Triple-negative breast cancer increased risk for local recurrence

Issue: December 25, 2012

Women with triple-negative breast cancer and no more than three positive lymph nodes after a mastectomy have an increased risk for local recurrence than women with breast cancer not classified as triple-negative, according to results of a case-control study presented at the 2012 American Society for Radiation Oncology Annual Meeting in Boston.

Perspective from Douglas Yee, MD

Triple-negative breast cancer (TNBC) occurs in approximately 10% to 25% of all breast cancer cases. Prior research has shown the basal subtype, approximated by TNBC, correlates with higher local recurrence risk in patients who undergo breast-conserving surgery. The benefits from post-mastectomy radiation therapy remain unclear in women with TNBC and 0 to 3 lymph nodes, according to background information provided by researchers.

Atif J. Khan, MD, an assistant professor of radiation oncology at Robert Wood Johnson Medical School in New Jersey, and colleagues retrospectively identified 22 women with 0 to 3 lymph nodes who are considered at risk for local recurrence after mastectomy and whose initial mastectomy tissue was available for evaluation. The 22 women did not receive post-mastectomy radiation therapy.

Khan and colleagues compared these specimens with those of 28 women with 0 to 3 lymph nodes who underwent a mastectomy without radiation therapy and had no evidence of disease at their last follow-up visit.

The researchers matched controls for age (± 3 years) and follow-up duration (<5 years vs. >5 years).

Researchers examined tissue specimens for signs of disease.

Women with TNBC were associated with a higher risk for local recurrence (OR=8.5; P=.048), study results showed.

On univariate analysis, ER-positive cancer, PR-positive disease or a combination were strongly associated with lower odds of local recurrence risk.

Use of chemotherapy also was associated with lower risk (OR=0.119; P=.0073), the researchers said.

“By further defining the risk of local recurrence in women with TNBC, clinicians can better determine whether radiation treatment should be a part of post-mastectomy therapy,” Khan said in a press release.

For more information:

Khan AJ. Abstract #350. Presented at: 2012 ASTRO Annual Meeting; Oct. 28-31, 2012; Boston.

Disclosure: The researchers report no relevant financial disclosures.

Perspective

Douglas Yee, MD

In this abstract, the authors identified patients who had locoregional recurrence (LRR) after mastectomy for breast cancers with 0 to 3 positive lymph nodes. In these 22 women, none received post-mastectomy radiotherapy. These cases were matched with other mastectomy patients who also did not receive post-mastectomy radiotherapy. They confirm an observation that tumors that lack ER, PR or HER-2 expression may be biologically more aggressive as a higher proportion of women who had an LRR lacked these markers.

The study has some weaknesses; the treatment years are not noted, it is not clear if all patients received systemic therapy, and this is not a consecutive series of patients who received mastectomy without radiotherapy. Despite these concerns, the findings support the concept that tumor biology should be a factor when making treatment decisions about both locoregional and systemic therapy.

Douglas Yee, MD

HemOnc Today Editorial Board member

Disclosures: Yee reports no relevant financial disclosures.