title: Assessment of follow-up, and the completeness and accuracy of cancer case ascertainment in three areas of India.
abstract: BACKGROUND
  A prospective study of diet and cancer has not been conducted in India; consequently, little is known regarding follow-up rates or the completeness and accuracy of cancer case ascertainment.
  
  
  METHODS
  We assessed follow-up in the India Health Study (IHS; 4671 participants aged 35-69 residing in New Delhi, Mumbai, or Trivandrum). We evaluated the impact of medical care access and relocation, re-contacted the IHS participants to estimate follow-up rates, and conducted separate studies of cancer cases to evaluate registry coverage (604 cases in Trivandrum) and the accuracy of self- and proxy-reporting (1600 cases in New Delhi and Trivandrum).
  
  
  RESULTS
  Over 97% of people reported seeing a doctor and 85% had lived in their current residence for over six years. The 2-year follow-up rate was 91% for Trivandrum and 53% for New Delhi. No cancer cases were missed among public institutions participating in the surveillance program in Trivandrum during 2003-2004; but there are likely to be unmatched cases (ranging from 5 to 13% of total cases) from private hospitals in the Trivandrum registry, as there are no mandatory reporting requirements. Vital status was obtained for 36% of cancer cases in New Delhi as compared to 78% in Trivandrum after a period of 4 years.
  
  
  CONCLUSIONS
  A prospective cohort study of cancer may be feasible in some centers in India with active follow-up to supplement registry data. Inclusion of cancers diagnosed at private institutions, unique identifiers for individuals, and computerized medical information would likely improve cancer registries.
authors.affiliation: Regional Cancer Center, Trivandrum, Kerala, India. amathew@rcctvm.org
authors.forename: Aleyamma
authors.initials: A
authors.lastname: Mathew
authors.forename: Carrie R
authors.initials: CR
authors.lastname: Daniel
authors.forename: Leah M
authors.initials: LM
authors.lastname: Ferrucci
authors.forename: Tulika
authors.initials: T
authors.lastname: Seth
authors.forename: Susan S
authors.initials: SS
authors.lastname: Devesa
authors.forename: Preethi S
authors.initials: PS
authors.lastname: George
authors.forename: Hemali
authors.initials: H
authors.lastname: Shetty
authors.forename: Niveditha
authors.initials: N
authors.lastname: Devasenapathy
authors.forename: Susan
authors.initials: S
authors.lastname: Yurgalevitch
authors.forename: Tanuja
authors.initials: T
authors.lastname: Rastogi
authors.forename: Dorairaj
authors.initials: D
authors.lastname: Prabhakaran
authors.forename: Prakash C
authors.initials: PC
authors.lastname: Gupta
authors.forename: Nilanjan
authors.initials: N
authors.lastname: Chatterjee
authors.forename: Rashmi
authors.initials: R
authors.lastname: Sinha
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D011446:Prospective Studies; D012042:Registries