title: The interval between cancer diagnosis among mothers and offspring in a population-based cohort.
abstract: BACKGROUND
  Familial cancers may be due to shared genes or environment, or chance aggregation. We explored the possibility that ascertainment bias influences cancer detection in families, bearing upon the time interval between diagnosis of affected mothers and offspring.
  
  
  METHODS
  The Jerusalem Perinatal Study (JPS) comprises all mothers (n = 39,734) from Western Jerusalem who gave birth 1964 -1976 and their offspring (n = 88,829). After linking identification numbers with Israel's Cancer Registry we measured the absolute time interval between initial cancer diagnoses in affected mother-offspring pairs. We tested the probability of obtaining intervals as short as those observed by chance alone, using a permutation test on the median interval.
  
  
  RESULTS
  By June 2003 cancer had developed in 105 mother-offspring pairs within the cohort. Common sites among mothers were breast (47%), colorectal (9%), non-Hodgkin lymphoma (NHL) (8%) and cervix (7%), while for offspring in affected pairs common cancers were leukemia (12.4%), thyroid (13.3%), NHL (10.5%), breast (10.5%) and melanoma (7.6%). The median interval between diagnoses was 5.9 years, but for 33% of affected pairs the interval was < or =3 years. The probability of this occurring by chance alone was 0.03. This held true whether the offspring's or mother's diagnosis was first (P < 0.01).
  
  
  CONCLUSIONS
  In a population-based cohort followed for three decades, the absolute interval between the diagnosis of cancer in mothers and their offspring is shorter than expected by chance. Explanations include shared environmental exposures or the possibility that cancer ascertainment in one pair member affects health behaviors in the other resulting in early diagnosis. The latter may bias the estimation of anticipation and survival in familial cancers.
authors.affiliation: Braun School of Public Health, Hadassah-Hebrew University, Jerusalem, Israel. ora@vms.huji.ac.il
authors.forename: Ora
authors.initials: O
authors.lastname: Paltiel
authors.forename: Yehiel
authors.initials: Y
authors.lastname: Friedlander
authors.forename: Lisa
authors.initials: L
authors.lastname: Deutsch
authors.forename: Rebecca
authors.initials: R
authors.lastname: Yanetz
authors.forename: Ronit
authors.initials: R
authors.lastname: Calderon-Margalit
authors.forename: Efrat
authors.initials: E
authors.lastname: Tiram
authors.forename: Hagit
authors.initials: H
authors.lastname: Hochner
authors.forename: Micha
authors.initials: M
authors.lastname: Barchana
authors.forename: Susan
authors.initials: S
authors.lastname: Harlap
authors.forename: Orly
authors.initials: O
authors.lastname: Manor
mesh_terms: D032721:Adult Children; D017668:Age of Onset; D020132:Anticipation, Genetic / Q000235:genetics*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D006689:Hodgkin Disease / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D006801:Humans; D015994:Incidence; D007557:Israel / Q000453:epidemiology; D007938:Leukemia / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D009035:Mothers / Q000706:statistics & numerical data*; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D044382:Population Groups / Q000235:genetics*; D012042:Registries / Q000706:statistics & numerical data; D012107:Research Design; D012878:Skin Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D013997:Time Factors