Stereotactic ablative radiotherapy for early stage lung cancer and lung metastases in a New Zealand population.

AIM: Stereotactic ablative radiotherapy (SABR) involves the delivery of high doses of precisely targeted radiation in a shorter time period than conventional radiotherapy. The aim of this study was to compare the outcomes of lung-based SABR in a New Zealand cohort to the global literature. METHODS: A single-institution retrospective analysis was performed on all patients who received lung-based SABR between May 2015 and September 2019 at Waikato Hospital, New Zealand. The study included both early stage lung cancer and lung oligometastases that measured less than 5cm. RESULTS: 102 patients received SABR to 116 lesions. Median follow-up was 19 months. The three-year rate of local control in the primary and metastatic cohorts was 85% and 82%, respectively. This reflects the three-year local control rate of 86% for primary lung cancer in the SPACE trial and the two-year local control rate of 81% for pulmonary oligometastases in a German study. Central primary lung cancer was associated with a higher risk of local recurrence (HR6.4 (1.3-31.5) p=0.02). The three-year progression-free survival rate in patients with early stage lung cancer and oligometastases was 56% and 26%, respectively. Maori patients with primary lung cancer had a significantly worse progression free survival (HR2.4 (1.1-5.1) p=0.03). There were no reported grade three toxicities. CONCLUSION: The use of lung-based SABR in a typical radiotherapy setting in New Zealand mirrors global outcomes.

A prospective feasibility study of MammoSite accelerated partial breast irradiation for early breast Cancer.

BACKGROUND: Accelerated partial breast irradiation is a potential alternative to standard whole breast irradiation, following breast-conserving surgery, in the management of breast cancer. The MammoSite applicator-based technique allows for the delivery of a higher dose of radiation to the tumour bed and adjacent area, over a shorter treatment period. AIMS: To investigate the long-term feasibility of the MammoSite technique in early stage breast cancer in an Irish cohort. METHODS: Sixty-two patients with early stage breast cancer were enrolled in this prospective study between November 2005 and October 2012 at the University Hospital Galway. A single-entry MammoSite applicator was inserted post-operatively. A CT scan was performed to assess the balloon to skin distance, the conformance of target tissue to balloon surface and balloon symmetry. A total dose of 34 Gy was delivered over 10 fractions twice daily. RESULTS: Median follow-up was 10 years. 91.9% (57/62) completed the full course of MammoSite treatment. Technical issues with the MammoSite balloon precluded three patients from completing the full course of treatment. On last follow-up, 6.4% (4/62) of patients had developed an ipsilateral breast recurrence. Half of these recurrences occurred more than 10 years after the initial breast cancer treatment. The most common toxicities observed were fibrosis (67.7%), pain (61.3%) and skin erythema (35.5%). CONCLUSION: The use of the MammoSite technique, as an alternative to standard whole breast irradiation, is feasible in a typical Irish clinical setting with integrated multidisciplinary team input.