Declining final round of treatment

Hi

I had my 4th round of chemo for breast cancer 8 days ago. I have an overseas holiday that falls 16 days after round 6 is due,  as long as round 5 goes ahead on the planned date.

This holiday was all booked and paid for well before my diagnosis. Round 4 was was the first of 3 docetaxel after 3 rounds of EC, I've been very poorly with it and still am. 

I'm considering declining round 6 so I'm not ill for holiday and also because I despise the side effects. Has anyone ever declined the full course of treatment? 

Thanks in advance