There were no differences in oncological outcomes between patients with gastrointestinal (GI) low-grade B-cell lymphoma who responded early to involved field radiotherapy and those that responded late, according to a new study from Korea.

“Clinical and endoscopic factors associated with delayed response after radiotherapy or the timing of follow-up in primary GI low-grade B-cell lymphoma (PG-LGBCL) have not been studied and the protocol of follow-up varies from institution to institution,” the researchers wrote.

Therefore, in this study the researchers assessed the clinical and pathological factors associated with delayed response to radiotherapy. The study included 43 patients who underwent radiotherapy for treatment of primary GI low-grade B-cell lymphoma between 2007 and 2018. Early responders were defined as those that had best response within 6 months of radiotherapy; delayed responders had best response after 6 months.

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All of the patients studied showed complete remission with radiotherapy. The best response time was a median of 3 months.

Of the 43 patients, 8 were considered delayed responders. These patients had a median duration of best response of 8.9 months. Of these patients, 5 had complete remission at second follow-up; 3 patients had complete remission at third follow-up.

Analyses showed no significant difference in pathologic type or tumor location between patients with early versus delayed response. The researchers did find a significant difference of deep invasion beyond the mucosal layer in endoscopic ultrasound between early vs delayed responders (P =.027).

The researchers concluded that “initial evaluation of radiotherapy after 6 months or interval increases could reduce unnecessary invasive tests.”


Choi KH, See HH, Jung SE, et al. Analysis of the response time to involved-field radiotherapy in primary gastrointestinal low-grade B-cell lymphoma. Radiat Oncol. 2020;15(1):210. doi:10.1186/s13014-020-01649-6