Original article
Validation of Surveillance, Epidemiology, and End Results TNM staging for testicular germ cell tumor

https://doi.org/10.1016/j.urolonc.2014.04.004Get rights and content

Abstract

Objectives

To evaluate the accuracy of testicular germ cell tumor category in the Surveillance, Epidemiology, and End Results (SEER) database following the 2010 American Joint Committee of Cancer revision of the TNM staging criteria.

Methods

We performed a retrospective review of our testicular cancer database from January 2010 to July 2011. Registrar extracted data on 76 patients were entered into the Cancer Surveillance Program database from 2 hospitals. We reviewed the SEER coding for each patient, including T, N, M, and S and overall stage group, as well as the range and S value given for tumor markers (lactate dehydrogenase, beta-human chorionic gonadotropin, and α-fetoprotein) both preorchiectomy and postorchiectomy. We then compared these values with the actual staging and tumor markers determined by patient medical record review by a single urologist.

Results

A high proportion of registry records were found to have inaccurate values of category: 71% of S category entries and 34% of N category entries, leading to an overall group stage inaccuracy of 77% in SEER data. Accuracy of overall combined stage group was significantly different between hospitals, with a higher percentage of errors at Hospital A (P< 0.05).

Conclusion

Despite improvements made to the SEER criteria for extracting data used to code testicular germ cell tumor TNM stage, considerable errors were identified, most notably in tumor marker and nodal status, resulting in an overwhelming number of errors in overall stage. Our findings suggest caution when utilizing SEER data for review of patients with testicular cancer and their staging.

Introduction

Testicular germ cell tumors (TGCTs) are the most common neoplasm of young men in the United States, with an estimated 8,590 new cases and 360 TGCT deaths in 2012 [1]. These cancers are highly curable, and from 2001 to 2007 the estimated 5-year survival rate for patients with TGCT was 97% [2]. Diagnostic and treatment decisions rely on accurate staging of tumors, which in turn depends in part on serum measurement of the tumor markers, beta-human chorionic gonadotropin (β-HCG), lactate dehydrogenase (LDH), and α-fetoprotein (AFP). Utilization of germ cell tumor markers for staging, prognostic, and treatment purposes has been extensively studied and reported [3]. Germ cell tumor markers play a vital role in not only staging but also assessing prognosis [4], and thereby making meaningful measures of trends in occurrence and survival.

The National Cancer Institute׳s Surveillance, Epidemiology, and End Results (SEER) program collects data from population-based cancer registries covering approximately 28% of the population of the United States, providing incidence and survival data used to measure cancer burdens, recognize important trends, formulate new hypotheses, establish research and clinical priorities, and evaluate consequences of preventive and therapeutic interventions. The value of registry data depends critically upon accuracy, which is generally considered very high. However, determination of clinical stage of TGCTs has unique challenges owing to reliance of clinical stage on tumor markers assessed following orchiectomy. In 2004, the SEER Collaborative Stage (CS) version 1 began to include tumor markers into the staging for testicular cancer patients, in accordance with the American Joint Committee of Cancer (AJCC) TNM staging [5]. However, these guidelines did not specify whether preorchiectomy or postorchiectomy tumor markers were to be extracted. In 2010, an effort was made to correct this ambiguity by implementation of the CS version 2 guidelines, which instruct registrars to extract both preorchiectomy and postorchiectomy tumor markers, the latter to be incorporated into the S category, corresponding to the 7th edition of the AJCC TNM staging [6]. As each marker has a separate half-life, extracting tumor markers too early may lead to erroneously high estimates of tumor category. We, therefore, hypothesized that SEER registry data may contain some degree of systematic error in the staging of TGCTs even after introduction of CS version 2 guidelines in 2010. To assess this possibility we conducted a validation study comparing category registered with SEER to that determined by a urologist based on review of original medical record data for patients with TGCT treated at University of Southern California (USC)–associated hospitals.

Section snippets

Materials and methods

We identified within SEER records incident TGCT diagnosed at USC-associated hospitals from January 2010 to July 2011. A single urologist then reviewed all available medical records for patients meeting these criteria and recorded TGCT clinical stage for each patient at presentation according to the AJCC 7th edition TNM staging criteria. T category was determined from the orchiectomy pathology report as available. If chemotherapy was instituted before orchiectomy or no path report available,

Results

Among patients with TGCT treated at USC-affiliated hospitals, 76 were identified as having data abstracted into the SEER registry following adoption of CS version 2 in January 2010. Characteristics of these patients are summarized in Table 1. Instances of disagreement between tumor stage as coded by the SEER registry and tumor stage as determined by an urologist are summarized in Table 2. We interpreted disagreement as representing error in SEER data. The N, M, and S categories were scored both

Discussion

Tumor category is coded in cancer registry records using data extracted from medical records by registrars according to specified guidelines. A series of revisions have been made in an attempt to eliminate ambiguities in past guidelines that left room for inaccuracies in TGCT stage information collected by registries. We report a validation study of accuracy of category coded in SEER records that was scored using information abstracted by registrars provided with the most recent CS version 2

Conclusion

Our findings suggest that caution is warranted when interpreting original SEER data on testicular cancer for purposes that require accurate stage information. The same considerations apply when evaluating published studies based on cancer registry data when TGCT stage is an important study variable. We suggest modifications to the CS version 2 to clarify some of the issues identified in our study.

References (15)

  • M.R. van Dijk et al.

    Survival of non-seminomatous germ cell cancer patients according to the IGCC classification: an update based on meta-analysis

    Eur J Cancer

    (2006)
  • National Cancer Institute. 〈http://www.cancer.gov/cancertopics/types/testicular〉 [accessed June...
  • Howlader N, Krapcho M, Neyman N, et al. SEER Cancer Statistics Review. Bethesda, MD: National Cancer Institute; pp....
  • T. Gilligan et al.

    American Society of Clinical Oncology Clinical Practice Guideline on uses of serum tumor markers in adult males with germ cell tumors

    J Clin Oncol

    (2010)
  • Collaborative Stage for TNM Edition 6. American Joint Committee for Cancer Staging,...
  • Collaborative Stage for TNM Edition 7. American Joint Committee for Cancer Staging,...
  • M.L. Biggs et al.

    Differences in testis cancer survival by race and ethnicity: a population-based study, 1973–1999 (United States)

    Cancer Causes Control

    (2004)
There are more references available in the full text version of this article.

Cited by (14)

  • Validation of testicular germ cell tumor staging in nationwide cancer registries

    2021, Urologic Oncology: Seminars and Original Investigations
    Citation Excerpt :

    Our findings at UT Southwestern are congruent with related analyses from previous publications. A validation study by Faber et al. demonstrated that inaccuracies in testicular cancer staging exist within their institutional registry for N, S, and composite staging even after the implementation of Version 2 guidelines in 2010 [8]. We sought to address the low concordance rates with our tumor registry and provide them a coaching opportunity to improve their abstraction of testicular cancer data.

  • Racial and socioeconomic disparities in retroperitoneal lymph node dissection and survival in nonseminomatous germ cell tumor: A population-based study

    2021, Urologic Oncology: Seminars and Original Investigations
    Citation Excerpt :

    Given that race and nSES were our primary covariates of interest and unknown values comprised a small fraction of the cohort, we further excluded patients with unknown nSES (n = 630) and unknown race (n = 200), leaving 9,279 patients. It has been suggested that SEER staging of testicular cancer is potentially inaccurate [9]. To address this, we employed 2 previously described methodologies to improve the integrity of SEER testicular cancer staging [10, 11].

  • Contemporary Assessment of Long-Term Survival Rates in Patients With Stage I Nonseminoma Germ-Cell Tumor of the Testis: Population-Based Comparison Between Surveillance and Active Treatment After Initial Orchiectomy

    2019, Clinical Genitourinary Cancer
    Citation Excerpt :

    Fourth, the SEER database does not provide information on the different types of CHT administered.27 Last, as reported in previous analyses,28 the SEER database may not accurately classify NSGCTT patients. However, it is important to underline that the SEER database is still considered the reference standard for data quality among cancer registries in the United States and globally.29

View all citing articles on Scopus
View full text