Simon Nutting, 39, from Walsall, flew head first over his handle bars on his cycle home from work on April 30.
Days later, he began to suffer with a stiff neck, which his doctor diagnosed as a sprain from his fall.
Within a week, a lump had grown and within a month he was diagnosed with an aggressive soft tissue cancer – Ewing sarcoma.
Simon credits his bike for saving his life, as doctors have warned the cancer which lay dormant and may have been untreatable if it was found any later.
Support worker Simon said: "I couldn't believe when a lump the size of a melon had grown on the side of my neck overnight.
"I had to do a double take when I saw my reflection in the mirror.
"Two days after my bike accident I had a stiff neck, but never in my wildest dreams would I have thought it was cancer.
"I've always been really healthy and exercised regularly, including cycling to work and back every day so was in complete shock when doctors finally gave me my diagnosis.
"I have five wonderful children and I didn't care what it took, I just wanted to get better for them.
"It's so scary to think that if I never had the bike accident the sarcoma would still be undetected today.
"Now I'm responding well to chemotherapy and know I'm going to kick cancer's butt, not just for me but for my beautiful wife and kids."
Simon's windpipe was left crushed as a result of the tumour growing so big so quickly - so he started treatment straight away.
Simon is now on his third cycle of chemotherapy, he has another three to complete before doctors can perform surgery to remove any of the remaining tumour.
Simon said: "It hasn't been an easy journey but I'm not giving in.
"I nearly died a few days into my first cycle of chemo after I had a bad reaction which meant my blood wouldn't clot and it started to leak.
"I feel really weak now, I weigh just eight-and-a-half stone after losing more than three stone in eight weeks.
"After my bike accident I got up and initially thought I had just a few grazes, I can't believe how much has changed in a few months.
"I was cycling home minding my own business when I had to brake suddenly, I'd recently changed my brake pads so my bike came to a halt and I went head first over the handle bars."
Simon's wife Emma, 29, a full-time mum, has now started fundraising to help Simon and their children, Aaron, seven, Jaime, five, Alexa, four, Tyler 2, and Charley, 14-months, as he can no longer work and provide for them.
Emma said: "My husband is such a loving, selfless man who always puts others first and now I want to help him.
"He's been through so much in the past four months and I want to take as much pressure off him as possible.
"We would never normally ask for anything from anyone but I've set up a gofundme page, http://www.gofundme.com/yefk58n to help us keep our heads above water until Simon can return to work.
"It's been a devastating time for us all and I'm so proud of Simon, he's fought the cancer every step of the way."
Simon was misdiagnosed countless times due to Ewing sarcoma being so rare, he was told he had a stiff neck, man-flu, an abscess and even two other types of cancer before being diagnosed properly.
Simon who now uses a wheelchair and zimmer frame to get around is now campaigning to raise awareness so that others are diagnosed sooner.
Simon said: "Ewing sarcoma's are usually more common in children and teenagers than adults so for a long time no-one knew what was wrong with me.
"I felt like I was passed from pillar to post so it was a huge relief when I was finally diagnosed, I just wanted to get started on the treatment to get better for my family.
"I want others to be aware of the signs and symptoms so that Ewing cancers can be found and treated sooner.
"I can't wait to finally move on from this awful chapter, I feel so lucky to be alive."
Julie Harrington, chief executive at Bone Cancer Research Trust said: "I urge anyone with any concerns to talk to their GP.
"Patients know their own body better than anyone. If you have any unexplained lumps or pain, do not hesitate to discuss the possibility of primary bone cancer with your doctor, at least to rule it out.
"It's simple – the earlier the diagnosis, the better chances of successful treatment and survival.
"We teamed up with the Royal College of GPs last year to launch a specialist e-learning module to help doctors spot the signs and symptoms of primary bone cancer faster.
"We realise doctors may only see one or two cases in their career, which is why we want to support them in early diagnosis and help patients start treatment as soon as possible.
"We are also working to fund research to help us create pioneering new treatments to help us diagnose this brutal disease, which affects 600 people every year in the UK and Ireland, even faster."
"To find out more about the Bone Cancer Research Trust, call or visit our website."