Minimally Invasive Conversion Surgery for Unresectable Gastric Cancer with Splenic Metastasis and Splenic Vein Tumor Thrombus: A Case Report.

While the importance of conversion surgery has increased with the development of systemic chemotherapy for gastric cancer (GC), reports of conversion surgery for patients with GC with distant metastasis and tumor thrombus are extremely scarce, and a definitive surgical strategy has yet to be established. Herein, we report a 67-year-old man with left abdominal pain referred to our hospital following a diagnosis of unresectable GC. Esophagogastroduodenoscopy and contrast-enhanced abdominal computed tomography (CT) revealed advanced GC with splenic metastasis. A splenic vein tumor thrombus (SVTT) and a continuous thrombus to the main trunk of the portal vein were detected. The patient was treated with anticoagulation therapy and systemic chemotherapy comprising S-1 and oxaliplatin. One year following chemotherapy initiation, a CT scan revealed progressive disease (PD); therefore, the chemotherapy regimen was switched to ramucirumab with paclitaxel. After 10 courses of chemotherapy resulting in primary tumor and SVTT shrinkage, the patient underwent laparoscopic total gastrectomy (LTG) and distal pancreaticosplenectomy (DPS). He was discharged without complications and remained alive 6 months postoperatively without recurrence. In summary, the wait-and-see approach was effective in a patient with GC with splenic metastasis and SVTT, ultimately leading to an R0 resection performed via LTG and DPS.

Splenic marginal zone lymphoma with monoclonal IgG: A case report.

RATIONALE: Splenic marginal zone lymphoma (SMZL), an indolent small B-cell lymphoma, is uncommon, and part of the patients exist plasmocytic differentiation and secrete monoclonal paraproteins including IgM predominantly. SMZL with monoclonal IgG is rarer. PATIENT CONCERNS: We report a case of SMZL (49-year-old, male) with monoclonal IgG, MYD88L265P mutation and hepatitis B virus infection. DIAGNOSES: The patient was presented to our hospital with aggravating complaints of dizziness, fatigue, postprandial abdominal distension, and night sweats. The diagnosis was confirmed by clinical manifestations, immunophenotype, bone marrow pathology. INTERVENTIONS: The patient received rituximab-based chemotherapy and sequential ibrutinib in combination with entecavir. OUTCOMES: After 1 year of follow-up, his blood routine examination had returned to normal with normal level of albumin and significantly lower globulin than before, and the spleen was of normal size. LESSONS: We conclude that rituximab-based chemotherapy is the main treatment option for the patients with SMZL, and Bruton's tyrosine kinase inhibitor has also shown beneficial efficacy.

[Adjuvant treatment of canine splenic hemangiosarcoma with autologous dendritic cell therapy - a prospective, randomized double-blind study]. / Adjuvante Behandlung des caninen Hämangiosarkoms der Milz mit der autologen dendritischen Zelltherapie ­ eine prospektive, placebokontrollierte, randomisierte Doppelblindstudie.

OBJECTIVE: Canine splenic hemangiosarcomas (HSA) are malignant mesenchymal tumors with a high tendency for metastasis. Median survival times after splenectomy followed by adjuvant chemotherapy usually range between 5 and 8 months. The aim of this prospective randomized double-blinded study was to examine the efficacy of a commercially available dendritic cell therapy (PetBioCell) following splenectomy. In addition, possible side effects of this therapy were evaluated. MATERIAL AND METHODS: Twenty-one dogs with histologically confirmed splenic HSA without metastasis (stages I or II) were included in the study. Ten dogs received the dendritic cell therapy, and 11 dogs received a placebo. Injections were administered according to the manufacturer's instructions monthly for the first 3 months and then every 3 months until death. Survival times and toxicoses of both groups were compared. RESULTS: Follow-up data were available for all 21 patients; the observation period ranging until euthanasia or metastasis-related death. One patient that had received the dendritic cell therapy was euthanized due to prostatitis and experienced the longest survival time (668 days). One dog in the placebo-group lived for 448 days after splenectomy. The median survival times in the dendritic cell therapy and the placebo group amounted to 74 and 126 days, respectively. There was no significant difference in tumor-free interval (t(18) = 1.4, p = 0.911) and survival times (t(19) = -0.094, p = 0.463) between the 2 groups. Toxicoses reported in both groups were mild and self-limiting. CONCLUSION: Immunotherapy using autologous, immature and unprimed dendritic cells according to the PetBioCell method failed to show efficacy on tumor-free interval and survival time in the presented dog population with splenic hemangiosarcoma.

Suppression or Inhibition of VEGFs on Splenic Angiosarcoma Cell with Traditional Chinese Medicine Zhi Gan Cao.

Primary splenic angiosarcoma is a very rare disease that causes the development of malignant tumors in the vascular endothelium of the splenic sinuses. Moreover, the disease maintains a very low survival rate for patients to live over 5 years, which is relatively low when compared to another splenic cancer, splenic lymphomas. The treatment options for splenic angiosarcoma narrow down to surgical removal or radiation combined with chemotherapy, but both cost a lot, so discovering potential alternative treatments may eventually increase the possible survival rate. Ginseng and Zhi Gan Cao are both common herbs in Traditional Chinese Medicine (TCM); however, the price of Ginseng is much higher than that of Zhi Gan Cao. A possible reason could be the frequent studies and researches over Ginseng's active ingredient, ginsenoside rh2 or rg3 as they are both potent cancer treatments. The reason to study Zhi Gan Cao and predict its possible potential in cancer treatment is due to the similarity between its active ingredient and the active ingredient in Ginseng, namely, ginsenoside rh2 and licorice saponins. Both TCM contain the active ingredient, triterpenoid saponin, as their main composition, and the further text will predict the possible research and results that may be taken in vitro to reveal the question of whether licorice saponin has the potential to become a major treatment for splenic angiosarcoma or not.

Identification of genomic alterations with clinical impact in canine splenic hemangiosarcoma.

Canine hemangiosarcoma (HSA) is an aggressive cancer of endothelial cells with short survival times. Understanding the genomic landscape of HSA may aid in developing therapeutic strategies for dogs and may also inform therapies for the rare and aggressive human cancer angiosarcoma. The objectives of this study were to build a framework for leveraging real-world genomic and clinical data that could provide the foundation for precision medicine in veterinary oncology, and to determine the relationships between genomic and clinical features in canine splenic HSA. One hundred and nine dogs with primary splenic HSA treated by splenectomy that had tumour sequencing via the FidoCure® Precision Medicine Platform targeted sequencing panel were enrolled. Patient signalment, weight, metastasis at diagnosis and overall survival time were retrospectively evaluated. The incidence of genomic alterations in individual genes and their relationship to patient variables including outcome were assessed. Somatic mutations in TP53 (n = 44), NRAS (n = 20) and PIK3CA (n = 19) were most common. Survival was associated with presence of metastases at diagnosis and germline variants in SETD2 and NOTCH1. Age at diagnosis was associated with somatic NRAS mutations and breed. TP53 and PIK3CA somatic mutations were found in larger dogs, while germline SETD2 variants were found in smaller dogs. We identified both somatic mutations and germline variants associated with clinical variables including age, breed and overall survival. These genetic changes may be useful prognostic factors and provide insight into the genomic landscape of hemangiosarcoma.

Low-risk HPLLs/ABC score patients with splenic marginal zone lymphoma can be safely managed without treatment: Results from a prospective Spanish study.

The aims of our study were to analyse compliance with the 2014 GELTAMO SMZL Guidelines, in patients with splenic marginal zone lymphoma (SMZL), and to evaluate the outcome according to the HPLLs/ABC-adapted therapeutic strategy. Observational prospective multicenter study of 181 SMZL patients diagnosed between 2014 and 2020. Lymphoma-specific survival (LSS), composite event-free survival (CEFS) and response rates were assessed. 57% of the 168 patients included in the analysis followed the Guidelines. The overall response rate was higher in the rituximab chemotherapy and in the rituximab arms compared with the splenectomy arm (p < 0.001). The 5-year overall survival was 77% and the 5-year LSS of 93%. There were no differences in the 5-year LSS according to the treatment received (p = 0.68). The 5-year CEFS in the overall series was 45%, and there were significant differences between scores A and B (p = 0.036). There were no significant differences when comparing LSS and progression-free survival in patients treated with rituximab or rituximab chemotherapy at diagnosis or after observation. Our data support HPLLs/ABC score as a practical tool for the management of SMZL, observation as the best approach for patients in group A and rituximab as the best treatment for group B.

Timely adjuvant chemotherapy improves outcome in dogs with non-metastatic splenic hemangiosarcoma undergoing splenectomy.

Timely delivery of adjuvant chemotherapy has been shown to be advantageous in many human cancers and canine osteosarcoma. Adjuvant chemotherapy has been shown to improve outcome for canine splenic hemangiosarcoma. The aim of this retrospective study was to investigate whether timely adjuvant chemotherapy administration resulted in better outcome in dogs with non-metastatic splenic hemangiosarcoma undergoing splenectomy. Medical records were searched for dogs with non-metastatic, splenic hemangiosarcoma that received splenectomy and adjuvant chemotherapy. The number of days from surgery to the first chemotherapy dose (StoC) was evaluated to identify the cut-off value associated with the best survival advantage. StoC and other possible prognostic factors were tested for influence on time to metastasis (TTM) and overall survival (OS). Seventy dogs were included. Median StoC was 20 days (range: 4-70). The time interval associated with the greatest survival benefit was 21 days. Median TTM and OS of dogs with StoC ≤ 21 days were significantly longer than those with StoC >21 days (TTM: 163 vs. 118 days, p = .001; OS: 238 vs. 146 days, p < .001). On multivariable analysis, StoC >21 days was the only variable significantly associated with increased risk of tumour progression (HR 2.1, p = .010) and death (HR 2.3; p = .008). Starting adjuvant chemotherapy within 21 days of surgery may be associated with a survival benefit in dogs with non-metastatic splenic hemangiosarcoma, possibly due to the early targeting of newly recruited metastatic cells after surgery.

[Laparoscopic Splenectomy for Metachronous Splenic Metastasis of Fallopian Tube Cancer with Synchronous Rectal Metastasis-A Case Report].

A 59-year-old woman underwent simple abdominal total hysterectomy with bilateral salpingo-oophorectomy, partial omentectomy, and extirpation of intrapelvic disseminated nodules for right fallopian tube cancer with rectal metastasis and peritoneal dissemination as primary debulking surgery(PDS). The histopathological diagnosis was high grade serous carcinoma( HGSC)of the right fallopian tube. After adjuvant chemotherapy with 4 courses of paclitaxel-carboplatin(TC), low anterior resection of the rectum for rectal metastasis and pelvic and para-aortic lymph node dissection were performed as interval debulking surgery(IDS). Histopathologically, lymph node metastasis was detected only in the right obturator lymph node. After adjuvant chemotherapy with 4 courses of TC, bevacizumab maintenance monotherapy was administered. Three years after PDS, laparoscopic splenectomy for splenic metastasis and extirpation of the solitary peritoneal metastases were performed as secondary debulking surgery(SDS). After adjuvant chemotherapy with 4 courses of TC, olaparib maintenance monotherapy was administered. The patient has remained alive without recurrence for 4 years after SDS and for 7 years after PDS. No case of metachronous splenic metastasis from fallopian tube cancer with synchronous rectal metastasis has been reported; however, long-term prognosis may be expected with PDS, IDS and SDS for platinum-sensitive HGSC.

Hepatosplenic lymphoma and visceral mast cell tumor in the liver of a dog with synchronous and multiple primary tumors.

An 11-year-old spayed female American Cocker Spaniel was presented with a 4-week history of anorexia and a 1-week history of abdominal distension. Clinicopathologic and imaging abnormalities included intra-abdominal hemorrhage, granular lymphocytes (GLs) in abdominal fluid smears, a splenic mass, and hepatomegaly with diffuse multiple hypoechogenic nodules. Based on the cytologic, histologic, and immunohistochemical evaluation of the spleen and liver, the diagnosis was hepatosplenic T-cell lymphoma (HSTCL) of GLs. Postoperatively, the dog was maintained in good condition with chemotherapy (ACNU [nimustine], L-asparaginase, and prednisolone). However, on day 85, ultrasound-guided fine-needle aspiration of the liver revealed a proliferation in neoplastic mast cells not associated with the GLs. The dog was diagnosed with a visceral mast cell tumor (MCT) originating from the liver. The chemotherapy was switched to vinblastine and toceranib. The dog remained in good condition until day 141 but died due to the progression of MCT on day 158. Liver cytology on day 155 showed no GLs, although HSTCL is thought to be resistant to chemotherapy. After the definitive diagnosis of HSTCL, we monitored this patient's response to chemotherapy with blood tests, including complete blood counts, ultrasound imaging, and cytologic aspirates of liver. Although canine HSTCL has a poor prognosis, the possibility of a new neoplasm, including visceral MCT, should be considered. Periodic liver cytology might be worthwhile in dogs receiving chemotherapy for HSTCL.

Refractory Splenic Marginal Zone Lymphoma Responsive to Combination Venetoclax and Bortezomib (Velcade) (V2) Therapy.

Standard treatment regimens for the management of patients with refractory splenic marginal zone lymphoma (SMZL) are currently unavailable. Here, we report a case of SMZL, which, after failing multiple therapeutics, demonstrated an impressive clinical response to combined Venetoclax and Velcade (V2), a treatment combination currently being investigated in the setting of refractory multiple myeloma. We also report a unique histopathology and mutational profile that may have important implications for the characterization and prognosis of SMZL.

Isolated splenic metastasis of endometrial cancer 12 years after treatment: A case report and literature review.

RATIONALE: The spleen is an uncommon metastatic organ for malignant solid tumors because of its special anatomy and microenvironment. Isolated splenic metastasis of endometrial cancer is an extremely rare clinical event, with only 17 cases reported in literature. PATIENT CONCERNS: We report the case of a 58-year-old woman with abdominal distension and nausea for 7 months who had undergone surgery and chemotherapy for endometrioid adenocarcinoma 12 years previously. A space-occupying lesion in the upper pole of the spleen was observed on an abdominal ultrasound. DIAGNOSIS: The spleen was resected, and splenic metastasis of endometrial adenocarcinoma was histologically confirmed. INTERVENTIONS: Splenectomy was performed, and no lymph nodes or other metastases were observed. The patient received postoperative chemotherapy with 6 cycles of docetaxel and carboplatin. OUTCOMES: The patient recovered well 11 months postoperatively, with no evidence of recurrence or metastatic disease. LESSON: Since the time interval between the diagnosis of primary endometrial cancer and splenic metastasis may be very long, it may be necessary to monitor the recurrence of endometrial cancer after primary treatment.

Evaluation of the anti-tumour activity of Coriolus versicolor polysaccharopeptide (I'm-Yunity) alone or in combination with doxorubicin for canine splenic hemangiosarcoma.

Canine splenic hemangiosarcoma (HSA) is an aggressive tumour of vascular endothelium that carries a grave prognosis following standard of care treatment with surgery and doxorubicin. A previous pilot study revealed potential anti-tumour activity of I'm-Yunity polysaccharopeptide (PSP) for canine HSA. The aim of this prospective study was to assess patient outcome when treated with PSP alone or in combination with doxorubicin post-splenectomy compared to patients treated with surgery and doxorubicin that received a placebo in place of PSP. Dogs undergoing splenectomy for splenic HSA were eligible. Following splenectomy, owners were offered treatment with PSP alone or adjuvant doxorubicin chemotherapy (unblinded). Patients with owners that selected to proceed with doxorubicin chemotherapy were blindly randomized to receive placebo or PSP. Dogs were evaluated weekly for 15 weeks, then scheduled for monthly visits until death. One hundred and one dogs were included in the final analysis: 51 PSP alone, 25 doxorubicin/placebo, and 25 combination PSP/doxorubicin. On multivariate analysis, dogs treated with single agent PSP, female dogs, decreased haematocrit at diagnosis, and stage III disease were negatively significantly associated with outcome; however, an interaction between treatment group and sex was documented. Gender-specific outcomes revealed no significant difference in survival between treatment groups for male dogs, but female dogs treated with PSP alone had significantly reduced survival compared to females receiving doxorubicin/placebo (HR 0.21; p = .004). Anaemia (HR 5.28; p < .001) and stage III disease (HR 2.9; p = .014) remained negatively associated with survival when controlling for sex and treatment group. The addition of PSP to doxorubicin post-splenectomy did not improve survival in dogs with splenic HSA.

Cisplatin Plus Capecitabine After Adjuvant S-1 in Metastatic Gastric Cancer: A Phase II T-CORE1102 Trial.

BACKGROUND/AIM: This phase II study assessed the efficacy of capecitabine plus cisplatin in patients with advanced gastric cancer refractory to adjuvant S-1. PATIENTS AND METHODS: This single-arm, open-label, multicenter, phase II study was conducted by Tohoku Clinical Oncology Research and Education Society (T-CORE) in Japan. Patients aged ≥20 years with advanced HER2-negative gastric cancer that was refractory to S-1 were enrolled. Patients received 80 mg/m2 cisplatin on day 1 intravenously and 1,000 mg/m2 capecitabine twice daily from day 1 to day 14, in 3-week cycles. The primary endpoint was progression-free survival (PFS). The threshold overall response rate (ORR) was estimated to be 15%. The secondary endpoints were overall survival (OS), time to treatment failure, ORR, and toxicities. RESULTS: In total, 21 patients were enrolled from seven hospitals. The median patient age was 63 years. Nineteen patients received the protocol treatment. Median PFS was 3.7 months [90% confidence interval (CI)=2.7-5.6 months], which did not reach the predefined threshold of 4.0 months. ORR was 5.9% (95%CI=0.0-17.1%). Median OS was 11.9 months (95% CI 6.3-19.4 months). Febrile neutropenia was observed in 5.3% of patients. The most frequently observed grade 3 non-hematologic toxicities were nausea (15.8%) and hyponatremia (15.8%). CONCLUSION: The addition of a fluoropyrimidine to a platinum agent after adjuvant therapy is not suitable for gastric cancer.

A case of severe vasculitis after FLOT chemotherapy in a patient with metastatic gastric cancer who received multiple line chemotherapy.

INTRODUCTION: Leukocytoclastic vasculitis is a histopathological term describing vasculitis in which the inflammatory infiltrate in small vessels consists of neutrophils. Although FLOT is given perioperatively in locally advanced, resectable gastric or gastroesophageal junction adenocarcinoma, it has recently become a popular treatment option for metastatic cancers. In this case report, we present a case of FLOT-induced LCV. CASE REPORT: We present a 52-year-old patient with metastatic gastric adenocarcinoma treated with FLOT. The patient developed necrotizing vasculitis in the lower extremity after 5 cycles of FLOT. MANAGEMENT & OUTCOME: After discontinuation of the FLOT regimen, the necrotizing morbid LCV gradually regressed with steroid therapy. DISCUSSION: To the best of our knowledge, our case is the first case of LCV that developed after FLOT chemotherapy. The clinical appearance of the patient, occurrence after chemotherapy, erythematous rash developing on bilateral lower extremities, and palpable purpuric vasculitis made us suspect. We found a potential relationship between FLOT and vasculitis according to the Naranjo scale (score 4 + ).

Risk-tailored treatment of splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is a rare lymphoproliferative disease involving B-cells and affecting elderly patients. SMZL plague peripheral blood and bone marrow, spleen. Lymph nodes are generally spared. SMZL is due to a protracted antigen stimulation of B lymphocytes and of microenvironment leading B-cell to polyclonal and then oligoclonal/monoclonal growth, promoting lymphoproliferation. Integration of the NOTCH2 and NFk-B signaling has been recently identified as the primary mechanism of neoplastic proliferation in SMZL. In total 20% of cases carry mutations in NOTCH2. Although SMZL has an indolent course, progression to diffuse large B-cell lymphoma occurs in about 10-15% of patients. Establishing the prognosis is a key step in disease management, depending on both individual risk and patients' health status. This review discusses tailored treatment of SMZL patients. Progression risk factors include nodal and extra-nodal involvement, peripheral lymphocytosis, anemia and thrombocytopenia. Patients with two or more score points have a median survival of <5 years. Watch and wait strategy is appropriate in low-risk and asymptomatic patients, whereas treatment of symptomatic patients ranges from splenectomy to rituximab monotherapy or associated with chemotherapy.

NOTCH signaling in the pathogenesis of splenic marginal zone lymphoma-opportunities for therapy.

NOTCH signaling is a highly conserved pathway mediated by four receptors (NOTCH 1-4) playing critical functions in proliferation, differentiation, and cell death. Under physiologic circumstances, NOTCH2 is a key regulator in marginal zone differentiation and development. Over the last decade, growing data demonstrated frequent NOTCH2 mutations in splenic marginal zone lymphoma (SMZL) underscoring its critical role in the pathogenesis of this disease. Moreover, NOTCH2 specificity across studies supports the rationale to assess its value as a diagnosis biomarker in a disease without pathognomonic features. These data make NOTCH signaling an appealing target for drug discovery in SMZL; however, prior efforts attempting to manipulate this pathway failed to demonstrate meaningful clinical benefit, or their safety profile prevented further development. In this review, we discuss the current knowledge of NOTCH implications in the pathogenesis and as a potential druggable target in SMZL.

[A Case of Splenectomy for Isolated Splenic Metastasis after Surgery for Gastric Cancer].

Splenic metastasis of gastric cancer is rare. Cases of long-term survival after the resection of metachronous solitary splenic metastasis have been reported, and proactive resection should be performed. A 77-year-old man was presented to our hospital with anorexia. Further investigation showed type 2 gastric cancer in the greater curvature of the stomach in the lower body. Subsequently distal gastrectomy was performed on October 2018. The pathological stage was T3N2M0, Stage ⅢA, and the patient was treated with S-1 as adjuvant chemotherapy for 1 year. Two years after surgery, enhanced computed tomography(CT)showed a solitary splenic tumor with a diameter of 10 mm. Six months later, the tumor had grown to 25 mm, and PET-CT revealed no other tumors. Thus we diagnosed the patient as metachronous solitary splenic metastasis of gastric cancer, and splenectomy was performed on June 2021. Histopathological diagnosis was a metastasis of gastric cancer. The patient was treated with S-1 and remains recurrence-free for 1 year after the second operation.

A Rare Case of Factor VII Inhibitor in a Patient Presenting with Primary Splenic Marginal Zone Lymphoma.

BACKGROUND Here, we report the novel presentation of a factor VII inhibitor in association with a new diagnosis of splenic marginal zone lymphoma in a previously healthy 38-year-old woman. There are only 4 reported cases of factor VII inhibitors, none of which are secondary to a splenic marginal zone lymphoma. CASE REPORT Our patient, a 38-year-old woman, presented reporting increased abdominal swelling and early satiety. She was found to have pancytopenia, an elevated international normalized ratio (INR), normal partial thromboplastin time (PTT), and massive splenomegaly. Further investigation revealed a morphology and immunophenotype most consistent with splenic marginal zone lymphoma. A mixing study was unable to bring the INR into normal range after 60 min, confirming a factor VII inhibition. Therefore, the final diagnosis was primary splenic marginal zone lymphoma and secondary factor VII inhibitors. Owing to the elevated INR, both chemotherapy and splenectomy were avoided and we began a 4-week course of weekly rituximab infusions. After a second course of 4 treatments, there was a resolution of both the coagulopathy and the splenomegaly. At this point, the splenectomy was safely performed. Maintenance rituximab continued for 2 years. Our patient has now been in remission 12 years. CONCLUSIONS We successfully treated a rare factor VII inhibitor and its underlying splenic marginal zone lymphoma with rituximab immunotherapy. A complete response was documented by splenectomy. The patient's 12-year remission of both the lymphoma and the inhibitor helps to support the causative relationship between the lymphoma and the factor VII inhibitor.

Hepatosplenic T-cell lymphoma: treatment challenges.

PURPOSE OF REVIEW: Hepatosplenic lymphoma (HSTCL) is a rare T-cell malignancy occurring in young males, associated with immune deficiency in 20% of the cases which, despite aggressive treatments, has a poor survival. Specific recommendations for first-line treatment remain debatable. RECENT FINDINGS: Published data covering case reports or series of HSTCL concur that allogeneic stem cell transplant should be proposed as a consolidation after response to chemotherapy in all patients eligible for transplant. In the light of two recent clinical examples, we also confirm that specific chemotherapy and a first-line consolidation with allogeneic transplantation when a donor is available to represent a treatment of choice these rare and distinctive lymphomas. Recent molecular studies are summarized in this review and suggest potential targets for new therapeutic strategies. SUMMARY: Major progresses have been achieved in improving the outcome of HSTCL l patients using intensive chemotherapy and allogeneic transplantation.

Undetectable minimal residual disease is an independent prognostic factor in splenic marginal zone lymphoma.

The role of minimal residual disease (MRD) in splenic marginal zone lymphoma (SMZL) has not been well studied. We prospectively designed a study to evaluate undetectable MRD (uMRD) by multiparameter flow cytometry as a prognostic factor. Residual disease level of <0·01% was defined as uMRD. A total of 71 newly diagnosed patients with bone marrow involvement were enrolled and all received rituximab-based therapy. The overall response rate (ORR) was 98·5% (70/71), with a complete remission (CR) rate of 54·9% (39/71). There were a total of 295 MRD detections in bone marrow and 77·4% patients (55/71) had uMRD. The 5-year progression-free survival (PFS) [(74·8 ± 6·5)% vs. (31·4 ± 12·6)%, P < 0·001] and 5-year overall survival (OS) [(87·2 ± 5·6)% vs. (68·9 ± 13·4)%, P = 0·035] were significantly higher in uMRD patients than in MRD-positive patients. The 5-year PFS in partial remission (PR) patients with positive MRD was significantly poorer than that of PR patients with uMRD [(21·1 ± 12·9)% vs. (83·3 ± 8·8)%, P = 0·005]. Multivariate prognostic analysis revealed that uMRD was an independent good prognostic factor for PFS (hazard ratio 0·162, 95% confidence interval 0·041-0·635; P = 0·009). All these results highlight uMRD as an independent prognostic factor in patients with SMZL, especially for patients who only achieve PR.