Statement: the primary trial results show that Participants receiving lapatinib 1500 milligrams (mg) orally were more likely to achieve DFS at 5 years than placebo patients, however, there was less than a 30% difference in DFS rate between the two cohorts.
Primary_evidence: Outcome Measurement:    Number of Participants (Par.) With Any Recurrence of the Initial Disease, Second Primary Cancer, Contralateral Breast Cancer, or Death (Disease-free Survival [DFS])   DFS=interval between the date of randomization and the date of the first occurrence of an objective disease recurrence, a second primary cancer, or death from any cause. The date of the event is the earliest date of the occurrence of any of the following: local recurrence (LR) following mastectomy; LR in ipsilateral breast following lumpectomy; regional recurrence; distant recurrence; contralateral breast cancer, including ductal carcinoma in situ; other second primary cancer (excluding squamous or basal cell carcinoma of the skin, melanoma in situ, carcinoma in situ of the cervix, or lobular carcinoma in situ of the breast); death from any cause without a prior event. Par. who started additional anti-cancer adjuvant therapy prior to the recurrence of their disease were to be censored. Par. who did not withdraw from the study and did not experience a specified event or death were to be censored (follow-up ongoing) at the last visit date available at which progression was assessed.   Time frame: From randomization until date of the first occurrence of an objective disease recurrence, a second primary cancer, or death from any cause (assessed up to 6 years; 1 year of treatment, 5 years of follow-up [median of 5.3 years for final analysis]) Results 1:    Arm/Group Title: Lapatinib 1500 mg   Arm/Group Description: Participants received lapatinib 1500 milligrams (mg) orally once daily. Treatment was continued for a maximum of 12 months or until disease recurrence or development of a second primary cancer, withdrawal from study treatment due to unacceptable toxicity, or consent withdrawal.   Overall Number of Participants Analyzed: 1571   Measure Type: Number   Unit of Measure: Participants  Any recurrence or death: 252   Censored, New Anti-cancer Agent/Radiotherapy: 1   Censored, Follow-up Ended: 1318 Results 2:    Arm/Group Title: Placebo   Arm/Group Description: Participants received matching placebo orally once daily. Treatment was continued for a maximum of 12 months or until disease recurrence or development of a second primary cancer, withdrawal from study treatment due to unacceptable toxicity, or consent withdrawal.   Overall Number of Participants Analyzed: 1576   Measure Type: Number   Unit of Measure: Participants  Any recurrence or death: 290   Censored, New Anti-cancer Agent/Radiotherapy: 1   Censored, Follow-up Ended: 1285