The financial cost of having cancer is greater than the cost of having a child, according to research conducted by a charity.
Macmillan Cancer Support said most patients are £570 worse off each month due to a combination of being too ill to work and additional outgoings such as paying to travel to and from hospital for appointments.
It compared that to a local government survey which it said found it costs parents a monthly average of £448.41 per child under the age of 11, making cancer £121.59 more expensive than parenthood every month - and £1,459.08 more costly a year.
Cancer and its treatments can also leave patients feeling the cold more and one in five (21%) see their yearly energy bill increase by almost £200 on average.
With many cancer patients at risk of spiralling into debt, Macmillan has called on the Government to use the Financial Guidance and Claims Bill, which is currently going through parliament, to change the law so that banks and building societies have a legal obligation to act in the best interests of their customers, particularly if they are vulnerable.
This could include flexibility on mortgage payments, interest freezes on credit cards and loans, or ensuring customers are signposted to financial help as early as possible.
Macmillan provides benefits advice and grants to cancer patients - giving out a record £13.9 million in 2017 alone to help cover the extra costs of their diagnosis.
But the charity's research reveals that just 11% of people with cancer actually tell their bank about their diagnosis - mainly because they do not think their bank would be able to help or they are worried about the consequences.
Mother-of-three Christine Martindale faced a serious financial struggle when she was diagnosed with cancer of the parotid, part of the salivary gland.
The 60-year-old former social worker from Falmouth, Cornwall, said: "I was in the middle of moving house when I was diagnosed and there came a point when I thought, 'I just can't cope'.
"I had to withdraw my house from the market and lost money on a survey for another home.
"My finances continued to dwindle and I had to borrow from my daughter, friends and family to cover my expenses. I even got a lodger to help cover my mortgage.
"When I was pregnant I could prepare for the arrival of my children and it was an experience I could share. But cancer was never planned and it was not foreseen. People didn't gather around me like they did for a baby - I felt in isolation."
Lynda Thomas, the charity's chief executive, said: "Cancer does not wait until you get a promotion at work or until you have enough savings in the bank. It arrives unexpectedly, shaking up everything from your health to your finances.
"Without the right support, the sudden financial impact of the disease can be crippling.
"Macmillan can't plug these growing gaps alone. The Financial Guidance and Claims Bill presents a unique opportunity for the Government to support banks and other financial services providers to make a positive difference to the lives of people living with cancer.
"Progress has been made, but this change in the law will provide more consistent support and prevent vulnerable customers spiralling into debt."