Same accuracy on KNN for different distance metrics

I am new to data analysis and I am trying to run a kNN classifier on a lung cancer dataset with multiple attributes. For all k values I tasted (1 to 10), I obtain the same accuracy when using either Manhattan or Euclidean distances. I am not sure what this is saying about the data? Is the reason that there’s no difference the fact that I don’t use a large enough data set (300 entries with a 70% training split)?

Thanks!