Predictors of follow-up exercise behavior 6 months after a randomized trial of exercise training during breast cancer chemotherapy.
OBJECTIVE
Exercise during breast cancer chemotherapy is beneficial but it needs to be maintained into survivorship to optimize long-term benefits. Here, we report the predictors of follow-up exercise behavior 6 months after a randomized exercise trial in breast cancer patients.


METHODS
Breast cancer patients (N = 242) initiating adjuvant chemotherapy were randomly assigned to usual care (n = 82), supervised resistance exercise (n = 82), or supervised aerobic exercise (n = 78) for the duration of their chemotherapy. At baseline and postintervention, data were collected on demographic, medical, behavioral, fitness, psychosocial, and motivational variables. At 6-month follow-up, participants were mailed a questionnaire that assessed exercise behavior over the past 6 months and were categorized as either meeting both aerobic and resistance exercise guidelines, either exercise guideline, or neither exercise guideline.


RESULTS
Two hundred one (83.1%) participants provided 6-month follow-up data with 85 (42.3%) meeting neither exercise guideline, 74 (36.8%) meeting either exercise guideline, and 42 (20.9%) meeting both exercise guidelines. In multivariate regression analysis, seven variables independently predicted the likelihood of meeting exercise guidelines at follow-up including higher pretrial exercise (beta = 0.23; P = 0.002), younger age (beta = -0.15; P = 0.028), breast conserving surgery (beta = 0.15; P = 0.033), strength improvements (beta = 0.15; P = 0.028), lower postintervention fatigue (beta = 0.13; P = 0.067), a more positive attitude (beta = 0.12; P = 0.086), and lower postintervention body mass index (beta = -0.11; P = 0.105).


CONCLUSIONS
Exercise behavior 6 months after a randomized trial was predicted by a wide range of demographic, medical, behavioral, fitness, psychosocial, and motivational variables. These findings may help facilitate the uptake of exercise behavior during the transition from breast cancer patient to survivor.
Courneya
Kerry S
KS
Faculty of Physical Education and Recreation, University of Alberta, E-488 Van Vliet Center, Edmonton, AB, Canada. kerry.courneya@ualberta.ca
Friedenreich
Christine M
CM
Reid
Robert D
RD
Gelmon
Karen
K
Mackey
John R
JR
Ladha
Aliya B
AB
Proulx
Caroline
C
Vallance
Jeffrey K
JK
Segal
Roanne J
RJ
D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000628:therapy*; D005081:Exercise Therapy; D005260:Female; D015438:Health Behavior; D006801:Humans; D010349:Patient Compliance; D011379:Prognosis; D011795:Surveys and Questionnaires; D013997:Time Factors
D000970:Antineoplastic Agents