Ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery

Postoperative irradiation significantly reduces the incidence.

Rates of ipsilateral breast cancer recurrence after breast conservation surgery followed by whole breast radiation with modern treatment has fallen to less than 5-10% in the long term.

Despite present day surgical and irradiation techniques approximately when in 10 women treated with lumpectomy and irradiation will experience recurrence of breast in the ipsilateral breast.

Increased risk in young women.

Presence and quantity of cancer cells at resection margin are major factors affecting IBTR.

Breast recurrence viewed as a local event or a marker for biologic aggressive disease, destined for the development of distant metastases.

Negative margins does not indicate the absence of residual tumor in the breast, measurement of the margin width is an inexact science, and the rates of local recurrence vary with tumor biology and are decreased with systemic therapy.

Patients at high risk for IBTR include women with node negative disease with 5 cm or greater lesions, if the lesion is greater than 2 cm and fewer than 10 axillary nodes have been removed, estrogen receptor negativity, nuclear grade 3, or the presence of lymphovascular invasion.

NKI70 gene test can identify subgroups of women within increased risk of local recurrence after breast conserving surgery and may predict for local recurrence after mastectomy(Nuyten DS).

8-year accrued rate of IBTR 7% in patients with negative and close margins, 14% in patients with focally positive margins and 27% in those patients with extensively positive margins.

Relative risk of ipsilateral breast cancer recurrence is 3.0 without radiation therapy and improvement in local control associated with an 8.6% improvement in overall survival, indicating that locally recurrent disease is a nidus for distant metastases not present at the time of initial treatment.

IBTR in women are selected for breast conserving surgery with mammography has fallen steadily to less than 10% a 10 years follow-up ( Anderson SJ et al).

Whole breast irradiation plus regional nodal irradiation significantly improved disease free survival, but not overall survival, in a randomized, multicenter phase 3 trial of women with node positive or high risk, node negative disease treated with Breast conservative therapy (BCT) and adjuvant therapy (whelan TJ et al).

In the above study of 1832 women with a median follow-up of 62 months, whole breast irradiation plus RNI significantly reduced risk of locoregional recurrence from 5.5 to 3.2%, and distant recurrence from 13% to 7.6%.

In the above study disease-free survival improved from 84% for whole breast irradiation to 89.7% for whole breast radiation plus RNI, but overall survival was not statistically significant.

The addition of regional nodal irradiation (RNI)to WBI results in a 42% reduction in local regional recurrence in a 36% reduction in distant recurrence in patients treated with the BCT, and disease-free survival at five years after radiation therapy increased 33% if RNI was also done (Whelan T et al).

Patients with primary invasive breast cancer <2cm diameter, grade 1 and node negative, treated by wide local excision (WLE) with clear margins were randomised into a 2×2 clinical trial of factorial design with or without radiotherapy and with or without tamoxifen: The actuarial breast cancer specific survival in 1135 randomised patients at 10years was 96%, local recurrence was reduced in patients randomised to radiotherapy (HR) and to tamoxifen (HR 0.33), and LR after WLE alone was 1.9% per annum versus 0.7% with RT alone and 0.8% with tamoxifen alone (Blamey RW et al),

In the above study no patient randomized to both adjuvant treatments developed LR, and LR at 2.2% per annum for surgery alone versus 0.8% for either adjuvant radiotherapy or tamoxifen and 0.2% for both treatments.

Society of Surgical Oncology and American Society for Radiation Oncology (SSO-ASTRO) using a meta-analysis of 28,162 patients concluded: Positive margins, as defined as ink on invasive cancer or ductal carcinoma in situ, are associated with At least a twofold increase in ipsilateral breast tumor recurrence.

In the above scenario, the increased risk of ipsilateral recurrence is not removed by a radiation boost, systemic therapy, or favorable biology.

SSO_ASTRO concludes that negative margins, with no ink on tumor, optimizes ipsilateral breast tumor recurrence and wide margin with widths do not lower the risk.

SSO_ASTRO concludes that the routine practice of obtaining wider negative margins widths is not indicated.

SSO_ASTRO concludes that the rate of ipsilateral breast tumor recurrence are reduced with the use of systemic therapy.

SSO_ASTRO concludes that margins wider than no ink on tumor are not indicated based on the biologic subtype of breast cancer.

SSO_ASTRO concludes the choice of whole breast radiation delivery technique, fractionation, and boost dose should not be dependent on margin width.

SSO_ASTRO concludes wider negative margins than no ink are not indicated for invasive lobular carcinoma.

SSO_ASTRO concludes breast cancer in women 40 years of age or younger is associated with both increased ipsilateral breast tumor recurrence after breast conserving therapy and increased local relapse on the chest wall after mastectomy, and is also more frequently associated with adverse biologic pathologic features.

SSO_ASTRO concludes there is no evidence that increased margin width modifies the increased risk of ipsilateral breast tumor recurrence in young patients.

SSO_ASTRO concludes that when there is an extensive intraductal component, there is no evidence of increased risk of ipsilateral breast tumor recurrence when margins are negative.

SSO_ASTRO concludes that there was no statistical significant difference in local recurrence when margins are 1 mm, 2, and 5 mm.

Following ipsilateral recurrence the subsequent breast conservation surgery is associated with rates for a second in breast recurrence of 20-30%.