A list of considerations from Breastcancer.org author Beesie:
Do you want to avoid radiation? If your DCIS isn't near the chest wall, then it may be possible to avoid radiation if you have a mastectomy. This is a big selling point for many women who choose to have mastectomies. However you should be aware that there is no guarantee that radiation may not be necessary even if you have a mastectomy, if some DCIS is found near the chest wall. Radiation might also be recommended if it turns out that you have a large area of invasive cancer in addition to the DCIS and/or if it turns out that you are node positive (which is only possible if you have invasive cancer).
Do you want to avoid Tamoxifen? For those who are ER positive who have DCIS, this may be possible if you have a mastectomy and particularly if you have a bilateral mastectomy. Tamoxifen provides 3 benefits: 1) It reduces the risk of local recurrence; 2) it reduces the risk of the development of a new breast cancer in either breast; and 3) it reduces the risk of a distant recurrence. For most women, a mastectomy will reduce the first risk to a low enough level that the benefit from Tamox will be minimal. For most women, a bilateral mastectomy will reduce the second risk to a low enough level that the benefit from Tamox will be minimal. The third benefit, protection against a distant recurrence (i.e. mets), isn’t a factor for women who have DCIS, since by definition DCIS cannot move beyond the breast. However for those who have invasive cancer, this is a crucial benefit and is not affected at all by the type of surgery. So if you have an invasive tumor that is ER+, usually Tamoxifen (or an AI) will be recommended whether you have a lumpectomy, mastectomy or a BMX. However if you have DCIS (and therefore face virtually no risk of mets) or a very small non-aggressive invasive tumor (and therefore face only a very small risk of mets), it may be possible to pass on Tamox with little change in your long-term prognosis.
Does the length of the surgery and the length of the recovery period matter to you? For most women, a lumpectomy is a relatively easy surgery and recovery. After a lumpectomy, radiation usually is given for 6 weeks. A mastectomy is a longer, more complex surgery and the recovery period is longer. How do you feel about going through a longer surgery and a longer, more restricted recovery period?
If you have a lumpectomy, how will you deal with the side effects from Rads? For most patients the side effects of rads are not as difficult as they expected, but most women do experience some side effects. You should be prepared for some temporary discomfort, fatigue and skin irritation, particularly towards the end of your rads cycle. Most side effects go away a few weeks after treatment ends but if you have other health problems, particularly heart or lung problems, you may be at risk for more serious side effects. This can be an important consideration and should be discussed with your doctor.
If you have a mastectomy, do you plan to have reconstruction? If so, be aware that reconstruction, even "immediate" reconstruction, is usually a long process - many months - and most often requires more than one surgery. Some women have little discomfort during the reconstruction process but other women find the process to be very difficult - there is no way to know until you are going through it. Are you prepared for this?
If you have a MX or BMX, how will you deal with possible complications with reconstruction? Some lucky women breeze through reconstruction but unfortunately, many have complications. These may be short-term and/or fixable or they may be long-term and difficult to fix. Common problems include ripples and indentations and unevenness. You may have lingering side effects (muscle pain, spasms, itching, etc.) on one side or both. If you don't end up with symmetry (symmetry is not a sure thing by any means, even if you have a bilateral mastectomy with reconstruction done on both sides at the same time), will you regret the decision to remove your breasts or your healthy breast? Are you prepared for the possibility of revision surgery?
If you have MX or BMX, how you do feel about your body image and how will this be affected by a mastectomy? A reconstructed breast is not the same as a real breast. Some women love their reconstructed breasts while some women hate them. Most probably fall in-between. Reconstructed breasts usually looks fine in clothing but may not appear natural when naked. They may not feel natural or move naturally, particularly if you have implant reconstruction. If you do choose to have a mastectomy, one option that will help you get a more natural appearance is a nipple sparing mastectomy (NSM). Not all breast surgeons are trained to do NSMs so your surgeon might not present this option to you. Ask your surgeon about it if you are interested and if he/she doesn’t do nipple sparing mastectomies, it may be worth the effort to find a surgeon who does do NSMs in order to see if this option is available for you (your DCIS can’t be right up near the nipple).
If you have a MX or BMX, how do you feel about losing the natural feeling in your breast(s) and nipple(s)? Are your nipples important to you sexually? A mastectomy will change your body for the rest of your life and you have to be prepared for that. Keep in mind as well that even if you have a nipple sparing mastectomy, except in rare cases (and except with a new untested reconstruction procedure) the most feeling that can be retained in your nipples is about 20% - the nerves that affect 80% of nipple sensation are by necessity cut during the surgery and cannot be reconnected. Any breast/nipple feeling you regain will be surface feeling only (or phantom sensations, which are actually quite common and feel very real); there will be no feeling inside your breast, instead your breast will feel numb. For some, loss of breast/nipple sensation is a small price to pay; for others, it has a huge impact on their lives.
If you have a MX or BMX, how will you deal emotionally with the loss of your breast(s)?Some women are glad that their breast(s) is gone because it was the source of the cancer, but others become angry that cancer forced them to lose their breast(s). How do you think you will feel? Don't just consider how you feel now, as you are facing the breast cancer diagnosis, but try to think about how you will feel in a year and in a few years, once this diagnosis, and the fear, is well behind you. Keep in mind as well that most women are pleased with their decision to have a mastectomy or bilateral when it's first done - they are relieved that the cancer is gone and the surgery is over and in most cases it wasn't nearly as bad as they feared. For women who are affected by the loss, the real impact usually doesn't hit until many months or even years later. That’s why trying to think ahead to a time when this diagnosis is long behind you is important.
If you have a MX or BMX, will removal of your breast(s) help you move on from having had cancer or will it hamper your ability to move on? Will you feel that the cancer is gone because your breast(s) is gone? Or will the loss of your breast(s) be a constant reminder that you had breast cancer?
If you have a lumpectomy, how will you deal emotionally with your 6 month or annual mammos and/or MRIs? For the first year or two after diagnosis, most women get very stressed when they have to go for their screenings. The good news is that usually this fear fades over time. However some women choose to have a BMX in order to avoid the anxiety of these checks.
Do you know what your doctors estimate your recurrence risk will be if you have a lumpectomy and radiation? Is this risk level one that you can live with or one that scares you? Will you live in constant fear or will you be satisfied that you've reduced your risk sufficiently and not worry about it except when you have your 6 month or annual screenings? If you will always worry, then having a mastectomy might be a better option for you; many women get peace of mind by having a mastectomy. Be aware however that while a mastectomy will likely significantly reduce your local (in the breast area) recurrence risk, a recurrence or the development of a new BC is still possible after a mastectomy. Lots to consider.
Do you know your risk to get BC in your other (the non-cancer) breast? Is this a risk level that scares you? Or is this a risk level that you can live with? Keep in mind that DCIS cannot recur in the contralateral breast so your current diagnosis doesn't impact your other breast. However, anyone who's been diagnosed with BC one time is at higher risk to be diagnosed again and this may be compounded if you have other risk factors. Find out your risk level from your oncologist. When you talk to him or her, determine if BRCA genetic testing might be appropriate for you based on your family history of cancer and/or your age and/or your ethnicity (those of Ashkenazi Jewish descent are at higher risk). Those who are BRCA positive are very high risk to get BC and for many women, a positive BRCA test result is a compelling reason to have a bilateral mastectomy. On the other hand, for many women a negative BRCA test result helps with the decision to have a lumpectomy or single mastectomy rather than a bilateral. Talk to your oncologist. Don't assume that you know what your risk is; you may be surprised to find that it's much higher than you think, or much lower than you think (my risk was much less than I would ever have thought).
How will you feel if you have a lumpectomy or single MX and at some point in the future (maybe in 2 years or maybe in 30 years) you get BC again, either a recurrence in the same breast or a new BC in either breast? Will you regret your decision and wish that you'd had a bilateral mastectomy? Or will you be grateful for the extra time that you had with your breasts, knowing that you made the best decision at the time with the information that you had?
How will you feel if you have a bilateral mastectomy and no cancer or high risk conditions are found in the other breast? Will you question (either immediately or years in the future) why you made the decision to have the bilateral? Or will you be satisfied that you made the best decision with the information you had?