title: A population-based study of incidence and patient survival of small cell carcinoma in the United States, 1992-2010.
abstract: BACKGROUND
  In contrast to the well-described epidemiology and behavior of small cell lung carcinoma (SCLC), little is known about extrapulmonary small cell carcinoma (EPSCC).
  
  
  METHODS
  Using data from the Surveillance, Epidemiology and End Results (SEER) Program (1992-2010), we calculated age-adjusted incidence rates (IRs), IR ratios (IRRs), annual percent change (APC), relative survival (RS), RS ratios (RSRs), and the respective 95% confidence intervals (95% CI) of SCLC and EPSCC according to primary site. We used the SEER historic stage variable that includes localized (confined to the organ of origin), regional (direct extension to adjacent organ/tissue or regional lymph nodes), and distant (discontinuous metastases) stages and combined localized and regional stages into "limited" stage.
  
  
  RESULTS
  The incidence of SCLC (IR = 76.3/million person-years; n = 51,959) was 22-times that of EPSCC (IR = 3.5; n = 2,438). Of the EPSCC sites, urinary bladder, prostate, and uterine cervix had the highest incidence (IRs = 0.7-0.8); urinary bladder (IRR = 4.91) and stomach (IRR = 3.46) had the greatest male/female disparities. Distant-to-limited stage site-specific IRRs of EPSCC were significantly elevated for pancreas (IRR = 6.87; P < 0.05), stomach, colon/rectum, ovary, and prostate (IRRs = 1.62-2.42; P < 0.05) and significantly decreased for salivary glands, female breast, uterine cervix, and urinary bladder (IRRs = 0.32-0.46). During 1992-2010, significant changes in IRs were observed for EPSCC overall (APC = 1.58), small cell carcinoma of the urinary bladder (APC = 6.75), SCLC (APC = -2.74) and small cell carcinoma of unknown primary site (APC = -4.34). Three-year RS was significantly more favorable for patients with EPSCC than SCLC for both limited (RSR = 2.06; 95% CI 1.88, 2.26) and distant stages (RSR = 1.55; 95% CI 1.16, 2.07). Among limited stage small cell carcinoma, RS was most favorable for salivary glands, female breast, and uterine cervix (RS = 52-68%), whereas RS for nearly all sites with distant stage disease was <10%.
  
  
  CONCLUSIONS
  EPSCC comprises a heterogeneous group of diseases that appears, at least in part, etiologically distinct from SCLC and is associated with more favorable stage-specific patient survival.
authors.affiliation: Oklahoma City Veterans Affairs Health Care System, Oklahoma City, OK, 73104, USA. doresg@mail.nih.gov.|Department of Health and Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA. doresg@mail.nih.gov.
authors.forename: Graça M
authors.initials: GM
authors.lastname: Dores
authors.affiliation: Hematology and Oncology Associates, St. Louis, MO, 63136, USA. qubaiaho@yahoo.com.
authors.forename: Osama
authors.initials: O
authors.lastname: Qubaiah
authors.affiliation: Oklahoma City Veterans Affairs Health Care System, Oklahoma City, OK, 73104, USA. ankur.mody@va.gov.
authors.forename: Ankur
authors.initials: A
authors.lastname: Mody
authors.affiliation: John Peter Smith Hospital, Fort Worth, TX, 76104, USA. drghabache@gmail.com.|University of North Texas Health Science Center, Fort Worth, TX, 76106, USA. drghabache@gmail.com.
authors.forename: Bassam
authors.initials: B
authors.lastname: Ghabach
authors.affiliation: Department of Health and Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA. devesas@exchange.nih.gov.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Devesa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012727:Sex Characteristics; D055752:Small Cell Lung Carcinoma / Q000453:epidemiology* / Q000473:pathology / Q000556:secondary; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000556:secondary; D016019:Survival Analysis; D014481:United States; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000556:secondary