Percentage of participants according to number of blood tests (0, 1, 2, 3, 4 and >=5) at 1 to 4 weeks after administration of palbociclib is reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study. Here, "Overall Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Percentage of participants according to number of blood tests (0, 1, 2, 3, 4 and >=5) at 5 to 8 weeks after administration of palbociclib is reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study. Here, "Overall Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Percentage of participants according to number of blood tests (0, 1, 2, 3, 4 and >=5) at 9 to 12 weeks after administration of palbociclib is reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study. Here, "Overall Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Percentage of participants according to number of blood tests (0, 1, 2, 3, 4 and >=5) at 13 to 16 weeks after administration of palbociclib is reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study. Here, "Overall Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Percentage of participants according to number of blood tests (0, 1, 2, 3, 4 and >=5) at 17 to 20 weeks after administration of palbociclib is reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study. Here, "Overall Number of Participants Analyzed" signifies number of participants evaluable for this outcome measure.

Time to treatment failure of palbociclib was defined as time from the date of first palbociclib prescription to the date of lost to follow-up or to the date of the next line of therapy, defined as the end of palbociclib treatment. Time to treatment failure of palbociclib was censored at participant disenrollment or end of study period.

All eligible participants who were enrolled and whose data was included in the study.

All eligible participants who were enrolled and whose data was included in the study.

Number of participants according to regimen of first subsequent therapy after end of palbociclib at first line and second line are reported in this outcome measure. The regimen was defined as any breast cancer treatment(s) received within 30 days of earlier treatment initiation. Only regimens used by >=3 participants in participants treated with palbociclib in the first or second line settings were reported. One participant may be included in more than one regimen.

All eligible participants who were enrolled and whose data was included in the study. Here, 'Overall Number of Participants Analyzed' signifies number of participants evaluable for this outcome measure and 'Number Analyzed' signifies number of participants evaluable for the specified rows.

Time to treatment failure of subsequent therapy after palbociclib was defined as time from the date of first next line of therapy after end of palbociclib treatment to the date of lost to follow-up or to the date of the second next line of therapy. Time to treatment failure was censored at participant disenrollment or end of study period.

All eligible participants who were enrolled and whose data was included in the study. Here, 'Overall Number of Participants Analyzed' signifies number of participants evaluable for this outcome measure.

BMI was calculated using the formula: BMI=(weight)/(height/100)^2.

All eligible participants who were enrolled and whose data was included in the study. Here, 'Overall Number of Participants Analyzed' signifies number of participants evaluable for this outcome measure.

Charlson Comorbidity Index predicts the ten-year mortality for a participant who may have a range of comorbid conditions. 17 comorbidities were assessed with associated weights from 1 to 6, based on the adjusted risk of mortality. The total score is derived by summing up the weights of comorbid conditions presented. The minimum score value is 0 and maximum is 37. A higher score means a greater mortality risk.

All eligible participants who were enrolled and whose data was included in the study.

Index year was considered as the year corresponding to the start date of the first palbociclib line. Number of participants according to index year (2017, 2018, 2019, 2020, 2021) are reported in this outcome measure.

All eligible participants who were enrolled and whose data was included in the study.

One participant may be included in more than one breast cancer treatment.

All eligible participants who were enrolled and whose data was included in the study. Here, 'Overall Number of Participants Analyzed' signifies number of participants evaluable for this outcome measure.

All eligible participants who were enrolled and whose data was included in the study.

All eligible participants who were enrolled and whose data was included in the study.

Number of participants according to the type of endocrine therapy (fulvestrant, letrozole, exemestane, anastrozole, tamoxifen, toremifen and other) combined with palbociclib at first line, second line and third line is reported in this outcome measure. "Other" included participants prescribed >=1 endocrine therapies and those prescribed medroxyprogesterone.

All eligible participants who were enrolled and whose data was included in the study. Here, 'Overall Number of Participants Analyzed' signifies number of participants evaluable for this outcome measure and 'Number Analyzed' signifies number of participants evaluable for the specified rows.