Long-Term Clinical Outcome and Predictive Factors for Relapse after Radiation Therapy in 145 Patients with Stage I Gastric B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue Type

Abstract

This study aimed to evaluate the clinical outcomes of radiation therapy (RT) for stage I gastric mucosa-associated lymphoid tissue (MALT) lymphoma and find predictive factors for relapse after RT. This retrospective study included 145 patients without a prior history of treatment, except Helicobacter pylori eradication therapy, who were irradiated for stage I gastric MALT lymphoma. The gastric body was the most commonly involved location of the dominant lesion (66.9%), and H. pylori infection at first diagnosis was detected in 61 (42.1%) patients. The median RT dose was 30 Gy (range, 24–40). Seven patients had an autoimmune disease. All patients except one achieved a complete remission at post-treatment endoscopic biopsy after a median of 2 months (range, 1–36). During the median follow-up at 51 months (range, 2–146), 11 patients experienced relapses: in the stomach (n = 5), in a distant site (n = 4), and in both (n = 2). The five-year overall, local relapse-free, distant relapse-free, and relapse-free survival (RFS) rates were 98.6%, 94.0%, 97.1%, and 92.3%, respectively. In multivariate analysis for RFS, the location of MALT lymphoma other than in the gastric body was significantly associated with an increased risk of relapse (hazard ratio 5.85 (95% CI 1.49–22.9), p = 0.011). RT results in favorable clinical outcomes in patients with stage I gastric MALT lymphoma. Tumor location could be a predictive factor for relapse after RT.

Long term outcomes of gastric mucosa‐associated lymphoid tissue lymphoma treated with radiotherapy: A multi‐center retrospective cohort study

“…Our outcomes are consistent with other published series. 5 , 6 , 7 , 8 , 10 This study confirms that these excellent outcomes also apply to an Australian population.…”

“…Gastric perforation has historically been a significant clinical concern after radiotherapy for gastric MALT MZL. However, in our series this was not reported and similarly in recently reported series we could not find a single report of this severe toxicity 5–8,10,12 . Another understandable concern from patients is often the risk of second malignancy with radiotherapy, however there were no in‐field occurrences of this in our series.…”

“…A number of studies have reported late distant failures for MALT lymphomas. 7 , 11 , 12 Median time to distant failure in these series range from 47 to 62 months which is shorter than the median time to distant failure we report of 89 months. Our results reinforce that in those patients with a previous diagnosis of gastric MALT MZL, there is an increased risk of developing further distant MALT MZL in the longer term.…”

“…In one study 1 the Australian age‐standardized incidence rates of MZL were reported as 5 per 1,000,000 compared with—for example, ‐ the US; 18 per 1,000,000, and the UK; 26 per 1,000,000. Although direct comparison should be evaluated with caution (due to differences in reporting, case definition and registration, etc) this may provide insight into the relatively lower numbers in our series when compared to other recently published data 6–8 . However, despite this geographic variability, there appears at least to be concordance with respect to radiotherapy outcomes.…”

“…Retrospective studies have demonstrated excellent long term outcomes with minimal toxicity. 6 , 7 , 8 …”