Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials: A Systematic Review

Charlotte N. Steins Bisschop; Kerry S. Courneya; Miranda J. Velthuis; Evelyn M. Monninkhof; Lee W. Jones; Christine Friedenreich; Elsken van der Wall; Petra H. M. Peeters; Anne M. May

doi:10.1371/journal.pone.0120996

Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials: A Systematic Review

Charlotte N. Steins Bisschop, Kerry S. Courneya, Miranda J. Velthuis, Evelyn M. Monninkhof, Lee W. Jones, Christine Friedenreich, Elsken van der Wall, Petra H. M. Peeters, Anne M. May^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Purpose

Important considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates.

Methods

Randomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the dropout rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received.

Results

40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7+/-9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0+/-12.8%) were even lower.

Conclusions

Control groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.

Original language	English
Article number	e0120996
Number of pages	13
Journal	PLoS ONE [E]
Volume	10
Issue number	3
DOIs	https://doi.org/10.1371/journal.pone.0120996
Publication status	Published - 27 Mar 2015

Keywords

RANDOMIZED CONTROLLED-TRIAL
QUALITY-OF-LIFE
BREAST-CANCER SURVIVORS
RECEIVING ADJUVANT CHEMOTHERAPY
AEROBIC EXERCISE
PROSTATE-CANCER
RESISTANCE EXERCISE
PHYSICAL-ACTIVITY
CARDIORESPIRATORY FITNESS
ANDROGEN SUPPRESSION

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@article{5a48ff48e1c04bfb91d94b2ca607020d,

title = "Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials: A Systematic Review",

abstract = "PurposeImportant considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates.MethodsRandomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the dropout rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received.Results40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7+/-9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0+/-12.8%) were even lower.ConclusionsControl groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.",

keywords = "RANDOMIZED CONTROLLED-TRIAL, QUALITY-OF-LIFE, BREAST-CANCER SURVIVORS, RECEIVING ADJUVANT CHEMOTHERAPY, AEROBIC EXERCISE, PROSTATE-CANCER, RESISTANCE EXERCISE, PHYSICAL-ACTIVITY, CARDIORESPIRATORY FITNESS, ANDROGEN SUPPRESSION",

author = "Bisschop, {Charlotte N. Steins} and Courneya, {Kerry S.} and Velthuis, {Miranda J.} and Monninkhof, {Evelyn M.} and Jones, {Lee W.} and Christine Friedenreich and {van der Wall}, Elsken and Peeters, {Petra H. M.} and May, {Anne M.}",

year = "2015",

month = mar,

day = "27",

doi = "10.1371/journal.pone.0120996",

language = "English",

volume = "10",

journal = "PLoS ONE [E]",

issn = "1932-6203",

publisher = "Public Library of Science",

number = "3",

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TY - JOUR

T1 - Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials

T2 - A Systematic Review

AU - Bisschop, Charlotte N. Steins

AU - Courneya, Kerry S.

AU - Velthuis, Miranda J.

AU - Monninkhof, Evelyn M.

AU - Jones, Lee W.

AU - Friedenreich, Christine

AU - van der Wall, Elsken

AU - Peeters, Petra H. M.

AU - May, Anne M.

PY - 2015/3/27

Y1 - 2015/3/27

N2 - PurposeImportant considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates.MethodsRandomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the dropout rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received.Results40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7+/-9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0+/-12.8%) were even lower.ConclusionsControl groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.

AB - PurposeImportant considerations for exercise trials in cancer patients are contamination and differential drop-out among the control group members that might jeopardize the internal validity. This systematic review provides an overview of different control groups design characteristics of exercise-oncology trials and explores the association with contamination and drop-out rates.MethodsRandomized controlled exercise-oncology trials from two Cochrane reviews were included. Additionally, a computer-aided search using Medline (Pubmed), Embase and CINAHL was conducted after completion date of the Cochrane reviews. Eligible studies were classified according to three control group design characteristics: the exercise instruction given to controls before start of the study (exercise allowed or not); and the intervention the control group was offered during (any (e.g., education sessions or telephone contacts) or none) or after (any (e.g., cross-over or exercise instruction) or none) the intervention period. Contamination (yes or no) and excess drop-out rates (i.e., drop-out rate of the control group minus the dropout rate exercise group) were described according to the three design characteristics of the control group and according to the combinations of these three characteristics; so we additionally made subgroups based on combinations of type and timing of instructions received.Results40 exercise-oncology trials were included based on pre-specified eligibility criteria. The lowest contamination (7.1% of studies) and low drop-out rates (excess drop-out rate -4.7+/-9.2) were found in control groups offered an intervention after the intervention period. When control groups were offered an intervention both during and after the intervention period, contamination (0%) and excess drop-out rates (-10.0+/-12.8%) were even lower.ConclusionsControl groups receiving an intervention during and after the study intervention period have lower contamination and drop-out rates. The present findings can be considered when designing future exercise-oncology trials.

KW - RANDOMIZED CONTROLLED-TRIAL

KW - QUALITY-OF-LIFE

KW - BREAST-CANCER SURVIVORS

KW - RECEIVING ADJUVANT CHEMOTHERAPY

KW - AEROBIC EXERCISE

KW - PROSTATE-CANCER

KW - RESISTANCE EXERCISE

KW - PHYSICAL-ACTIVITY

KW - CARDIORESPIRATORY FITNESS

KW - ANDROGEN SUPPRESSION

U2 - 10.1371/journal.pone.0120996

DO - 10.1371/journal.pone.0120996

M3 - Article

C2 - 25815479

SN - 1932-6203

VL - 10

JO - PLoS ONE [E]

JF - PLoS ONE [E]

IS - 3

M1 - e0120996

ER -

Control Group Design, Contamination and Drop-Out in Exercise Oncology Trials: A Systematic Review

Abstract

Keywords

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