Observational Study of Incidence Rates of Esophageal Cancer in Women Taking Medications for the Prevention or Treatment of Osteoporosis (MK-0217A-352)

• Percentage of Participants With Exposure to Study Drugs (Case-Cohort Analysis) [ Time Frame: Exposure to study drug at least 720 days before disease onset ] [ Designated as safety issue: No ]
  To determine the use of study drugs (alendronate, etidronate, ibandronate, risedronate, and raloxifene) among female participants with esophageal cancer (cases) and a comparison subcohort, a case-cohort analysis was performed using women meeting criteria from the General Practice Research Database (GPRD, United Kingdom). Exposure to osteoporosis drugs administered 720 days before cancer onset was determined in cases and compared to contemporaneous assessments in a comparison subcohort matched by year of birth and membership in the GPRD on the case's onset date. Cases were confirmed and case onset dates determined by electronic algorithm (based on electronic medical record data) or by medical record review.
• Number of Cases of Esophageal Cancer Per 100,000 Woman-Years (Intent-to-Treat Analysis) [ Time Frame: Up to approximately 7.3 years of follow-up ] [ Designated as safety issue: Yes ]
  To assess the relative risk of esophageal cancer associated with osteoporosis study drugs (alendronate, etidronate, ibandronate, risedronate, and raloxifene), initiators of osteoporosis drugs and non-initiators (comparators, women sharing match criteria with the initiator) entered an inception cohort for every three-month period, beginning in the first quarter of 1996. Assignment to study drug exposure group remained fixed from the start of follow-up, analogous to an intent-to-treat analysis. The risk of esophageal cancer among initiators of study drug compared to non-initiators of study drug was estimated through calculation of a hazard ratio. For calculation of 721+ day hazard ratios, only esophageal cancer cases occurring at least 721 days from initiation of study drug were used. For calculation of 1441+ day hazard ratios, only esophageal cancer cases occurring at least 1441 days from initiation of study drug were used.

This is a 2-phase retrospective database study, using both case-cohort and inception (intention-to-treat) cohort analyses to evaluate any association between oral treatments for osteoporosis and the risk of esophageal cancer in women.

Women who have at least two years of experience in the GPRD and are 55 or older between 1996 and 2008; all cases of esophageal cancer were identified and matched to all women in the comparison sample (all women with same year of birth drawn from the random subsample of 25,000).

• Esophageal Cancer
• Squamous Cell Carcinoma
• Adenocarcinoma

• Drug: Alendronate
  Other Name: FOSAMAX®
• Drug: Etidronate
  Other Name: DIDRONEL®
• Drug: Ibandronate
  Other Name: BONIVA®
• Drug: Risedronate
  Other Names:

  • ACTONEL®
  • ATELVIA®
• Drug: Raloxifene
  Other Name: EVISTA®

• Esophageal Cancer Cases
  Participants with any United Kingdom General Practice Research Database (GPRD) Medical code for esophageal cancer (cases). Cases were confirmed and case onset dates determined by electronic algorithm (based on electronic medical record data) or by medical record review.
  Interventions:

  • Drug: Alendronate
  • Drug: Etidronate
  • Drug: Ibandronate
  • Drug: Risedronate
  • Drug: Raloxifene
• Comparison Sample (Case-Cohort)
  Participants who were matched to cases by age and membership in the GPRD on the case's onset date, and had not experienced any form of esophageal cancer or Paget's Disease and had not received oral or intravenous steroids or chemotherapy or radiotherapy, as indicated by GPRD codes.
  Interventions:

  • Drug: Alendronate
  • Drug: Etidronate
  • Drug: Ibandronate
  • Drug: Risedronate
  • Drug: Raloxifene
• Non-treated Comparators
  Participants who did not initiate treatment of osteoporosis with a study drug
• Alendronate
  Participants initiating treatment for osteoporosis with alendronate
  Intervention: Drug: Alendronate
• Etidronate
  Participants initiating treatment for osteoporosis with etidronate
  Intervention: Drug: Etidronate
• Ibandronate
  Participants initiating treatment for osteoporosis with ibandronate
  Intervention: Drug: Ibandronate
• Risedronate
  Participants initiating treatment for osteoporosis with risedronate
  Intervention: Drug: Risedronate
• Raloxifene
  Participants initiating treatment for osteoporosis with raloxifene
  Intervention: Drug: Raloxifene

Inclusion Criteria:

• Cases:

  • Women in the database aged 55 or older between 1996 and 2008 with diagnosis of esophageal cancer

• Comparator Controls:

  • Each case was matched to all women in the random subcohort of 25,000 who had the same year of birth as the case and were in the database at the time of diagnosis.

Exclusion Criteria:

• Women with diagnosis of any other cancer or Paget's Disease or who have received oral or intravenous steroids before the index date