Long-term follow-up in low-grade gastric MALT lymphoma (LGGML): Effect of persistent monoclonality (m+) on outcome

Abstract

6560 Background: limited data exist whether, in the long-term, the PCR for the rearranged immunoglobulin heavy chain region may define groups with different prognosis. Methods: 113 pts from the same area in the North East of Italy with stage I LGGML were prospectively monitored clinically and endoscopically. Wotherspoon score 0–3 was defined as histological remission (R) and score 4–5 as histological presence of lymphoma (P). Results: H. Pylori was eradicated in about 95% of the cases. After a median follow-up of 66 mo (24–132), three groups of pts were identified. Group A: 60 pts achieved R within 24 mo from diagnosis. Median time to R was very short (3 mo). At diagnosis 38/60 (63%) cases presented m+, 16/60 (27%) had negative monoclonality (m-) and in 6 data were not available. In the m+ subset median time to m- was 12 mo (3–24). In the m- subset, 2 pts presented isolated findings of m+. All remained in continuous R with m- at a median follow-up of 66 mo (24–120). Group B: 33/113 pts were in R, but with m+ at ≥ 24 mo; median time to R was 6 mo (3–24). 30 pts were m+ at diagnosis: 21 of these presented intermittently occurring monoclonality between 24 and 72 mo (median 42) while 12 presented more repeated positive samples between 36 and 90 mo (median 48). All are in continuous R. Group C: 18 pts presented P at 24–30 mo; median follow-up was 60 mo (36–132). 9/18 pts presented Pm+ at a median of 5 yrs (30–72), while 9 achieved R (either with m+ or m-) at a median of 42 mo (30–102). Median persistence of m+ was 48 mo (24–114). Conversion into high-grade lymphoma did not occur. 2 pts underwent gastrectomy after 1 yr and showed no evidence of relapse up to 84 mo. Overall, in groups B and C, we had evidence of m+ between 24 and 114 mo (median 48 mo) in 48 pts (43%) either in R (33) or P (15). Conclusions: i) monoclonality did not influence outcome, either in R or P ii) pts achieving rapid R are probably cured iii) in the P subset oncological therapies can be delayed, if not avoided, provided a close monitoring iii) for treatment decision making, routine histology remains the standard tool. No significant financial relationships to disclose.