Clinicopathologic and immunohistochemical study of surgically treated primary gastric MALT lymphoma

Surgery and chemotherapy versus chemotherapy as treatment of high-grade MALT gastric lymphoma

BACKGROUND AND OBJECTIVES

Treatment of high-grade MALT (mucosa-associated lymphoid tissue) gastric lymphoma remains uncertain. To assess efficacy and toxicity of the most common therapies--surgery followed by chemotherapy or chemotherapy alone--we began a controlled clinical trial in patients in early stage (I and II 1).

METHODS

One hundred and two patients were randomized to be treated with surgery followed by six cycles of CEOP-Bleo (cyclophosphamide, epirubicin, vincristine, prednisone, and bleomycin at standard doses) (52 cases) or with chemotherapy alone (49 cases).

RESULTS

Complete response rates were 94% [95% confidence interval (CI): 88-99%] and 96% (93-100%), respectively. Actuarial curves at 5 yr showed that event-free survival were 70% (95% CI: 59-74%) in patients treated with surgery and chemotherapy, that were not statistically significant to 67% (95% CI: 51-69%) in the patients who received chemotherapy (p = 0.5). Also, overall survival that was not statistically significant: 78% (95% CI: 70-88%) in the combined treatment and 76% (95% CI: 70-87%) in chemotherapy (p = 0.8). Acute and late toxicity were mild and well controlled. No acute leukemia or second neoplasm has been observed.

CONCLUSIONS

The use of surgery and chemotherapy did not improve outcome in patients with early-stage high-grade gastric MALT lymphoma. It is apparent that chemotherapy alone is sufficient treatment in this select group of patients.

Surgery and chemotherapy versus chemotherapy as treatment of high-grade MALT gastric lymphoma

BACKGROUND AND OBJECTIVES

Treatment of high-grade MALT (mucosa-associated lymphoid tissue) gastric lymphoma remains uncertain. To assess efficacy and toxicity of the most common therapies--surgery followed by chemotherapy or chemotherapy alone--we began a controlled clinical trial in patients in early stage (I and II 1).

METHODS

One hundred and two patients were randomized to be treated with surgery followed by six cycles of CEOP-Bleo (cyclophosphamide, epirubicin, vincristine, prednisone, and bleomycin at standard doses) (52 cases) or with chemotherapy alone (49 cases).

RESULTS

Complete response rates were 94% [95% confidence interval (CI): 88-99%] and 96% (93-100%), respectively. Actuarial curves at 5 yr showed that event-free survival were 70% (95% CI: 59-74%) in patients treated with surgery and chemotherapy, that were not statistically significant to 67% (95% CI: 51-69%) in the patients who received chemotherapy (p = 0.5). Also, overall survival that was not statistically significant: 78% (95% CI: 70-88%) in the combined treatment and 76% (95% CI: 70-87%) in chemotherapy (p = 0.8). Acute and late toxicity were mild and well controlled. No acute leukemia or second neoplasm has been observed.

CONCLUSIONS

The use of surgery and chemotherapy did not improve outcome in patients with early-stage high-grade gastric MALT lymphoma. It is apparent that chemotherapy alone is sufficient treatment in this select group of patients.

Expression of COX-2, iNOS, p53 and Ki-67 in gastric mucosa-associated lymphoid tissue lymphoma

AIM: To assess the expression of cyclooxygenase-2 (COX-2), nitric oxide synthase (iNOS), p53 and Ki-67 in gastric mucosa-associated lymphoid tissue (MALT) lymphoma and clarify the relationship between COX-2 expression and iNOS or p53 expression in these patients.

METHODS: The expressions of COX-2, iNOS, p53 and Ki-67 were detected in 32 gastric MALT lymphoma specimens and 10 adjacent mucosal specimens by immunohistochemical Envision method.

RESULTS: COX-2 and iNOS expressions were significantly higher in gastric MALT lymphoma tissues than those in adjacent normal tissues. The expression of COX-2 was observed in 22 of 32 cases of MALT lymphoma tissues (68.8%). A positive cytoplasmic immunoreactivity for iNOS was detected in 17 of 31 cases (53.1%). COX-2 expression in gastric MALT lymphoma tissues was positively correlated with iNOS expression (r = 0.448, P = 0.010) and cell proliferative activity analyzed by Ki-67 labeling index (r = 0.410, P = 0.020). The expression of COX-2 protein did not correlate with age, sex, stage of disease, lymph node metastasis or differentiation. The accumulation of p53 nuclear phosphoprotein was detected in 19 (59.4%) of tumors. p53 protein was expressed in 11 of 23 assessed LG tumors and in 8 of 9 assessed HG tumors. The difference of p53 positivity was found statistically significant between LG and HG cases (P = 0.0302). The p53 accumulation correlated with advanced clinical stage (stage III + IV vs stage I + II, P = 0.017). There was a significant positive correlation between COX-2 expression and p53 accumulation status (r = 0.403, P = 0.022). The mean PI of Ki-67 in each grade group were 36.0% ± 7.73% in HG and 27.4% ± 9.21% in LG. High-proliferation rate correlated with HG tumors (r = 0.419, P = 0.017). The correlation coefficient showed a significant positive correlation between PI and COX-2 expression in MALT lymphoma patients (r = 0.410, P = 0.020).

CONCLUSION: COX-2 expresses in the majority of gastric MALT lymphoma tissues and correlates with cellular proliferation and iNOS expression. COX-2 overexpression is closely associated with p53 accumulation status. iNOS and COX-2 may play a synergistic role in the pathogenesis of gastric MALT lymphoma.