[Hopeful]

Ok, I'll make it even more user-friendly - here are salient quotes from the article I linked above, posted in the Articles of Interest Forum:

With the absolute benefits of treatment yet to be determined, investigators also are looking closely at the risks associated with skipping adjuvant treatment.

The findings of an observational cohort study presented at the annual meeting of the American Society of Clinical Oncology (ASCO) suggest that women with early HER2 positive T1aN0M0 breast cancers can safely do so because of the low distant recurrence rate observed in this patient subgroup. A higher rate was observed in those with T1bN0M0, indicating that adjuvant systemic therapy may be more relevant in this patient population.

The study assessed outcomes among 237 women with HER2-positive T1a (116 patients) or T1b (121 patients) tumors diagnosed between 2000 and 2006, all of whom had negative nodes and no metastases. Most did not receive adjuvant chemotherapy or trastuzumab.

With a median duration of follow-up of 5.8 years, the rate of distant recurrence was 0.9% among patients with T1a tumors versus 5.8% among those with T1b, lead investigator Dr. Louis Fehrenbacher, an oncologist with Kaiser Permanente in Vallejo, Calif., reported in a poster presentation, analyzing data from the tumor registry of the Kaiser Permanente Clinical Care Program of Northern California.

Results for the actuarial distant recurrence-free interval showed a 5-year rate of 96.5% for the patients as a whole, with 99.1% and 94.0% in the T1a and T1b groups, respectively.

"The take-home message is, I think, the T1a's have too low of a risk of distant invasive recurrence to justify chemotherapy or trastuzumab," Dr. Fehrenbacher said in an interview. "We need to specifically individualize the risk of the patient based on the size of their primary [tumor], because the T1a's and T1b's are quite different in our findings."

In a recent review article looking into whether the existing data supports a definitive treatment threshold for patients with T1aN0M0 or T1bN0M0 HER2-positive breast cancer, Dr. Pusztai, along with lead author Dr. Catherine M. Kelly of Waterford Regional Hospital in Waterford, Ireland and colleagues, wrote that "a blanket recommendation to treat all small HER2 positive breast cancer with trastuzumab-based therapy will almost certainly lead to clinically significant cardiotoxicity in some without any benefit in breast cancer recurrence."

Hopeful