastrointestinal stromal tumors: A multi-center cohort study

Background: Several issues on neoadjuvant imatinib therapy remain controversial despite its widespread application for rectal gastrointestinal stromal tumors (GIST). We aimed to describe the clinicopathological characteristics of this specific population, and compare the surgical and oncologic outcomes between patients with or without neoadjuvant imatinib therapy.

Patients and methods: A cohort of 58 consecutive locally advanced rectal GIST patients receiving surgical treatment between January 2007 and July 2019 at Sun Yat-sen University Cancer Center and Yunnan Cancer Hospital was retrospectively analyzed. Recurrence-free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier method.

Results: There were 33 (56.9%) patients who received neoadjuvant imatinib therapy. Among them, 20 (60.6%) patients had partial response (PR) as their best response, 11 (33.3%) patients had stable disease (SD), and 2 (6.1%) patients had progressive disease (PD). The median tumor size reduced from 5.2 to 4.0 cm after treatment (p < 0.001), and an attained “maximal response” was primarily achieved (32/33) on the 12th month after treatment. The most common adverse event was anemia. There were 27 adverse events occurred, most of which were grade 1 (19/27). With respect to intraoperative and postoperative surgical outcomes, no significant difference was found between patients with or without neoadjuvant Imatinib therapy except that patients with neoadjuvant treatment had a significant higher rate of preventive ileostomy (p = 0.004). Patients received neoadjuvant treatment had a superior 2-years RFS outcome than those without, though the difference was no significant (91.7% vs. 78.9%, p = 0.203). There were no significant differences in the 2-years OS rates (95.2% vs. 91.3%, p = 0.441).

Conclusion: Neoadjuvant imatinib therapy is an effective and safe treatment for locally advanced rectal GISTs. Further studies are warranted to validate the long-term prognostic benefit for patients with rectal GISTs receiving neoadjuvant imatinib therapy.