Are 550cc implants too small if wanting to achieve a D cup & would high or moderate profile implants give me a larger look?

I hope all is going well with your cancer treatment. I believe 600 mL implants are appropriate. That's the average size I place in most women. Your plastic surgeon should have various sizes of up to 800 mL to make sure that you get the appropriate implant for your height and frame. I always use high profile implants. This is unlike cosmetic breast surgery. In reconstruction you're not only adding volume but you're replacing breast tissue high-profile implants do that nicely.Best wishes.Earl Stephenson Jr. MD DDS FACS

Thanks for your question. The limit of volume expansion is affected by the pocket and quality of the overlying skin. Your plastic surgeon will be able to tell you if there is still more room available. If it borderline, you can always give it more time. Best of Luck!

Thank you for the question. Unfortunately, online consultants will not be able to provide you with specific enough advice to be truly helpful.   Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation or reconstruction surgery (regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural” or "D cup" etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate.
 The use of computer imaging technology may also be very helpful during this communication process.

3.  Once you feel you have communicated your goals clearly,   allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery (after the use of temporary sizers assessed with you in the upright position).
I hope this (and the attached link, devoted to larger looks) helps.