LOS ANGELESSurgical margin width offers a reasonable prognostic
surrogate for the more complicated multiparameter Van Nuys Prognostic
Index to predict breast cancer recurrence after treatment for ductal
carcinoma in situ (DCIS), but the index still provides superior
accuracy, Melvin J. Silverstein, MD, of the University of Southern
California, said at the San Antonio Breast Cancer Symposium.
He said that the index should be superior because it
incorporates four factors (tumor size, biologic classification based
on tumor grade and necrosis, and excision margin width), but it is
clearly more difficult to use.
In 1999, Dr. Silverstein and his colleagues published a paper
advocating the use of margin width as the sole determinant of
treatment for DCIS (N Engl J Med 340:1455-1461, 1999). Afterwards,
the group was inundated with questions about whether to abandon
the Van Nuys Prognostic Index, Dr. Silverstein said. This led
the researchers to compare the prognostic value of the index vs
surgical margins alone in DCIS patients.
A surgical margin of greater than 10 mm was associated with a 12-year
recurrence-free survival of 96%, compared with 99% for patients with
a score of 3-4 (the best possible score) on the index. The difference
did not achieve statistical significance but showed a trend in favor
of the index.
The data came from an evaluation of 523 DCIS patients treated by
breast-conserving surgery (with or without radiation therapy). A
total of 88 local recurrences have been documented, 41 invasive
cancers and 47 DCIS recurrences. All but seven recurrences were at or
near the site of the primary lesion, suggesting inadequate surgery,
There was a single recurrence of DCIS associated with an index score
of 3-4. Five recurrences were observed in patients who had wide
margins, but two recurrences were invasive and one patient had
metastatic disease and subsequently died. At the other end of the
spectrum, an index score of 8 or 9 was associated with poorer
outcomes than was the single prognostic factor of narrow surgical margins.
Dr. Silverstein stressed that the index remains the preferred method
at his institution. The best possible score on the index is 3 (low
biologic classification, small size, wide margins), while the worst
is 9 (large, poorly excised tumor with a high biologic
classification). His analyses have shown that DCIS patients with a
score of 3-4 derive no benefit from radiation therapy; a score of 5-7
is associated with a 15% benefit from radiation therapy, and a score
of 8-9 with a 30% benefit.
His group recommends excision alone for DCIS patients with scores of
3-4, excision plus irradiation for those with scores of 5-7, and
mastectomy for patients with scores of 8-9.