The association between renal cell carcinoma and multiple myeloma ...

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2010 THE AUTHORS; BJU INTERNATIONAL Urological Oncology

2010 BJU INTERNATIONAL

RENAL CELL CARCINOMA AND MULTIPLE MYELOMA OJHA ET AL.

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The association between renal cell carcinoma and multiple myeloma: insights from population-based data

BJU INTERNATIONAL

Rohit P. Ojha1*†, Eva L. Evans†, Martha J. Felini†, Karan P. Singh‡ and Raymond Thertulien§ *Division of Population Sciences, Dana-Farber Cancer Institute, Boston, MA, †Department of Epidemiology, and ‡ Department of Biostatistics, University of North Texas Health Science Center, Fort Worth, TX, and §Cancer Centers of North Carolina, US Oncology, Asheville, NC, USA Accepted for publication 1 September 2010 1

At second affiliation when study was conducted

Study Type – Prevalence (population based cohort) Level of Evidence 3b OBJECTIVE • To evaluate the hypothesis of an association between renal cell carcinoma and multiple myeloma. PATIENTS AND METHODS • Data from nine population-based registries in the Surveillance, Epidemiology and End Results programme were used to evaluate two separate cohorts of patients diagnosed between 1973 and 2006: patients diagnosed with renal cell carcinoma as a primary malignancy (n = 57 190) and patients diagnosed with multiple myeloma as a primary malignancy (n = 34 156). • We estimated standardized incidence ratios (SIRs) with corresponding 95% confidence intervals (CIs) by dividing the number of observed cases of multiple myeloma within the renal cell carcinoma cohort and the number of renal cell carcinoma cases within the multiple

INTRODUCTION Survivors of a primary malignancy have an increased risk of developing a second primary malignancy because of shared risk factors (genetic and environmental), antecedent cancer therapy, or other factors [1]. Patients with renal cell carcinoma are particularly susceptible to second primary malignancies

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What’s known on the subject? and What does the study add? Several case-series have hypothesized a potential association between renal cell carcinoma and multiple myeloma. Nonetheless, this hypothesis has not been systematically explored in a population-based setting with sufficient sample size to estimate a magnitude of association. Our analyses revealed a bidirectional relation between renal cell carcinoma and multiple myeloma, which typically indicates that common risk factors influence both malignancies. Our findings may be useful for raising awareness among clinicians that a diagnosis of multiple myeloma may be within the spectrum of second malignancies among patients with renal cell carcinoma and that a diagnosis of renal cell carcinoma may be within the spectrum of second malignancies among patients with multiple myeloma.

myeloma cohort by the number of expected cases for each malignancy in the US general population.

multiple myeloma had a higher relative risk of renal cell carcinoma than the general population (SIR = 1.89, 95% CI 1.47–2.40).

RESULTS

CONCLUSION

• The renal cell carcinoma cohort yielded 88 multiple myeloma cases during 293 511 person-years of follow up. Patients with renal cell carcinoma had a higher relative risk of multiple myeloma than the general population (SIR = 1.51, 95% CI 1.21–1.85). • The multiple myeloma cohort yielded 69 renal cell carcinoma cases during 100 804 person-years of follow up. Patients with

• Our analyses revealed a bidirectional association between renal cell carcinoma and multiple myeloma, which typically indicates shared risk factors.

[2,3]; previous studies have identified associations between renal cell carcinoma and cancers of the bladder [2–5], prostate [2–4,6], colon [2–4] and lung [2,4,5] as well as malignant melanoma [2,7,8] and nonHodgkin lymphoma [2,4,8–10]. Recently, several case-series analyses have prompted investigators to postulate an association between renal cell carcinoma and multiple

myeloma [10–16]. Although case-series are vital for generating hypotheses, this type of study design is insufficient for determining an association because of the small sample size and the lack of a comparison group [17]. A study with sufficient sample size and an appropriate comparison group is necessary to determine if an association exists between renal cell carcinoma and multiple myeloma.

KEYWORDS renal cell carcinoma, multiple myeloma, second primary malignancy, risk factors

2010 THE AUTHORS

BJU INTERNATIONAL

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2 0 1 0 B J U I N T E R N A T I O N A L | 1 0 8 , 8 2 5 – 8 3 0 | doi:10.1111/j.1464-410X.2010.09892.x

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O J H A ET AL.

We used population-based data from the Surveillance, Epidemiology and End Results (SEER) registries to evaluate the hypothesis of an association between renal cell carcinoma and multiple myeloma and so provide insight regarding the necessity for clinicians to be aware of the potential for a diagnosis of a second primary multiple myeloma among patients with renal cell carcinoma. PATIENTS AND METHODS We used data from nine population-based registries in the SEER programme [18] to evaluate two separate patient cohorts diagnosed with a primary malignancy between 1 January 1973 and 31 December 2006: patients diagnosed with renal cell carcinoma and patients diagnosed with multiple myeloma. We compiled person-years of observation for individuals in each cohort after initial primary cancer diagnosis until date of death, the end of the observation period (31 December 2006), or subsequent primary diagnosis of multiple myeloma in all patients with an initial diagnosis of renal cell carcinoma or subsequent primary diagnosis of renal cell cancer in all patients with an initial diagnosis of multiple myeloma. We estimated overall, age-specific (1 0y ea rs

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This population-based investigation was designed to evaluate the hypothesis generated from several recent case-series that renal cell carcinoma and multiple myeloma are associated. Our analyses revealed a bidirectional association between renal cell carcinoma and multiple myeloma; the relative risk of multiple myeloma incidence was 51% higher among patients with renal cell carcinoma than in the general population and the relative risk of renal cell carcinoma incidence was 89% higher among multiple myeloma patients than in the general population. The highest overall relative risks were observed within the first year after diagnosis of the primary malignancy. In general, the bidirectional association between these malignancies suggests shared risk factors rather than treatment-related consequences [21], which is consistent with other reported second primary malignancies among patients with renal cell carcinoma [2]. Furthermore, chemotherapy and radiation therapy are not conventional treatment options for renal cell carcinoma, which decreases the potential for treatment-related concerns [2].

FIG. 1. Relative risks of multiple myeloma incidence among patients with renal cell carcinoma and renal cell carcinoma incidence among patients with multiple myeloma by duration since diagnosis of primary malignancy.