New research says that the success rate in breast cancer treatment depends largely on the doctor treating it and the methods he or she chooses. Given these findings, what’s the best way to standardize care so that women will be confident that they are receiving the best treatment possible?

The team found that the surgeon’s treatment methods make up a significant portion of the success rate over the following years.

The study reviewed almost 1,000 women who had ductal carcinoma in situ, which is common and noninvasive form of breast cancer. The researchers tracked, for up to 18 years, how the cancer was treated, including what type of surgery was done (mastectomy or breast conserving surgery), whether radiation therapy followed, and whether the cancer came back in the same breast during follow-up.

When taking into account the surgery, the researchers looked at the margins involved – how close the cancer was to the edge of the tissue that was removed – more distance, known as a negative margin, is preferable, and an important factor in breast surgery.

The team found that the surgeon’s treatment methods make up a significant portion of the success rate over the following years. They estimate that surgeon’s methods account for 15-30% of the likelihood that the cancer returned in the five years after the initial treatment.

Over the ten years following treatment, surgeon variation accounted for 13-30% of the recurrence rate. Not using radiation therapy after surgery or having too little distance between the cancer and the tissue removed both significantly upped recurrence rates. Opting for breast conservation surgery rather than mastectomy also upped the odds of recurrence. And all of these issues are avoidable.

The finding that so much of the variation in cancer success over the long term is due to variation in doctor’s methods is "troubling", say researchers. They suggest that the problem may stem from doctors simply not being aware of the importance of negative margins in breast cancer surgery, or "differences in beliefs" about the role that radiation plays in treatment. Doctor-patient communication may also play a part in treatment methods. It’s still unclear, however, whether treatment decisions are mainly a result of the preferences of the doctor, the patient, or a combination of the two.

Luckily, the researchers did control for insurance differences and found that insurance did not seem to play a role in treatment choices.

So what’s the answer? If doctors who currently fall under the average in radiation use or in surgery methods would simply come closer to the average, breast cancer treatment outcomes would improve dramatically. How to encourage these changes remains a question, but hopefully this study and others like it will prompt the medical community to make some changes. Some research has suggested that teaching hospitals and academic institutions may have better success rates than other facilities.

In the meantime, women should discuss treatment options thoroughly with their doctors. Asking questions about treatment choices, surgery methods (go ahead and mention margins), and even recurrence rates is a good way to understand your care thoroughly and receive the best treatment possible.

The study was carried out by researchers at the RAND Corporation, and published in the December 19, 2011 issue of The Journal of the National Cancer Institute.