Chances are, you flipped your tuna cakes too early. Wait until the tuna cake has formed a nice golden brown crust on the pan side before flipping. If you flip it too early, the tuna cake will still be soft and prone to falling apart. u003cbr/u003eu003cbr/u003eAnother cause can be too much mayonnaise or other liquids. If your tuna cake mixture is very wet and sticking to your hands, it's too wet and will be difficult to form into patties.