Background: The Van Nuys Prognostic Index (VNPI) is a simple score for predicting the risk of local recurrence (LR) in patients with Ductal Carcinoma In Situ (DCIS) conservatively treated. This score combines three independent predictors of Local Recurrence. The VNPI has recently been updated with the addition of age as a fourth parameter into the scoring system (University of Southern California/ VNPI).
Patients and methods: Our database consisted of 408 women with DCIS. Applying the USC/VNPI we reviewed retrospectively 259 patients who were treated with breast conserving surgery with or without radiotherapy (RT). Of these patients 63.5% had a low VNPI score, 32% intermediate and 4.5% a high score. In the low score group, the majority of the patients underwent Conservative Surgery (CS) without RT while in the intermediate group, almost half of the patients received RT. Eighty-three percent (83%) of the patients with high VNPI were treated with Conservative Surgery plus RT. Nodal assessment by Sentinel Lymph Node Biopsy was obtained in 32 patients since 2002.
Results: Twenty-one Local Recurrences were observed (8%) with a mean follow up of 130 months: sixteen were invasive. No statistically significant differences in Disease Free Survival were reached in all groups of VNPI score between patients treated with Conservative Surgery or Conservative Surgery plus RT. However it was noted that the higher the VNPI score, the lower was the risk of local recurrence in the group treated additionally with RT, even though it was not statistically significant. Further analysis included those patients treated with Conservative Surgery alone and followed up. Disease-free survival (DFS) at 10 years was 94% with low VNPI and 83% in both intermediate and high score (P < 0.05). No significant differences were observed in the subgroups of VNPI. The Local Relapse rate after Conservative Surgery alone, increased with tumor size, margin width, and pathology classification (P < 0,05), while age was not found to be a significant factor. Lesions with only mammographic appearances are associated with lower DFS but it did not reach significance (P = ns), while assumption of estrogenic hormones and familial history of breast cancer are significant factors associated with a higher risk of local recurrence. After multivariate analysis including seven clinical and pathological factors, the only significant predictors of local recurrence remained margin width of surgical excision, previous therapy with estrogens (contraceptives or Hormone Replacement Therapy) and the Van Nuys pathologic classification. The overall survival breast cancer specific was 99% and no differences were observed between groups (P = ns). The comparison of patients treated with a total mastectomy and those conservatively treated showed a significantly better local relapse free survival rate obtained with mastectomy (98.2% vs. 89.7% at 10 years P = 0.02). However, the overall cause-specific survival did not prove any better outcome (98.7% in both groups). Of the 32 patients who underwent a Sentinel Lymph Node Biopsy, four were found to have micrometastases and all of them had a previous Directional Vacuum Assisted Biopsy.
Conclusions: Although in our series there is not a significant difference in LR rates by the parameter of age, the new USC/VNPI is still a simple and reliable scoring system for therapeutic management of DCIS. We did not find any statistically significant advantage in groups treated with the addition of RT. Obtaining wide surgical margins appears to be the strongest prognostic factor for local recurrence, regardless of other pathological factors or the addition of adjuvant radiation therapy. However, only prospective randomized studies can precisely predict the risk of LR of conservatively treated DCIS. The clinical significance of Sentinel Lymph Nodes micrometastases Immuno-Histo-Chemistry-detected found in DCIS patients remains uncertain. However, we hypothesize that the anatomical disruption after preoperative biopsy procedures increases the likelihood of epithelial cell displacement and the frequency of IHC-positive Sentinel Lymph Nodes, both of which are directly proportional to the degree of manipulation.