Milly's disease - epithelioid hemangioendothelioma (EHE) - affects the vascular system, and is thought to be responsible for less than 1 per cent of cancers.
Tumours can involve liver, lung, bone, lymph node, skin and other soft tissues, and can occur simultaneously at multiple sites. There are rarely symptoms, or only minor ones, given the severity of the disease, and a number of cases - as Milly's was - are found by chance.
Today, sitting in the elegantly restored cottage Milly shares with Alastair and their two dogs - a whippet called Olive, and Kiwi the lurcher - we leaf through wedding photos [the official album is not even back yet]. She pours coffee into brand new, quirkily printed Alice in Wonderland mugs that were wedding presents. She must feel like she, too, has fallen down the rabbit hole into a strange and weird alternate reality.
"We had honestly felt so lucky," she says of life, pre-diagnosis.
"Alastair and I had met at university, fallen in love, established our careers, and then he proposed with a ring in 2014. We thought we had landed on our feet."
But three weeks before the wedding, Milly, a keen rider, fell from her horse and broke her collarbone. While being X-rayed in A&E, she mentioned to a consultant that her chest was sore, too, and he arranged a precautionary X-ray.
The following week, as she recovered from surgery to set the broken collarbone, Milly was surprised to get a phone call from one of the hospital's senior radiologists, a friend of her mother's. "Nothing to worry about, but there's something odd about your chest X-ray," he said.
"We need to get a CT scan of your chest and abdomen." A few days later, he called with the results. "We've found 40 small tumours in your lungs and five in your liver," he said.
"We don't know what they are. It could be any number of illnesses. It could be cancer."
Milly admits: "Obviously I was upset, but I was also in shock. My wedding was just 10 days away by this point. Alastair just seemed to go into autopilot. He'd get up, go to work, come home, take me to a doctor's appointment, and all the time be worrying about whether the right glasses had been ordered, and if we'd have enough champagne. It was surreal."
Milly was sent for an MRI of her liver, then a needle biopsy, and told the results might not be back before the wedding. She suffered terrible doubts. "I thought, 'If I am not going to live, is it fair to get married?' I was still holding it together in public, but desperately worried and uncertain inside."
The couple discussed putting the wedding on hold, but both decided they wanted to go ahead, with their parents' support.
"I called some friends who were junior doctors, and asked them, 'If it is cancer, how long have I got?' One told me, honestly: 'If it is liver and lung cancer, you'll be lucky to see Christmas.' It was hard to hear."
And then on the Friday - 24 hours before the wedding - Milly and Alastair were called to the hospital for provisional results. "That was when they told me they thought it was EHE, and it was so rare, there had never been a case at Tunbridge Wells before. Survival, I was told, seemed to be between two and 10 years."
Remarkably, Milly's reaction was positive. "I thought, 'That's better than six months.' Hopefully I would see Christmas and next summer."
Alastair, though shaken, took his cue from Milly and after they broke the news to her bridesmaids they pressed on with the rehearsal that afternoon.
"I remember thinking, 'This wedding is going to be like a funeral, except I can be part of it. The next time I come down the aisle it will be in a coffin.' And when we started saying the vows - in sickness and in health, till death do us part, Alastair really broke down. They were not easy words to say.
"Afterwards I asked the vicar if I could have five minutes outside with her. We sat together in the graveyard outside this ancient little church in Horsmonden, on a sunny evening, and I asked if there was any space for me. And she reassured me there was."
The wedding itself sped by, with Milly "loving the church service" but too exhausted and overwhelmed to enjoy the reception. "The 'me' before diagnosis would have been first up on the dance floor, but now I wanted to sit in a corner and watch it all go by."
The honeymoon had been cancelled, and the couple spent the next two weeks at home quietly taking stock.
Milly was referred to the Royal Marsden, where she met one of the UK's experts on EHE, Professor Ian Judson. He had good news: EHE can be desperately aggressive but also relatively benign - what he called an "indolent" type - which is how he classified Milly.
This type of EHE develops slowly, although there is no knowing when it will become aggressive. Sadly for Milly and Alastair, one factor that can contribute to it doing so is oestrogen. There is some evidence EHE is accelerated by puberty or pregnancy, meaning the couple face more difficult decisions in the future regarding children.
Prof Judson suggested waiting and watching the lung tumours, while resecting the liver (cutting out areas of damaged tissue and allowing it to regenerate). This, too, risks pushing the cancer into a more aggressive mode, which drugs can only slow, rather than leading to remission.
Milly was scheduled for the resection but further scans showed that she would require two operations rather than one and she became concerned it would be too invasive and risky. Instead, researching online and through a supportive Facebook group, she read of ablation therapy in the US, where the tumours are effectively burnt, frozen or electrocuted to "kill" them in the liver.
After some discussion, Milly was referred by the Marsden to a radiologist who performs this procedure, and will become the first Briton to have the operation on EHE in the UK, early next year.
Milly has become expert on EHE in the few months since her diagnosis. "There are two scientists in America - Brian Rubin and Seth Pollock - who are leading the research worldwide into this cancer. They have already found a gene fusion which is disease-defining, which means that the cancer is not hereditary. Exploring it further could help find a targeted treatment, not just for this cancer, but also other types of cancer, too."
Living with this "ticking time bomb" is hard, says Milly. "It is so rare; there is no pathway to follow, no clues as to when it will become aggressive. I will be monitored closely with scans every few months, and I have support from a counsellor who has helped me come to terms with the disease. And I have chosen to make my diet as healthy as I can with juicing, vitamins and green tea."
She smiles with the determination that got her through that wedding. "I'll just zap the tumours with broccoli until I need to zap them with something else."
