How does chemotherapy work? - Hyunsoo Joshua No
-
0:07 - 0:11During World War I, one of the
horrors of trench warfare -
0:11 - 0:15was a poisonous yellow cloud
called mustard gas. -
0:15 - 0:18For those unlucky enough to be exposed,
-
0:18 - 0:22it made the air impossible to breathe,
burned their eyes, -
0:22 - 0:26and caused huge blisters on exposed skin.
-
0:26 - 0:32Scientists tried desperately to develop an
antidote to this vicious weapon of war. -
0:32 - 0:37In the process they discovered the gas
was irrevocably damaging the bone marrow -
0:37 - 0:42of affected soldiers— halting its
ability to make blood cells. -
0:42 - 0:47Despite these awful effects,
it gave scientists an idea. -
0:47 - 0:53Cancer cells share a characteristic with
bone marrow: both replicate rapidly. -
0:53 - 0:55So could one of the atrocities of war
-
0:55 - 0:58become a champion in the
fight against cancer? -
0:58 - 1:02Researchers in the 1930s
investigated this idea -
1:02 - 1:05by injecting compounds derived
from mustard gas -
1:05 - 1:08into the veins of cancer patients.
-
1:08 - 1:13It took time and trial and error to find
treatments that did more good than harm, -
1:13 - 1:15but by the end of World War II,
-
1:15 - 1:20they discovered what became known
as the first chemotherapy drugs. -
1:20 - 1:23Today, there are more than 100.
-
1:23 - 1:26Chemotherapy drugs are delivered
through pills and injections -
1:26 - 1:33and use "cytotoxic agents," which means
compounds that are toxic to living cells. -
1:33 - 1:38Essentially, these medicines cause some
level of harm to all cells in the body— -
1:38 - 1:40even healthy ones.
-
1:40 - 1:45But they reserve their most powerful
effects for rapidly-dividing cells, -
1:45 - 1:48which is precisely the hallmark of cancer.
-
1:48 - 1:51Take, for example, those first
chemotherapy drugs, -
1:51 - 1:56which are still used today and
are called alkylating agents. -
1:56 - 1:58They’re injected into the bloodstream,
-
1:58 - 2:01which delivers them to
cells all over the body. -
2:01 - 2:06Once inside, when the cell exposes
its DNA in order to copy it, -
2:06 - 2:10they damage the building blocks of
DNA’s double helix structure, -
2:10 - 2:13which can lead to cell death unless
the damage is repaired. -
2:13 - 2:16Because cancer cells multiply rapidly,
-
2:16 - 2:20they take in a high concentration
of alkylating agents, -
2:20 - 2:24and their DNA is frequently exposed
and rarely repaired. -
2:24 - 2:28So they die off more often
than most other cells, -
2:28 - 2:30which have time to fix damaged DNA
-
2:30 - 2:35and don’t accumulate the same
concentrations of alkylating agents. -
2:35 - 2:41Another form of chemotherapy involves
compounds called microtubule stabilizers. -
2:41 - 2:44Cells have small tubes that assemble
to help with cell division -
2:44 - 2:48and DNA replication, then break back down.
-
2:48 - 2:51When microtubule stabilizers
get inside a cell, -
2:51 - 2:54they keep those tiny tubes
from disassembling. -
2:54 - 2:59That prevents the cell from completing
its replication, leading to its death. -
2:59 - 3:04These are just two examples of the six
classes of chemotherapy drugs -
3:04 - 3:06we use to treat cancer today.
-
3:06 - 3:11But despite its huge benefits,
chemotherapy has one big disadvantage: -
3:11 - 3:17it affects other healthy cells in the body
that naturally have to renew rapidly. -
3:17 - 3:21Hair follicles, the cells of the mouth,
the gastrointestinal lining, -
3:21 - 3:27the reproductive system, and bone marrow
are hit nearly as hard as cancer. -
3:27 - 3:32Similar to cancer cells, the rapid
production of these normal cells -
3:32 - 3:35means that they’re reaching for
resources more frequently— -
3:35 - 3:39and are therefore more exposed to
the effects of chemo drugs. -
3:39 - 3:42That leads to several common side
effects of chemotherapy, -
3:42 - 3:47including hair loss, fatigue, infertility,
nausea, and vomiting. -
3:47 - 3:51Doctors commonly prescribe options
to help manage these side-effects, -
3:51 - 3:54such as strong anti-nausea medications.
-
3:54 - 3:59For hair loss, devices called cold caps
can help lower the temperature -
3:59 - 4:02around the head and
constrict blood vessels, -
4:02 - 4:06limiting the amount of chemotherapy
drugs that reach hair follicles. -
4:06 - 4:09And once a course of chemo
treatment is over, -
4:09 - 4:13the healthy tissues that’ve been badly
affected by the drug will recover -
4:13 - 4:15and begin to renew as usual.
-
4:15 - 4:22In 2018 alone, over 17 million people
world-wide received a cancer diagnosis. -
4:22 - 4:27But chemotherapy and other treatments
have changed the outlook for so many. -
4:27 - 4:31Just take the fact that up to 95% of
individuals with testicular cancer -
4:31 - 4:35survive it, thanks to advances
in treatment. -
4:35 - 4:40Even in people with acute myeloid
leukemia— an aggressive blood cancer— -
4:40 - 4:44chemotherapy puts an estimated
60% of patients under 60 -
4:44 - 4:48into remission following their
first phase of treatment. -
4:48 - 4:51Researchers are still developing
more precise interventions -
4:51 - 4:55that only target the intended
cancer cells. -
4:55 - 4:58That’ll help improve survival rates
while leaving healthy tissues -
4:58 - 4:59with reduced harm,
-
4:59 - 5:04making one of the best tools we have
in the fight against cancer even better.
- Title:
- How does chemotherapy work? - Hyunsoo Joshua No
- Speaker:
- Hyunsoo Joshua No
- Description:
-
View full lesson: https://ed.ted.com/lessons/how-does-chemotherapy-work-hyunsoo-joshua-no
During World War I, scientists were trying to develop an antidote to the poisonous yellow cloud known as mustard gas. They discovered the gas was irrevocably damaging the bone marrow of affected soldiers. This gave the scientists an idea: cancer cells and bone marrow both replicate rapidly. Could mustard gas be used to fight cancer? Hyunsoo No details the discovery and development of chemotherapy.
Lesson by Hyunsoo Joshua No, directed by Artrake Studio.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:05
Elise Haadsma approved English subtitles for How does chemotherapy work? | ||
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