Almost a fifth of women who have been diagnosed with breast cancer after spotting a potential symptom wait more than a month before seeing their GP, jeopardising their chances of effective treatment, a poll has found.

Research by YouGov for Breast Cancer Care published on Monday also found that one in 20 women wait more than six months, with potentially fatal consequences.

Nearly a third of the women who waited more than a month to visit their GP believed their symptoms were not a serious issue and one in five were too scared to see the doctor because of their fear it might be breast cancer.

Breast Cancer Care’s chief executive, Samia al Qadhi, said: “There have been many awareness raising campaigns around breast cancer symptoms, but our survey suggests that the job still isn’t done.

“The sooner a cancer is diagnosed, the more effective treatment is likely to be, so it is extremely concerning that some women are waiting more than six months to visit their GP after finding a breast symptom.

“We know how scary it can be to find a breast change, but we want to reassure women that an early diagnosis of breast cancer can mean simpler and more effective treatment.

“We are urging women of any age to get to know their body by looking at and feeling their breasts regularly, there’s no right or wrong way, and if they find any unusual changes for them to not put off visiting their GP.”

About 55,000 people are diagnosed with breast cancer every year in the UK, with approximately 65% of cases identified through symptoms.

YouGov surveyed 409 people between 11 and 16 February, 403 of whom were women. It found that 17% of women who have been diagnosed with breast cancer after spotting a potential symptom waited more than a month before seeing their GP, the equivalent of about 6,000 women every year in the UK.

One in ten women surveyed did not have a lump, but less common symptoms such as puckering or dimpling of the skin or redness or rash on the breast, which can in some cases indicate a rare fast-growing type of the disease known as inflammatory breast cancer. Inflammatory breast cancer accounts for between 1% and 4% of all breast cancers.

Nearly a tenth (8%) of women surveyed said they waited to see their GP because they did not want to be a nuisance.

Mother-of-one Fiona Lewis, 44, from Taunton, was diagnosed with breast cancer in 2012, two months after first noticing that her breast had a strange grainy texture and had hardened.

“It was such a shock when I was diagnosed,” she said. “I had two tumours and my treatment included a mastectomy followed by chemotherapy, Herceptin and Tamoxifen.”

“For anyone out there who feels anything the slightest bit unusual or weird in their breasts I would say, get it checked out. Trust your instincts, even if it isn’t a lump or a common symptom, if it feels different, go to your GP.”

Macmillan Cancer Support said that early diagnosis was imperative if UK cancer survival rates were to catch up with other European countries. It recently published research showing that with a five-year survival rate for breast cancer of 81% in 2009, the UK was at a level exceeded 10 years before in Sweden, France and Italy.

Responding to Breast Cancer Care’s findings, Macmillan’s director of policy and research, Dr Fran Woodard, said: “It is crucial that people recognise the symptoms for cancer and seek help as soon as possible.

“UK cancer survival rates currently trail behind much of Europe. If we are serious about bridging this gap we need to address issues such as early diagnosis as a matter of urgency. As well as helping people to recognise cancer symptoms, we must also support GPs to make timely referrals and ensure people are tested as quickly as possible.”