One of the earliest descriptions of someone with cancer comes from the fourth century BC. Satyrus, tyrant of the city of Heracleia on the Black Sea, developed a cancer between his groin and scrotum. As the cancer spread, Satyrus had ever greater pains. He was unable to sleep and had convulsions.

Advanced cancers in that part of the body were regarded as inoperable, and there were no drugs strong enough to alleviate the agony. So doctors could do nothing. Eventually, the cancer took Satyrus’ life at the age of 65.

Cancer was already well known in this period. A text written in the late fifth or early fourth century BC, called Diseases of Women, described how breast cancer develops:

hard growths form […] out of them hidden cancers develop […] pains shoot up from the patients’ breasts to their throats, and around their shoulder blades […] such patients become thin through their whole body […] breathing decreases, the sense of smell is lost […]

Other medical works of this period describe different sorts of cancers. A woman from the Greek city of Abdera died from a cancer of the chest; a man with throat cancer survived after his doctor burned away the tumour.

Where does the word ‘cancer’ come from?

The word cancer comes from the same era. In the late fifth and early fourth century BC, doctors were using the word karkinos – the ancient Greek word for crab – to describe malignant tumours. Later, when Latin-speaking doctors described the same disease, they used the Latin word for crab: cancer. So, the name stuck.

Even in ancient times, people wondered why doctors named the disease after an animal. One explanation was the crab is an aggressive animal, just as cancer can be an aggressive disease; another explanation was the crab can grip one part of a person’s body with its claws and be difficult to remove, just as cancer can be difficult to remove once it has developed. Others thought it was because of the appearance of the tumour.

The physician Galen (129-216 AD) described breast cancer in his work A Method of Medicine to Glaucon, and compared the form of the tumour to the form of a crab:

We have often seen in the breasts a tumour exactly like a crab. Just as that animal has feet on either side of its body, so too in this disease the veins of the unnatural swelling are stretched out on either side, creating a form similar to a crab.

Not everyone agreed what caused cancer

In the Greco-Roman period, there were different opinions about the cause of cancer.

According to a widespread ancient medical theory, the body has four humours: blood, yellow bile, phlegm and black bile. These four humours need to be kept in a state of balance, otherwise a person becomes sick. If a person suffered from an excess of black bile, it was thought this would eventually lead to cancer.

The physician Erasistratus, who lived from around 315 to 240 BC, disagreed. However, so far as we know, he did not offer an alternative explanation.

How was cancer treated?

Cancer was treated in a range of different ways. It was thought that cancers in their early stages could be cured using medications.

These included drugs derived from plants (such as cucumber, narcissus bulb, castor bean, bitter vetch, cabbage); animals (such as the ash of a crab); and metals (such as arsenic).

Galen claimed that by using this sort of medication, and repeatedly purging his patients with emetics or enemas, he was sometimes successful at making emerging cancers disappear. He said the same treatment sometimes prevented more advanced cancers from continuing to grow. However, he also said surgery is necessary if these medications do not work.

Surgery was usually avoided as patients tended to die from blood loss. The most successful operations were on cancers of the tip of the breast. Leonidas, a physician who lived in the second and third century AD, described his method, which involved cauterising (burning):

I usually operate in cases where the tumours do not extend into the chest […] When the patient has been placed on her back, I incise the healthy area of the breast above the tumour and then cauterize the incision until scabs form and the bleeding is stanched. Then I incise again, marking out the area as I cut deeply into the breast, and again I cauterize. I do this [incising and cauterizing] quite often […] This way the bleeding is not dangerous. After the excision is complete I again cauterize the entire area until it is dessicated.

Cancer was generally regarded as an incurable disease, and so it was feared. Some people with cancer, such as the poet Silius Italicus (26-102 AD), died by suicide to end the torment.

Patients would also pray to the gods for hope of a cure. An example of this is Innocentia, an aristocratic lady who lived in Carthage (in modern-day Tunisia) in the fifth century AD. She told her doctor divine intervention had cured her breast cancer, though her doctor did not believe her.

From the past into the future

We began with Satyrus, a tyrant in the fourth century BC. In the 2,400 years or so since then, much has changed in our knowledge of what causes cancer, how to prevent it and how to treat it. We also know there are more than 200 different types of cancer. Some people’s cancers are so successfully managed, they go on to live long lives.

But there is still no general “cure for cancer”, a disease that about one in five people develop in their lifetime. In 2022 alone, there were about 20 million new cancer cases and 9.7 million cancer deaths globally. We clearly have a long way to go.

Konstantine Panegyres, McKenzie Postdoctoral Fellow, Historical and Philosophical Studies, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

It’s one of the most pervasive messages about technology and sleep. We’re told bright, blue light from screens prevents us falling asleep easily. We’re told to avoid scrolling on our phones before bedtime or while in bed. We’re sold glasses to help filter out blue light. We put our phones on “night mode” to minimise exposure to blue light.

But what does the science actually tell us about the impact of bright, blue light and sleep? When our group of sleep experts from Sweden, Australia and Israel compared scientific studies that directly tested this, we found the overall impact was close to meaningless. Sleep was disrupted, on average, by less than three minutes.

We showed the message that blue light from screens stops you from falling asleep is essentially a myth, albeit a very convincing one.

Instead, we found a more nuanced picture about technology and sleep.

What we did

We gathered evidence from 73 independent studies with a total of 113,370 participants of all ages examining various factors that connect technology use and sleep.

We did indeed find a link between technology use and sleep, but not necessarily what you’d think.

We found that sometimes technology use can lead to poor sleep and sometimes poor sleep can lead to more technology use. In other words, the relationship between technology and sleep is complex and can go both ways.

How is technology supposed to harm sleep?

Technology is proposed to harm our sleep in a number of ways. But here’s what we found when we looked at the evidence:

• bright screen light – across 11 experimental studies, people who used a bright screen emitting blue light before bedtime fell asleep an average of only 2.7 minutes later. In some studies, people slept better after using a bright screen. When we were invited to write about this evidence further, we showed there is still no meaningful impact of bright screen light on other sleep characteristics including the total amount or quality of sleep
• arousal is a measure of whether people become more alert depending on what they’re doing on their device. Across seven studies, people who engaged in more alerting or “exciting” content (for example, video games) lost an average of only about 3.5 minutes of sleep compared to those who engaged in something less exciting (for example, TV). This tells us the content of technology alone doesn’t affect sleep as much as we think
• we found sleep disruption at night (for example, being awoken by text messages) and sleep displacement (using technology past the time that we could be sleeping) can lead to sleep loss. So while technology use was linked to less sleep in these instances, this was unrelated to being exposed to bright, blue light from screens before bedtime.

Which factors encourage more technology use?

Research we reviewed suggests people tend to use more technology at bedtime for two main reasons:

• to “fill the time” when they’re not yet sleepy. This is common for teenagers, who have a biological shift in their sleep patterns that leads to later sleep times, independent of technology use.
• to calm down negative emotions and thoughts at bedtime, for apparent stress reduction and to provide comfort.

There are also a few things that might make people more vulnerable to using technology late into the night and losing sleep.

We found people who are risk-takers or who lose track of time easily may turn off devices later and sacrifice sleep. Fear of missing out and social pressures can also encourage young people in particular to stay up later on technology.

What helps us use technology sensibly?

Last of all, we looked at protective factors, ones that can help people use technology more sensibly before bed.

The two main things we found that helped were self-control, which helps resist the short-term rewards of clicking and scrolling, and having a parent or loved one to help set bedtimes.

Why do we blame blue light?

The blue light theory involves melatonin, a hormone that regulates sleep. During the day, we are exposed to bright, natural light that contains a high amount of blue light. This bright, blue light activates certain cells at the back of our eyes, which send signals to our brain that it’s time to be alert. But as light decreases at night, our brain starts to produce melatonin, making us feel sleepy.

It’s logical to think that artificial light from devices could interfere with the production of melatonin and so affect our sleep. But studies show it would require light levels of about 1,000-2,000 lux (a measure of the intensity of light) to have a significant impact.

Device screens emit only about 80-100 lux. At the other end of the scale, natural sunlight on a sunny day provides about 100,000 lux.

What’s the take-home message?

We know that bright light does affect sleep and alertness. However our research indicates the light from devices such as smartphones and laptops is nowhere near bright or blue enough to disrupt sleep.

There are many factors that can affect sleep, and bright, blue screen light likely isn’t one of them.

The take-home message is to understand your own sleep needs and how technology affects you. Maybe reading an e-book or scrolling on socials is fine for you, or maybe you’re too often putting the phone down way too late. Listen to your body and when you feel sleepy, turn off your device.

Chelsea Reynolds, Casual Academic/Clinical Educator and Clinical Psychologist, College of Education, Psychology and Social Work, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.