Chemo or no chemo

Had 5cm lump removed from breast and 3 lymph nodes one of which was cancerous, seen oncologist today and I am to have radiotherapy for sure but they want me to decide about chemo as they can't know if a rogue cell has gotten into my system. The chemo would be first and last nearly 6 mths but only improves my survival rate by 6 % so I really don't know if its worth doing.... Anyone been in a similar situation?