Title: Trajectories of quality of life in breast cancer survivors during the first year after treatment:
a longitudinal study
Version: 0 Date: 08 Nov 2022
Reviewer's report:
Interesting paper which set new light on trajectories in QoL among breast cancer patients after
primary treatment, by identifying trajectory groups. This helps to identify high-risk breast cancer
patients who need care after end of treatment.
General comments:
- References are often missing, in particular in the introduction.
- Long sentences are used, which makes it difficult to read. Please use shorter sentences
throughout the manuscript.
Abstract:
- Line 36: 'This study aimed to identify trajectories of changes..' use either trajectories or changes
but not both.
- Methods section: describe which questionnaires are used.
- Line 52: 'QOL after the end of primary treatment' instead of 'QOL at the end of primary
treatment'.
Introduction:
- Line 63: Reference is missing.
- Line 64: Reference is missing.
- Line 63-63: 'However, ... remarkably' sentence is unclear
- Line 68: surgery is not an adjuvant treatment. Adjuvant treatment is after surgery.
- Line 70: References are missing. To which study do you refer?
- Line 72: describe what sort of unpleasant symptoms, this is quite vague.
- Line 75: Reference is missing.
- Line 78: define the intervention period, so this is clear for the reader.
- Line 84: The same information is given as in Line 86. Therefore, change to: 'Therefore,
this prospective study uses trajectory analysis to identify changes in the QOL of breast cancer
patients during the first year after the end of primary treatment and to identify multidimensional
factors influencing these changes.
- Delete line 86-88: 'This analysis...  patient access.' You mentioned this in the sentence before
already.
- Line 89: Delete the word ' Furthermore.'
- Line 90: What are secondary problems? Define this.
- Line 91: stop sentence after 'individual needs.' and start new sentence: 'This can be done by
effectively supporting...' Sentence is too long.
- Line 93-95: You mentioned this already at line 73-75: combine these sentences.
- Line 103: You already mentioned the aim of this study at line 84. Combine these sentences.
- Line 106: change into: '...focusing on the factors influencing the QOL reported in previous
studies.'
- Line 106: Specify which factors exactly are used.
- Hypothesis is missing.
Methods:
- Use numbers to describe the different inclusion and exclusion criteria. This is easier to read.
- Describe which sorts of primary treatment patients received (chemotherapy, radiotherapy,
endocrine therapy, surgery?)
- Line 116-117: '... and could communicate and respond to questionnaires.' This is not a scientific
way to say. Use e.g.: sufficient command of the language was required.
- Line 132: Describe full name of FACIT.
- Line 141: add the word with: 'Psychological symptoms are included with two written...'
- Psychological problems are measured as part of symptom experience and they are measured
as part of self-efficacy. Why are psychological items with 2 questionnaires? Which items are
used, all of them? Or are they combined? What happened if the patients filled in the items of
both questionnaires differently?
- Line 168-169: delete the sentence. Unnecessary information.
- Line 169-170: 'Participants who met...' this is already mentioned on page 5.
- Data collection: describe where the clinical information was substracted from.
- Line 181: define a 'small' absolute BIC
- Line 185-187: start the data analysis section with these sentences.
- Line 186: Is an independent t-test used as well? Describe this.
- Line 189: describe which factors are taken into account in the regression analyses.
Results:
- Line 203: there is 2 times 'and' in the sentence, rewrite.
- Line 204: Start with the number of included patients in the study.
- Add number of patients to the text, not only percentages.
- Table 1: define Low/moderate/high QOL (on what is this based?)
- Line 212: add: N=number.
- Line 214: add: 'Of the total group, the mean score for physical symptoms...'
- Line 219: change small n in low/moderate/high QOL groups to capital N
- Line 220: add: N=number
- Line 228: describe in the methods section that the trajectory groups are based on a previous
study. Not in the results section.
- Line 265: add P-value.
- Line 269: Describe in the title which time interval is analyzed in the table.
- Table 4: Why is only T1 analyzed and not T2-T4? It is a longitudinal study and the strength of
this study is the long time period measured after end of primary treatment. By only analyzing
T1, this strength is not used and information is missing. Add T2-T4 to the table.
Discussion:
General comment: when you are describing a study, please add the number of patients and the
treatment they received. This information helps to interpret the results from the literature (e.g.
Line 275: add number and treatment of patients, Line 296, Line 308).
- Line 282: which time period exactly? Define it.
- Line 282: 'some patients' report the exact number.
- Line 283-287: these are new results. New results should not be described in the discussion,
but should already be reported in the results section. Please describe these results in the results
section.
- Line 288-289: what about response shift? Do you think this could have influenced the results
as well?
- Line 290: give some examples of strategies (e.g. using Patient-Reported Outcome Measures?).
This is a little vague now.
- Why do you think that social support has an influence on QOL and not appraisal/ tangible
support? Please explain.
- Line 320: delete the word 'basic'
- Line 320-321: how do the results of this study exactly help with developing strategies to
improve QOL? I understand the idea, but it is a little vague now. Please describe more clear in
which way the results of these study can contribute to these strategies.
- Line 323: Do you mean selection bias?
- Line 325: why where the measurement points insufficient? Please explain.
- Line 326: Why is it a limitation that the shape and number of trajectory groups was affected?
Please explain.
- Line 326: You did a power calculation. Why still expand the number of patients? On what is
this based? Please explain.
- Line 327: 'and the measurement time points.' You already mentioned this.
- Line 334: change into: premature menopause and decline in cognitive function
- Line 335: Which QOL tool exactly? Please explain.
- Line 345: change reduced for low: '...low QOL by determining...'