He did, though, have to contend with a lot of other things. He was just 19 years old, had recently moved out of his home near Kilmore, about 70 kilometres north of Melbourne, and set himself up in an apartment in St Kilda, where he planned to live while studying film at Swinburne University. He remained in close contact with his parents, who had just moved to the bucolic surrounds of Hidden Valley, not far from Kilmore, and would often return home to babysit the family dog when his parents were away.

A shy, sensitive and happy young man, Scrivens had also started dating a young woman called Jessica, and had his heart set on becoming a film producer.

"All my dreams were coming true," he recalls.

But one day he started to feel very sick, very often. He would wake up in the morning and vomit in weird colours – green, pink – and was so exhausted that he would collapse straight into bed after a shower, without even the energy to dry himself. He had a constant headache that was sometimes so terrible he couldn't drive.

Over several weeks he saw a host of doctors who in turn searched for sinus problems, a stomach bug, a caffeine addiction. There were no answers. Watching her son barely able to get out of bed, his mother Sue was becoming very worried.

"A friend of mine is a pharmacist, and when I took in the fourth prescription for anti-nausea drugs, she said 'I don't mean to alarm you, but if he was mine I'd be demanding an MRI'," she recalls.

Finally, one Friday night, Sue drove Thomas to the Epworth Hospital's emergency department. The doctor on duty shone a light into Scrivens' eyes for what seemed like the longest time, then sent him for an immediate MRI.

Scrivens slid into the narrow tunnel of the MRI machine and watched, just in front of him, a room in which the images were being interpreted by the specialists. As he waited for the machine to do its work, the room began to fill up with more and more people. Then one doctor – Scrivens remembers this clearly – put his head in his hands and shook it in despair.

Three years later, and significantly against the odds, Scrivens is still here. But the battle continues. He has a grade 4 glioma, the commonest of brain tumours and the most serious: it is a condition that can be treated, but not cured. His tumour is in the frontal lobe, the largest part of the brain and therefore the most common place for them to occur. But brain cancer can strike any part of the organ, and the prognosis then hangs on the grade of the tumour and its position, which determine whether it can be operated on or not.

Brain cancer has been one of the less talked about areas of oncology: while breast, lung, skin and even bowel cancer are often at the centre of the cancer debate, brain tumours are somehow thought of separately, even though they are the same thing.

This has changed recently with several high-profile cases, and the moving speech made by Carrie Bickmore, the co-host of Channel 10's The Project, when she accepted her Gold Logie earlier this year. Bickmore's husband Greg Lange died from brain cancer in 2010.

On top of the insidiousness of the disease itself, there are secondary problems caused by a large mass infiltrating the sensitive brain. Tumours can cause seizures, affect eyesight, language, judgment, balance and memory. They can cause incontinence and even change someone's personality. So treatment can come down to a balance of risks: do doctors operate – knowing that the more of the tumour they can remove, the better the prognosis – when it could take away a person's ability to speak? How do you weigh up quality of life in this situation, particularly when there is no cure?

"The patient's experience is going to be totally different depending on which bit of the brain is involved," says Dr Lawrence Cher, Scrivens' doctor and a neuro-oncologist at the Austin Hospital. "And sometimes it can be multiple parts of the brain. So you have something that's affecting the patient physically – can they use their hand or their leg? – but it can also affect their ability to communicate, to understand what's going on around them."

The personality change can be particularly trying for people already under enormous stress. Many times, Cher says, he has seen relationships – particularly if they may have been a little shaky to start with – crumble under the combined weight of the illness and a personality change.

"There's a whole range of things that go to make up the complexity of a person that can change almost immediately after a diagnosis," says Dianne Legge, brain tumour support officer at the Austin's Olivia Newton-John Cancer and Wellness Centre.

While the prognosis for malignant brain tumours is often grim – they are notoriously difficult to eradicate altogether, commonly reappearing in a different part of the brain – survival rates have improved since the early 2000s. That was when the chemotherapy drug temozolomide became commercially available, the first drug designed specifically to treat brain cancer by getting through the blood brain barrier, the body's clever border control system that prevents certain toxins reaching the brain. After temozolomide became more widely available, Cher says, the two-year survival rate jumped from 10 per cent to 27 per cent.

Progress in the understanding of molecular biology – the cellular composition of the tumour and which drug might best defeat it – has also significantly improved the outlook for patients. But there's no telling who will respond best to a particular treatment, or what obstacles might present themselves along the way. That is why Cher never likes to answer the "how long have I got?" question, at least not in the early days, "because people will hear a figure, and that's what sticks in their minds".

Cher has been a doctor since the mid-1980s, and a neuro-oncologist for 20 years. In that time, he's had to break a lot of bad news, including the kind when there are no treatment options left, and it's time to talk palliative care. It is always difficult but Cher – a kindly, calm man who looks like he'd also enjoy a joke, circumstances permitting – finds that a particular formula works: give the patient and their loved ones the facts, strip back the medical jargon, stick to "realistic optimism or optimistic realism".

Certainly, Thomas Scrivens and his family have appreciated that approach. Sue Scrivens says that she can email Cher at 11pm and get an answer straight back – having that kind of access and support has made a difficult situation much easier.

And Thomas, by nature a bit of a joker, has enjoyed sharing his humour with Cher. The doctor particularly enjoyed Scrivens' T-shirt with Homer Simpson on the front, a hole in his head and the words "files have been deleted" underneath.

Andy Emiris and his wife Angie readily testify to the power of maintaining a sense of humour when life takes a dark turn. One Sunday morning in August last year, Andy – a keen boxer and fitness buff – washed both family cars and set out for a 10-kilometre run.

When he came home, he began behaving strangely. Instead of taking a shower as he usually would, Emiris was wandering around in his underwear, troubled by a "chemical smell". Soon after, he complained that he could taste the chemical too; his behaviour soon became so unusual that Angie called an ambulance.

In the emergency department at the Northern Hospital, Emiris leapt to his feet when another patient was called.

"That's me," he said.

"No, it's not, love" Angie replied.

Andy walked to the nurses station, where a nurse repeated the name.

"Yeah, that's me," he insisted. Only it wasn't.

Worried, Angie went to get him a bottle of water and when she returned, Andy was staring into the distance with his teeth clenched, completely unresponsive. Although he never lost consciousness, Emiris was having a seizure that would last for about 12 hours, with only brief windows of recovery.

After a number of tests, Emiris returned home with a diagnosis of epilepsy. But something still wasn't right. An initial MRI had been difficult to read because of the increased activity in his brain, but a further scan revealed the terrible truth: a grade 4 glioma in his temporal lobe.

A neurosurgeon removed as much of the tumour as possible, and then, like Scrivens, he underwent six weeks of concurrent radiation therapy and chemotherapy.

Since then, Emiris' bi-monthly MRIs have shown that the tumour is stable. There have been a few hiccups along the way: a case of Ramsay Hunt syndrome – a rare form of shingles – caused paralysis in his face and a mouth full of blisters, from which he has now recovered.

While Andy's health is as good as can be expected, cancer has radically changed the Emirises' lives. A mechanical engineer who worked as an operations manager, he can no longer work, and Angie has given up part-time work to become his full-time carer. They are of course pleased that the tumour is quiet, but waiting for an MRI is a stressful time. "It's an aggressive S.O.B," Emiris says.

He knows that, in all likelihood, it will be back, but he doesn't know when.

"We've all got a use-by date, it's just not nice to know that yours is going to come up sooner than you expected," he says.

Their children Katie, 19, and Jackson, 16, have been a great support, Emiris says, as has his employer who keeps in regular contact to check how he's faring. But the disease is never far from their thoughts.

"The shock of it all just never goes away," Angie says. "I suppose from my point of view, I can see how Andy was before it happened – really fit and health conscious, we'd like to go out and have a couple of drinks. Then for your whole life to just change, you just don't know what's round the corner."

Both try to stay positive and maintain a sense of humour. Apart from Angie and the kids, Andy has two other great loves: a boat he takes out onto Lake Eildon and refers to as his "summer wife", and a gleaming, white FGX XR8 in his garage that he has recently, thanks to his relative good health, been able to drive again. The number plate on the beast – bought after his diagnosis – is "FIGHTN", to remind himself that it's what he's doing every day. (Angie laughs that he recently returned from a trip to Eildon with copious pictures of the boat and the car. Together.)

He's eating as healthily as he can – he takes no sugar and eats an alkaline diet – but he names regaining his licence as the greatest advance in recent times.

"That was a huge step for me," he says.

That loss of independence is something Scrivens knows well. His dreams of becoming a film producer have been abandoned, and he has not been able to work or study or even drive for some time. His mother Sue has given up working in the family business and is now his full-time carer, while Jess, that nice young woman he was dating when he was diagnosed, is now his wife, and works full-time to keep some much-needed income rolling in. Cancer, quite apart from everything else, can cause a significant financial burden.

After Scrivens' initial surgery to remove the tumour and the six hard weeks of chemo and radiotherapy, he was placed on a randomised clinical trial for a new drug in 2013. He suspects he was in the group that received the placebo because not long after, an MRI gave them the worst possible news: the tumour had come back, very quickly, and this time was in a part of the brain that controls memory and so was inoperable. Had he chosen to do nothing at that stage, he was told, he had six to eight weeks to live.

"I think that really hit me harder than anything," Sue says. "That it was so aggressive after all that radiotherapy and chemotherapy."

But for Thomas, still so young, doing nothing was not an option.

"I think I was very pissed off, because I'd put so much work into the eight weeks of chemo and radio and the clinical trial," he says. "And I felt that all of that was for nothing."

Cher then suggested a multi-country clinical trial for a new drug and this time, because it was in its early trial phase, Scrivens would definitely be receiving the real thing and not a placebo.

So far, it has been remarkably successful in shrinking the tumour and keeping it at bay – Scrivens has been on the drug longer than anyone else in the trial, and his tumour has stayed stable. But it has had a terrible effect on his eyes: it has significantly reduced his vision and caused painful ulcers on his corneas, which in turn make his eyes red, swollen and sensitive to light.

He is now on a prolonged break from the drug (though still part of the trial) to give his eyes a rest, hopefully restoring his vision and reducing the pain. In the meantime, Cher and his colleagues will keep a close watch on the tumour.

Scrivens is relentlessly positive and upbeat. He is now talking about finishing some counselling studies he started and then had to stop when he became too ill. Eventually he would like to find work as a counsellor, and it's hard to imagine anyone more suited to that profession. He and Jess would like to travel some more too, perhaps to visit relatives in England, or somewhere else entirely.

He'd like to have less of his life taken up by that menace in his head, and "just have some fun and enjoy what's out there in the world". In short, he'd like to be 22 years old.

Tom Scrivens' fundraising site, set up by his sister Sarah, is fundrazr.com/campaigns/9Qfu7

The devil inside: facts about brain cancer

In 2011, more than 1724 brain cancers were diagnosed in Australia, and in 2012, there were 1241 deaths caused by the disease.

The risk is of being diagnosed with a brain cancer by age 85 is about 1 in 96 for men and 1 in 149 in women.

Symptoms of brain tumours include: headaches, nausea and vomiting, loss of balance, drowsiness, difficulty speaking or remembering words, disturbed vision, hearing, smell or taste, general irritability, depression or personality changes.

The prognosis depends on the type of tumour, the patient's age and general health and when the cancer is diagnosed. Across all brain cancers, the five-year survival rate in Australia is 22 per cent.

Source: Cancer Council Australia