Non-Marrow Tumors Increase Among Myeloma Patients As Survival And Detection Methods Improve
Published: Mar 26, 2010 12:44 pm
As survival increases among multiple myeloma patients and as detection methods improve, a higher rate of plasma cell tumors are being detected outside the bone marrow of these patients, a new study published in the Annals of Oncology suggests. The authors also concluded that the increase is not caused by high-dose therapy or novel therapeutic agents.
Non-marrow tumors, also known as extramedullary disease, occur when plasma cell tumors develop outside of the bone marrow in soft tissue or organs.
Coinciding with the use of high-dose therapy and targeted drugs such as Revlimid (lenalidomide), Velcade (bortezomib), or thalidomide (Thalomid), the rate of non-marrow myeloma has increased, and many researchers are concerned there may be a connection between the two events. In this study, researchers examined the relationship between treatment with high-dose therapy or novel agents and non-marrow tumors.
Researchers analyzed the data of 1003 patients treated at the University of Pavia in Italy between 1971 and 2007. Patients were divided into three groups according to the treatments that were available during their time period. Group 1 included patients treated between 1971 and 1993, when conventional dose chemotherapy was commonly used. Group 2 included patients treated between 1994 and 1999, when high-dose therapy was introduced as first-line therapy for patients under the age of 65 years. Group 3 included patients treated between 2000 and 2007, after the introduction of novel agents. Researchers followed up with patients for a median of 30 months.
Of the 1003 participants, 7 percent had already developed tumors outside the bone marrow at the time of their myeloma diagnosis, and 6 percent developed non-marrow tumors within the follow-up period, bringing the total to 13 percent.
Researchers noticed that the chance of a patient developing a non-marrow tumor increased over time – from an average of 1 out of 150 patients per year between 1971 and 1993 to 1 out of 65 patients per year between 1993 and 1999 and to 1 out of 20 patients per year between 2000 and 2007.
Among patients with non-marrow tumors at diagnosis, those who received high-dose therapy had survival similar to patients who never developed non-marrow tumors. However, patients with non-marrow tumors at diagnosis who did not receive high-dose therapy experienced a shorter progression free survival.
Patients who developed non-marrow tumors during the course of their myeloma experienced both shorter progression free and overall survival.
Despite the increase in non-marrow tumors in recent years, the researchers determined that treatment with high-dose therapy, Velcade, Revlimid or thalidomide did not increase the risk of developing non-marrow tumors.
Instead, the researchers found that more non-marrow tumors are being detected because patients are living longer and because detection methods are improving, allowing physicians to detect tumors that would have gone unnoticed in previous decades.
Over the three time periods studied, median overall survival increased from 32 months to 45 months to 54 months. From 2000 to 2007, the onset of tumors beyond the marrow occurred much later after multiple myeloma diagnosis than in previous years (an average of 34.6 months versus 18.9 months). Therefore, researchers concluded that as life expectancy for multiple myeloma lengthens, tumors outside the bone marrow have more time to develop, contributing to the sudden increase in non-marrow tumors.
The study authors wrote that they are unaware of any studies focusing on treatment for myeloma patients with non-marrow tumors. However, they stated that some studies have indicated that Velcade may be effective, while thalidomide appears to have low efficacy in this population of myeloma patients.
For more information, please see the journal Annals of Oncology (abstract).