The clinical relevance of various methods of classifying ipsilateral breast tumour recurrence as either true local recurrence or new primary

PURPOSE

Describes the relevance of -various classification methods for ipsilateral breast tumour recurrence (IBTR) as either true recurrence (TR) or new primary (NP) on both disease-specific survival (DSS) and distant metastasis-free survival (DMFS).

METHOD

Two hundred and thirty-four of 4359 women undergoing breast-conserving therapy experienced IBTR. We compared the impact of four known classification methods and two newly created classification methods.

RESULTS

For three of the methods, a better DSS was observed for NP compared to TR with the hazard ratio (HR) ranging from 0.5 to 0.6. The new Twente method classification, comprising all classification criteria of three known methods, and the new Morphology method, using only morphological criteria, had the best HR and confidence interval with a HR 0.5 (95% CI 0.2-1.0) and a HR 0.5 (95% CI 0.3-1.1), respectively. For DMFS, the HR for NP compared to TR ranged from 0.6 to 0.9 for all six methods. The new Morphology method and the Twente method noted the best HR and confidence intervals with a HR 0.6 (95% CI 0.3-1.1) and a HR 0.6 (95% CI 0.4-1.2), respectively.

CONCLUSION

IBTR classified as TR or NP has a prognostic value for both DSS and DMFS, but depends on the classification method used. Developing and validating a generally accepted form of classification are imperative for using TR and NP in clinical practice.

No breast cancer subgroup can be spared postoperative radiotherapy after breast-conserving surgery. Fifteen-year results from the Swedish Breast Cancer Group randomised trial, SweBCG 91 RT

BACKGROUND

Breast-conserving surgery (BCS) followed by radiotherapy (RT) is an established treatment for women with T1-2N0 breast cancers. Since subgroups of patients have low ipsilateral breast tumour recurrence (IBTR) rates, it is important to study whether RT is necessary for all patients.

PATIENTS AND METHODS

A total of 1187 women with primary T1-2N0M0 breast cancer were randomised, after standardised sector resection, to postoperative whole breast RT or no local treatment. Adjuvant systemic therapy was offered to patients with stage II cancers. Patients were followed with clinical examinations and annual mammography for 10 years and thereafter referred to the Swedish mammography screening program.

RESULTS

After 15 years of follow-up, a higher cumulative incidence of IBTR was observed in control patients, 23.9%, versus irradiated patients, 11.5%, P<0.001. Recurrence-free survival was inferior, 51.7% versus 60.4%, P=0.0013. The main effect of RT was seen during the first 5 years. However, overall survival was not significantly lower 68.4% versus 71.1%, P=0.68, nor was breast cancer-specific mortality significantly higher.

CONCLUSIONS

RT after BCS significantly reduced the incidence of IBTR at 15 years of follow-up. We were unable to identify subgroups which could be spared RT. Breast cancer mortality was not significantly reduced after RT. Good predictive markers for radiation sensitivity and improved adjuvant systemic therapy are needed to omit RT after BCS.