1 00:00:00,330 --> 00:00:07,710 Now, about ten days ago, the revolt, the ten year revolt for the Nelson lung cancer screening trial came out. 2 00:00:08,640 --> 00:00:14,970 All right. And you're in the midst of me writing an article that's going to go out in the BMJ, hopefully by the end of the week. 3 00:00:15,600 --> 00:00:20,309 So everything I say now, if it sounds good, will go in there. And if you don't understand it, I'll have to rethink it. 4 00:00:20,310 --> 00:00:24,990 For a woman to start with is going back a year and that's what was plain. 5 00:00:24,990 --> 00:00:28,620 I want you to just watch this two minute video. Let's see if we can make this work. 6 00:00:29,420 --> 00:00:37,860 The disease is early. It's a no brainer. It might be regular techniques and standards, but it's not that simple. 7 00:00:38,580 --> 00:00:44,490 The latest screening rollout testing them today comes in the form of lung health checks. 8 00:00:45,360 --> 00:00:54,480 These checks started out in trucks in a supermarket car parks in Manchester, where the incidence of lung cancer is around double the national average. 9 00:00:54,630 --> 00:01:07,290 Your arms away from the chest. NHS England says the Manchester projects on 2541 patients and found 61 lung cancer picking them up at an earlier stage. 10 00:01:08,640 --> 00:01:17,400 Now the trucks will visit ten new areas at a cost of £70 million over four years, targeting people at high risk of lung cancer. 11 00:01:18,210 --> 00:01:21,360 They say it will save hundreds of lives across the country. 12 00:01:21,960 --> 00:01:23,640 But not everyone agrees. 13 00:01:25,530 --> 00:01:34,170 NEWSNIGHT has seen a letter from senior doctors and public health officials concerned even the chief executive of NHS England. 14 00:01:34,980 --> 00:01:38,760 It raises substantial objections to lung health checks. 15 00:01:39,420 --> 00:01:44,100 They say proponents identify the homes and overplay the benefits. 16 00:01:44,520 --> 00:01:50,790 They point to Canadian data which attempt to quantify deaths for every thousand people 17 00:01:50,790 --> 00:01:57,990 scans annually for three years 391 who showed apparent indications of lung cancer. 18 00:01:58,710 --> 00:02:03,060 However, only 40 of those positives are genuine. 19 00:02:04,440 --> 00:02:11,430 Of those, 47 would not have died of the disease, 30 would have died anyway. 20 00:02:12,120 --> 00:02:21,600 And just three lives are saved. Meanwhile, the false positives all suffered major complications as a result of treatment. 21 00:02:22,200 --> 00:02:28,740 And one of those four will die. But. 22 00:02:30,460 --> 00:02:41,770 So that was interesting, wasn't it? We spent £70 million on trucks that now go into supermarkets and case find. 23 00:02:41,770 --> 00:02:49,180 People don't screen their case, find people for lung cancer, inviting people at high risk in high risk areas. 24 00:02:49,530 --> 00:02:52,720 One of them is is North Manchester, where I'm from originally, 25 00:02:53,050 --> 00:02:59,550 and this is a copy of the letter to Simon Stevens and you can see it coming from my email account. 26 00:02:59,920 --> 00:03:08,560 So I'm one of the then senior doctor people who like to make a nuisance of myself by making us think about what we're doing in health care. 27 00:03:09,190 --> 00:03:16,870 Very interesting to me how little people actually think about and go behind what we actually do in the system. 28 00:03:17,560 --> 00:03:22,870 We tend to do things and roll them out. And here's one other point, too. 29 00:03:22,870 --> 00:03:26,380 There is concern that there is no benefit to all cause mortality. 30 00:03:26,620 --> 00:03:31,090 What they would do now come back to the National Lung Screening trial with an American trial. 31 00:03:31,510 --> 00:03:38,590 But in Europe, there's been a trial called the Nelson, and it was published in a conference and it wasn't quite clear what was going on. 32 00:03:39,070 --> 00:03:46,750 We are concerned that enthusiasm for screening feeds a deliberate and independent effort to understand the benefits relative to the cost. 33 00:03:47,770 --> 00:03:51,160 Because this is not going to cost 70 million and this is only in a few areas. 34 00:03:51,460 --> 00:03:54,700 This is going to cost in excess of a billion because the. 35 00:03:54,700 --> 00:03:58,440 NELSON As your theme of annual screening, 36 00:03:58,480 --> 00:04:05,110 in fact it involved four screens within the first two and a half years and it's not even clear what happens beyond that, 37 00:04:05,110 --> 00:04:12,870 whether you should keep screening. So I wrote a blog last year called Understanding Lung Cancer Screening, and in their report, 38 00:04:12,910 --> 00:04:17,410 some really interesting point for the point about what what you've just seen in the programme 39 00:04:17,860 --> 00:04:25,800 that the screening reduce lung cancer mortality by 26% in men and between 39 and 60% in women. 40 00:04:25,810 --> 00:04:30,820 That's what within the come with them. But remember it's this thing called lung cancer mortality. 41 00:04:32,230 --> 00:04:40,840 Now immediately we read I think what happens is we remove these words in our mind and the something comes into our psyche that reduces mortality, 42 00:04:41,260 --> 00:04:44,860 because if you reduce mortality by that much, that would be really impressive. 43 00:04:44,860 --> 00:04:48,490 Wouldn't you be like, what's the on about? Okay. 44 00:04:49,870 --> 00:04:56,589 And what they do is when they do these projects, you get this stage shift of the people who are turning up. 45 00:04:56,590 --> 00:05:07,780 In Manchester, about 18% were diagnosed at stage one and after the scans turned up, more people were diagnosed with stage one, nearly half the people. 46 00:05:08,050 --> 00:05:14,410 So immediately we go, that's a good thing. Surely if you get people earlier, you can intervene. 47 00:05:15,010 --> 00:05:19,450 And that going back to that chart, remember the chart, we said there are some fast and some don't progress. 48 00:05:20,050 --> 00:05:23,860 This makes an assumption that everyone is going to progress. Therefore it's a good thing. 49 00:05:25,210 --> 00:05:33,010 Okay, now here's the analysis. This was this is I love this stuff and I think we need more of this type of stuff because it's really helpful. 50 00:05:33,250 --> 00:05:40,240 This is the Canadian Task Force, which was in the Deborah Cohen article in NEWSNIGHT, and she taken this and broke it down. 51 00:05:40,540 --> 00:05:44,290 And it's very helpful to look at this type of stuff. Okay. 52 00:05:44,680 --> 00:05:51,249 But one of the arguments in the next why it didn't apply in the UK is they had a much more inclusive early diagnosis. 53 00:05:51,250 --> 00:05:56,920 So the size of the nodule matter. So if you take very small nodules, you end up in everybody. 54 00:05:57,310 --> 00:06:00,640 If you take larger modules, you can reduce this number. 55 00:06:01,210 --> 00:06:03,910 And the Nelson said we're going to reduce this number. 56 00:06:04,300 --> 00:06:10,570 So what they've come out with really, Matt, is they're going to say we reduce the false positives and the risks of overdiagnosis. 57 00:06:11,470 --> 00:06:18,400 Okay. So remember, and this is one of the things so when you look at this, this is a thousand people. 58 00:06:18,400 --> 00:06:26,890 Yeah. And I'll come back to some of seven of the 40 diagnosed lung cancers would not have caused illness or death overdiagnosis. 59 00:06:27,160 --> 00:06:31,360 So it's seven per thousand. Yeah. So you identify a thousand people, 60 00:06:31,360 --> 00:06:39,150 you screen them and of them 40 people will have a diagnosis of lung cancer after they've had the but seven of them wouldn't 61 00:06:39,160 --> 00:06:46,660 have progressed whatever that's the overdiagnosis in 33 was that's a sort of estimate of how much overdiagnosis is going on. 62 00:06:47,470 --> 00:06:50,500 Okay. So the Nelson trial comes out. 63 00:06:50,920 --> 00:06:55,329 So this is some of the information I'm now going to provide you and try and walk 64 00:06:55,330 --> 00:06:59,260 you through how I think about trying to tease out the important information. 65 00:06:59,890 --> 00:07:06,940 Now, one of the things about evidence based medicine, which is really interesting, is you really can make a name for yourself if you can be bothered, 66 00:07:08,200 --> 00:07:11,950 because nobody else can be bothered to look at this stuff and try and understand it. 67 00:07:12,430 --> 00:07:17,740 There's only a few people who really can say, I am going to try and understand this and share that information. 68 00:07:18,010 --> 00:07:24,879 So if you want a route to a really impressive career, just having to look at sort of spend an hour of my time and try and understand 69 00:07:24,880 --> 00:07:28,570 it so I can do a talk like this in your own institution and maybe write it up. 70 00:07:30,710 --> 00:07:34,340 So so this is a bit which I wrote the year before. 71 00:07:34,370 --> 00:07:39,770 This is the press release and when it came, but they said we doing the screening and the abstracts. 72 00:07:39,800 --> 00:07:47,090 This was at the conference reported there were 214 lung cancer deaths in the male control lab and 57 deaths in the screen arm. 73 00:07:47,660 --> 00:07:52,070 Yeah. See that thing happening again? The lung cancer disappears. 74 00:07:52,880 --> 00:07:58,520 Yeah. So suddenly. Well, okay. And so actually, it reduces and it comes back again. 75 00:07:58,520 --> 00:08:05,570 Mortality rate ratio for men is 26% reduction in death or 26% reduction in lung cancer death. 76 00:08:06,230 --> 00:08:13,010 Yeah. So and this is how it how it then gets interpreted decrease mortality by 26% in high risk men. 77 00:08:13,820 --> 00:08:18,469 Why are we not getting on with it? Then you see what really matter. 78 00:08:18,470 --> 00:08:26,330 These language matters could get missed out and then this gets interpreted into this and therefore we end up with a screening program. 79 00:08:26,780 --> 00:08:35,660 Now, this is a Nelson trial that came out February six, half the reduce lung cancer mortality volume 50 screening in a randomised controlled trial. 80 00:08:36,330 --> 00:08:44,780 Okay, now how long for mortality was significantly lower among those who underwent volume screening? 81 00:08:44,780 --> 00:08:49,390 Among those who underwent no screening. Okay. All right. 82 00:08:49,400 --> 00:08:56,900 I'm going to try now break that down, because when I read this stuff, I never feel that informed. 83 00:08:57,980 --> 00:09:01,580 I read these abstracts and I try and go, What is this trying to tell me? 84 00:09:01,850 --> 00:09:08,160 And look at the way the data is presented. Things like 4.91 cases per 1000 person years. 85 00:09:08,180 --> 00:09:13,850 What does that mean? What's a difference between 4.90.91 of a person? 86 00:09:14,420 --> 00:09:16,730 Is that important? How are we supposed to interpret that? 87 00:09:16,940 --> 00:09:23,710 Then you flip to relative rate, cumulative rate ratios, and then you come back to another one and then you've got the rate ratio. 88 00:09:23,720 --> 00:09:29,360 So we flip in math all the time. And so even I find this really difficult to understand. 89 00:09:29,900 --> 00:09:33,680 And the only people who don't are the ones who don't read it so soon. 90 00:09:33,730 --> 00:09:38,780 If you read these and you go, This is difficult, you should do. Because it's not clear to me if this is deliberate, 91 00:09:39,890 --> 00:09:50,840 an attempt to make sure nobody quite understand this so you can make this or it's just incompetence or it's deliberate about everything, isn't it? 92 00:09:51,620 --> 00:09:54,950 But it certainly isn't wrote in, in a way, to understand the information. 93 00:09:55,430 --> 00:09:59,260 So let me take you through the information and you can see. 94 00:09:59,300 --> 00:10:04,879 So the first thing is table two screening test results in each screening round for male participants. 95 00:10:04,880 --> 00:10:08,780 So the first thing is a go. Right, here we go. Round one, two, three, four. 96 00:10:09,110 --> 00:10:12,440 Okay. So there's 22,600. Yeah. 97 00:10:12,950 --> 00:10:17,960 And uptake of that I'm happy here is 90%. 98 00:10:18,260 --> 00:10:24,620 That's helpful information. 90%. That's qua what isn't it. In a screening round, this is a pretty compliant population, but that's helpful. 99 00:10:24,950 --> 00:10:31,130 But what I do then is try and break this down into useful information because I don't think these figures help me. 100 00:10:32,120 --> 00:10:39,620 So I break everything down to one thing. If I just take that thousand people a bit like Deborah and showed us what, and if you take a thousand people, 101 00:10:39,890 --> 00:10:46,560 71 people will have a positive test for screening round of which 31 will detect lung cancer. 102 00:10:46,560 --> 00:10:51,360 That's 44%. Yeah. And 40 will be falsely diagnosed. 103 00:10:51,620 --> 00:10:59,390 Yep. Happy with that. And so that's that figure there, the 44% I was round up because I don't believe there's such a thing as a half a person. 104 00:11:00,020 --> 00:11:04,310 Yeah. And, and so it's either 44 or 44, but that doesn't matter. 105 00:11:05,210 --> 00:11:11,570 So you happy? That's my first step. When I interpret the take a thousand people, how many will have a positive test? 106 00:11:12,020 --> 00:11:18,770 Now, if I took that and took that away, you can actually say anything sensible about that could be based on that table. 107 00:11:19,490 --> 00:11:22,700 But once you give a thousand, it becomes really simple. All right. 108 00:11:23,060 --> 00:11:30,920 But 71 people have a positive test and nearly a half of them will have that lung cancer and just over half won't. 109 00:11:31,070 --> 00:11:35,180 And that's that important figure there. Okay. So that's my first bit. 110 00:11:35,840 --> 00:11:44,600 My second bit then is to start to look at this piece of information which tries to tease out some of these issues of overdiagnosis. 111 00:11:47,120 --> 00:11:51,380 So what what this says, if you look at the whole number of cases here. 112 00:11:52,010 --> 00:11:57,650 Yeah. Any lung cancer, if 344 and in the control group it's 404. 113 00:11:58,220 --> 00:12:04,430 Yeah. So the difference between the two is what they're trying to say is the overdiagnosis component. 114 00:12:04,430 --> 00:12:08,140 You've got 40 excess cancers that you've detected. Yeah. 115 00:12:09,080 --> 00:12:13,040 And that's in the group they say an excess of was found among the male participants in the screening 116 00:12:13,040 --> 00:12:19,880 group ten years after randomisation a suggested excess in the in the incidence rate of 20%. 117 00:12:20,300 --> 00:12:25,230 That's what it's got in the paper. But again I can't understand that just doesn't make sense to me. 118 00:12:25,250 --> 00:12:28,880 What am I supposed to use that information. So again, I take. 119 00:12:29,180 --> 00:12:35,240 Okay if it 40 cases overdiagnosis per fictional thousand people screened that's six per 1000. 120 00:12:36,110 --> 00:12:40,160 Very similar to the actual number in the analysis, isn't it? But the same actually. 121 00:12:40,580 --> 00:12:44,790 That's helpful. It backs up and verified. It makes me feel that makes sense. 122 00:12:45,470 --> 00:12:50,060 So I find this information much more useful than that which is on interpret all to me. 123 00:12:50,060 --> 00:12:58,820 I don't know how I'm supposed to use that. Well, and then third, we come to table four, which is a incredibly interesting table. 124 00:12:59,060 --> 00:13:05,720 If a cause of death of deceased male participants at ten years follow all the important information. 125 00:13:05,870 --> 00:13:10,879 So let's just break this down. The first bit of information is the cause of death. 126 00:13:10,880 --> 00:13:19,940 And here's the lung cancer death. Okay. Hundred and 16 screening group versus 210 in the control group where you can see that death. 127 00:13:20,690 --> 00:13:24,740 And that's point 76. That's where you get the 24% reduction. 128 00:13:25,550 --> 00:13:29,629 Everybody happy with that? That's your lung cancer specific. 129 00:13:29,630 --> 00:13:34,490 Mortality is a really important piece of information. 130 00:13:35,090 --> 00:13:47,420 Okay. Which is down here. But again, you see how here we have the numbers and then suddenly we now go two deaths per thousand person year. 131 00:13:47,450 --> 00:13:51,260 Why did we do that? What's going on now? 132 00:13:51,410 --> 00:13:56,840 And in fact, when you do that, what you see here is actually there's no difference. 133 00:13:56,840 --> 00:14:02,990 And in fact, there's 1% more death in the screening group than there is in the non screening group, 134 00:14:03,920 --> 00:14:09,110 which is really interesting and I don't mean it with all this mortality and if you go on the table, you'll see. 135 00:14:09,110 --> 00:14:13,820 Well, I was speaking to Jeff Aronson today. I mean, are there any clinicians in the room? 136 00:14:15,080 --> 00:14:17,790 So on death certificate, I've done that with you. 137 00:14:18,020 --> 00:14:22,940 How many people would say the cause of death is symptom funds and abnormal clinical and laboratory findings? 138 00:14:25,340 --> 00:14:29,450 If you did the death certificate, you would be in front of the GMC in the beginning. 139 00:14:29,450 --> 00:14:32,989 You don't know what you're doing. That's a medical student potentially. 140 00:14:32,990 --> 00:14:37,730 He's got all these elevated tests. So I'm like, These people are supposed to be blindly allocating this, 141 00:14:38,030 --> 00:14:44,900 but somehow you're 86% more likely to die if you've had screening from symptom signs and abnormal clinical and lab finding. 142 00:14:45,890 --> 00:14:47,710 Just somewhat. Not right in my mind. 143 00:14:48,390 --> 00:14:54,590 And not only that, look at this you are twice as likely to die from integrated nutritional and metabolic diseases. 144 00:14:56,060 --> 00:15:03,260 So imagine if I released a paper thing. Screening increases double your risk of death from endocrine and nutritional and metabolic diseases. 145 00:15:03,560 --> 00:15:10,790 You'd be incredibly worried about that. So this part of the graph is extraordinary to me what's going on that actually, 146 00:15:10,790 --> 00:15:15,230 although you're talking about this reduction in lung cancer, we've actually seen some increases in other diseases. 147 00:15:16,190 --> 00:15:22,010 So what I do that is I try and bring everything together into one piece of information that help me understand it. 148 00:15:22,350 --> 00:15:30,440 Okay. And this is what it looks like. This is a flow chart, which I do for and I put the important information about who's in the trial. 149 00:15:30,680 --> 00:15:35,630 And so I take 2000 high risk individuals. A thousand have lung cancer in 2000 don't. 150 00:15:35,930 --> 00:15:43,430 Yeah. So the first thing, if there's 132 that that and hundred and 30 that there's a little bit more. 151 00:15:43,430 --> 00:15:51,440 But you can say it's no difference really easy. But there are some death there are 24 of these are caused by lung cancer as opposed to 32 here. 152 00:15:51,860 --> 00:16:03,800 But extraordinarily, there are 108 or the causes here compared to 99% more likely to die from another cause if you have screening. 153 00:16:04,550 --> 00:16:11,720 Oh, my God. And then under of the Fathom screen you have 71 will have a positive screening test of the 31 154 00:16:11,720 --> 00:16:18,200 will have lung cancer 40 will be both positive and of the 31 effect will be overdiagnosed. 155 00:16:19,430 --> 00:16:27,140 That's that's my one slide to explain to you about lung cancer and the effect of screening. 156 00:16:27,980 --> 00:16:35,030 Now, if I was in a decision making mode, if I explained and showed you people that you can come back to the end of this talk, we might put it up. 157 00:16:35,600 --> 00:16:40,760 It can help you really understand simply the numbers when you do it this way. 158 00:16:41,180 --> 00:16:42,649 But actually it takes a bit of time. 159 00:16:42,650 --> 00:16:48,290 I've done this for years and it still took me a bit of time to tease around the paper, to pull them bit of information. 160 00:16:48,290 --> 00:16:52,730 But every table in the paper is unhelpful to me to get to this point. 161 00:16:53,780 --> 00:16:57,380 Isn't that interesting? And all the information we want is in that way. 162 00:16:59,570 --> 00:17:03,080 So I think this is incredibly interesting when it comes to decision making. 163 00:17:03,410 --> 00:17:04,639 And I want to point this. 164 00:17:04,640 --> 00:17:11,959 This is a systematic review that basically shows of all the studies, you put them all together that actually you come to the same example. 165 00:17:11,960 --> 00:17:18,740 It doesn't include the now for mortality data, but when you add that in, you'll see there's no mortality effect and it gets this pretty similar, 166 00:17:18,740 --> 00:17:24,770 about 20% reduction for GFR screening if you put in lung cancer survival. 167 00:17:25,010 --> 00:17:28,820 Lung cancer survival. Okay, now. 168 00:17:29,140 --> 00:17:34,150 For really interesting epidemiological concepts to think about lead time bias. 169 00:17:34,150 --> 00:17:38,380 I'm not really going to discuss, but that's why five year survival rates are a waste of time. 170 00:17:39,520 --> 00:17:43,360 The more you screen, the more people pick up earlier, the more they're going to live longer. 171 00:17:43,360 --> 00:17:49,150 But you might not affect overall survival. That's a very clear concept that we understand and trying to understand. 172 00:17:49,420 --> 00:17:51,940 But ten years ago, everything came in five year survival. 173 00:17:52,330 --> 00:17:58,660 And the classic one is in America, our five year survival for 80% for prostate cancer in the UK, the 5%. 174 00:17:59,350 --> 00:18:02,589 And that's why we can't have UK national health care. 175 00:18:02,590 --> 00:18:06,190 But actually the mortality rate and the survival is identical. 176 00:18:06,190 --> 00:18:09,550 You die at the same point. Both the US and the UK, you don't affect survival. 177 00:18:10,000 --> 00:18:16,329 But this is competing interests. Competing interests. The key diagnoses bias and slippery linkage bias. 178 00:18:16,330 --> 00:18:20,110 Isn't that interesting bias? If so, the first is competing risks. 179 00:18:21,670 --> 00:18:25,840 Competing ref means that things compete for your for our death simpler. 180 00:18:26,860 --> 00:18:31,899 And one of the problems is again is if you censor people when they've had the event of 181 00:18:31,900 --> 00:18:36,400 interest so if they die of some of the cause means they can't die of lung cancer either. 182 00:18:37,870 --> 00:18:44,859 So you also have a mathematical problem that you take them out of the analysis and therefore actually 183 00:18:44,860 --> 00:18:51,700 overestimate in the screening group the event rates if you don't account for competing interest. 184 00:18:52,450 --> 00:18:59,560 Yeah. So some studies don't take account of competing interests and prostate cancer is one of the best way we know you do that. 185 00:18:59,830 --> 00:19:02,860 People would effectively prefer a more likely outcome now. 186 00:19:03,130 --> 00:19:10,120 But in lung cancer is incredibly important. But there are also mathematical issues in terms of the censoring, which is important. 187 00:19:10,120 --> 00:19:17,920 And this paper is really neat because what it says is your kaplan-meier hazard ratios overestimate the effect 188 00:19:18,040 --> 00:19:22,570 if you don't account for the fact you're taking people out because you sense that them when they died. 189 00:19:23,650 --> 00:19:27,220 The second thing is these two concepts which are really interesting, 190 00:19:27,430 --> 00:19:33,700 we run about a thing called the catalogue of bias and IT Fund, and these are two new additions to the catalogue of bias. 191 00:19:34,360 --> 00:19:38,800 Sticky diagnosis bias occurs when death from other causes in the experimental group, 192 00:19:38,950 --> 00:19:44,229 in the screening group are incorrectly attributed to the disease is a target screening. 193 00:19:44,230 --> 00:19:48,879 So you could do it both ways. You can say, oh, I think we're interested in lung cancer. 194 00:19:48,880 --> 00:19:55,810 We're going to attribute this to lung cancer because that's in our minds, it's a it's a thought heuristic that happens. 195 00:19:56,380 --> 00:20:02,200 But you can do it the other way when you flip it the other way, which biases the favour, the screening group. 196 00:20:02,200 --> 00:20:04,209 So you can do it the other way when you're slippery. 197 00:20:04,210 --> 00:20:11,860 And so there are different biases occurring which particularly can occur if you're really invested in screening. 198 00:20:12,760 --> 00:20:21,910 You might falsely attribute things to biochemical factors when actually they may have had a lung cancer, they may have had something happen. 199 00:20:22,420 --> 00:20:25,350 You've removed the lung cancer, but a year later they died. 200 00:20:25,360 --> 00:20:30,370 You don't go, well, actually, maybe that was attributable to lung cancer, so you split the diagnosis. 201 00:20:31,840 --> 00:20:37,960 So I'm going to finish here with this position statement that the World Health Organisation talked about. 202 00:20:37,990 --> 00:20:46,780 I think it's very important in terms of screening both lead to an improvement in any results defined in terms of mortality, physical, 203 00:20:46,780 --> 00:20:54,820 social and emotional function, pain and satisfaction among those in whom early diagnosis is achieved or in the other members of the community. 204 00:20:56,320 --> 00:20:57,220 Why is that important? 205 00:20:57,520 --> 00:21:09,490 Well, okay, I'm okay if you have a screen detected group that actually there's no overall mortality effect if you affect some of these other issues. 206 00:21:10,360 --> 00:21:19,270 So for instance, if you can remove my lung cancer at stage one and I have a better quality of life because of that, I still die at the same point. 207 00:21:19,840 --> 00:21:27,070 That's a worthwhile intervention. So all of the outcomes have health related quality of life in there, 208 00:21:27,550 --> 00:21:32,650 but nobody has reported the health related quality of life beyond the first six months or a year, 209 00:21:32,920 --> 00:21:37,180 because all they're interested in is the emotional impact of the first six months after screening, 210 00:21:37,360 --> 00:21:40,600 and they say everything's okay by the year you're okay. 211 00:21:40,810 --> 00:21:44,950 But actually we really interested in what is the overall impact of quality of life. 212 00:21:44,950 --> 00:21:51,609 But none of this has been reported and it's really quite an important issue that what we 213 00:21:51,610 --> 00:21:57,909 stuck on is this measuring screening is where it started with this idea of a cancer. 214 00:21:57,910 --> 00:22:06,040 Specific mortality is why we screen. But actually a common phenomenon is we don't improve overall mortality. 215 00:22:06,430 --> 00:22:11,140 And that's exactly what's happening in lung cancer. The question now is, 216 00:22:11,350 --> 00:22:23,110 and this is where the debate is is quite a significant number of people consider we should now roll out c.t screening based on that Neilsen data. 217 00:22:24,460 --> 00:22:28,930 Some people who keep writing to everybody saying this could be a. 218 00:22:29,080 --> 00:22:36,040 Significant error because it will divert resources so that when you need your diagnosis, 219 00:22:36,040 --> 00:22:40,270 there won't be enough radiography there to help you and you need to be treated quickly. 220 00:22:40,930 --> 00:22:45,280 You could invest the money somewhere else. For instance, an amazing smoking reduction. 221 00:22:45,490 --> 00:22:50,290 You've got a belly in pain to play with. You might actually, if you can get people to smoke less. 222 00:22:50,290 --> 00:22:53,500 That would be still the biggest prevention and public health issue you can deal with. 223 00:22:53,860 --> 00:23:01,510 So if you were the person faced with that graph, where would you spend your billion in the next year? 224 00:23:02,590 --> 00:23:06,250 Would you spend it on CT screening or would you spend it on something else? 225 00:23:07,090 --> 00:23:07,930 Thank you very much.