A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant...

Area of Science:

• Oncology
• Radiotherapy
• Medical Imaging

Background:

• Accurate identification of the clinical target volume (CTV) in early-stage breast cancer is challenging on planning computed tomography (CT) scans.
• Surgical clips can aid in CTV delineation and tracking post-operatively, especially after seroma absorption.

Purpose of the Study:

• To assess the efficacy of a surgical clip-based protocol for CTV delineation in early-stage breast cancer patients undergoing radiotherapy.
• To evaluate the post-operative shrinkage pattern of the CTV in relation to radiotherapy and chemotherapy treatments.

Main Methods:

• A protocol using surgical clips for CTV delineation was implemented.
• Two patient groups were studied: 27 receiving radiotherapy alone (RT/alone) and 15 receiving chemotherapy followed by radiotherapy (Chemo/RT).
• CT scans were acquired at various time points post-surgery and during radiotherapy for both groups.

Main Results:

• No significant difference in initial mean CTV between the RT/alone and Chemo/RT cohorts.
• The RT/alone group showed a significant 38.4% CTV volume reduction by 40 Gy.
• The Chemo/RT group exhibited significant volume reduction between early post-operative scans and planning CT, with minimal further shrinkage thereafter.

Conclusions:

• Surgical clips effectively localize the post-surgical seroma for radiotherapy targeting.
• Early seroma shrinkage allows for CT treatment planning within the recommended timeframe (7 weeks) to minimize disease recurrence.