Radiography (2005) 11, 109e115

Comfort as a determiner of treatmentposition in radiotherapy of the male pelvis

J. Cox a,*, A. Davison b

a School of Medical Radiation Sciences, The University of Sydney,P.O. Box 170, Lidcombe NSW 1825, Australiab Faculty of Health Sciences, The University of Sydney,Lidcombe NSW 1825, Australia

Received 3 September 2004; accepted 12 January 2005Available online 13 March 2005

KEYWORDSSupine;Prone;Prostate cancer;Anxiety;Treatment position;Radiotherapy;Comfort

Abstract Purpose A comfortable treatment position in radiotherapy maypromote patient stability and contribute to the best possible patient experience.Patients receiving radical radiotherapy for prostate cancer lie supine or prone, butlittle evaluation has been made of the comfort of these positions. The purpose ofthis research was to evaluate the comfort of the prone and supine positions and toassess any influence of feelings of anxiety.Methods Self-reported comfort and anxiety levels were measured using visualanalogue scales in the first and last weeks of treatment for patients receivingradical prostatic radiotherapy. The subjects were from two hospitals, 23 routinelytreated lying prone and 21 routinely treated lying supine. Six subjects from eachgroup were interviewed in the first week of treatment.Results Comfort levels were high and no significant difference was foundbetween treatment positions or between the first and last weeks of treatment.Anxiety levels were low with no significant variation according to position or weekof treatment. Little correlation was seen between reported anxiety and comfortlevels. Interview data supported the quantitative findings. Supine subjectsindicated the need for lateral elbow support to improve feelings of stability.Conclusions For radiotherapy of male patients without pain or other complicat-ing factors, selection between the prone and supine positions may be made withoutconsidering comfort. Supine patients should be provided with lateral elbowsupport. Further research is indicated into the comfort of these positions forfemales and the phenomenon of low reported anxiety in male cancer patients.� 2005 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

* Corresponding author. Tel.: C61 9351 9501; fax: C61 2 9351 9146.E-mail address: j.cox@fhs.usyd.edu.au (J. Cox).

1078-8174/$ - see front matter � 2005 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.doi:10.1016/j.radi.2005.01.003

110 J. Cox, A. Davison

Introduction

Comfort is an important aspect of radiotherapy.Although radiotherapy patients may suffer frompain related to their disease or to side-effectsfrom treatment, the radiotherapy itself is painless.There is no need for patients to be uncomfortablein the treatment room, so it is sensible to makethem as comfortable as possible, if only for theirgeneral sense of well-being. There is also thepossibility that patients may move if they do notfeel comfortable, thereby reducing the accuracyof treatment. It would therefore be useful whenselecting a treatment position to know which is themore comfortable.

Comfort has been considered most in three re-search domains: medical, nursing and ergonomic.The medical literature considers comfort more inits absence, for instance, in the assessment ofdiscomfort in mammography,1,2 with discomfortregarded as the most painless version of pain.However, discomfort has also been defined in themedical world as ‘a subjective unpleasant feelingthat the patient does not interpret as pain’.3(p146)

Enhancement of patient comfort is one of theprimary goals of nurses4 and it is considered to bea multi-dimensional construct covering the physi-cal, social, psychospiritual and environmentaldimensions.5 Ergonomicists tend to view comfortand discomfort mostly in the physical domain,whether they are assessing the comfort of pos-ture,6 chairs7 or vision.8 However, in one largepiece of ergonomics research,9 when subjectswere asked to describe comfort and discomfort insitting, some affective elements such as feelings ofrelaxation and well-being arose. Using factoranalysis, the authors found that descriptions couldbe clustered under the major branches of comfortand discomfort. Examples of words that subjectsprovided in relation to comfort are ‘‘relaxed, atease, happy, content, pleased, pleasant’’. Discom-fort was associated with biomechanical factors‘‘that produce feelings of pain, soreness, numb-ness, stiffness, and so on’’ (p. 385). Thus theremay be some connection between a person’sperception of physical comfort and that person’spsychological state, for instance his level ofanxiety.

Patients receiving radical radiotherapy for pros-tate cancer are normally treated lying supine orprone, with arguments for each of these positions.Thus, if it is considered desirable to maintain a fullbladder, the patient may be better treated supine,due to the discomfort of maintaining a full bladderwhen prone. The prone position has the advantage

of reducing the volume of small bowel in thepelvis,10 which could reduce treatment side-effects. One recent piece of research suggeststhat supine is the most comfortable treatmentposition for this group of patients.11 Twentypatients compared the prone and supine treat-ment positions in a cross-over study where theyreceived half their radiotherapy in one positionand half in the other position. This direct compar-ison showed a significant difference between thecomfort levels of the two positions. However,given that many patients over the years have beentreated in both positions with relative success, thetopic warrants further investigation.

The primary aim of this project was to evaluatethe comfort of the prone and supine positions todetermine whether one of these positions waspreferable for treatment of prostate cancer. Asecondary aim was to assess the connection be-tween feelings of anxiety and perceptions ofcomfort.

Method

Approval for the experiment was gained from theHuman Ethics Committees of the University ofSydney and the South-Eastern Sydney and SouthWestern Sydney Area Health Services. Forty-seven patients undergoing radical radiotherapyfor carcinoma of the prostate were recruited intothe study. No data were available as a basis fora power analysis to determine subject numbers.It was felt that approximately 22 subjects ineach of two groups would be adequate asadditional power would be gained by collectinga combination of quantitative and qualitativedata.

The subjects were a convenience sample se-lected sequentially from patients presenting fortreatment at two different radiation oncologycentres in Sydney. No change in the treatmentprotocol was required for this study and patientswere treated in the standard position for thecentre.

The two hospitals are located in different areasof the Sydney metropolitan region. One hospitaldraws its patients from an inner urban region withboth high and low socio-economic areas in closeproximity to each other as well as from a countryregion. The other hospital draws its patients fromthe surrounding low to moderate socio-economicouter urban area. No attempt was made to de-termine the socio-economic status of individualsubjects in this study.

Comfortable positions for prostate radiotherapy 111

The supine patients lay on their backs on a flatcouch with nomattress. The pelvis was located overa transparent mylar (plastic) sheet. A rectangularfoam cushion 7 cm thick was placed under theirheads and a pillow was placed under their knees.

The prone patients lay face down on a flat couchwith no mattress. The pelvis was located overa transparent mylar sheet. The patient’s head wasstraight and his face was placed into a plastic-covered foam cushion (Pronpillow�). The cushionhad a void under the face so that all pressure wastaken by the forehead and chin and breathing wasnot impeded. A triangular cushion was placedunder the lower legs so that the knees lay on thecouch and the feet were raised in the air.

No restraining devices such as alpha cradles orthermoplastic moulds were used with any of thepatients.

Each subject was approached to take part in theexperiment on the second or third day of the courseof treatment. They were not approached on the firstday because this is usually a longer session thansubsequent treatments and the first day of treat-ment may be stressful to patients. It was notthought appropriate to add to the subjects’ stresson this day. The subjects gave their age, weight andheight, answered questions on their favourite sleep-ing position, and completed two visual analoguescales (VAS), one assessing the comfort of thetreatment couch, and one scoring their currentlevel of anxiety. The visual analogue scales werecompleted again in the final week of treatment.This was at least 4 weeks after the first scales werecompleted.

The comfort VAS had been tested in a previousexperiment12 and was shown to be independent ofsubject age and body mass index. A similar scalehad also been used to assess the comfort ofstabilisation devices.13 The VAS for anxiety iscommonly used and correlates well with otheranxiety measures.14e16 The scales consisted of two10 cm long lines with extremes of the conditionmarked at each end (see Fig. 1).

The first six subjects from each institution werealso interviewed in a semi-structured manner toobtain more information about the treatmentpositions. Subjects were asked specific questions

As anxious asI could

possibly be

Not anxiousat all

Extremelycomfortable

Unbearablyuncomfortable

Figure 1 Visual analogue scales.

related to their comfort in the treatment position,whether they felt they moved during treatment,whether they had any pressure, pain or breathingdifficulties, and how long they felt they could lie inthe position. The subjects were asked if they couldprovide a definition for the concept ‘comfort’.They were then asked to address more broadlythe question, ‘‘How did you feel lying in theretoday?’’ which gave them the opportunity toexpand on both the physical and psychologicalaspects of the experience.

Results

Two of the subjects were lost to the study andincomplete data were collected for one, giving fulldata for 44 subjects, 23 subjects lying prone and 21lying supine.

Subject group characteristics

Age and body mass index of the two groups wascompared, with BMI defined thus17(p18):

BMIZWeight

Height2

where weight is in kg and height is in m.A two-tailed t test assuming equal variances

(aZ 0.025) was carried out to compare the groups.The mean age of the prone group was 68.6 years (SD5.88) and the supine group was 67.2 years (SD5.03), with no significant difference between thegroups (t41, pZ 0.407). The mean BMI of the pronegroup was 27.99 (SD 4.75) and the supine group was28.21 (SD 3.44), with no significant differencebetween the groups (t41, pZ 0.861).

Comparison of comfort scoresbetween groups

The comfort scores for each group were in thelower (most comfortable) end of the scale (seeTable 1). A two-tailed t test assuming equalvariances (aZ 0.025) showed no significant differ-ence between the comfort scores of the prone andsupine groups on the week 1 measurements (t41,pZ 0.96). Similarly, no significant difference wasfound between the groups on the final treatmentweek measurements (t41, pZ 0.997).

Comparison of comfort scoresbetween weeks

A two-tailed t test assuming equal variances(aZ 0.025) showed no significant difference

112 J. Cox, A. Davison

between the comfort scores of the prone group onthe first and final weeks of treatment (t44,pZ 0.114). Similarly, no significant differencewas seen between the comfort scores of the supinegroup over this time period (t38, pZ 0.295). Thesimilarity of the distributions can be seen in Fig. 2.Where 0 indicates ‘extremely comfortable’ and 10indicates ‘unbearably uncomfortable’, most sub-jects in both groups reported a moderate to highdegree of comfort (see Fig. 2).

Anxiety levels

The anxiety scores for both positions in the firstand last weeks of treatment were in the higher(least anxious) part of the scale. They were non-normal in distribution (see Table 2), leading to theneed to apply non-parametric statistics.

Comparison of anxiety scoresbetween groups

A ManneWhitney test showed no significant differ-ence between the anxiety scores for the prone andsupine groups of subjects, either in the first week(ZZ�0.71, pZ 0.944) or the final week of treat-ment (ZZ�0.106, pZ 0.915).

Table 1 Descriptive statistics for comfort scores

Supine Prone

Week 1 Final week Week 1 Final week

Mean 2.42 1.72 2.39 1.72Standarddeviation

2.23 1.92 1.51 1.29

Median 1.40 0.85 2.00 1.80Kurtosis 1.22 1.25 �1.93 �0.60Skewness 1.25 1.55 0.33 0.65

The kurtosis and skewness values indicate the data followsa normal distribution.

Change in comfort scores over time

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10Comfort score

Nu

mb

er o

f su

bjects

Week 1

Final week

Figure 2 Week 1 and final week’s comfort scores. Notethat prone and supine values are grouped together asthere was no significant difference between the groups.

Comparison of anxiety scoresbetween weeks

AWilcoxon Signed Ranks Test showed no significantdifference between the first and final week anxi-ety scores for the prone group of subjects(ZZ�0.211, pZ 0.833). Similarly, no significantdifference was seen between the anxiety scoresfor the supine group over the time period(ZZ�1.719, pZ 0.086). Where 0 indicates anextreme level of anxiety and 10 indicates noanxiety at all, most subjects in both groupsreported little anxiety (see Fig. 3).

Correlation of comfort with anxiety

There was little correlation between subjects’opinions as to the comfort of the couch and theirstated anxiety levels, with a Pearson coefficientof �0.157 (see Fig. 4).

Favourite side to lie

Some subjects reported that they slept in severalpositions, so results do not total 44 (see Table 3).The majority of subjects reported that they lay onone or both sides throughout the night. No subjectsslept prone. Given the small numbers of subjects

Table 2 Descriptive statistics for anxiety levels

Supine Prone

Week 1 Final week Week 1 Final week

Mean 8.03 8.60 7.96 8.29Standarddeviation

2.52 1.69 2.86 2.36

Median 9.10 9.20 9.10 9.20Kurtosis 2.57* 9.00* 3.92* 5.59*Skewness �1.78 �2.67* �2.13* �2.36*

*Shows indicators of non-normality.

Change in anxiety over time

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10Anxiety score

Nu

mb

er o

f su

bjects

Week 1

Final week

Figure 3 Week 1 and final week’s anxiety scores.Prone and supine values are grouped together as therewas no significant difference between the groups.

Comfortable positions for prostate radiotherapy 113

in the sleeping position groups, it is difficult to findany strong relationships between sleeping positionand comfort levels of treatment positions (seeTable 4). Those who slept supine found the supinetreatment position to be extremely comfortable(mean 0.76).

Interview data

The qualitative interview data were subjected totheme analysis followed by grouping of themes toestablish major areas of agreement. Only one itememerged in the qualitative data that demonstrateda difference between prone and supine; the needfelt by supine subjects for elbow support. Severalsupine subjects reported that their arms felt un-supported at the sides and they needed some sortof lateral extension on the table for their elbows.All subjects were highly aware of the necessity toremain still during treatment, so this concernabout the supine subjects’ arms sliding laterallyincreased the tension that they were feeling. Theyfelt that this state of ‘‘rigor mortis’’ meant that‘‘you can’t relax too much’’. No prone subjectsexpressed this concern.

No subjects indicated that they felt pain,difficulty in breathing or movement in the treat-ment position. The general consensus was that thesubjects could lie in the required position for

Correlation between comfort and anxiety

0

2

4

6

8

10

12

0 2 4 6 8 10Comfort score (0 = 'extremely comfortable')

An

xiety sco

re

(10 =

'n

ot an

xio

us at all')

Figure 4 Scatter plot of comfort versus anxiety scores.Because of the lack of significant differences betweenpositions and first and final week scores, all subjectshave been grouped together.

Table 3 Favourite side to lie

Position Number of subjects

Side (or sides) 36Supine 10 (some plus side)Prone 0All positions 1

Numbers total was more than 44 because some subjects hadseveral preferences.

about 30 min. The only synonym for ‘comfort’the subjects could provide was ‘relaxed’, as in‘‘I was just completely relaxed.’’

The interview data supported the VAS ratings ofhigh levels of comfort and low levels of anxiety asall subjects stated that they felt comfortable inthe treatment position and almost all subjectsdenied feeling anxious. The few subjects whoadmitted to anxiety defined themselves thus:‘‘I’m an anxious type of person’’. Most subjectsseemed philosophical: ‘‘It’s just something thatyou’ve got to accept in your life’’.

Discussion

The normal distribution seen in the comfort scoresusing the VAS-Comfort is similar to the distribu-tions seen in a previous experiment12 and supportsits use for this type of subjective evaluation. Onepotential confounder of the results is the fact thatlow levels of comfort were located at the lowscoring end of the VAS while low levels of anxietywere located at the high scoring end of the scale.Great care was therefore taken to ensure that thesubjects were aware of the difference and accu-rately rated their comfort and anxiety levels.

Anxiety was assessed in this experiment be-cause the literature indicated that there may besome connection between the physical and psy-chological aspects of comfort. Thus, a high level ofanxiety in a patient might make him intolerant ofthe position in which he is required to lie,especially with the strain of being required toremain very still during treatment, and he maytherefore feel that the position is uncomfortable.The possible multi-faceted nature of the concept‘comfort’ is supported by the subjects’ synonym,‘relaxed’, which could be regarded as having anaffective component.

The strong skew to the favourable side of theanxiety scale as well as comments made in the

Table 4 Mean comfort scores across both weeks forsleeping positions, where subjects stated two posi-tions (the first position stated was used)

Treatmentposition

Sleepingposition(no. of subjects)

Mean comfort score

Mean SD

Prone All (2) 3.23 0.25Supine (5) 2.36 0.84Side/sides (16) 1.82 1.09

Supine All (1) 6.15Supine (5) 0.76 0.43Side/sides (15) 2.26 1.30

114 J. Cox, A. Davison

interviews indicates that in fact these patientsclaimed to be experiencing very little anxiety,rather less than one might expect given theircircumstances. This lack of anxiety has beenexpressed elsewhere by patients suffering fromprostate cancer,18,19 although women have ex-pressed higher anxiety levels,20,21 and warrantsfurther investigation. The recently validated Me-morial Anxiety Scale for Prostate Cancer22 mayprove more discriminating in the measurement ofanxiety in patients suffering from prostate cancer.If there was a connection between comfort andanxiety, it was impossible to find in this experi-ment due to the high levels of comfort and lowlevels of anxiety expressed.

These findings contradict the results of Bayleyet al. who found that the supine position wassignificantly more comfortable than the proneposition.11 While the research design of Bayleyet al. had the advantage of repeated measureswithin a single cohort, thus limiting potentialvariables, there is the possibility that, when a di-rect comparison is requested, subjects will try tofind a difference between the two positions. Theresearch reported here was carried out witha separate cohort for each position, but nosignificant difference was found in age and bodymass index between the groups, so they can beassumed to be very similar. The fact that nosignificant difference was found in the comfort ofthe two positions indicates that either position issatisfactory for treatment. The addition of quali-tative data adds depth to quantitative findings23

and in this case supports the findings of nodifference in comfort between the positions. Anindication of patient satisfaction is the statementof the subjects in both positions that they could liefor at least 30 min in that position.

When a treatment technique is being designed,particularly for prostate cancer patients, butpossibly for any patients where the choice is tolie prone or supine, the results of this studysuggest that physical comfort does not favourone position over the other. It is therefore notnecessary to consider this factor when planningtreatment. It could be hypothesised that there isunlikely to be movement related to discomfort ineither position, although this also requires furtherinvestigation. Respiration-related movement ofinternal structures, for instance, has been shownby some authors to be greater in the proneposition,24,25 although it is not clear how clinicallysignificant this movement may be.

Women may find lying prone on their breaststo be a problem, and this warrants further in-vestigation. Similarly, patients with previous

pathology or accompanying physical injury orimpairment may need to consider alternativepositioning.

It is clear from the interviews that the supineposition could be improved by the addition oflateral elbow support. The supine subjects didnot feel that they moved at all, but there mayhave been unconscious movements related to thelack of arm support. While these subjects did notclaim to be particularly uncomfortable, there wasevidence that they felt tense and concerned aboutthe difficulty they experienced holding their armsfirmly on their abdomens. Thus arm supports arejustified, if only to ease the patient’s state ofmind.

Conclusion

Further research is needed into anxiety levels inmale radiotherapy patients and the potential foranxiety to impact upon impressions of comfortduring the treatment process.

No significant difference was seen between theprone and supine positions for male patients interms of physical comfort. Both caused littlediscomfort. Thus the decision regarding positioncan be based on other relevant factors such asstability, ease of visualisation of field placementmarks and relative location of mobile organs, withthe proviso that supine patients be given lateralelbow support.

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