Impact of the radiation boost on outcomes after breast-conserving surgery and radiation

The Effect of Wire Versus Magnetic Seed Localization on Lumpectomy Cavity Size

PURPOSE

Our purpose was to assess whether an association exists between surgical localization technique and lumpectomy cavity size on radiation therapy planning computed tomography (CT) scan.

METHODS AND MATERIALS

A single-institution retrospective review was conducted of women undergoing breast conserving surgery with wire or magnetic seed guided lumpectomy followed by adjuvant radiation therapy from 2018 to 2021. Patients of a surgeon only performing 1 localization technique or undergoing bracketed localization were excluded. The primary outcome was lumpectomy cavity size on simulation CT. Confounding due to imbalance in patient and tumor factors was addressed with overlap weights derived from a propensity score analysis and used in a weighted multivariable analysis. Secondary outcomes included positive margins, total pathologic volume, boost delivery, and boost modality.

RESULTS

Of 617 women who received lumpectomy during the study period, 387 were included in final analysis. Tumors of patients undergoing seed localization were more likely unifocal, assessable by ultrasound, and smaller. Seed use rates ranged from 27.7% to 70.7% per surgeon. There was no difference in positive margins (6.4 vs 5.4%, P = .79) or second surgeries (9.4 vs 8.1%, P = .79) between groups. Close margin rates were similar for ductal carcinoma in situ (P = .35) and invasive carcinoma (P = .97). In unadjusted bivariable analyses, wire localization was associated with larger total pathology volume (P = .004), but localization technique showed no association with CT cavity volume (P = .15). After adjusting for potentially confounding variables, multivariable analysis failed to show an association between localization technique and either CT cavity (P = .35) or total path volume (P = .08). There was no difference in indicated-boost delivery (P = .15) or electron boost (P = .14) by localization technique.

CONCLUSIONS

There was no significant difference in CT cavity size by localization technique, suggesting choice between surgical techniques does not impede radiation therapy boost delivery.

Guidelines for breast cancer management in Bosnia and Herzegovina

Breast cancer is the most common cancer among women. In Bosnia and Herzegovina, accurate data on the status of breast cancer are lacking due to the absence of a central registry. Multiple international guidelines imply that institutions that monitor breast cancer patients should have optimal therapeutic options for treatment. In addition, there have been several international consensus guidelines written on the management of breast cancer. Application of consensus guidelines has previously been demonstrated to have a positive influence on breast cancer care. The importance of specialty breast centers has previously been reported. As part of the 2021 Bosnian-Herzegovinian American Academy of Arts and Sciences (BHAAAS) conference in Mostar, a round table of multidisciplinary specialists from Bosnia and Herzegovina and the diaspora was held. All were either members of BHAAAS or regularly participate in collaborative projects. The focus of the consortium was to write the first multidisciplinary guidelines for the general management of breast cancer in Bosnia and Herzegovina. Guidelines were developed for each area of breast cancer treatment and management. These guidelines will serve as a resource for practitioners managing breast cancer in the Bosnia and Herzegovina region. This might also be of benefit to the ministry of health and any future investors interested in developing breast cancer care policies in this region of the world.

A novel technique for treating deep seated breast cavity boosts

Breast boost irradiation is an integral component to the standard of care for early staged breast cancer. The use of reduced tangents is common for deep seating tumor bed; however, reduced tangents result in non-conformal plans delivering prescription dose to large volumes of breast tissue. To improve conformity, a novel technique of integrating a single conformal arc with reduced tangents has been developed. With this technique, a conformal arc was placed between a pair of reduced tangents to better conform the prescription dose to the target volume. This new technique improves the conformity but was also shown to potentially increase max dose to nearby critical structures, such as the heart, due to exit dose from the arc. This tangent and arc technique has been implemented at our clinic in cases where the exit dose is not critical to the heart.

Hypofractionation Radiotherapy vs. Conventional Fractionation for Breast Cancer: A Comparative Review of Toxicity

The use of postoperative radiation therapy after breast-conserving surgery was longstanding standard practice. The treatment protocol used a standard fractionation of 50 Gy in 25 fractions plus a boost. Recently, the hypofractionation approach has gained support based on Canadian and English studies that claimed equal tumor control and similar toxicity to the standard protocol.

We conducted a review of the literature of hypofractionation studies and compared the reported toxicity with the general literature. We placed special emphasis on breast fibrosis after hypofractionation versus standard fractionation. We found a striking difference in the breast toxicity reported by the hypofractionation literature regarding breast fibrosis as compared to standard fractionation. Breast fibrosis should be explored further via additional studies and discussed with potential breast-conserving surgery patients.

Hypofractionation with concomitant boost using intensity-modulated radiation therapy in early-stage breast cancer in Mexico

Aim

To evaluate whether hypofractionation with integrated boost to the tumour bed using intensity-modulated radiation therapy is an acceptable option and to determine whether this treatment compromises local control, toxicity and cosmesis.

Background

Retrospective studies have demonstrated that patients who are treated with HF and integrated boost experience adequate local control, a dosimetric benefit, decreased toxicity and acceptable cosmesis compared with conventional fractionation.

Materials and methods

A retrospective, observational and longitudinal study was conducted from January 2008 to June 2015 and included 34 patients with breast cancer (stage 0-II) who were undergoing conservative surgery.The prescribed doses were 45 Gy in 20 fractions (2.25 Gy/fraction) to the breast and 56 Gy in 20 fractions (2.8 Gy/fraction) to the tumour bed.

Results

Thirty-four patients were included. The mean follow-up was 49.29 months, and the mean age was 52 years. The mean percentage of PTV from the mammary region that received 100% of the prescribed dose was 97.89% (range 95-100), and the mean PTV percentage of the tumour bed that received 100% of the dose was 98% (95-100).The local control and the overall survival were 100%, and the cosmesis was good in 82% of the patients. Grade 1 acute toxicity was present in 16 patients (47%), and grade 1 chronic toxicity occurred in 6 cases (18%).

Conclusion

The results of the present study demonstrate that hypofractionation with integrated boost using intensity-modulated radiation therapy is an acceptable option that provides excellent local control and low toxicity.

Adjuvant Photothermal Therapy Inhibits Local Recurrences after Breast-Conserving Surgery with Little Skin Damage

Adjuvant treatments following breast-conserving surgery (BCS) are essential to reduce the risk of local recurrences in patients with breast cancer. However, current adjuvant treatments are based on ionizing radiation, which brings radiation-induced damage and amplifies the risk of death. Here we explore the feasibility of using non-ionizing light to induce photothermal therapy as an adjuvant treatment to BCS. In an orthotopic breast cancer mice model, we demonstrate that adjuvant photothermal therapy (aPTT) decreases the incidence of local recurrences after BCS with no expense of cosmetic outcome. In comparison with conventional photothermal therapy, the technique used in aPTT provides more uniformly distributed light energy and less risk of skin burns and local recurrences. Overall, this work represents a departure from the traditional concept of using PTT as an alternative to surgery and reveals the potential of using PTT as an alternative to adjuvant radiation therapy, which is valuable especially for patients susceptible to radiation damage.

Impact of tumour bed boost integration on acute and late toxicity in patients with breast cancer: A systematic review

The purpose of this systematic review was to summarise the evidence from studies investigating the integration of tumour bed boosts into whole breast irradiation for patients with Stage 0-III breast cancer, with a focus on its impact on acute and late toxicities. A comprehensive systematic electronic search through the Ovid MEDLINE, EMBASE and PubMed databases from January 2000 to January 2015 was conducted. Studies were considered eligible if they investigated the efficacy of hypo- or normofractionated whole breast irradiation with the inclusion of a daily concurrent boost. The primary outcomes of interest were the degree of observed acute and late toxicity following radiotherapy treatment. Methodological quality assessment was performed on all included studies using either the Newcastle-Ottawa Scale or a previously published investigator-derived quality instrument. The search identified 35 articles, of which 17 satisfied our eligibility criteria. Thirteen and eleven studies reported on acute and late toxicities respectively. Grade 3 acute skin toxicity ranged from 1 to 7% whilst moderate to severe fibrosis and telangiectasia were both limited to 9%. Reported toxicity profiles were comparable to historical data at similar time-points. Studies investigating the delivery of concurrent boosts with whole breast radiotherapy courses report safe short to medium-term toxicity profiles and cosmesis rates. Whilst the quality of evidence and length of follow-up supporting these findings is low, sufficient evidence has been generated to consider concurrent boost techniques as an alternative to conventional sequential techniques.

Society of Surgical Oncology-American Society for Radiation Oncology consensus guideline on margins for breast-conserving surgery with whole-breast irradiation in stages I and II invasive breast cancer

PURPOSE

To convene a multidisciplinary panel of breast experts to examine the relationship between margin width and ipsilateral breast tumor recurrence (IBTR) and develop a guideline for defining adequate margins in the setting of breast conserving surgery and adjuvant radiation therapy.

METHODS AND MATERIALS

A multidisciplinary consensus panel used a meta-analysis of margin width and IBTR from a systematic review of 33 studies including 28,162 patients as the primary evidence base for consensus.

RESULTS

Positive margins (ink on invasive carcinoma or ductal carcinoma in situ) are associated with a 2-fold increase in the risk of IBTR compared with negative margins. This increased risk is not mitigated by favorable biology, endocrine therapy, or a radiation boost. More widely clear margins than no ink on tumor do not significantly decrease the rate of IBTR compared with no ink on tumor. There is no evidence that more widely clear margins reduce IBTR for young patients or for those with unfavorable biology, lobular cancers, or cancers with an extensive intraductal component.

CONCLUSIONS

The use of no ink on tumor as the standard for an adequate margin in invasive cancer in the era of multidisciplinary therapy is associated with low rates of IBTR and has the potential to decrease re-excision rates, improve cosmetic outcomes, and decrease health care costs.

Plastic surgery for breast conservation therapy: how to define the volume of the tumor bed for the boost?

PURPOSE

To describe the procedure of definition of the boost volume using pre- and post-operative computed tomography (CT) and surgical clips in the tumor bed after oncoplastic surgical procedure.

PATIENTS AND METHODS

Thirty-one consecutive breast cancer patients who underwent simple lumpectomy or oncoplastic surgery were studied. All of them underwent pre- and post-operative CT scan in treatment position to evaluate the planning target volume (PTV) boost volume and define the primary tumor (gross tumor volume (GTV)) and tumor bed zones (CTV), with an overall margin of 5 mm in lateral and 10 mm in craniocaudal directions, corresponding to localization and setup uncertainties.

RESULTS

Thirteem patients underwent simple lumpectomy and 18 oncoplastic surgery. The volumetric analysis showed that the intersection between GTV and CTV clips was significantly higher in patients with three and more clips (28.4% vs 3.14%; p < 0.001). In the case of patients with oncoplastic surgery, more than three clips were needed to define the tumor bed volume with accuracy. The number of clips was directly related to the exact definition of the boost volume.

CONCLUSIONS

The use of more than three clips allows better definition of the PTV boost volume after oncoplastic surgical procedure.

Society of Surgical Oncology-American Society for Radiation Oncology consensus guideline on margins for breast-conserving surgery with whole-breast irradiation in stages I and II invasive breast cancer

PURPOSE

Controversy exists regarding the optimal margin width in breast-conserving surgery for invasive breast cancer.

METHODS

A multidisciplinary consensus panel used a meta-analysis of margin width and ipsilateral breast tumor recurrence (IBTR) from a systematic review of 33 studies including 28,162 patients as the primary evidence base for consensus.

RESULTS

Positive margins (ink on invasive carcinoma or ductal carcinoma in situ) are associated with a two-fold increase in the risk of IBTR compared with negative margins. This increased risk is not mitigated by favorable biology, endocrine therapy, or a radiation boost. More widely clear margins do not significantly decrease the rate of IBTR compared with no ink on tumor. There is no evidence that more widely clear margins reduce IBTR for young patients or for those with unfavorable biology, lobular cancers, or cancers with an extensive intraductal component.

CONCLUSION

The use of no ink on tumor as the standard for an adequate margin in invasive cancer in the era of multidisciplinary therapy is associated with low rates of IBTR and has the potential to decrease re-excision rates, improve cosmetic outcomes, and decrease health care costs. J Clin Oncol 32. 2014 American Society of Clinical Oncology®, American Society for Radiation Oncology®, and Society of Surgical Oncology®. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without written permission by the American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology.

[Brachytherapy of breast cancer]

For breast cancer, interstitial brachytherapy remains an accurate irradiation technique for delivering a high dose (increasing the local control) in a small volume (decreasing the toxicity). In this article, we present the technical data related to the breast brachytherapy proceeding, from the implantation of the vectors to the treatment itself, including the planning. The different indications of breast brachytherapy include all the breast irradiations focusing on the initial tumour bed (partial irradiation of the breast), such as boost, accelerated and partial breast irradiation (APBI) and second conservative radiosurgical treatment in case of ipsilateral in-breast recurrence. The results in terms of efficacy and toxicity are presented for each indication. Interstitial breast brachytherapy, performed according with the standard rules, remains a major technique for breast cancer treatment.

[Radiotherapy of invasive breast cancer: French national guidelines]

The French National Cancer Institute (INCa) and Société française de sénologie et pathologie mammaire (SFSPM), in collaboration with a multidisciplinary experts group, have published the French national clinical practice guidelines on a selection of 11 currently debated questions regarding the management of invasive breast cancer. Those guidelines are based on a comprehensive analysis of the current published evidence dealing with those issues, secondly reviewed by 100 reviewers. Radiotherapy was concerned by five of the 11 questions: indications for the boost after whole gland irradiation; hypofractionated radiotherapy; partial breast irradiation; indications for mammary internal nodes irradiation, and indications of radiotherapy after neo-adjuvant chemotherapy.

Relationship between irradiated breast volume and late normal tissue complications: a systematic review

The concept of radiation dose-volume effect has been exploited in breast cancer as boost treatment for high risk patients and more recently in trials of Partial Breast Irradiation for low risk patients. However, there appears to be paucity of published data on the dose-volume effect of irradiation on breast tissue including the recently published report on Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC). This systematic review looks at the current literature for relationship between irradiated breast volume and normal tissue complications and introduces the concept of dose modulation.