Tangential intensity modulated radiation therapy (IMRT) to the intact breast.

INTRODUCTION: Inverse-planned intensity modulated radiation therapy (IP-IMRT) has potential benefits over other techniques for tangential intact breast radiotherapy. Possible benefits include increased homogeneity, faster planning time, less inter-planner variability and lower doses to organs at risk (OAR). We therefore conducted a pilot study of previously treated intact breast patients to compare the current forward-planned 'field-in-field' technique (FP-IMRT) with an IP-IMRT alternative. METHODS: The IP-IMRT plans of 20 patients were generated from a template created for the planning system. All patients were prescribed adjuvant whole breast radiotherapy using a hypofractionated regimen of 40.05 Gy in 15 fractions over 3 weeks. Plans were assessed based on visual inspection of coverage as well as statistical analysis and compared to the clinically acceptable FP-IMRT plans. Patients were planned retrospectively in Monaco 3.2® using a laterality-specific, tangential planning template. Minor adjustments were made as necessary to meet the planning criteria in the protocol. Dose coverage, maximums, homogeneity indices and doses to OAR were recorded. RESULTS: The IP-IMRT plans provided more consistent coverage (38.18 Gy vs. 36.08 Gy of D95; P = 0.005), a comparable though higher average maximum (D2 = 42.52 Gy vs. 42.08 Gy; P = 0.0001), more homogeneous plans (homogeneity index = 0.908 vs. 0.861; P = 0.01) and somewhat lower V20 heart and lung doses (0.11% vs. 0.89% for heart; 5.4% vs. 7.52% for lung) than FP-IMRT (P > 0.05). CONCLUSION: Clinically acceptable plans have been generated using the IP-IMRT templates in Monaco. Improvements in consistency and quality were seen when compared to the FP-IMRT plans. The template-based process is an efficient method to inversely plan IMRT for breast patients.

Use of hypofractionated post-mastectomy radiotherapy reduces health costs by over $2000 per patient: An Australian perspective.

INTRODUCTION: The most recent clinical practice guidelines released by Cancer Australia draw attention to unanswered questions concerning the health economic considerations associated with hypofractionated radiotherapy. This study aimed to quantify and compare the healthcare costs at a regional Australian radiotherapy institute with respect to conventionally fractionated post-mastectomy radiotherapy (Cf-PMRT) versus hypofractionated post-mastectomy radiotherapy (Hf-PMRT) administration. METHODS: Medical records of 196 patients treated with post-mastectomy radiotherapy at the NSW North Coast Cancer Institute from February 2008 to June 2014 were retrospectively reviewed. Australian Medicare item numbers billed for patients receiving either Cf-PMRT of 50 Gy in 25 daily fractions or Hf-PMRT of 40.05 Gy in 15 daily fractions were calculated. Decision tree analysis was used to model costs. Independent-samples t-tests and Mann-Whitney U-tests were used to compare crude average costs for Cf-PMRT and Hf-PMRT and determine which treatment components accounted for any differences. RESULTS: Hf-PMRT, with or without irradiation to the regional lymph nodes, was associated with significantly reduced Medicare costs ($5613 AUD per patient for Hf-PMRT vs $8272 AUD per patient for Cf-PMRT; P < 0.001). Savings associated with Hf-PMRT ranged from $1353 (22.1%) for patients receiving no regional irradiation to $2898 (32.0%) for patients receiving both axillary and supraclavicular therapy. CONCLUSIONS: Hf-PMRT results in a significant reduction in the financial costs associated with treating breast cancer patients in a regional Australian setting when compared with Cf-PMRT.

Target localisation for tumour bed radiotherapy in early breast cancer.

INTRODUCTION: To compare clinical and CT techniques in localisation of the tumour bed in patients undergoing adjuvant breast radiotherapy for breast cancer. METHODS: Patients were CT scanned in the treatment position following clinical delineation of the whole breast, surgical scar and boost volume. Computed tomography boost volumes were contoured in three dimensions. A definitive treatment plan was generated to encompass the CT-localised planning target volume (PTV) with ≥90% isodose using electrons. A hypothetical plan was also generated to cover the clinically determined boost field for comparison. The primary end point was the difference in PTV coverage by the 90% isodose between the plans based on clinically and CT localised boost volumes. RESULTS: The plans for 50 patients were evaluated. The median percentage of PTV encompassed by the 90% isodose using the clinical and CT techniques was 29% (range 5-90%) and 83% (range 25-100%), respectively. PTV coverage by the 90% isodose using the clinical technique was at least 10% less than that using CT technique in 88% of patients (95% confidence interval 77-95%; P < 0.0001). CONCLUSION: Tumour bed boost PTV coverage was insufficient using clinical determination as compared with CT localisation. This study supports CT planning for target volume localisation of the tumour bed boost in patients treated with breast-conserving therapy for breast cancer.

Tubular breast carcinoma: an argument against treatment de-escalation.

PURPOSE: To evaluate the role of adjuvant radiotherapy in management of patients with tubular carcinoma of the breast. METHODS: One hundred seventy-eight patients treated for tubular carcinoma were identified from the Queensland Radium Institute database. A retrospective review of medical records identified 115 patients meeting eligibility criteria: breast-conserving surgery for a histological diagnosis of tubular carcinoma, minimum follow up of 12 months and adequate medical records. RESULTS: Median follow up was 64 months. There were no significant differences between patient characteristics treated with and without radiotherapy. Median age at diagnosis was 54 (36-78) years. Ninety-five percent tumours were T1 and four patients had positive axillary lymph nodes. Of 94 patients treated with adjuvant radiotherapy, one developed local relapse. Five of 21 patients who did not have adjuvant radiotherapy failed locally. Five-year relapse-free survival with and without radiotherapy was 100 and 89%, respectively (hazard ratio for radiotherapy: 0.06; 95% confidence interval 0.01-0.32, P = 0.001). CONCLUSION: Radiotherapy has a significant impact on relapse-free survival in patients treated with breast-conserving surgery for tubular carcinoma.