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The UK HeartSpare study¹ has previously compared voluntary and ABC techniques of DIBH in 23 patients prospectively and found that they are comparable in terms of positional reproducibility and normal tissue sparing. However, voluntary DIBH is preferred by patients and radiographers and takes less time to deliver.

There are no previous studies comparing ABC with SGRT techniques of DIBH. We aimed to compare ABC and SGRT techniques as a pilot study at the Christie in 2 patient cohorts receiving adjuvant radiotherapy following a diagnosis of localised breast cancer, to assess the feasibility, reproducibility, dosimetric and patient experience outcomes.

Both techniques are currently fully available at the Christie. We recruited 10 SGRT and 14 ABC patients. We devised a proforma to obtain:

1) timings of i) Pre-treatment (including coaching time if applicable), ii) RTP acquisition time, iii) set-up time (time from set up of equipment to beam on (excluding the 3 field)) and iv) treatment time (beam on to off).

2) Questionnaire of patient satisfaction (comfort and reproducibility)

3) Questionnaire of radiographer satisfaction (comfort, reproducibility, feasibility)

We additionally recorded number of moves required during treatment, mean heart dose and lung depth on both the low and high dose RTP scans.

All patients had left sided breast tumours and were well matched for all baseline demographics.

There was no difference between ABC and SGRT for set-up time RTP acquisition, treatment time, mean heart dose, and lung depth (mean, range vs mean range). Both pre-treatment time and number of moves required (mean range vs mean range) were greater with ABC than SGRT. At 5 fractions, overall time (pre-treatment and then 5 fractions) was 136 mins for SGRT vs 177.5 for ABC, p=0.08, For 15 fractions, it was 351 vs 422.5 mins, p=0.14.

Patient satisfaction was matched across both groups with no significant difference seen for any of the questions asked. Radiographer satisfaction was matched for the majority of questions. There was a significant difference with satisfaction related to difficulty in use of equipment with more radiographers ranking the ABC equipment a little difficult to use (64% vs 17%, p < 0.05)

SGRT, as compared to ABC techniques of DIBH in adjuvant treatment of patients with localised breast cancer, has a significantly shorter pre-treatment time and number of set-up moves during treatment. It provides a better radiographer and patient experience without compromising the doses to the heart. We will have more confidence to phase out ABC as a DIBH technique in the Christie.

1. Bartlett FR, Colgan RM, Carr K, et al. The UK HeartSpare Study: randomised evaluation of voluntary deep-inspiratory breath-hold in women undergoing breast radiotherapy. Radiotherapy and Oncology:Journal of the European Society for Therapeutic Radiology and Oncology. 2013 Aug;108(2):242-247.