Scintigraphy with technetium-99m methoxyisobutylisonitrile in multiple myeloma patients: correlation with the International Staging System.

(99m)Tc-2-methoxyisobutylisonitrile ((99m)Tc-MIBI) scintigraphy has been suggested in multiple myeloma (MM) patients. According to the International Staging System (ISS), serum b2-microglobulin (Sbeta(2)M) and serum albumin (SA) are dominant predictive factors and different cut-off values of these factors can separate patients into various stages of the disease. The purpose of this study was to assess the relationship between ISS staging, by Sbeta(2)M and SA, and the (99m)Tc-MIBI scan findings. Twenty-five MM patients have been studied. Eighteen patients were at stage I, three at stage II and four at stage III of MM. (99m)Tc-MIBI scans were obtained and scored according to intensity (I) and extent (E) of the radiotracer uptake. A summed score (S) for the (99m)Tc-MIBI scan was calculated for each patient. A statistically significant negative correlation between E, I and S uptake scores versus the SA levels (P=0.004, 0.049 and 0.018 respectively), as well as a statistically significant positive correlation between E and S scores and the Sbeta(2)M levels (P=0.012 and 0.032) were detected. A statistically significant difference between the E and S uptake scores among the MM patients examined for every stage separately was also found (P=0.007 and 0.024 respectively). The gradual increase of the E and S scores across the three stages of MM was also significant (P=0.003 and 0.021 respectively), despite the relatively small number of patients in stages II and III. In seven patients who died at the end of the follow-up period all three scores were significantly increased as compared to the scores of the patients who remained alive at that time. In conclusion, this study provides additional evidence that (99m)Tc-MIBI scan not only reflects myeloma disease activity in bone marrow but it is also well correlated with the Sbeta(2)M and SA levels according to ISS.

Discordant response or progression in patients with myeloma treated with thalidomide-based regimens.

UNLABELLED: Thalidomide-based regimens (TBR) are now widely used for the treatment of refractory multiple myeloma and have shown significant activity in newly diagnosed patients. In some patients with secretory disease, we observed discrepancies between the reduction of the monoclonal protein levels and the plasma cell infiltration in the bone marrow and/or extramedullary sites of relapse after treatment with TBR. The purpose of this study was to assess the incidence and analysis of this phenomenon in all myeloma patients treated with TBR in our Institution. PATIENTS AND METHODS: We studied all patients who received TBRs and had a follow up time of at least 6 months. Partial response (PR) was defined as at least 50% reduction of serum myeloma protein and soft tissue plasmacytomas and/or > 90% reduction of Bence Jones protein excretion and minor response as a > 25% reduction of the serum myeloma protein or > 50% reduction of the Bence Jones myeloma protein. RESULTS: Between July 1999 and July 2002 we treated 94 patients with advanced myeloma and 9 patients with newly diagnosed disease with TBR. Sixty-seven patients (66%) achieved either partial or minor response. In 4 patients (3 with advanced and 1 with newly diagnosed myeloma) the bone marrow was heavily infiltrated by plasma cells, despite a decrease of the paraprotein levels ranging from 38% to 68%. This discordance between monoclonal protein levels and bone marrow plasmacytosis was noted in 6% of patients rated as responders and in 11% of responding patients who actually had a repeat bone marrow assessment. Furthermore 6 responding patients, after achieving a PR which lasted between 5 and 9 months, relapsed with bone marrow (all cases), and extramedullary (2 cases) plasmacytosis, without increase of serum and/or urine monoclonal protein. This hyposecretory conversion was noted in 12.5% of relapsing patients. CONCLUSION: Our data indicate that after treatment with TBR some patients with myeloma show discordant responses of the monoclonal protein levels and the bone marrow or extramedullary plasmacytosis. If our data are confirmed, they may have practical implications for assessment of response and follow up of patients treated with TBR.