Diagnosis of Second Primary Malignancies Associated With Prolonged Survival Among Patients With MM

Incidence of certain second primary malignancies (SPMs) were associated with increased overall survival (OS) among patients with multiple myeloma (MM), according to abstract findings presented at the 64th American Society of Hematology Meeting and Exposition.¹

There is significant literature regarding the incidence of SPMs in patients with MM, in which therapies used to treat the disease, such as immunomodulatory drugs, have been implicated to increase risk of specific SPMs.²

Despite survival rates of patients with MM continuing to improve, and subsequently increasing long-term risk of SPMs among survivors, researchers note that there remains a relative paucity of data regarding prognosis and mortality in this population.

Aiming to determine outcomes of patients with MM who receive a diagnosis of SPM, authors conducted a retrospective analysis of real-world data from the American Society of Clinical Oncology (ASCO) CancerLinQ MM registry, which includes records from more than 100 oncology practices and hospitals in the United States.

Eligible patients with MM included those who received their diagnosis between 2009 and 2021 with International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) codes utilized for SPM diagnoses of interest: acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML), breast cancer, colorectal cancer, nonmelanoma cutaneous cancers, melanoma, non-Hodgkin lymphoma (NHL), diffuse large B cell lymphoma (DLBCL), lung cancer, prostate cancer, and any SPM.

The primary end point assessed was OS from the date of initial MM diagnosis, which was compared between patients with MM vs without a later diagnosis of a SPM. A total of 34,234 patients met inclusion criteria, of whom 10.62% developed any SPM (n = 3634).

“Analyses were conducted with STATA version 17.0 (College Station, Texas); critical alpha level was set at .05. Kaplan-Meier curves were generated to demonstrate OS. Median OS and HRs were calculated for all patients later diagnosed during the reporting period with a SPM vs without, and by specific SPMs vs all patients without that SPM,” researchers explained.

Findings indicated that all patients who subsequently received a diagnosis of an SPM reported a median OS of 130 months compared with 103 months in those without such a diagnosis (HR, 0.741; 95% CI, 0.6900.796; P < .001).

When comparing survival rates by specific SPMs, median OS was shown to be prolonged in patients who later received a diagnosis of certain SPMs vs those without any SPM:

• median OS of patients with MM who received a diagnosis of nonmelanoma cutaneous cancers vs those without an SPM (141 months vs 105 months; HR, 0.472; 95% CI, 0.398-0.559; P < .001)
• median OS of patients with MM who received a diagnosis of breast cancer vs those without an SPM (median OS not reached vs 105 months; HR, 0.584; 95% CI, 0.475-0.717; P < .001)
• median OS of patients with MM who received a diagnosis of prostate cancer vs those without an SPM (median OS not reached vs 105 months; HR, 0.599; 95% CI, 0.483-0.743; P < .001)
• median OS of patients with MM who received a diagnosis of NHL vs those without an SPM (median OS not reached vs 105 months; HR, 0.702, 95% CI, 0.594-0.831; P < .001)
• median OS of patients with MM who received a diagnosis of DLBCL vs those without an SPM (median OS not reached vs 106 months; HR, 0.712; 95% CI, 0.516-0.984; P = .04)
• median OS of patients with MM who received a diagnosis of melanoma vs those without an SPM (median OS not reached vs 105 months; HR, 0.743; 95% CI, 0.611-0.904; P = .003)

Conversely, survival was worse in patients who received a diagnosis of AML (67 months vs 106 months; HR, 1.522; 95% CI, 1.267-1.828; P < .001) and lung cancer (76 months vs 106 months; HR, 1.374; 95% CI, 1.157-1.632; P < .001) than those without any SPM. Survival was not shown to be significantly affected in patients who received a diagnosis of colorectal cancer, ALL, or CLL.

Researchers acknowledged that findings show many factors could explain why patients who received a diagnosis of any SPM were more likely to live longer than patients who did not receive a diagnosis of an SPM. This could reflect patients with more indolent disease biology or those who received better treatments, resulting in higher longevity and immortal time bias.

They noted that further study and results analyzing the timing of SPM diagnosis (post MM) and its subsequent impact on OS are forthcoming and will be presented.

“The finding that both AML and lung cancer as SPMs resulted in shorter survival is consistent with what would be expected in the general population, and serves as a good internal control. In summary, this study is the first to shed light on prognosis of patients with MM diagnosed with various SPMs,” the authors concluded.

References

1. Cooper JD, Thornton JA, Gibson SJ, Pham K, Sunderland K, DeStefano CB. Survival of patients with multiple myeloma diagnosed with second primary malignancies: an ASCO CancerLinQ analysis. Presented at: 64th American Society of Hematology Annual Meeting and Exposition; December 10-13, 2022; New Orleans, LA. Abstract 4510. https://doi.org/10.1182/blood-2022-170859

2. Poh C, Keegan T, Rosenberg AS. Secondary primary malignancies in multiple myeloma: a review. Blood Rev. 2021;46:100757. doi:10.1016/j.blre.2020.100757