Table 1 Study population selection process

Initial sample included in the SEER database

142,689

Initial diagnosis date on or after January 1, 2001

135,608

Patients whose first diagnosis recorded in the SEER database was STS

21,167

Patients with evidence (i.e., claim in Medicare data or diagnosis in SEER database) of metastatic disease

8537

 Initially diagnosed at metastatic stage^a

3391

 Initially diagnosed at non-metastatic stage^a

5146

Patients 65 years or older at time of metastatic STS diagnosis

6712

Patients who were alive at initial diagnosis of STS (i.e., reporting source other than autopsy or death certificate)

6705

Patients who were not enrolled in an HMO for at least 6 months prior to initial diagnosis of STS to end of follow-up period

5166

Patients who have continuous enrollment in Medicare Part A and B (non-HMO) for at least 6 months prior to initial diagnosis of STS until end of follow-up period

4353

Patients who are not lost to follow-up prior to the assigned advanced STS diagnosis date^b

4324

Patients with a date of advanced STS diagnosis different than initial STS diagnosis (patients excluded if no surgery after initial STS diagnosis and no secondary neoplasm claim)

4298

Patients with a date of advanced STS diagnosis different than initial STS diagnosis (patients excluded if initial STS diagnosis and secondary neoplasm claim on the same date)

4274

Final study population

4274