Please assess the completion status of the following clinical trial:

Trial Title: Comparative Effectiveness of Sentinel Lymph Node Biopsy for Ductal Carcinoma In Situ

Study Design Characteristics:
- Allocation: None
- Intervention Model: None
- Observational Model: COHORT
- Primary Purpose: None
- Time Perspective: RETROSPECTIVE
- Masking: None
- Phase: None
- Number of Arms: None

Eligibility Criteria:
Inclusion Criteria:~* Female DCIS patients older than 67 years and younger than 94 years who were enrolled in a fee-for-service Medicare program and resided in the SEER areas.~* Aim 1: DCIS patients who received breast conserving surgery (BCS) as their first surgery~* Aim 1: DCIS patients who were diagnosed DCIS between January 1998 and December 2011~* Aim 2: DCIS patients who were diagnosed DCIS between January 2001 and December 2013~Exclusion Criteria:~* Aim 1: DCIS patients who received mastectomy as their first surgery~* Aim 2: DCIS patients who received BCS at the beginning yet received mastectomy in the end

- Gender: FEMALE
- Minimum Age: 67 Years
- Maximum Age: 94 Years
- Healthy Volunteers: f

Study Arms:
- Aim 1 Cohort (Type: None): The Aim 1 Cohort is constructed to perform analysis to address study objective Aim 1. This cohort includes patients diagnosed at ages 67-94 years with DCIS between January 1998 and December 2011, and received BCS as their first surgery. Patients in this cohort include those who received sentinel lymph node biopsy (SLNB) and who didn't receive SLNB.~The Aim 1 Cohort and the Aim 2 Cohort can overlap.
- Aim 2 Cohort (Type: None): The Aim 2 Cohort is constructed to perform analysis to address study objective Aim 2. This cohort includes patients diagnosed at ages 67-94 years with DCIS between January 2001 and December 2013, and received BCS as their first surgery. Patients in this cohort include those who received sentinel lymph node biopsy (SLNB) and who didn't receive SLNB.~The Aim 1 Cohort and the Aim 2 Cohort can overlap.

Based on this trial design, predict the completion outcome and termination type (if applicable).