Surprising Results From Our Dutch Survey With Breast Cancer Patients



In 2019, the Know Your Lemons Foundation (KYL) partnered with B-Force of Borstkankervereniging Nederland, a breast cancer patient association based in the Netherlands, to conduct a study among 1,407 breast cancer patients.

The purposes of the study were to gain insight on patient experience: the paths to getting diagnosed, which breast cancer symptoms were frequently discovered, how those symptoms were discovered, and how screening played a role in detection.

About 53% of women in the study were under the age of 50 (the age of eligibility for the Dutch mammography screening program).

The age group with the most breast cancer diagnoses were women in their 40s, followed by women in their 50s, after which came—almost on par—women in their 30s and 60s, and 1 woman who was diagnosed in her teens.


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How was breast cancer found? 

The study showed that 72% of women were symptomatic, meaning they first saw or felt a lump or change in their chest area. Meanwhile 23% were asymptomatic, and instead had their cancer first discovered during a screening mammogram.

Of those who were symptomatic, 70% said they found the symptom by accident, whereas 25% found it during a self-exam.

Looking at the different age groups it is interesting to note that in every age group, apart from age 60-69 (where 49% said they first discovered the lump during a mammogram), breast cancer was most often first discovered through a symptom that the patient reported. After age 50, over 43% of women said they found the cancer with the help of a mammogram that was part of their screening program.

If those eligible to be screened (ages 50-69) had not received a mammogram and never presented symptoms, 23% of breast cancer cases would have been diagnosed at later – and therefore potentially terminal -– stages. That equates to 326 women in this study.

This shows the importance of screening programs and even more so the importance of accessibility to such programs.

What stage was the cancer found in? 

The most common stage was Stage 2 (27%), followed by Stage 3 (22%), Stage 1 (17%), and Stage 4 (6%). 29% of those who took the survey reported that they could not remember the stage their cancer was found in, highlighting the need for better patient education.

When we compared the group of patients who had seen the Know Your Lemons campaign to the patients who had not, we found there was a 39% decrease in Stage 4 cancer diagnoses in women who had been educated by the Know Your Lemons campaign.


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How big was the lump? 

Of those who discovered the lump by accident, around half said that the lump was between 1cm and 3cm in diameter. This is in line with KYL’s lump size comparison as shown below.




Did you have multiple signs of breast cancer? 

In an accompanying survey of 190 respondents, only 11% said they had more than one symptom of breast cancer. However, when patients were shown the 12 Signs of Breast Cancer image and asked to list the symptoms they had, 41% reported having had more than one symptom of breast cancer.

This showed a large gap between what patients understood about symptoms prior to seeing the image versus what they knew after seeing the image. In the large survey of 1,400 patients 46% said that the lemon image taught them a new symptom or symptoms of breast cancer:




55% of women had seen the image prior to the study, indicating that despite a small budget the campaign had reached a large number of the public in the Netherlands.

Given the improved reduction in Stage 4 diagnoses and the identified patient knowledge gap when it comes to symptoms, it is likely that the Know Your Lemons campaign could have a positive effect on early detection for breast cancer if promoted widely.

To learn about how you can get involved in this important work and support our mission to improve early detection of breast cancer through creative and empowering education, go to




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