Neoadjuvant imatinib can cause significant shrinkage of gastric gastrointestinal stromal tumors (GISTs), thus facilitating the minimally invasive resection of the tumor, according to a study published in Annals of Surgical Oncology.

The current treatment for localized GISTs is surgical resection. Studies have validated the use of adjuvant imatinib for patients who are at high risk for recurrence; however, data on the efficacy of imatinib as neoadjuvant therapy are more variable. 

“The main drawback is that patients receiving neoadjuvant imatinib cannot be completely risk-stratified, because the mitotic rate of the tumor specimen is confounded by treatment effects, and pretreatment biopsies are often either inadequate or subject to sampling error,” Li and colleagues explained.


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In the specific case of gastric GISTs, studies have suggested that neoadjuvant imatinib increases the likelihood of surgeons achieving margin-negative resection and the preservation of the stomach. Some physicians hence prescribe neoadjuvant imatinib to decrease the tumor size prior to resection, but data in strong favor of its use are still lacking.

Li and colleagues conducted a study in which they reviewed patients who underwent surgical resection for gastric GISTs. The tumor diameters must be larger than or equal to 4.5 cm since tumors smaller than 4.5 cm were always surgical resected without neoadjuvant imatinib at their institution. The research team identified 71 patients, 43 of whom received neoadjuvant imatinib.

They discovered that after a median of 7.2 months of neoadjuvant imatinib, the gastric tumor shrunk by a median of 34% in diameter. “Of the 29 patients who received neoadjuvant therapy to facilitate minimally invasive resection, 21 patients (72%) underwent successful minimally invasive resection,” they reported.

Li and colleagues concluded that neoadjuvant imatinib may be useful for downstaging large gastric GISTs prior to surgical resection.

Reference

Li GZ, Fairweather M, Raut CP, Wang J. Use of neoadjuvant imatinib to facilitate minimally invasive resection of gastric gastrointestinal stromal tumorsAnn Surg Oncol. Published online May 27, 2022. doi:10.1245/s10434-022-11891-9