WEBVTT 1 00:00:00.660 --> 00:00:03.060 Hi, everyone, and welcome to this module 2 00:00:03.060 --> 00:00:05.133 on the Global Burden of Cancer. 3 00:00:06.660 --> 00:00:08.580 In this presentation, we have three main goals. 4 00:00:08.580 --> 00:00:11.160 So first, we're going to define cancer. 5 00:00:11.160 --> 00:00:12.900 Then we're going to survey cancer incidence 6 00:00:12.900 --> 00:00:15.180 and prevalence in the US and globally. 7 00:00:15.180 --> 00:00:17.790 And finally, we're going to describe cancer mortality 8 00:00:17.790 --> 00:00:19.860 in the US and globally. 9 00:00:19.860 --> 00:00:21.810 So to begin with, what is cancer? 10 00:00:21.810 --> 00:00:23.490 Well, cancer can be succinctly defined 11 00:00:23.490 --> 00:00:25.290 as deranged cell division. 12 00:00:25.290 --> 00:00:27.210 It's the uncontrolled growth and spread 13 00:00:27.210 --> 00:00:29.043 of abnormal cells in the body. 14 00:00:29.910 --> 00:00:32.160 It can arise from virtually any tissue in the body 15 00:00:32.160 --> 00:00:35.280 and are usually named with the anatomic site of origin. 16 00:00:35.280 --> 00:00:38.370 That being said, the vast majority of all cancers 17 00:00:38.370 --> 00:00:41.643 are solid tumors that originate in epithelial cells. 18 00:00:42.480 --> 00:00:44.790 Epithelial cells are the lining 19 00:00:44.790 --> 00:00:46.770 of different organs of the body, 20 00:00:46.770 --> 00:00:49.320 including those of the gastrointestinal tract, 21 00:00:49.320 --> 00:00:52.470 the genitourinary tract, and the reproductive tract. 22 00:00:52.470 --> 00:00:56.673 And because these cancers make up so many of the cases 23 00:00:57.990 --> 00:01:00.060 that afflict humans and cause death in humans, 24 00:01:00.060 --> 00:01:03.183 they'll be the great focus of this course. 25 00:01:04.410 --> 00:01:05.730 So that being said too, 26 00:01:05.730 --> 00:01:10.730 we have about 90% cancers in epithelial cells. 27 00:01:11.040 --> 00:01:13.200 We have some smaller categories of cancers 28 00:01:13.200 --> 00:01:14.940 that while they don't affect as many people 29 00:01:14.940 --> 00:01:16.440 or cause as many cases, 30 00:01:16.440 --> 00:01:18.000 are nonetheless then important to know. 31 00:01:18.000 --> 00:01:21.330 So 8% of malignant neoplasms or cancers 32 00:01:21.330 --> 00:01:23.580 arise from cells of the immune system. 33 00:01:23.580 --> 00:01:27.030 Less than 2% happen in connective tissues 34 00:01:27.030 --> 00:01:30.780 and less than 1% develop in the central nervous system. 35 00:01:30.780 --> 00:01:34.560 And cancer can cause death by metastasizing 36 00:01:34.560 --> 00:01:37.290 or spreading to vital organs 37 00:01:37.290 --> 00:01:41.130 and really making the functions of those organs impossible 38 00:01:41.130 --> 00:01:45.240 and shutting down these biological processes 39 00:01:45.240 --> 00:01:47.610 that are necessary for life. 40 00:01:47.610 --> 00:01:52.350 And while we've made a lot of progress in both the medical 41 00:01:52.350 --> 00:01:57.330 and the public health field over the past number of years, 42 00:01:57.330 --> 00:01:59.100 it's unfortunate but many forms of cancer 43 00:01:59.100 --> 00:02:01.980 still remain incurable and are responsible 44 00:02:01.980 --> 00:02:04.773 for significant mortality in the US and globally. 45 00:02:05.670 --> 00:02:08.430 So kind of reflecting that too, we have this quotation 46 00:02:08.430 --> 00:02:11.580 from a book titled "The Pathologic Basis of Disease" 47 00:02:11.580 --> 00:02:13.950 that came out in 1974. 48 00:02:13.950 --> 00:02:15.600 And when we think about cancer, 49 00:02:15.600 --> 00:02:18.480 we still feel a lot of these things. 50 00:02:18.480 --> 00:02:23.480 It's a scary disease and it really is responsible 51 00:02:24.480 --> 00:02:27.570 both for a medical and a biologic burden 52 00:02:27.570 --> 00:02:30.450 as well as social effects, 53 00:02:30.450 --> 00:02:33.870 effects on one's family, one's livelihood. 54 00:02:33.870 --> 00:02:35.610 And these are all kind of themes 55 00:02:35.610 --> 00:02:38.040 that we'll keep in mind over the coming weeks 56 00:02:38.040 --> 00:02:39.810 and that we'll have opportunities to explore 57 00:02:39.810 --> 00:02:41.763 in discussion posts and projects. 58 00:02:43.200 --> 00:02:46.650 So to speak a little bit about the global burden of cancer, 59 00:02:46.650 --> 00:02:50.730 in 2020, there were 19.29 million new cases of cancer 60 00:02:50.730 --> 00:02:52.923 and 9.96 million cancer deaths. 61 00:02:53.850 --> 00:02:56.400 And all these data are from GLOBOCAN 62 00:02:56.400 --> 00:02:59.100 are the Global Observatory of Cancer. 63 00:02:59.100 --> 00:03:00.450 And this is a really great resource 64 00:03:00.450 --> 00:03:04.020 for updated cancer statistics that span mortality incidence, 65 00:03:04.020 --> 00:03:08.430 prevalence, different sexes, and different cancer sites 66 00:03:08.430 --> 00:03:10.290 in different parts of the world. 67 00:03:10.290 --> 00:03:13.620 So in the future, when we're doing discussion posts 68 00:03:13.620 --> 00:03:15.750 and when we're working on projects, 69 00:03:15.750 --> 00:03:16.980 this is a really great resource 70 00:03:16.980 --> 00:03:19.830 for getting accurate, updated information 71 00:03:19.830 --> 00:03:22.380 about different questions 72 00:03:22.380 --> 00:03:26.160 or different research areas that you have. 73 00:03:26.160 --> 00:03:30.420 So more men experience cancer than women. 74 00:03:30.420 --> 00:03:35.420 In 2020, that was a difference of about 1 million cases. 75 00:03:36.054 --> 00:03:39.180 And more men also die of cancer than women. 76 00:03:39.180 --> 00:03:40.890 So the number of deaths 77 00:03:40.890 --> 00:03:44.340 in men was about 25% higher than among women. 78 00:03:44.340 --> 00:03:46.530 And the age-standardized cancer incidence in men 79 00:03:46.530 --> 00:03:48.570 was 19% higher than in women. 80 00:03:48.570 --> 00:03:53.570 So about 222 people per 100,000 people 81 00:03:54.690 --> 00:03:59.257 or men had cancer versus 186 per 100,000. 82 00:04:01.800 --> 00:04:05.820 So to talk a little bit about the specific cancer types, 83 00:04:05.820 --> 00:04:08.430 lung cancer was by far the deadliest malignancy 84 00:04:08.430 --> 00:04:12.060 and it caused 18% of total cancer deaths in 2020. 85 00:04:12.060 --> 00:04:16.320 And we see from this, or after lung cancer, 86 00:04:16.320 --> 00:04:19.830 the number of cases really decreased quite significantly. 87 00:04:19.830 --> 00:04:23.940 So of all other cancer types, no single cancer type 88 00:04:23.940 --> 00:04:27.390 is causing more than 1 million deaths in 2020. 89 00:04:27.390 --> 00:04:31.203 We see that colon and rectum cancer come close, 90 00:04:32.160 --> 00:04:36.480 but the rest are all killing under a million people in 2020. 91 00:04:36.480 --> 00:04:41.480 So still obviously significant mortality numbers, 92 00:04:41.580 --> 00:04:46.320 but really lung cancer is a significant driver 93 00:04:46.320 --> 00:04:48.183 of mortality among cancers. 94 00:04:50.250 --> 00:04:52.890 So next, if we look at the ratio of mortality to incidence, 95 00:04:52.890 --> 00:04:56.160 which isn't a perfect measure of fatality 96 00:04:56.160 --> 00:04:57.420 but is a pretty good estimate, 97 00:04:57.420 --> 00:04:59.250 we see it's highest for pancreatic cancer, 98 00:04:59.250 --> 00:05:02.190 liver cancer, lung cancer, and esophageal cancer. 99 00:05:02.190 --> 00:05:04.710 And there's a number of reasons for this ratio 100 00:05:04.710 --> 00:05:06.810 and we're going to dig into them a little bit 101 00:05:06.810 --> 00:05:08.490 over the coming weeks. 102 00:05:08.490 --> 00:05:12.047 And finally, cancer deaths constitute approximately 13.5% 103 00:05:12.047 --> 00:05:15.240 of the 60 million annual deaths worldwide. 104 00:05:15.240 --> 00:05:17.010 And that's a 2012 statistic. 105 00:05:17.010 --> 00:05:19.300 And you'll note that your textbook 106 00:05:20.430 --> 00:05:23.910 relies on statistics from 2012. 107 00:05:23.910 --> 00:05:26.100 So a lot of times we'll see those 108 00:05:26.100 --> 00:05:29.640 and I'll do my best to present the updated statistics 109 00:05:29.640 --> 00:05:30.930 where it's relevant. 110 00:05:30.930 --> 00:05:32.790 And a lot of times the trends have continued 111 00:05:32.790 --> 00:05:37.790 from 2012 to 2020 and 2022. 112 00:05:37.950 --> 00:05:42.480 But because a lot of the examples that your book uses 113 00:05:42.480 --> 00:05:46.383 are going to be from the early 2010s, 114 00:05:47.430 --> 00:05:50.583 the course will also discuss those in depth. 115 00:05:51.810 --> 00:05:55.290 So worldwide, cancer is the third leading cause of death 116 00:05:55.290 --> 00:05:57.750 behind heart disease and infectious conditions. 117 00:05:57.750 --> 00:06:01.230 But that being said, in high-income countries, 118 00:06:01.230 --> 00:06:03.330 which are abbreviated as HICs, 119 00:06:03.330 --> 00:06:04.920 cancer is the leading cause of death 120 00:06:04.920 --> 00:06:06.780 in people under the age of 85 years. 121 00:06:06.780 --> 00:06:08.770 So it's surpassed heart disease 122 00:06:09.810 --> 00:06:11.640 and has become the leading cause of death. 123 00:06:11.640 --> 00:06:14.520 And we'll see too, one of the other themes 124 00:06:14.520 --> 00:06:15.690 that we'll explore in this course 125 00:06:15.690 --> 00:06:18.000 is the differences in cancer mortality 126 00:06:18.000 --> 00:06:20.610 and incidence among different areas of the world. 127 00:06:20.610 --> 00:06:23.940 So we'll look at high-income countries, or HICs, 128 00:06:23.940 --> 00:06:26.850 and low and middle-income countries, or LMICs, 129 00:06:26.850 --> 00:06:29.340 and look at the ways that rates are increasing 130 00:06:29.340 --> 00:06:32.973 or decreasing and some of the reasons for those changes. 131 00:06:34.500 --> 00:06:36.240 So as I mentioned, the global burden of cancer 132 00:06:36.240 --> 00:06:37.953 is higher in men than women. 133 00:06:38.910 --> 00:06:41.220 And this is looking at those 2012 statistics 134 00:06:41.220 --> 00:06:42.750 that are going to be listed in your textbook. 135 00:06:42.750 --> 00:06:45.240 So the number of cancer deaths among men 136 00:06:45.240 --> 00:06:47.700 was 31% higher than among women. 137 00:06:47.700 --> 00:06:50.160 And the age-standardized cancer incidence in men 138 00:06:50.160 --> 00:06:53.040 was 24% higher than in women. 139 00:06:53.040 --> 00:06:56.493 So, pretty much higher in men. 140 00:06:57.720 --> 00:06:59.160 We see this figure 141 00:06:59.160 --> 00:07:01.230 that really, clearly shows the differences. 142 00:07:01.230 --> 00:07:02.790 And again, I'll draw your attention 143 00:07:02.790 --> 00:07:05.280 to the really high burden 144 00:07:05.280 --> 00:07:10.280 that lung cancer wages on mortality. 145 00:07:10.500 --> 00:07:14.640 So of this 2012 data, we see that liver, lung, stomach, 146 00:07:14.640 --> 00:07:17.280 as well as the other major cancers that I mentioned 147 00:07:17.280 --> 00:07:20.100 are really causing the bulk of the mortality 148 00:07:20.100 --> 00:07:22.500 when we talk about cancer in men. 149 00:07:22.500 --> 00:07:24.990 And we're going to spend the next number of weeks digging 150 00:07:24.990 --> 00:07:26.850 into each of these cancers one at a time 151 00:07:26.850 --> 00:07:31.320 to really explore their role in incidence and mortality, 152 00:07:31.320 --> 00:07:32.700 some of the risk factors, 153 00:07:32.700 --> 00:07:34.743 and the ways to prevent these cancers. 154 00:07:36.570 --> 00:07:40.950 And finally, the chart for the global cancer deaths in women 155 00:07:40.950 --> 00:07:44.610 as we'll see, is similar as it is for men, 156 00:07:44.610 --> 00:07:48.180 though you'll note that in the left hand, 157 00:07:51.750 --> 00:07:55.540 the scale on the left hand of the graph is much lower 158 00:07:57.060 --> 00:07:58.110 than it was for men. 159 00:07:58.110 --> 00:08:03.110 So for men, the chart reached up to a million or 1,100,000. 160 00:08:03.600 --> 00:08:05.970 And here the legend only reaches up to 600,000 161 00:08:05.970 --> 00:08:08.820 because the number of deaths in women 162 00:08:08.820 --> 00:08:10.563 is so much less than it is in men. 163 00:08:13.140 --> 00:08:17.610 And finally, to briefly mention this difference 164 00:08:17.610 --> 00:08:20.850 that a lot of cancers are due to cells 165 00:08:20.850 --> 00:08:22.210 of the epithelial tract 166 00:08:24.300 --> 00:08:26.440 or rather epithelial cells 167 00:08:27.360 --> 00:08:32.193 that are located in many tracts of the body. 168 00:08:33.420 --> 00:08:36.480 And this nine-to-one prominence of carcinomas 169 00:08:36.480 --> 00:08:39.600 are in cancers of the epithelial cells 170 00:08:39.600 --> 00:08:41.910 relative to other forms of cancer 171 00:08:41.910 --> 00:08:45.270 really shows how much faster these cells are dividing 172 00:08:45.270 --> 00:08:47.130 than other cell populations in the body. 173 00:08:47.130 --> 00:08:50.010 So for example, the cells of the gastrointestinal tract 174 00:08:50.010 --> 00:08:52.650 are dividing at such a faster rate 175 00:08:52.650 --> 00:08:56.460 than muscle cells or fat cells or bone cells, 176 00:08:56.460 --> 00:08:58.690 and it's this rapid cell division 177 00:08:59.910 --> 00:09:02.770 that really creates opportunities for cancers to form 178 00:09:03.840 --> 00:09:06.543 and exist in a human's body.