Wide Local Excision and Radiotherapy for the Treatment of Ductal Carcinoma in situ of the Breast: the Hong Kong Experience

Validation of a nomogram in the prediction of local recurrence risks after conserving surgery for Asian women with ductal carcinoma in situ of the breast

AIMS

At our centre, ductal carcinoma in situ (DCIS) was commonly treated with breast-conservation therapy (BCT). Local recurrence after BCT is a major concern. The aims of our study were to review the outcomes of DCIS treatment in our patients and to evaluate a nomogram from Memorial Sloan Kettering Cancer Centre (MSKCC) for predicting ipsilateral breast tumour recurrence (IBTR) in our Asian population.

MATERIALS AND METHODS

Chart reviews of 716 patients with pure DCIS treated from 1992 to 2011 were carried out. Univariable Cox regression analyses were used to evaluate the effects of the 10 prognostic factors of the MSKCC nomogram on IBTR. We constructed a separate National Cancer Centre Singapore (NCCS) nomogram based on multivariable Cox regression via reduced model selection by applying the stopping rule of Akaike's information criterion to predict IBTR-free survival. The abilities of the NCCS nomogram and the MSKCC nomogram to predict IBTR of individual patients were evaluated with bootstrapping of 200 sets of resamples and the NCCS dataset, respectively. Harrell's c-index was calculated for each nomogram to evaluate the concordance between predicted and observed responses of individual subjects.

RESULTS

Study patients were followed up for a median of 70 months. Over 95% of patients received adjuvant radiotherapy. The 5 and 10 year actuarial IBTR-free survival rates for the cohort were 95.5 and 92.6%, respectively. In the multivariate analysis, independent prognostic factors for IBTR included use of adjuvant endocrine therapy, presence of comedonecrosis and younger age at diagnosis. These factors formed the basis of the NCCS nomogram, which had a similar c-index (NCCS: 0.696; MSKCC: 0.673) compared with the MSKCC nomogram.

CONCLUSION

The MSKCC nomogram was validated in an Asian population. A simpler NCCS nomogram using a different combination of fewer prognostic factors may be sufficient for the prediction of IBTR in Asians, but requires external validation to compare for relative performance.

Trends and patterns of breast conservation treatment in Hong Kong: 1994-2007

PURPOSE

Breast conservation treatment (BCT) was quite unpopular in Hong Kong until the early 1990s, but the trends and patterns of BCT use in the past 14 years have not been studied since. The purpose of this study was to identify the latest trends and patterns.

METHODS AND MATERIALS

All consecutive cases of female breast cancer referred to a community oncology center in Hong Kong between 1994 and 2007 were retrospectively reviewed. Of the 2,375 women with T1-2 invasive breast cancer who underwent surgery, 1,137 (48%) had T1 (</=2 cm) disease and 1,238 (52%) had T2 (>2 cm-</=5 cm) disease. Median patient age was 51 years (range, 24-95 years); 65% patients had their surgery in public hospitals.

RESULTS

Of the total patient cohort, 2,153 (91%) patients presented with palpable breast masses and only 104 (4%) with mammographically detected cancers. Overall, 721 (30%) and 1,654 (70%) patients underwent BCT and mastectomy, respectively. There was no significant increase in the BCT rates (31%, SD 5%; p = 0.804) or mammographic detection rates (5%, SD 1%; p = 0.125) in Hong Kong between 1994 and 2007. In multivariate analyses, age </=50 years (OR 2.479; p < 0.001), mammographically detected tumors (OR 1.868; p = 0.007), T1 tumors (OR 3.159; p < 0.001), surgeries in private hospitals (OR 1.288; p = 0.018), and negative nodal status (OR 1.886; p < 0.001) were independent factors predictive of a higher likelihood of a woman having BCT.

CONCLUSIONS

Our results indicate a satisfactory acceptance of BCT by patients who are young and have small tumors, node-negative disease, or surgery in private hospitals. However, the continuing unpopularity of breast screening is likely a major factor limiting the broad use of BCT.

Techniques of tumour bed boost irradiation in breast conserving therapy: current evidence and suggested guidelines

Breast conservation surgery followed by external beam radiotherapy to breast has become the standard of care in management of early carcinoma breast. A boost to the tumour bed after whole breast radiotherapy is employed in view of the pattern of tumour bed recurrences in the index quadrant and was particularly considered in patients with some adverse histopathological characteristics such as positive margins, extensive intraductal carcinoma (EIC), lymphovascular invasion dose in patients even without such factors and for all age groups. The maximum absolute reduction of local recurrences by the addition of boost is especially seen in young premenopausal patients. At the same time, the addition of boost is associated with increased risk of worsening of cosmesis and no clear cut survival advantage. Radiological modalities such as fluoroscopy, ultrasound and CT scan have aided in accurate delineation of tumour bed with increasing efficacy. A widespread application of these techniques might ultimately translate into improved local control with minimal cosmetic deficit. The present article discusses the role of radiotherapy boost and the means to delineate and deliver the same, identify the high risk group, optimal technique and the doses and fractionations to be used. It also discusses the extent of adverse cosmetic outcome after boost delivery, means to minimise it and relevance of tumour bed in present day scenario of advanced radiotherapy delivery techniques like Intensity modulated radiation therapy (IMRT).

Surveillance mammography after breast conservation therapy in Hong Kong: effectiveness and feasibility of risk-adapted approach

Annual surveillance mammography is commonly recommended after breast conservation therapy (BCT). We retrospectively reviewed its effectiveness on 511 invasive and non-invasive breast cancers treated with BCT between 1994 and 2003. The median follow-up was 5.9 years. The 5-year actuarial ipsilateral breast tumour recurrence (IBTR) rate was 4.5% and contralateral breast cancer (CBC) rate was 2.0% (representing eight times increase in risk). IBTR of 43% and 62% CBC were first detected by surveillance mammography. The IBTR detection rates per 1000 mammograms were 5.2 for patients (n=349) with one or more IBTR risk factors (age 45, positive/close margins or histological grade 3) and 0.6 for patients (n=162) without. No survival difference was observed between different modes of IBTR detection (p=0.342). In conclusion, a risk-adapted approach of limiting ipsilateral surveillance to patients with IBTR risk is possible but its implementation will be complicated by the continued need of contralateral surveillance.

Clinical Outcome of Breast Conservation Therapy for Breast Cancer in Hong Kong: Prognostic Impact of Ipsilateral Breast Tumor Recurrence and 2005 St. Gallen Risk Categories

PURPOSE

The aim of this study was to evaluate the clinical outcome of breast conservation therapy (BCT) for invasive breast cancers in our predominantly Chinese population.

METHODS AND MATERIALS

Clinical outcomes of 412 T1-2 invasive breast cancers treated by wide local excision and external radiotherapy from 1994 to 2003 were retrospectively analyzed. Only 7% lesions were first detected by mammograms. Adjuvant tamoxifen and chemotherapy were added in 74% and 45% patients, respectively.

RESULTS

The median follow-up was 5.4 years. The 5-year actuarial ipsilateral breast tumor recurrence (IBTR) rate, distant failure-free survival, cause-specific survival, and overall survival were 4%, 92%, 96%, and 98%, respectively. The 5-year distant failure-free survival for the low-risk, intermediate-risk, and high-risk categories (2005 St. Gallen) were 98%, 91%, and 80%, respectively (p = 0.0003). Cosmetic results were good to excellent in more than 90% of the assessable patients. Grade 3 histology (hazard ratio [HR], 4.461; 95% CI, 1.216-16.360; p = 0.024), age (HR, 0.915; 95% CI, 0.846-0.990; p = 0.027), and close/positive final margins (HR, 3.499; 95% CI, 1.141-10.729; p = 0.028) were significant independent risk factors for IBTR. Both St. Gallen risk categories (p = 0.003) and IBTR (HR, 5.885; 95% CI, 2.494-13.889; p < 0.0005) were independent prognostic factors for distant failure-free survival.

CONCLUSIONS

Despite the low percentage of mammographically detected lesions, the overall clinical outcome of BCT for invasive breast cancers in the Chinese population is comparable to the Western series. The 2005 St. Gallen risk category is a promising clinical tool, but further validation by large studies is warranted.