Benchmarking clinical practice quality: an audit of ipsilateral breast tumor recurrence in patients managed for T1/T2 breast carcinoma.

AIM: Breast conserving surgery and adjuvant radiotherapy has equivalent oncological outcomes to mastectomy and is the standard of care for treatment of early-stage invasive breast cancer. Auditing is an essential component of ongoing quality assurance and clinical governance. It also serves to identify patient and tumor factors that have prognostic and therapeutic implications. The aim of this paper is to report on the clinical audit of treatment outcomes for patients undergoing adjuvant radiation treatment for early breast cancer at the Northern Sydney Cancer Care Centre. METHODS: A total of 1252 patients with T1/2 breast cancer received adjuvant radiation treatment between January 2003 and December 2010. Medical records, including the departmental database, were reviewed to extract pathological, treatment, patient and clinical details. RESULTS: Median follow-up was 54 months (mean 56.4 months). Sixty-six (5.27%) patients died from breast cancer, and 27 (2.16%) patients died from other disease. Twenty-three (1.84%) patients were alive with metastatic disease, 7 (0.56%) patients were alive following ipsilateral breast tumor recurrence and 7 (0.56%) patients were alive with nodal recurrence. 9 (0.72%) patients were alive with contralateral breast cancer. Documented rates of late toxicity were low: 6.8% of patients had grade 1 late toxicity and 1.6% of patients had grade 2-3 late toxicity. CONCLUSION: Our ipsilateral breast tumor recurrence rate of 0.56% is well within international standards, as is our toxicity rate. We propose that centralized data collection be implemented on a nation-wide level for breast cancer patients undergoing radiotherapy. Further research is planned to identify potential markers of radio-resistance, and allow tailoring of treatment technique to optimize oncological outcome.

Intensity modulated radiotherapy and 3D conformal radiotherapy for whole breast irradiation: a comparative dosimetric study and introduction of a novel qualitative index for plan evaluation, the normal tissue index.

INTRODUCTION: We report on a retrospective dosimetric study, comparing 3D conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (hIMRT). We evaluated plans based on their planning target volume coverage, dose homogeneity, dose to organs at risk (OARs) and exposure of normal tissue to radiation. The Homogeneity Index (HI) was used to assess the dose homogeneity in the target region, and we describe a new index, the normal tissue index (NTI), to assess the dose in the normal tissue inside the tangent treatment portal. METHODS: Plans were generated for 25 early-stage breast cancer patients, using a hIMRT technique. These were compared with the 3DCRT plans of the treatment previously received by the patients. Plan quality was evaluated using the HI, NTI and dose to OARs. RESULTS: The hIMRT technique was significantly more homogenous than the 3DCRT technique, while maintaining target coverage. The hIMRT technique was also superior at minimising the amount of tissue receiving D 105% and above (P < 0.0001). The ipsilateral lung and contralateral breast maximum were significantly lower in the hIMRT plans (P < 0.05 and P < 0.005), but the 3DCRT technique achieved a lower mean heart dose in left-sided breast cancer patients (P < 0.05). CONCLUSION: Hybrid intensity modulated radiotherapy plans achieved improved dose homogeneity compared to the 3DCRT plans and superior outcome with regard to dose to normal tissues. We propose that the addition of both HI and NTI in evaluating the quality of intensity modulated radiotherapy (IMRT) breast plans provides clinically relevant comparators which more accurately reflect the new paradigm of treatment goals and outcomes in the era of breast IMRT.