RCHOP Therapy Overcome Gastric Diffuse Large B Cell Lymphoma without Surgery
Authors: Mishima Yuko , Terui Yasuhito , Yokoyama Masahiro , Sakajiri Sakura , Nishimura Noriko , Nakano Kenji , Nara Eriko , Suzuki Kazuhito , Nasu Kentaro , Takahashi Shunji , Takeuchi Kengo , Hatake Kiyohiko 
Published: October 2019

Abstract
Abstract 1760

Background
Other than MALT, gastric diffuse large B cell lymphoma is a very common disease in malignant lymphoma. However the treatment strategy is controversial. Although a high efficacy of rituximab plus CHOP (RCHOP) has been proven in diffuse large B cell lymphoma (DLBCL), the decision to operate is still usual among surgeons in limited stage of gastric DLBCL. Koch et al. described that CHOP14 with radiotherapy is very effective for aggressive gastric lymphoma without surgery. In this report, though, the histology was various and mixed with MALT and DLBCL. Studies about only gastric DLBCL were very few, but, in some small size studies about RCHOP to gastric DLBCL, a good prognosis has been shown. If chemotherapy with radiotherapy alone gave rise to a complete response to gastric lymphoma, the patients could avoid gastric resection. Therefore it is necessary to devise a strategy for gastric DLBCL treatment.

Patients and Methods
We retrospectively analyzed the patients who diagnosed with gastric DLBCL between November 2003 and October 2008. The cases with limited stage were treated with 3 cycles of RCHOP with radiotherapy and the cases with advanced stage were treated with 6 cycles of RCHOP without radiation. All cases were evaluated with PET/CT after treatment. Statistical analysis of progression free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier estimators. Comparison between categories was performed by means of log-rank test. We estimated age-adjusted IPI, GC or non GC subtype, and hemoglobin level (Hb<11.0 g/dl) as risk factors. Using Cox proportional hazards regression analysis, multivariate analysis was performed about these risk factors.

Result
Total 40 cases were analyzed in this study. Median age was 65.5 years old and males were 21 (52.5%). For age-adjusted IPI, low was 22, low-intermediate was 9, high intermediate was 3, and high was 6. 15 cases (27.5%) were limited stage and they all received 3 cycles of RCHOP with radiation. 25 cases (72.5%) were stage II or more, and they all were treated with 6 cycles of RCHOP. GC and non-GC types were 30 (75%) and 10 (25%), respectively. The average of observation duration was 1274 days. Four cases dropped out from these regimens because of adverse event. CR rate was 92.8% (37/40) and one case progressed and one case relapsed. Two year-OS and PFS rate were 95.2% and 91.8%, respectively. Main adverse events were grade 4 neutropenia47.5% and febrile neutropenia 17.5%. There was no case with gastric bleeding after chemotherapy. There was one case of SIADH induced by vincristine, one case of grade 3 of hepatotoxity, confusion, and one case of intestinal pneumonia, respectively. Secondary gastric cancer after radiotherapy did not occur. We performed univariate statistical analysis about aa-IPI, GC or non GC subtype, and Hb level, then, there was tendency of poor prognosis only in high risk of aa-IPI (p=0.0512). However there was no significant difference in multivariate analysis.

Discussion
RCHOP with or without radiation therapy was a very effective regimen and well-tolerated for gastric DLBCL patients. The result of our study, which was a small sample size, showed a better result than previous reports about DLBCL with RCHOP. Although the cases with severe bleeding or deep ulcer were included in this study, bleeding stopped and severe ulcers improved after chemotherapy in all such cases, so surgical treatment was not necessary. There was no report about direct comparison of the therapy with or without surgical treatment in gastric DLBCL, although RCHOP with radiation could preserve the organ and keep quality of life after treatment. We should recommend RCHOP with or without radiation for gastric DLBCL as the first line treatment.

Disclosures:
No relevant conflicts of interest to declare.