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Impact of computed tomography screening for lung cancer on participants in a randomized controlled trial (NELSON trial)
Article first published online: 16 MAY 2008
Copyright © 2008 American Cancer Society
Volume 113, Issue 2, pages 396–404, 15 July 2008
How to Cite
van den Bergh, K. A. M., Essink-Bot, M.-L., Bunge, E. M., Scholten, E. Th., Prokop, M., van Iersel, C. A., van Klaveren, R. J. and de Koning, H. J. (2008), Impact of computed tomography screening for lung cancer on participants in a randomized controlled trial (NELSON trial). Cancer, 113: 396–404. doi: 10.1002/cncr.23590
- Issue published online: 8 JUL 2008
- Article first published online: 16 MAY 2008
- Manuscript Accepted: 25 MAR 2008
- Manuscript Revised: 15 FEB 2008
- Manuscript Received: 15 NOV 2007
- The Netherlands Organization for Health Research and Development (ZonMW). Grant Number: 22000130
- Dutch Cancer Society (KWF). Grant Number: EMCR 2001–2371
- Health Insurance Innovation Foundation (Innovatiefonds Zorgverzekeraars)
- lung neoplasms;
- mass screening;
- quality of life;
- spiral computed tomography
Computed tomography (CT) screening is an important new tool for the early detection of lung cancer. In the current study, the authors assessed the discomfort associated with CT scanning and the subsequent wait for results and health-related quality of life (HRQoL) over time.
A total of 351 participants in the Dutch-Belgian randomized controlled trial for lung cancer screening in high-risk subjects (the NELSON trial) who had an appointment for a baseline CT scan were asked to complete questionnaires regarding their experienced discomfort and HRQoL before, 1 day after, and approximately 6 months after the CT scan. HRQoL was measured as generic HRQoL (12-item Short Form [SF-12] and EuroQol questionnaire [EQ-5D]), generic anxiety (State-Trait Anxiety Inventory [STAI-6]), and lung cancer-specific distress (Impact of Event Scale [IES]). Approximately 76.9% of the participants completed all 3 questionnaires.
Approximately 87% to 99% of participants reported experiencing no discomfort related to the CT scan. The median SF-12, EQ-5D, STAI-6, and IES scores did not appear to change relevantly over time. Approximately 46.0% and 51.3%, respectively, of the participants reported discomfort in connection with having to wait for the results of the CT scan and dreading those results. These patients had relevantly higher STAI-6 and IES scores (P < .01) (unfavorable) at all 3 assessments.
The current evaluation of the potential adverse effects of CT screening for lung cancer on HRQoL demonstrated no negative effects. However, waiting for the CT scan results was reported to be discomforting by approximately half of the participants. Minimizing the waiting time for the test results is therefore recommended. Cancer 2008. © 2008 American Cancer Society.
Lung cancer is the most common cancer worldwide and the most common cause of death from cancer.1, 2 Recent research has indicated that lung cancer can now be diagnosed at an earlier stage if high-risk subjects are screened with computed tomography (CT).3 However, there is debate regarding whether CT screening for lung cancer reduces mortality from the disease. Therefore, the results of ongoing randomized controlled studies are eagerly awaited.4–7
In general, the health benefits of CT screening for lung cancer to the general population should outweigh the physical and psychologic harm caused by the test, diagnostic follow-up, and possible overtreatment.8, 9 At the individual level, relatively few subjects will benefit from screening, whereas all subjects who participate in screening are subjected to (unfavorable) side effects, including the discomfort, anxiety, and distress associated with lung cancer CT screening. In particular, the percentage of subjects with lung nodules detected by screening (approximately 15–20%) who are advised to undergo a repeat CT scan after 3 months may experience a decrease in their health-related quality of life (HRQoL). The impact of CT screening on HRQoL can be taken into account in the overall balance of the favorable and unfavorable effects of lung cancer screening and cost-effectiveness analyses when screening has been proven to reduce lung cancer mortality.9, 10 To our knowledge, no empiric data regarding the discomfort of CT scanning and the impact of CT screening for lung cancer on HRQoL have been published to date. The objective of the current study was to explore the potentially adverse side effects of CT screening for lung cancer. We assessed the discomfort experienced by subjects during CT scanning and the discomfort associated with waiting for the results in addition to exploring the impact of CT screening on HRQoL over time in a subsample of the screening group of the Dutch-Belgian randomized controlled trial for lung cancer screening in high-risk subjects (the NELSON trial).
MATERIALS AND METHODS
The recruitment procedure for and selection criteria of the NELSON trial have been reported in a previous study.6 In brief, a selection of Dutch and Belgian subjects registered in population registries and aged between 50 and 75 years was sent a questionnaire containing questions regarding smoking history and health. Subjects who had smoked >15 cigarettes per day for >25 years or >10 cigarettes per day for >30 years, those who still smoked, or those who had quit ≤10 years ago were invited to the trial. Exclusion criteria were self-reported moderate or bad health status in combination with an inability to climb 2 stairs; a history of renal cancer, melanoma, or breast cancer; a history of lung cancer diagnosed <5 years previously or >5 years previously but for which the person was still under medical treatment; a chest CT scan performed <1 year before study recruitment; and a body weight ≥140 kg.6 Informed consent was obtained from 15,822 high-risk subjects who were subsequently randomized (at a ratio of 1:1) to either a screening group or control group that received no screening.
Participants in the CT screening group could receive a positive, indeterminate, or negative test result within 3 weeks after the baseline CT scan was performed. A positive test result was obtained in the case of a nodule that was solid and measured >500 mm3; solid, pleural-based, and measured >10 mm minimum dimension (dmin); or partially solid, with a solid component that measured >500 mm3 and required referral to a pulmonologist for workup and diagnosis. A positive test result was obtained in the case of a nodule that was solid and measured between 50 and 500 mm3; solid, pleural-based, and measured between 5 and 10 mm dmin; partially solid, with a nonsolid component that measured ≥8 mm mean dimension (dmean); partially solid, with a solid component that measured between 50 and 500 mm3; or nonsolid and measured ≥8 mm dmean. These participants were advised to undergo a repeat CT scan in another 3 to 4 months to assess possible nodule growth. If there was significant nodule growth, a histologic diagnosis was obtained. Participants with a negative CT result were invited to an annual repeat scan (first incidence screening).11 The trial (including the HRQoL study) was approved by the Dutch Ministry of Health and by the ethics committee of Rotterdam, Haarlem, and Utrecht in the Netherlands. Informed consent was obtained from all participants.
We selected a consecutive sample of 351 participants randomized to the screening arm who had an appointment for a CT scan between June 2005 and November 2005 at the screening centers in Haarlem and Utrecht. These participants were sent a questionnaire 1 week before the baseline CT scan was performed (Time 1 [T1]), and asked to complete the questionnaire before the CT scan was performed. One day after this baseline CT scan, participants received a second questionnaire (Time 2 [T2]). They were asked to complete this questionnaire within 1 week to assess the HRQoL impact while waiting for the results of the baseline CT scan. Finally, a third questionnaire was sent approximately 6 months after the baseline CT was performed (Time 3 [T3]). This questionnaire was not sent to participants who did not undergo baseline CT screening (n = 10), those with a positive test result at baseline (n = 15) or significant growth noted at the time of the repeat scan (n = 5), or those who indicated that they did not wish to receive any further questionnaires (n = 1) (Fig. 1). T1 questionnaires completed after baseline CT screening and T2 questionnaires completed after receiving the baseline CT result were excluded from analysis. T3 questionnaires that were completed by participants with an indeterminate result who had not yet undergone their repeat CT scan or who were still waiting for the result of the repeat scan were also excluded.
Discomfort of CT scanning and waiting for the CT results
Respondents were asked to rate the discomfort experienced during the CT scanning procedure at T2. Items on the questionnaire were adapted from earlier studies assessing the impact of cancer screening tests.12–14 Items to assess the discomfort of the test procedure included lying in the short tunnel, lying on the CT table as it moves through the arch of the CT scanner, lying still without breathing, having to remove metal objects, taking 3 breaths, coughing on command, and being alone during CT scanning. Two items related to waiting for the CT results included “discomfort of waiting for the CT scan result” and “dreading the CT scan result.” All items had 5 response options ranging from “no discomfort at all” to “extreme discomfort.” Respondents were also asked to identify the most discomforting part of the CT scan (the prospect of CT scanning, undergoing CT scanning, or waiting for the CT scan result).
HRQoL is commonly defined as the subject's functioning and well-being in the physical, psychologic, and social domains in relation to disease and treatment.15 It can be measured with generic, disease-specific, and domain–specific questionnaires. Generally, the empiric evaluation of lung cancer screening can serve 2 different purposes.16 One is to measure HRQoL for use in cost-effectiveness analyses of lung cancer screening and to compare the results with other (cancer screening) studies.9, 10 Another purpose is to provide a more detailed description of all (negative) psychosocial consequences with measures specifically developed for that purpose. The results of such studies can be used, for example, for counseling and the development of informational brochures in the event that lung cancer screening is indeed introduced. Data from generic measures are both necessary and important for equation and calibration against other adverse health outcomes. The focus of the current study was on the first purpose, and therefore we directed our attention toward the effect of lung cancer screening on generic HRQoL.
The participants' generic HRQoL was measured with the 12-item Short Form (SF-12) and the EuroQol questionnaire (EQ-5D).17–20 The SF-12 is a shorter alternative to the SF-36 and consist of a Physical Component Summary (PCS) and a Mental Component Summary (MCS).20 We used the acute (1-week recall) form of Version 1. Each participant completed the SF-12 at T1 and T3. A higher score indicates a better HRQoL. One missing item was allowed and was imputed by the median.
The EQ-5D classifies generic HRQoL in 5 items: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression with 3 response options (no, some/moderate, and unable/extreme).19 Furthermore, respondents were asked to rate their own health directly on the visual analogue scale (VAS) of the EQ-5D, ranging from 0 (labeled as “worst imaginable health status”) to 100 (labeled as “best imaginable health status”). Utility scores were based on the U.K. EQ-5D tariff.21 One missing item was allowed. Participants completed all items of theEQ-5D at T1 and rated their own health at all 3 assessments.
Generic anxiety was measured using the Dutch translation of the short form of the Spielberger State-Trait Anxiety Inventory (STAI-6).22 Six items related to anxiety (calm, tense, upset, relaxed, content, and worried) were rated on a 4-point scale. The total summary score was calculated in subjects without missing values and could range from 20 to 80, with higher scores indicating more anxiety. The STAI-6 is reported to have a good reliability and validity and was found to be useful for the evaluation of the effectiveness of screening programs on anxiety levels.22 STAI-6 was measured at all 3 assessments.
Lung cancer-specific distress was measured using the Impact of Event Scale (IES).23, 24 The 15 IES items were tailored to the specific event: “lung cancer.” Each item was scored on a 4-point scale: not at all (score of 0), rarely (score of 1), sometimes (score of 3), and often (score of 5). The total score and subscales (avoidance and intrusion) were calculated for those subjects who completed ≥75% of the questions on each subscale and were corrected for the total number of questions of the subscale. The summary score of the total scale could range from 0 to 75, with a higher score indicating more lung cancer-specific distress. The IES was measured at all 3 assessments.
Demographic and Other Data
At T1, the questionnaire contained items regarding sex, age, marital status, and smoking status. Participants who answered the question “Do you smoke?” with “yes, daily” or “yes, sometimes” were defined as current smokers.25 All other participants were therefore former smokers because all NELSON trial participants are ever-smokers. At T2, participants were asked whether they had ever undergone a CT scan before (of their lungs or otherwise), because participants who had undergone a prior CT scan may experience CT scanning differently.
Respondents were divided into 2 age groups based on their age at T1. Responses to the discomfort items were used as a single item and were recategorized by combining the responses “rather,” “very,” or “extremely” because these answers were endorsed by only a few participants. The Cronbach α for the SF-12, STAI-6, and IES were 0.77 or higher. Nonparametric, 2-sided tests were used for the analysis because the score distribution of all continuous data was not normal.
Differences in the distribution of background characteristics between various subgroups (men vs women, those aged <60 years vs those aged ≥60 years, education, current vs former smokers) were analyzed by the chi-square test for nominal/ordinal variables and the Mann-Whitney U test for continuous variables. We used the chi-square test to test for differences in the distribution of reported discomfort between participants who had previously undergone a CT scan and those who had not. Chi-square and Kruskal-Wallis tests were used to determine whether the reported discomfort of CT scanning and HRQoL scores (the SF-12, VAS, STAI-6, and IES) at T1 and T2 were associated with the “most discomforting part of CT scanning” as reported by the respondents at T2.
We used Mann-Whitney U tests to test the significance of differences in the mean HRQoL scores (SF-12, VAS, STAI-6, and IES) by sex, age, smoking history, and screening result, and whether discomfort was experienced while waiting for the results of the CT scan. To test for differences in HRQoL over time, paired Wilcoxon signed rank tests were conducted. To determine the clinical relevance of the significant differences between means at 2 assessments or subgroups, we used the minimal important difference (MID), which is defined as half of a standard deviation.28 The MID can serve as a default value for important patient-perceived changes in HRQoL. HRQoL questionnaires were found to be sufficiently reliable (Cronbach α >0.70) as to allow these analyses to be performed.
Response and Respondent Characteristics
The response rate of each questionnaire was ≥90.0% (Fig. 1). The mean time between the baseline CT scan and completion of the T3 questionnaire was 6.4 months (standard deviation [SD] of 0.8 months; range, 3.8–9.4 months). At least 1 of the 3 questionnaires was returned by 336 participants (95.7%); 270 completed all 3 questionnaires (76.9%).
Approximately 51% of the respondents to the T1 questionnaire were aged <60 years. Men were more often married/living with a partner than women (P < .01) and current smokers were younger than former smokers (P < .01). No other significant differences between background characteristics and subgroups (men vs women, age <60 years vs age ≥60 years, education, current vs former smokers) were found (Table 1). The results of the CT scan for the T3 respondents were negative for 83.0% of subjects (n = 239) and indeterminate for 17.0% (n = 49) for their baseline CT scan and all were negative for their most recent CT scan when completing the T3 questionnaire.
|Characteristics||% (Except when indicated)||Response|
|Age, y||Mean: 60.3||323|
|Lower vocational or lower secondary general education||40.4||131/324|
|Intermediate vocational or higher secondary general education||22.5||73/324|
|Higher vocational education or university||19.4||63/324|
|Marital status: married/ living with partner||64.2||201/313|
|Smoking: current smokers*||74.7||236/316|
The vast majority of the respondents (87.8–98.7%) did not report any discomfort related to the various aspects of the CT scan (Table 2). Approximately half of the respondents reported at least some discomfort while waiting for the results (46.4%) and dreading the results (50.5%). One hundred nine respondents (34.1%) had undergone a CT scan before participating in this trial (4 of whom had undergone CT scans of their lungs). These respondents reported neither significantly more nor significantly less discomfort in connection with the CT scan than respondents who never undergone a CT scan (data not shown).
|Measure||Total item response||Not at all||Some||Rather, very, or extremely|
|Discomfort of CT scan||Lying in the short tunnel||322||290||90.1||30||9.3||2||0.6|
|Lying on the CT table as it moves through the arch of the CT scan||321||285||88.8||32||10.0||4||1.2|
|Lying still without breathing during CT scanning||319||280||87.8||36||11.3||3||0.9|
|Having to remove metal objects||307||303||98.7||4||1.3||0|
|Taking 3 breaths||313||282||90.1||25||8.0||6||1.9|
|Coughing on command||230||217||94.3||10||4.3||3||1.3|
|Being alone during CT scanning||319||301||94.4||15||4.7||3||0.9|
|Result of CT scan||Discomfort from waiting for CT scan result||319||171||53.6||124||38.9||24||7.5|
|Dreading the CT scan result||321||159||49.5||138||43.0||24||7.5|
Baseline HRQoL scores and comparison with reference groups
At T1, the average PCS and MCS scores of the SF-12 were 48.2 (SD of 9.1) and 51.3 (SD of 10.5), respectively. These scores were in the same range as age-adjusted and sex-adjusted Dutch reference scores (data not shown). Approximately 62% of the respondents reported general health problems on at least 1 of the items on the EQ-5D self-classifier (Table 3). Approximately 15% reported experiencing some pain or discomfort only. Generic anxiety scores (STAI-6) (mean score of 34.1 [SD of 7.7]) were comparable to the Dutch general population.
|Total Item response||No.||%|
|Daily activities problems||324||85||26.2|
|Pain or discomfort||324||169||52.2|
|Anxiety or depression||321||73||22.7|
|Mean (SD), Median|
|VAS||323||323||76.3 (13.5), 79.0|
|Utility score*||324||324||0.82 (0.19), 0.80|
HRQoL over time
The median SF-12 scores did not change significantly over time during screening (Table 4). The EQ-5D, VAS, STAI-6, and IES scores were found to differ significantly over time, but the scores were low (favorable) and the reported changes were smaller than the MID (Table 4). Dropout participants could have influenced the results of the HRQoL analyses over time. Using the same analyses but only taking the HRQoL assessments of subjects who responded to all 3 questionnaires (270 subjects [76.9%]) into account, we noted similar results (data not shown).
|(T1) 1 day before screening||(T2) within 1 week after screening||(T3) 6 months after screening||Significant difference|
|Mean (SD)||Median||Mean (SD)||Median||Mean (SD)||Median||T1 vs T2||T1 vs T3||T2 vs T3|
|SF-12 physical health (PCS)|
|Total group||48.2 (9.1)||51.3||48.7 (9.4)||51.9|
|Men||48.5 (9.2)||51.6||49.5 (8.8)||52.4|
|Women||47.9 (9.1)||51.3||48.0 (10.1)||50.6|
|SF-12 mental health (MCS)|
|Total group||51.3 (10.5)||54.2||50.6 (12.0)||55.4|
|Men||52.5 (10.6)||55.9*||51.5 (11.0)||55.8|
|Women||50.1 (10.4)||52.2*||49.6 (12.9)||55.1|
|EQ-5D, VAS Self-reported health status|
|Total group||76.3 (13.5)||79.0||76.8 (12.6)||80.0||75.8 (13.7)||80.0||§|
|Men||76.5 (13.9)||79.0||76.9 (13.2)||80.0||77.6 (14.1)||80.0‡|
|Women||76.1 (13.2)||76.0||76.8 (11.7)||80.0||73.9 (13.0)||78.0‡||§||†|
|Total group||34.1 (7.7)||33.3||32.7 (8.4)||30.0||34.3 (9.1)||33.3||†||†|
|Men||33.3 (7.5)||33.3||31.9 (7.8)||30.0||33.3 (8.5)||33.3||†||§|
|Women||34.9 (7.8)||33.3||33.6 (8.9)||33.3||35.2 (9.8)||33.3||§||§|
|IES total score|
|Total group||6.9 (9.6)||3.0||5.6 (8.8)||1.0||5.1 (8.0)||2.0||†||†|
|Men||5.9 (7.7)||3.0||5.0 (7.8)||1.0‡||4.8 (7.1)||2.0||†||§|
|Women||7.9 (11.2)||3.0||6.5 (9.9)||2.0‡||5.6 (9.0)||1.0||†|
|Total group||2.8 (4.3)||1.0||2.1 (3.9)||0.0||2.1 (3.7)||0.0||†||†|
|Men||2.5 (3.4)||1.0||1.7 (2.9)||0.0||1.9 (3.2)||0.0||†||§|
|Women||3.2 (5.0)||1.0||2.6 (4.7)||1.0||2.5 (4.3)||0.0||§|
|Total group||4.1 (6.2)||1.0||3.5 (5.9)||0.0||3.0 (4.7)||1.0||§||†|
|Men||3.4 (5.1)||1.0||3.3 (5.7)||0.0||2.9 (4.5)||1.0|
|Women||4.8 (7.0)||1.5||4.0 (6.2)||1.0||3.1 (5.1)||1.0||†|
Determinants of HRQoL
At the time of all assessments, some differences in HRQoL were found between men and women. HRQoL changes over time were somewhat different between men and women (Table 4). Overall, these differences all were smaller than the MID. No relevant differences were found between current and former smokers and no significant differences in HRQoL scores were noted between respondents in the high or the low age category. In addition, no differences were found at T3 between respondents with a negative baseline CT scan result and respondents with an indeterminate baseline CT scan result but a negative repeat CT scan result.
Correlation between the most discomforting part of the CT scan and reported discomfort and HRQoL
“Waiting for the CT scan result” was rated by 76.0% of respondents (n = 196) as the most discomforting part of the CT scan. The “prospect of CT scanning” was rated as the worst part by 17.8% (n = 46), and “undergoing CT scanning” was rated as the worst part by 6.2% (n = 16). These 3 groups differed significantly with regard to the amount of reported discomfort in 4 aspects of CT scanning. These aspects were lying in the short tunnel and on the table as it moves through the arch of the CT scan, lying still without breathing, and being alone (P = .005, .001, .019, and .050, respectively). The group who rated “undergoing CT scanning” as the most discomforting part of screening more frequently reported at least some discomfort with regard to these items compared with the other 2 groups.
The STAI-6 score (P < .05) and IES score (subscales) (P < .01), measured while waiting for the CT scan result (T2), were found to differ significantly between the 3 groups (“prospect of CT scanning,” “waiting for the CT scan result,” and “undergoing CT scanning”) The group who rated “waiting for the CT scan result” as the most discomforting part of screening had worse STAI-6 and IES scores than the other 2 groups. These differences were smaller than the MID.
One week before the baseline CT scan (T1), the 3 groups (“prospect of CT scanning,” “waiting for the CT scan result,” and “undergoing CT scanning”) differed significantly with regard to IES score (subscales) (P < .05). Contrary to our expectations, the group who rated “waiting for the CT scan result” as the most discomforting part of screening had the worst IES scores at T1. This difference was smaller than the MID.
Because the analyses to test differences among the 3 groups (196 respondents, 46 respondents, and 16 respondents) of the most discomforting part of the CT screening and HRQoL was comprised of 2 small groups, we also performed several extra analyses. Approximately half of the respondents reported at least some “discomfort of waiting for the CT scan result” and/or “dreading the CT scan result.” This group had significantly higher scores on STAI-6 and IES (P < 0.01) but not on the SF-12, VAS, or EQ-5D compared with those reporting no discomfort or dread at the time of all 3 assessments (Figs. 2 and 3). The differences found were significant and exceeded the MID. The HRQoL did not appear to change relevantly over time in either group (data not shown).
To our knowledge, the current study is the first empiric report of the potential adverse side effects of CT screening for lung cancer. The results demonstrated that screening for lung cancer with CT caused little discomfort and appeared to have no major impact on HRQoL. Nevertheless, approximately half of the respondents reported a negative impact of waiting for the CT scan results. Compared with the prospect of undergoing CT scanning or undergoing the CT scan, this part was also rated as the most discomforting part of CT screening.
The CT scan itself caused almost no discomfort. The reported discomfort was less than that from magnetic resonance imaging (MRI) scanning for breast cancer screening.12 This is credible because a CT scan has a shorter and more open tunnel, makes less noise, and subjects are not required to lie still for a period of 20 minutes because the entire procedure takes only approximately 5 minutes.
Somewhat surprisingly, on the basis of these results, the respondents' HRQoL was found to be comparable to that of the age-adjusted/sex-adjusted reference population. This does not concur with other studies regarding the impact of screening, in which the study population often demonstrated a better HRQoL compared with the age-adjusted/sex-adjusted reference population.14, 29–31 This does not suggest that the study population in the current study may be assumed to accurately reflect the general population; our respondents were all heavy smokers or former heavy smokers, and smokers generally have a worse HRQoL than nonsmokers.32 Nevertheless, the HRQoL of the respondents was comparable to, not worse than, that of the reference population. This may be accounted for by the finding that, due to the application of the NELSON trial selection criteria, subjects with moderate or bad health status combined with an inability to climb 2 stairs were excluded from participating in the study. Moreover, participants in screening studies tend to be comprised of the healthier subjects in a population.33 Hence, the respondents in the current study may belong to the group of healthy (former) smokers.
A review of the impact of cancer prevention and screening on QoL demonstrated indications for negative effects, which were most often transient.29 The results of the current study demonstrated no evidence of adverse effects on anxiety and distress due to CT screening for lung cancer. In addition, no negative impact was found after 6 months in subjects whose repeat scan results came back negative (after an indeterminate baseline CT result) compared with subjects with a negative CT result at baseline. Several explanations are possible for not finding changes in HRQoL over time, and for remaining within the normal limits. First, CT screening for lung cancer may simply not have a negative impact on average HRQoL. We did not find any effect on the IES, a HRQoL-specific instrument. Many subjects may have held the belief that they took action to deal with their lung cancer risk. Second, subjects' coping methods can generate and sustain positive psychologic states in the context of screening, thereby minimizing or avoiding the adverse mental and physical health effects of distress.34 Last, as was discussed in the literature, HRQoL measures used in screening (the SF-12, STAI-6, and VAS) are possibly insensitive with regard to measurement of the impact of screening in great detail. The specific questionnaire we used was not primarily developed for measuring HRQoL changes in screening.15, 16, 35 However, evaluating screening with generic questionnaires is important because it can be equated to and calibrated against other adverse health outcomes and screening programs.16 Moreover, it is necessary to balance the positive and negative effects of screening with cost.9, 10 It is doubtful whether insensitivity was an issue in the current study because we observed both significant and relevant differences in generic anxiety and lung cancer-specific distress between subgroups (eg, between the group of participants who reported “at least some discomfort of waiting for the CT scan result and/or dreading the CT scan result” and the group who did not). Although the average anxiety and lung cancer-specific distress remained within normal limits, this subgroup of half of the respondents was identified that had relevantly worse anxiety and lung cancer-specific distress scores during CT screening. Because anxiety and lung cancer-specific distress did not change over time in either group, this indicates, for example, that these respondents might have a higher predisposition toward anxiety.
Some selection bias in the current study cohort is possible because we chose only the first 351 participants with an appointment to undergo a CT scan between June 2005 and November 2005. These individuals were easy to approach and willing to participate. However, we have no reason to believe that they constitute a specific group.
Our first assessment was performed just before the baseline CT scan. It might be possible that the HRQoL was already affected by this event. An assessment made earlier in time than T1 would have measured the participants' baseline HRQoL.
An extra assessment after receiving the result of the baseline CT scan is recommended to determine whether HRQoL is affected by receiving a result and whether there are relevant differences between receiving a negative or indeterminate result. Waiting for a follow-up screening can increase anxiety.36 The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial included chest x-ray screening for lung cancer and found that there was a negative impact on HRQoL after receiving an abnormal result, but not after the follow-up result indicated no cancer.31 When we initiated the current study, the best method with which to measure specific HRQoL was the IES. Recently, a new instrument was developed to measure the psychologic consequences of screening, which is a study that is currently being performed.37
In conclusion, the results of the current study did not demonstrate unfavorable side effects of CT screening on HRQoL. However, approximately half of the respondents reported at least some “discomfort of waiting for the CT scan result” and/or “dreading the CT scan result.” Therefore, minimizing the waiting time for the test result is recommended.
We thank R. Faber, MSc, for establishing the questionnaire database and selecting the participants; A. C. de Jongh, Artex BV, Capelle aan de IJssel, The Netherlands for his assistance with the selection of the participants and handling of the mailings; and H. A. Gietema, PhD, for her contribution in formulating the discomfort items regarding computed tomography scanning
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