In addition to these evidence-based recommendations, the guideline development group also identifies points of best clinical practice in the original guideline document.
Levels of evidence (Ia-IV) and grading of recommendations (A-C) are defined at the end of the "Major Recommendations" field.
Reproductive Factors and Breast Cancer Risk
C - Women should be advised to breastfeed if possible, as this is likely to reduce their risk of breast cancer in addition to any other benefit.
Treatment of Breast Cancer During Pregnancy
There is no evidence that termination of pregnancy after diagnosis of breast cancer is necessary to improve prognosis.
Treatment during pregnancy will require discussion between the woman, the oncologist, and the obstetrician on the relative benefits of early delivery followed by treatment versus commencement of therapy while continuing the pregnancy. Generally the data for immediate treatment are reassuring, and delay or refusal to undergo therapy has serious consequences.
Although standard protocols are not available, surgery is usually the first-line treatment, with mastectomy or lumpectomy and axillary clearance being the preferred option and deferring reconstruction. [Evidence level III]
Provided that chemotherapy is not used in the first trimester (when it may induce spontaneous miscarriage), it appears to be relatively safe for subsequent use. Although there is a general recommendation to avoid the use of tamoxifen during pregnancy, there is a case report of its use during pregnancy with metastatic breast cancer. The use of radiotherapy to treat breast cancer in pregnancy is not absolutely contraindicated but an appropriate thickness of lead shielding should be used to reduce fetal dose. [Evidence level III]
If chemotherapy is necessary in the first trimester, termination of pregnancy may be proposed. One study advises that, if the cancer is detected in the second trimester and is early-stage, lumpectomy can be followed by chemotherapy and radiation can be withheld until after the birth of the child. In the third trimester, if cancer is detected close to term, it may be possible to defer treatment for a short period and induce delivery. [Evidence level IV]
Pregnancy after Treatment of Breast Cancer
Risk of Recurrence
C - Long-term survival after breast cancer does not appear to be affected by pregnancy.
Interval Before Attempting Conception
C - It is recommended that pregnancy should be deferred for at least two years after treatment.
As younger women have significantly lower survival rates and higher local and distant relapse rates than older women, those under 33 years of age might be better advised to delay pregnancy for at least three years, to reduce the risk of relapse. [Evidence level III]
One study has recommended that decisions about future conception should be based on the prognosis for the individual woman. They advise that women with stage-IV disease (with a five-year survival of less than 15%) should not consider a pregnancy and that women with stage-III disease should consider deferring pregnancy for at least five years after treatment. Women with recurrent stage-I or -II tumours should not contemplate conception because of the intensity of the required treatment and the poor prognosis. [Evidence level IV]
Fertility Treatment
There is no current information about the influence of ovarian stimulation on the risk of recurrence in women who have completed treatment for breast cancer.
Increasing numbers of women wish to consider fertility preservation prior to chemotherapy. Embryo freezing is well validated but only suitable for women with a partner. Egg freezing and ovarian tissue cryopreservation are not yet well established and women should be counselled as to the limited success of these approaches. High levels of circulating oestrogen during ovarian stimulation might have an adverse effect on oestrogen-sensitive tumours and this should be considered when counselling oestrogen-receptor positive women prior to chemotherapy.
Breastfeeding
There is no evidence that women who have completed treatment for breast cancer cannot breastfeed safely from the unaffected breast. Breast-conserving surgery may not inhibit lactation but radiotherapy causes fibrosis and lactation is unlikely in an irradiated breast. During treatment for breast cancer with chemotherapy or radiotherapy, women should not breastfeed.
Definitions:
Grading of Recommendations
Grade A - Requires at least one randomised controlled trial as part of a body of literature of overall good quality and consistency addressing the specific recommendation (evidence levels Ia, Ib)
Grade B - Requires the availability of well-conducted clinical studies but no randomised clinical trials on the topic of recommendations (evidence levels IIa, IIb, III)
Grade C - Requires evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities. Indicates an absence of directly applicable clinical studies of good quality (evidence level IV)
Levels of Evidence
Ia: Evidence obtained from meta-analysis of randomised controlled trials
Ib: Evidence obtained from at least one randomised controlled trial
IIa: Evidence obtained from at least one well-designed controlled study without randomisation
IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study
III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies, and case studies
IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities
