Fewer Tumors Recur With DCIS After Excision Plus Radiotherapy

May 23, 2011 — Significantly fewer patients with ductal carcinoma in situ (DCIS) experience a recurrence when treated with excision plus radiation therapy (RT) compared with excision alone.

However, when tumors recur in patients who are treated with additional RT, they are significantly more likely to be invasive cancer, according to results of a study presented at the American Society of Breast Surgeons (ASBS) 12th Annual Meeting.

Tumors that recur in patients who have been irradiated are also significantly more likely to occur in a different quadrant of the breast than tumors that recur after excision alone. Recurrences after excision plus RT are also more likely to take significantly longer to recur than tumors that recur after excision alone.

"This is the first study to focus on the pattern of recurrence in DCIS patients treated with lumpectomy," Janie Weng Grumley, MD, University of Southern California, Los Angeles, told a press conference here. "[And although] RT accompanied by wide local excision of DCIS reduces local cancer recurrence by 50%, when the cancer comes back, we found major differences in the recurrence pattern between patients who did and did not receive RT."

Prospective Data Reveal Recurrence Patterns

Data were prospectively collected on a total of 1014 patients with DCIS who had undergone breast-conserving therapy. Some 651 patients had no RT after excision, whereas 363 received postoperative RT. Mean follow-up for the excision alone group was 72 months, whereas the mean follow-up for the excision plus RT group was 109 months, a difference that was statistically significant (P < .01) but that reflects the fact that excision alone has not been accepted as an alternative approach to DCIS until fairly recently, Dr. Grumley noted.

At 10 years, the probability of any local recurrence among patients in the excision alone group was 30% compared with 18% for the excision plus RT group. Some 37% of tumors that recurred in the excision alone group were invasive vs 57% of those in the excision plus RT group. The mean time to any local recurrence was 53 months in the excision alone group vs 90 months in the excision plus RT group.

In addition, only 10% of recurring tumors in the excision alone group recurred in a different quadrant of the breast vs 28% of tumors that recurred in patients treated with excision plus RT, suggesting that women who receive additional RT are more at risk for a new primary cancer than women treated with excision alone.

Moreover, only 9% of patients in the excision alone group experienced recurrence after 10 years compared with 33% of the excision alone group.

Table. Tumor Recurrence in Patients Receiving Excision Alone and Those Receiving Excision With RT

RT = radiation therapy

Dr. Grumsley's team also found that there was a slight but statistically significant breast cancer–specific survival advantage for the excision alone group at 99.7% at 10 years vs 98.3% (P = .01). "A lot of patients think that after 5 years there is no need to think about cancer anymore, I'm safe, but you have to be aware of the fact that cancers [that have been treated with RT] can recur much later on — after 5 years," Dr. Grumley told Medscape Medical News. "So there is a very different pattern or recurrence depending on how patients are treated. The main conclusion to this study is that we have to follow patients who receive RT in a different way."

An ASBS spokesperson, Deanna Attai, MD, of the Center For Breast Care Inc, of Burbank, California, told Medscape Medical News that there is no doubt that RT is an important treatment modality for patients with breast cancer because "Investigators clearly showed that recurrence rates were much lower in women who received RT than those who did not."

On the other hand, women develop recurrences after initial treatment of their breast cancer, and for some of them, "it may not be in that 5-year window that we all like to think about. So a woman who has had breast cancer needs life-long surveillance because breast cancer can recur much later than within that 5-year window."

Dr. Grumley and Dr. Attai have disclosed no relevant financial relationships.

American Society of Breast Surgeons (ASBS) 12th Annual Meeting: Abstract 1642. Presented April 29, 2001.

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Cite this: Fewer Tumors Recur With DCIS After Excision Plus Radiotherapy - Medscape - May 23, 2011.