A Randomised Phase II Clinical Trial Comparing the Deliverability and Acute Toxicity of Wide Tangent versus Volumetric Modulated Arc Therapy to the Breast and Internal Mammary Chain

AIMS

Inclusion of the internal mammary chain in the radiotherapy target volume (IMC-RT) improves disease-free and overall survival in higher risk breast cancer patients, but increases radiation doses to heart and lungs. Dosimetric data show that either modified wide-tangential fields (WT) or volumetric modulated arc therapy (VMAT) together with [AQ1]voluntary deep inspiration breath hold (vDIBH) keep mean heart doses below 4 Gy in most patients. However, the impact on departmental resources has not yet been documented. This phase II clinical trial compared the time taken to deliver IMC-RT using either WT and vDIBH or VMAT and vDIBH, together with planning time, dosimetry, set-up reproducibility and toxicity.

MATERIALS AND METHODS

Left-sided breast cancer patients requiring IMC-RT were randomised to receive either WT(vDIBH) or VMAT radiotherapy. The primary outcome was treatment time, powered to detect a minimum difference of 75 min (5 min/fraction) between techniques. The population mean displacement, systematic error and random error for cone beam computed tomography chest wall matches in three directions of movement were calculated. Target volume and organ at risk doses were compared between groups. Side-effects, including skin (Radiation Therapy Oncology Group), lung and oesophageal toxicity (Common Terminology Criteria for Adverse Events v 4.03) rates, were compared between the groups over 3 months. Patient-reported outcome measures, including shoulder toxicity at baseline, 6 months and 1 year, were compared.

RESULTS

Twenty-one patients were recruited from a single UK centre between February 2017 and January 2018. The mean (standard deviation) total treatment time per fraction for VMAT treatments was 13.2 min (1.7 min) compared with 28.1 min (3.3 min) for WT(vDIBH). There were no statistically significant differences in patient set-up errors in between groups. The average mean heart dose for WT(vDIBH) was 2.6 Gy compared with 3.4 Gy for VMAT(vDIBH) (P = 0.13). The mean ipsilateral lung V17Gy was 32.8% in the WT(vDIBH) group versus 34.4% in the VMAT group (P = 0.2). The humeral head (mean dose 16.8 Gy versus 2.8 Gy), oesophagus (maximum dose 37.3 Gy versus 20.1 Gy) and thyroid (mean dose 22.0 Gy versus 11.2 Gy) all received a statistically significantly higher dose in the VMAT group. There were no statistically significant differences in skin, lung or oesophageal toxicity within 3 months of treatment. Patient-reported outcomes of shoulder toxicity, pain, fatigue, breathlessness and breast symptoms were similar between groups at 1 year.

CONCLUSION

VMAT(vDIBH) and WT(vDIBH) are feasible options for locoregional breast radiotherapy including the IMC. VMAT improves nodal coverage and delivers treatment more quickly, resulting in less breath holds for the patient. This is at the cost of increased dose to some non-target tissues. The latter does not appear to translate into increased toxicity in this small study.

A review of permanent marking for radiotherapy in the UK

INTRODUCTION

This paper presents the results of a survey of the routine use of permanent marks for radiotherapy in the UK. This was undertaken to provide an overview of current practice. Permanent marks are a somewhat invasive procedure, and should be subject to scrutiny and judicious application.

METHOD

The authors reviewed the literature on international radiotherapy permanent marking practice. Common themes that emerged were the psychology of permanent marking and ink-type considerations, current practice and training, and safety. These were used to develop a questionnaire in order to form an overview of the use of marks nationally, and to identify any recurrent issues. The questionnaire also sought information regarding locations and numbers of permanent marks used for common treatment sites. The survey was sent to 71 departments in the UK using email.

RESULTS

70% of departments responded. 62% of departments reported patients who had refused permanent marks. The reasons for refusal varied. India or drawing ink was used in 49 of the 51 departments (96%). The most common teaching method of tattooing involved combined observation and verbal coaching. Most departments had a written procedure for tattooing, but some did not. Although sharps injuries were rare, they were documented.

CONCLUSION

Most departments in the UK had encountered patient refusal of permanent marks, with breast patients representing the largest group which declined. There is variation in practice throughout the UK, and the equipment used is not specialised for tattooing purposes. Sharps injuries, although rare, do occur, and training methods are not consistent.

IMPLICATIONS FOR PRACTICE

The requirement for national guidelines is posited. Further investigation into the need for permanent marks in an era of state-of-the-art imaging technology is also required.