Challenges associated with longitudinal survivorship research: attrition and a novel approach of reenrollment in a 6-year follow-up study of older breast cancer survivors.

INTRODUCTION: Breast cancer is the most common type of cancer among older women. The vast majority of women with breast cancer become long-term survivors.
METHODS: We selected a convenience sample of women with: (1) stage I-IIIa disease, (2) age 65-years or older, and (3) permission from physician to contact. Data were collected over 6-years of follow-up from consenting patients' medical records, telephone interviews, and the National Death Index. Before year 4 of follow-up we attempted to relocate women lost to follow-up using a single protocol and when successful, invited them to reenroll in the study. In this secondary data-analysis, baseline characteristics were compared among subjects with continuous follow-up, those who reenrolled, died, or were lost to follow-up.
RESULTS: Among 660 subjects, 177 had complete follow-up, 182 reenrolled after a period of non-participation, 171 died, and 130 were lost to follow-up. No important differences were found between reenrolled women and those with continuous follow-up or those lost to follow-up. There were nominal differences in age and comorbidity among women lost to follow-up compared to those with complete follow-up. DISCUSSION/
CONCLUSIONS: This study highlights challenges in longitudinal research of cancer survivorship, specifically the potential benefit of reenrollment. IMPLICATIONS FOR CANCER SURVIVORS: Our findings provide a novel and promising approach to surmount some of the challenges in longitudinal research aimed at enhancing knowledge and the overall cancer survivorship experience of older adults.