ABSTRACT
PURPOSE/OBJECTIVE(S): To evaluate the role of surgical clips placement in the definition of boost treatment volume. MATERIALS/METHODS: Clinical Target Volumes (CTV) were defined as: CTV Breast, CTV Quadrant (based on physical exam and pre-surgical images), CTV Boost, defined by clip plus margin (1 cm for 2 or more clips and 2 cm for 1 clip only) plus radiological changes, CTV NT (normal tissue), defined by CTV Quadrant minus CTV Boost and CTV MISS (CTV that would be outside the treatment volume), defined by CTV Boost minus CTV Quadrant. RESULTS: A total of 247 patients were included. Upper lateral quadrant was the most common clinical location (47.3%). The median number of clips used was three. The mean volumes were: CTV Breast:982.52 cc, CTV Boost:36.59 cc, CTV Quadrant:285.07 cc, CTV NT:210.1 cc and CTV MISS:13.57 cc. Only 50.6% (125) of the patients presented the CTV Boost completely inside the CTV Quadrant and in 47.3% (117), partially inside. Among patients with any CTV MISS, 80.3% (98) had 10% or more of CTV Boost outside the treatment volume. Regarding CTV MISS, there were no statistically significant differences between the groups with 1 clip versus 2 or more clips, nor between patients with or without reconstructive surgery. In average, the CTV Boost was 87% smaller than the CTV Quadrant. The whole quadrant irradiation would lead to unnecessary irradiation of 26% of normal breast tissue. CONCLUSION: Surgical bed clipping is up most important in the definition of the boost volume irradiation to ensure precision minimizing geographical miss and optimizing surrounding normal tissue sparing.
Subject(s)
Breast Neoplasms/radiotherapy , Mastectomy, Segmental/instrumentation , Microsurgery/instrumentation , Adult , Aged , Aged, 80 and over , Breast Neoplasms/diagnosis , Breast Neoplasms/surgery , Equipment Design , Female , Follow-Up Studies , Humans , Mammography/methods , Middle Aged , Radiation Dosage , Radiotherapy Dosage , Retrospective Studies , Surgical Instruments , Tomography, X-Ray Computed/methods , Treatment Outcome , Tumor BurdenABSTRACT
BACKGROUND: and Purpose: Post-operative radiation therapy (PORT) is usually indicated for patients with breast cancer (BC) after neoadjuvant chemotherapy (NAC) and surgery. However, the optimal timing to initiation of PORT is currently unknown. MATERIAL AND METHODS: We retrospectively evaluated data from patients with BC who received PORT after NAC and surgery at our institution from 2008 to 2014. Patients were categorized into three groups according to the time between surgery and PORT: <8 weeks, 8-16 weeks and >16 weeks. RESULTS: A total of 581 patients were included; 74% had clinical stage III. Forty-three patients started PORT within 8 weeks, 354 between 8 and 16 weeks and 184 beyond 16 weeks from surgery. With a median follow-up of 32 months, initiation of PORT up to 8 weeks after surgery was associated with better disease-free survival (DFS) (<8 weeks versus 8-16 weeks: HR 0.33; 95% CI 0.13-0.81; p = 0.02; <8 weeks versus >16 weeks: HR 0.38; 95% CI 0.15-0.96; p = 0.04) and better overall survival (OS) (<8 weeks versus 8-16 weeks: HR 0.22; 95% CI 0.05-0.90; p = 0.036; <8 weeks versus >16 weeks: HR 0.28; 95% CI 0.07-1.15; p = 0.08). CONCLUSION: PORT started up to 8 weeks after surgery was associated with better DFS and OS in locally-advanced BC patients submitted to NAC. Our findings suggest that early initiation of PORT is critically important for these patients. However, the low numbers of patients and events in this study prevent us from drawing firm conclusions.
