Boon Chua

Effect of margins on ipsilateral breast tumor recurrence after breast conservation therapy for lymph node-negative breast carcinoma.

Breast conservative surgery (CS) with radiotherapy (RT) is the most commonly used treatment for early‐stage breast carcinoma. However, there is controversy regarding the importance of the pathologic margin status on the risk of ipsilateral breast tumor recurrence (IBTR). The current study evaluated the effect of the pathologic margin status on IBTR rates in a cohort of women with lymph node‐negative breast carcinoma treated with CS and RT.

Frequency and predictors of axillary lymph node metastases in invasive breast cancer

Background:  The objectives of the present study were to evaluate the incidence and predictors of axillary lymph node metastases (ALNM) in patients with breast cancer, and to identify if axillary surgery could be safely omitted in selected patients.

Long-Term Survival of Patients With Supraclavicular Metastases at Diagnosis of Breast Cancer

BACKGROUND Patients with supraclavicular metastases at diagnosis of breast cancer were classified between 1987 and 2002 as having stage M(1) breast cancer according to the tumor-node-metastasis (TNM) system. The 2003 edition of the TNM staging guidelines has classified such patients as having stage IIIC disease. To determine relative prognosis, we compared long-term survival in a population-based cohort of patients with isolated supraclavicular metastases (nodal-M(1)) to outcomes of patients with stage IIIB or M(1) (other) disease at presentation. MATERIALS AND METHODS Among patients with breast cancer and known tumor stage referred to the British Columbia Cancer Agency from 1976 to 1985, 336 IIIB, 233 M(1), and 51 nodal-M(1) patients were identified. Actuarial overall and breast cancer-specific survival rates were determined to 20 years. RESULTS Overall survival at 20 years was 13.2% for nodal-M(1) cases (95% confidence interval [CI], 5% to 26%), 9.4% for IIIB cases (95% CI, 6% to 14%), and 1.3% for M(1) (other) cases (95% CI, 0.4% to 3.5%; log-rank P <.0005). Overall survival was similar between nodal-M(1) and IIIB cases (P =.27). Breast cancer-specific survival at 20 years was 24.1% for nodal-M(1) cases (95% CI, 13% to 37%), 30.2% for IIIB cases (95% CI, 23% to 38%), and 3.9% for M(1) (other) cases (95% CI, 2% to 8%; log-rank P <.0005). Breast cancer-specific survival was significantly different for nodal-M(1) cases compared with either IIIB or M(1) (other) cases (P =.008 for both). CONCLUSION Patients with supraclavicular metastases at diagnosis have significantly better outcomes than patients with M(1) (other) disease and overall survival similar to patients with IIIB disease. Reclassification as stage IIIC is appropriate for patients with breast cancer who present with supraclavicular nodal metastases alone.

Treatment implications of a positive sentinel lymph node biopsy for patients with early-stage breast carcinoma.

Sentinel lymph node (SLN) mapping and biopsy is emerging as an alternative to axillary lymph node dissection (ALND) in determining the lymph node status of patients with early‐stage breast carcinoma. The hypothesis of the technique is that the SLN is the first lymph node in the regional lymphatic basin that drains the primary tumor. Non‐SLN (NSLN) metastasis in the axilla is unlikely if the axillary SLN shows no tumor involvement, and, thus, further axillary interference may be avoided. However, the optimal treatment of the axilla in which an SLN metastasis is found requires ongoing evaluation. The objectives of this study were to evaluate the predictors for NSLN metastasis in the presence of a tumor‐involved axillary SLN and to examine the treatment implications for patients with early‐stage breast carcinoma.

Outcomes of sentinel node biopsy for breast cancer in British Columbia, 1996 to 2001

BACKGROUND This study evaluated the outcomes of the first 5 years of sentinel node biopsy (SNB) in British Columbia (BC), Canada, 1996 to 2001. METHODS There were 547 SNB procedures for breast cancer performed by 29 surgeons at 12 hospitals in BC between October 1996 and July 2001. Identification, accuracy, and false-negative rates were determined and correlated to patient, tumor, and surgical factors with the chi-square test. RESULTS SNB mapping was performed using blue dye alone (15%), radiopharmaceutical alone (6%), or both (79%). A completion axillary dissection was performed in 93%. A median of 2 (range 1 to 16) sentinel nodes was biopsied. The overall identification rate was 88%, accuracy was 92%, and false-negative rate was 22%. All rates were improved in younger (age <50 years) compared with older women. A positive lymphoscintiscan and the mapping agent used were associated with higher identification rates but not accuracy or false negative rates. Increasing surgeon experience was not significantly associated with improvements in identification or false-negative rates. CONCLUSIONS The potential of SNB was not fully translated into surgical practice in BC by 2001.

A risk index for early node-negative breast cancer

This study compared the application of the St Gallen 2001 classification with a risk index developed at the New South Wales Breast Cancer Institute (BCI Index) for women with node‐negative breast cancer treated without adjuvant systemic therapy.

Increased Use of Adjuvant Regional Radiotherapy for Node‐Positive Breast Cancer in British Columbia

Abstract:  This study was to determine if the use of regional radiotherapy (RT) changed in British Columbia after publication of new randomized trial data in 1997. Women with pathologic T1–3N1, nonmetastatic breast cancer treated with a mastectomy or breast‐conserving surgery (BCS) were included. The use of regional RT was compared in two cohorts: cohort 1, July 1, 1995–June 30, 1997 (n = 834); and cohort 2, July 1, 1998–June 30, 2000 (n = 1072). All p‐values were two‐sided. Adjuvant systemic therapy was given to 96% and 95% of women in cohorts 1 and 2, respectively. Forty‐five percent of cohort 1 and 48% of cohort 2 had BCS. Regional RT was received by 44% of cohort 1 and 66% of cohort 2 (p < 0.001). Eighty‐eight percent and 90% of women with four or more positive nodes in cohorts 1 and 2 received regional RT, respectively. For women in cohorts 1 and 2 with one to three positive nodes, regional RT use increased from 32% to 54% after mastectomy, and from 23% to 59% after BCS, respectively (p < 0.001 for both). Publication of randomized trials and a coordinated guideline implementation process in British Columbia was associated with a significant increase in the use of regional RT in women with one to three positive nodes. 

Comparison of Radiotherapy Treatment Plans for Left-sided Breast Cancer Patients based on Three- and Four-dimensional Computed Tomography Imaging

AIMS The target volume for breast radiotherapy after conservative surgery for breast cancer may be affected by breathing motion. We investigated differences between conventional and four-dimensional computed tomography-based treatment planning and whether gating could improve dose volume parameters. MATERIALS AND METHODS Ten patients with left-sided breast cancer and surgical clips at the excision site had conventional treatment planning computed tomography and four-dimensional computed tomography. Treatment plans using two tangential beams (6 MV X-rays) were optimised for target coverage and homogeneity using a field in field technique for the three-dimensional scan. This plan was applied directly to four-dimensional datasets representing individual phases of the breathing cycle and combinations thereof (average and maximum intensity projection). Optimised plans were generated for the maximum inhalation scan to study what could potentially be achieved in gated radiotherapy. RESULTS Four-dimensional computed tomography with effective doses of around 10 mSv proved to be adequate for treatment planning in all patients. The average motion of the surgical clips was 3.7 mm (range 1.7-6.5mm), which was similar to the movement of the chest wall. With a margin of 7 mm for the whole breast to planning target volume, conventional three-dimensional computed tomography-based planning was found to adequately cover the target as seen on four-dimensional computed tomography without significant differences in normal tissue sparing. Improved sparing of the heart and lung could only be achieved by reducing the posterior margin of the target volume, which may be justified if four-dimensional computed tomography is used to determine the target and its motion. CONCLUSION No significant benefit has been shown for the use of four-dimensional computed tomography-based planning if motion management is not implemented concurrently with a reduced posterior margin between clinical and planning target volumes.

Timing of Radiotherapy and Outcome in Patients Receiving Adjuvant Endocrine Therapy

PURPOSE To evaluate the association between the interval from breast-conserving surgery (BCS) to radiotherapy (RT) and the clinical outcome among patients treated with adjuvant endocrine therapy. PATIENTS AND METHODS Patient information was obtained from three International Breast Cancer Study Group trials. The analysis was restricted to 964 patients treated with BCS and adjuvant endocrine therapy. The patients were divided into two groups according to the median number of days between BCS and RT and into four groups according to the quartile of time between BCS and RT. The endpoints were the interval to local recurrence, disease-free survival, and overall survival. Proportional hazards regression analysis was used to perform comparisons after adjustment for baseline factors. RESULTS The median interval between BCS and RT was 77 days. RT timing was significantly associated with age, menopausal status, and estrogen receptor status. After adjustment for these factors, no significant effect of a RT delay ≤20 weeks was found. The adjusted hazard ratio for RT within 77 days vs. after 77 days was 0.94 (95% confidence interval [CI], 0.47-1.87) for the interval to local recurrence, 1.05 (95% CI, 0.82-1.34) for disease-free survival, and 1.07 (95% CI, 0.77-1.49) for overall survival. For the interval to local recurrence the adjusted hazard ratio for ≤48, 49-77, and 78-112 days was 0.90 (95% CI, 0.34-2.37), 0.86 (95% CI, 0.33-2.25), and 0.89 (95% CI, 0.33-2.41), respectively, relative to ≥113 days. CONCLUSION A RT delay of ≤20 weeks was significantly associated with baseline factors such as age, menopausal status, and estrogen-receptor status. After adjustment for these factors, the timing of RT was not significantly associated with the interval to local recurrence, disease-free survival, or overall survival.

Does inverse-planned intensity-modulated radiation therapy have a role in the treatment of patients with left-sided breast cancer?

Introduction: The purpose of the study was to determine if multi‐field inverse‐planned intensity‐modulated radiation therapy (IMRT) improves on the sparing of organs at risk (heart, lungs and contralateral breast) when compared with field‐in‐field forward‐planned RT (FiF).