Rachel Drago is halfway through a course of chemotherapy which is due to finish in October
A woman who lost around four stone (25kg) in weight believes a diet may have saved her life because it made her realise she had two breast tumours.
Rachel Drago, from Monmouthshire, lost the weight in 100 days after deciding to get in shape when she turned 40.
Dropping from a 36F bra size to a 32D, she noticed a lump while in the shower. Two large tumours were later found in a hospital examination.
Soon after she underwent a mastectomy and is now on a course of chemotherapy.
Mrs Drago, who is a GP practice nurse in Usk, Monmouthshire, said she went on a diet "for all the usual reasons that people go on a diet for".
"Towards the end of this quite strict diet, being a good nurse and practising what I preach, I found a lump in April," said the 41-year-old.
"If I hadn't lost the weight I don't think I would have been able to find it.
"It wouldn't have been noticeable until it was much bigger. It was big enough as it was, and advanced enough."
She began dieting in January, shrinking from a size 18 to size 10 and losing 10in (25cm) from her chest.
The 5ft 2in (1.57m) mother-of-two, who weighed 8st 10lb (55kg) after the diet, hopes to complete a course in becoming a nurse practitioner next year that was put on hold for her treatment.
After the tumours were found she underwent the mastectomy within four weeks and had lymph nodes cleared from her arm and chest wall.
She is now midway through a course of chemotherapy, due to finish in October.
Mrs Drago, married to scientist Guido and mother to Francesca, 11, and Gabriella, nine, praised the care she received from NHS staff at the Royal Gwent Hospital, Newport.
She added: "As a nurse, I know that obesity is a killer, so I was determined to do something about it - but even I hadn't realised just what my fat was hiding."
Jill Donovan, oncology nurse specialist at Velindre hospital in Cardiff said cases of women noticing lumps after losing a considerable amount of weight was not uncommon.
"Not only did this woman's diet help her detect the tumours it will also help in terms of her survival," she added.
"It is important to encourage women with breast cancer to lead a healthy lifestyle in recovery, to watch their diet and ensure they exercise, because it helps with survival."