Neoadjuvant treatment with imatinib could help make huge and low-lying rectal gastrointestinal stromal tumor (GIST) operable and lead to better surgical outcomes, according to a new study published in PLoS One.

Rectal GIST is very rare, comprising 5% of all GISTs, which are rare themselves. However, rectal GIST has the worst prognosis and a recurrence rate of 87.5%.

The most effective treatment for rectal GIST is the complete surgical excision of the tumor. The effect of neoadjuvant treatment on clinical outcomes is not apparent.


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Here, a team of researchers from South Korea conducted a retrospective study on 33 patients to assess the effect of neoadjuvant imatinib treatment on rectal GIST. Of these 33 patients, 10 received neoadjuvant therapy with imatinib, while 23 did not. 

Read more about the prognosis of GIST

Patients who received neoadjuvant therapy had more common levator ani muscle displacement and significantly larger tumors compared to those who did not.

Following imatinib treatment, the tumor size significantly decreased. The researchers reported that there was no significant difference in resection margin involvement and sphincter preservation rates between patients who received imatinib and those who did not. 

There were also no differences in terms of morbidities, hospital stay, local recurrence, and disease-free survival between the 2 groups of patients. The propensity of patients treated with imatinib was similar to those who had surgery alone. 

“We thought reduced tumor sizes could enhance resectability and provide more chance to preserve sphincter for rectal GIST patients,” the researchers wrote. “Considering large tumor size and higher rate of sphincter invasion in the neoadjuvant group, imatinib treatment could be helpful as a conversion strategy to make huge and low-lying rectal GIST operable and achieve better surgical outcomes.”

Imatinib, sold under the brand name Gleevec® is a first-line tyrosine kinase inhibitor used both as adjuvant and neoadjuvant treatment for GIST.

Reference

Cheong C, Kang J, Min BS, Kim NK, Ahn JB, Lee KY. Impact of neoadjuvant treatment on rectal gastrointestinal stromal tumors. PLoS One. 2022;9;17(9):e0270887. doi:10.1371/journal.pone.0270887