The Strictly Come Dancing star, 32, was diagnosed with aggressive stage three breast cancer in May.
She found a lump while preparing for her honeymoon with husband Ben Jones in April and shared her diagnosis weeks later.
The professional dancer has since had an operation, a mastectomy and has had fertility treatment.
However, during an Instagram Live chat with breast cancer survivor and Paralympic gold medalist Erin Kennedy for the charity CoppaFeel! on Friday, Amy revealed the devastating news cancer had been found elsewhere in her body.
Devastating: Amy Dowden, 32, says doctors have discovered she has ‘another type of cancer’ after her initial breast cancer diagnosis earlier this year
Revealing doctors had found more tumours when she went for an MRI scan and had her mastectomy, Amy said: ‘For me, my journey, everything changed. I was originally going to have a lumpectomy, radiotherapy and hormone treatment.
‘But then, after my MRI, they found another tumour so then it changed into a mastectomy and then, after my mastectomy, unfortunately, they found even more tumours.
‘And my pathology wasn’t what they were expecting, and they found another type of cancer and then they told me I needed chemo – for me that was a massive blow.
‘It wasn’t in the plan, originally – and I know the plan you can’t get fixated on.
‘So, all of a sudden, then I realised, and you get scared, but the oncologist did say that with chemo I’ve got a really good chance of a cure.
‘I was really scared and I didn’t want to do chemo but then seeing someone like yourself (Erin) who’s carried on and for me straightaway it was my dancing, like, you can take away my boob but you can’t take my dancing away from me and that’s what I get really upset about.’
While Amy was hoping to return to Strictly Come Dancing this year, she said this will. now be on hold: ‘This year it means I’m not going to be able to dance with a celebrity on Strictly but I’m in such regular contact with the team. The BBC have just been utterly incredible.
‘We are just one big family and they’re going to be guided by me and there’s so many ways to be involved in the show.
Illness: The Strictly Come Dancing star has tried to remain positive after she was diagnosed with aggressive stage three breast cancer in May
‘I’m just staying really positive and hopeful that I’m still going to be part of the show in some way and my aim is to continue dancing – the oncologist said to me movement is really, really good for people on chemo, it’s important. So that was encouraging.’
Amy added of Erin: ‘And then obviously seeing someone like yourself and the way you’ve bounced back, it just gives me hope really.
‘So I have struggled in accepting that I’ve gotta have chemo and what comes with it – the hair loss and everything else – but I’m determined to continue in a healthy way as much as I can.’
Amy later took to her Instagram Stories to thank her followers for their support after she revealed her news.
She wrote: ‘Just want to thank everyone for their love and support.
‘I’ll tackle this next step the best I can and very blessed to have the love and support of my family and friends along with you guys, thank you!
‘The rest of the year looked very different to what was planned but hopefully I’ll enter 2024 cancer free and I’ll never take anything for granted and promise to live life to the full!’
The television personality, who recently underwent a single mastectomy, is waiting for results to learn whether she will require radiotherapy or radiotherapy combined with chemotherapy.
Grateful: Amy took to her Instagram Stories on Friday to thank her followers for their support after she revealed her news
She told The Mirror: ‘If I only have radiotherapy I’ll be back on Strictly this season. Once radiotherapy is done there’ll be nothing to stop me, there’s no pressure but Strictly is leaving the door open. It’s having something to work towards’.
‘I’m visualising myself on that Strictly dance floor. Just being back in the ballroom with the live audience, the adrenalin and the atmosphere. And the support from the whole Strictly family’.
She then went on to explain how routines could be altered to accommodate her, much like her 2020 parter JJ Chalmers.
The TV presenter and former royal marine injured in a bomb blast in Afghanistan, and Amy revealed: ‘I used to choreograph with one arm in my pocket for him. He’s been a great support, he says, ‘Cancer has messed with the wrong person’.
Amy has become a fan favourite since her first appearance on the show in 2017 and has teamed up with stars including Brian Conely, Tom Fletcher and Karim Zeroual.
Elsewhere in the interview Amy opened up about how she was left in tears and worrying the disease was ‘spreading inside’ ahead of her mastectomy.
Surgeons removed two tumours from her right breast as well as cancer ‘specs’ and lymph nodes, which have since been sent for analysis.
Amy went on to tell the publication she hadn’t yet looked at her reconstructed breast out of fear of ‘upsetting’ herself.
Dancing queen: It comes after Amy revealed she is determined to return to Strictly Come Dancing this year, despite her recent diagnosis
Treatment: The professional dancer has since had an operation, a mastectomy and has had fertility treatment since her initial diagnosis
According to the NHS a mastectomy is an operation to remove a breast. It’s used to treat breast cancer in women and breast cancer in men. The operation usually involves removing most of the breast tissue and skin, and the nipple.
It comes after Amy credited her Strictly Come Dancing colleagues for their incredible support after informing them of her breast cancer diagnosis during a group meeting.
Husband Ben, who exchanged vows with the dancer in South Wales last July, also credited family members for helping them maintain a positive outlook.
He told HELLO : ‘Amy has had a lot to deal with in her life and, as I expected, has shown great resilience in the past couple of weeks.
‘We are both surrounded by lots of family and friends who are going to be an important support to us in the coming months. We are both staying very positive and remain optimistic moving forward.’
The Strictly Come Dancing professional shared her diagnosis on Instagram in May and discussed the possibility of returning to the BBC show for its new series later this year.
She wrote: ‘Hey all, I’ve got some news which isn’t easy to share. I’ve recently been diagnosed with breast cancer but I’m determined to get back on that dance floor before you know it. Welsh love Amy.’
The dancer has battled gut condition Crohn’s disease since she was a child and said she has already been through ‘quite a lot’ in her life with health struggles.
Unexpected: She discovered a lump while preparing for her honeymoon with husband Ben Jones in April
She told HELLO at the time: ‘You just don’t ever think it’s going to happen to you. I hadn’t thought it was possible to get breast cancer at my age. My mum has had breast cancer, but she had it at a later age, in her 50s.’
Amy said it was taking part in the CoppaTrek! walk last June in support of breast health awareness charity CoppaFeel! that led her to discover her own cancer.
She realised that she doesn’t ‘check her breasts’ and then made a conscious effort to check herself, saying CoppaFeel! has ‘potentially saved her life’.
‘I don’t know how long this lump could have been there before I would have noticed and done something about it,’ she added.
Amy said she found a lump in her right breast in April, a day before she and her husband flew to the Maldives for a belated honeymoon after their wedding last July.
The dancer said she was ‘in shock’ and decided to keep an eye on the lump, before going to the doctor when the lump grew on her return home.
She was immediately sent for an emergency referral, where she was told the lump looked ‘suspicious’ and to ‘prepare for the worst’.
After a biopsy, Amy was told she had grade three breast cancer, saying her first question was when she could get back on the dance floor.
Grade three cancer is when the cells look very different to normal breast cells and tend to spread more quickly. The grade describes how a cancer cell looks under a microscope.
It is different to a cancer stage, which describes the size of the cancer and how far it has spread. Amy is yet to find out what stage of cancer she has.
Amy said her cancer has been caught ‘early’ and she is now waiting for more information before she is given a full treatment plan, which will include surgery.
What is breast cancer, how many people does it strike and what are the symptoms?
Breast cancer is one of the most common cancers in the world. Each year in the UK there are more than 55,000 new cases, and the disease claims the lives of 11,500 women.
What is breast cancer?
Breast cancer develops from a cancerous cell which develops in the lining of a duct or lobule in one of the breasts.
When the breast cancer has spread into surrounding breast tissue it is called an ‘invasive’ breast cancer. Some people are diagnosed with ‘carcinoma in situ’, where no cancer cells have grown beyond the duct or lobule.
Most cases develop in women over the age of 50 but younger women are sometimes affected. Breast cancer can develop in men, though this is rare.
Staging means how big the cancer is and whether it has spread. Stage 1 is the earliest stage and stage 4 means the cancer has spread to another part of the body.
The cancerous cells are graded from low, which means a slow growth, to high, which is fast-growing. High-grade cancers are more likely to come back after they have first been treated.
What causes breast cancer?
A cancerous tumour starts from one abnormal cell. The exact reason why a cell becomes cancerous is unclear. It is thought that something damages or alters certain genes in the cell. This makes the cell abnormal and multiply.
There are some risk factors that can increase the chance of developing breast cancer, such as genetics.
What are the symptoms of breast cancer?
The usual first symptom is a painless lump in the breast, although most breast lumps are not cancerous and are fluid filled cysts, which are benign.
The first place that breast cancer usually spreads to is the lymph nodes in the armpit. If this occurs you will develop a swelling or lump in an armpit.
For more information visit breastcancernow.org or call its free helpline on 0808 800 6000