1.	Phase III Randomized, Placebo-Controlled Study of Beta-Carotene and Vitamin E in the Prevention of Lung Cancer (Summary Last Modified 10/88) Phase: Phase III Type: Prevention Status: Closed Age: 50 to 69 Sponsor: Protocol IDs: DCPC-CPSB-10005
2.	Study of the Effect of Nutritional Intervention on Esophageal Cancer in Linxian, People's Republic of China (Summary Last Modified 10/88) Phase: Phase III Type: Prevention Status: Completed Age: 40 to 69 Sponsor: Protocol IDs: DCPC-CPSB-11204
3.	Phase III Study of Radiotherapy Alone vs Radiotherapy plus Oral Beta-Carotene in Patients with Advanced Cancer of the Head and Neck Phase: Phase III Type: Supportive care, Treatment Status: Closed Age: any age Sponsor: Protocol IDs: UCHSC-88251, NCI-V89-0098
4.	Phase III Randomized Placebo-Controlled Study of Beta Carotene for Chemoprevention of Second Primaries in Patients with Stage I/II Head and Neck Cancer Phase: Phase III Type: Prevention Status: Closed Age: adult Sponsor: NCI Protocol IDs: SWOG-9043, NCI-P93-0039
5.	Phase II Study of Isotretinoin (Ro4-3780) with Randomization to Isotretinoin or Beta Carotene Treatment in Patients with Premalignant Lesions of the Oral Cavity (Summary Last Modified 01/90) Phase: Phase II Type: Prevention Status: Closed Age: 15 and over Sponsor: Protocol IDs: MDA-DM-87017, NCI-P89-0001
6.	Phase II Study of Beta Carotene with Randomization to No Treatment or Beta Carotene Maintenance in Patients with Premalignant Lesions of the Oral Cavity (Summary Last Modified 11/92) Phase: Phase II Type: Prevention Status: Closed Age: 18 and over Sponsor: Protocol IDs: UARIZ-8979, NCI-P92-0012
7.	Phase II, Randomized, Placebo-controlled Study of Beta-Carotene for Chemoprevention of Premalignant Cervical Cancer (Summary Last Modified 06/93) Phase: Phase II Type: Prevention Status: Closed Age: 21 to 60 Sponsor: NCI Protocol IDs: UCI-90146, NCI-P92-0016
8.	Safety of Antioxidants During GYN Cancer Care Phase: Phase II Type: Treatment Status: Closed Age: No age specified Sponsor: Other Protocol IDs: 10006, NCT00284427
9.	Randomized, Placebo-Controlled Study of Beta Carotene for Chemoprevention of Premalignant Cervical Cancer Phase: No phase specified Type: Prevention Status: Closed Age: 16 to 65 Sponsor: Protocol IDs: AECM-CCI90-140, NCI-P92-0025
10.	Long-Term Monitoring of Potential Side Effects and Adherence in Subjects at High Risk for Lung Cancer Enrolled in Two Chemoprevention Studies with Beta Carotene and Retinol: Vanguard Study (Summary Last Modified 11/92) Phase: No phase specified Type: Prevention Status: Closed Age: 45 to 74 Sponsor: Protocol IDs: FHCRC-VANGUARD, NCI-P92-0028
11.	Randomized, Placebo-Controlled Beta Carotene and Retinol Efficacy Trial (CARET) for Chemoprevention of Lung Cancer in High-Risk Populations Phase: No phase specified Type: Prevention Status: Closed Age: 45 to 69 Sponsor: Protocol IDs: FHCRC-CARET, NCI-P92-0029
12.	Randomized, Placebo-Controlled Study of Beta Carotene for Chemoprevention of Cancer in Men: the Physicians' Health Study (Summary Last Modified 02/93) Phase: No phase specified Type: Prevention Status: Closed Age: 40 to 84 Sponsor: Protocol IDs: HMS-PHS, NCI-P93-0034
13.	Randomized, Placebo-Controlled Study of the Effects of Beta Carotene on the Rate of Colonic Cell Proliferation in Patients with Colon Cancer or Adenomatous Colonic Polyps and in Normal Subjects (Summary Last Modified 09/93) Phase: No phase specified Type: Prevention Status: Closed Age: 40 to 75 Sponsor: Protocol IDs: LUMC-B-CAROTENE, NCI-P93-0044
14.	Physicians' Health Study II Phase: No phase specified Type: Prevention Status: Completed Age: 50 and over Sponsor: NCI, Other Protocol IDs: CDR0000448630, BWH-1999-P-003315, BWH-1999-P-003318, BWH-83-00405, R01CA097193, NCT00270647