The role of high-dose-rate brachytherapy boost in breast-conserving therapy: Long-term results of the Hungarian National Institute of Oncology

Traditional Clinicopathological Biomarkers Still Determine Disease-Free and Overall Survival in Invasive Breast Cancer Patients: A Pilot Study

Background: Molecular classification, tumor diameter, Ki67 expression, and brachytherapy administration still act as the most potent potential predictors of breast cancer recurrence and overall survival. Methods: Over the period of 23 months, we included in the study 92 invasive breast cancer (IBrC) patients initially diagnosed at the Clinical Ward of Breast Cancer and Reconstructive Surgery, Oncology Center in Bydgoszcz, Poland. The probability of disease-free survival (DFS) and overall survival (OS) in relation to potential prognostic factors for the patients were determined using a Kaplan-Meier analysis, and univariate and multivariate Cox regression analyses evaluated the predictive factors of IBrC patients. The investigation of the potential prognostic model's accuracy was analyzed using the ROC curve. Results: Patients with tumor size < 2 cm, Ki67 expression < 20%, luminal-A molecular subtype, and extra-dose brachytherapy boost administration displayed the most favorable prognosis according to breast cancer disease-free survival and overall survival. The estimated 5 year probability of DFS and OS rates in women with tumor diameter < 2 cm were 89% and 90%, respectively. In tumor diameter > 2 cm, the estimated 5 year probability of DFS was 73% and OS was 76%. Interestingly, the tumor diameter of 1.6 cm with a specificity of 60.5% and a sensitivity of 75% occurred as the best threshold point to differentiate patients with cancer recurrence from those without cancer progression. Conclusions: Our study provides essential information on the clinicopathological profile and future outcomes of early stage IBrC patients. Furthermore, the tumor diameter cut-off value of 1.6 cm discriminating between disease recurrence and those without disease progression patients represents an innovative direction for further research.

Thermally boosted interstitial high-dose-rate brachytherapy in high-risk early-stage breast cancer conserving therapy - large cohort long-term results

Background

Early-stage high-risk breast cancer (BC) is standardly treated with breast-conserving therapy (BCT), combined with systemic therapy and radiotherapy (RT) ± tumor bed boost, e.g., with interstitial high-dose-rate brachytherapy (HDR-BT). To improve local recurrence rate (LRR), BT radiosensitization (thermal boost, TB) with interstitial microwave hyperthermia (MWHT) may be an option. The paper aims to report a retrospective single-institutional study on 5- and 10-year local control (LC), distant metastasis-free survival (DMFS), disease-free survival (DFS), overall survival (OS), cosmetic outcome (CO), and late toxicity (fibrosis, fat necrosis) after thermally enhanced HDR-BT boost to the BC tumor bed.

Materials and methods

In 2006-2018, 557 early-stage (I-IIIA) high-risk BC patients were treated with BCT. If indicated, they were administered systemic therapy, then referred for 40.0-50.0 Gy whole breast irradiation (WBI) and 10 Gy interstitial HDR-BT boost (group A). Eligible patients had a single MWHT session preceding BT (group B). Based on present risk factors (RF), medium-risk (1-2 RF) and high-risk subgroups (≥ 3 RF) were formed. Patients were standardly checked, and control mammography (MMG) was performed yearly. Breast cosmesis (Harvard scale) and fibrosis were recorded. LC, DMFS, DFS, and OS were statistically analyzed.

Results

Out of 557 patients aged 57 years (26-84), 364 (63.4%) had interstitial HDR-BT boost (group A), and 193 (34.6%) were preheated with MWHT (group B). Patients in group B had a higher clinical stage and had more RFs. The median follow-up was 65.9. Estimated 5-year and 10-year LC resulted in 98.5% and 97.5%, respectively. There was no difference in LC, DMFS, DFS, and OS between groups A and B and between extracted high-risk subgroups A and B. Five- and ten-year OS probability was 95.4% and 88.0%, respectively, with no difference between groups A and B. Harvard criteria-based CO assessment revealed good/excellent cosmesis in 74.9-79.1%. Tumor bed hardening was present in 40.1-42.2%. Asymptomatic fat necrosis-related macrocalcifications were detected in 15.6%, more frequently in group B (p = 0.016).

Conclusions

Thermally boosted or not, HDR-BT was locally highly effective as part of combined treatment. Five- and ten-year LC, DMFS, DFS, and OS were high and equally distributed between the groups, although TB was prescribed in more advanced one with more RFs. TB did not influence CO and fibrosis. TB added to late toxicity regarding asymptomatic fat necrosis detected on MMG.

Overall Survival and Related Factors of Patients Undergoing Breast-Conserving Surgery with Boost Through Interstitial Brachytherapy in a Cancer Center in Medellin, Colombia

Liza María González-HernándezPatients with breast cancer undergoing conservative surgery require management with radiotherapy to decrease the risk of recurrence. Moreover, the use of tumor bed boost in high-risk patients has shown an absolute reduction in the 10-year local recurrence risk from 23.9 to 13.5%. Therefore, this study aimed to estimate the overall survival of a group of patients undergoing conservative surgery with a boost through interstitial brachytherapy at a cancer center in Medellin, Colombia. A retrospective cohort study was performed, and records from 2014 to 2020 of patients with in situ or infiltrating breast cancer treated with a boost through interstitial brachytherapy were included. Univariate analysis was conducted to characterize the study population; median survival was calculated using the Kaplan-Meier method. Moreover, associations concerning survival were calculated with each of the factors independently. A total of 186 patients were included. Their overall survival was 93.5%, with a median survival of 79 months. The presence of negative hormone receptors, having two or more irradiated fields and having a locally advanced stage were factors associated independently with higher mortality. The overall survival of patients with in situ or infiltrating breast cancer was favorable and correlated with studies regarding intervention with a boost through interstitial brachytherapy and the factors associated with higher mortality, such as having a locally advanced stage.

Predictors of poor cosmesis in breast cancer patients treated with adjuvant whole breast radiation therapy plus high-dose-rate interstitial brachytherapy boost after breast conservation surgery

Purpose

To identify patient, tumor, and treatment-related factors, which predict cosmesis in breast cancer survivors treated with adjuvant whole breast irradiation (WBI) plus high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIBT) boost after breast conservation surgery.

Material and methods

At least 12 months after completion of radiotherapy, cosmetic outcomes were measured both objectively with BCCT.core software (using a front view digital photograph), and subjectively according to Harvard's criteria. MIBT dose fractionation regimen was 13.6 Gy/4 fractions (bid). To evaluate the correlation between cosmetic scores and dose-volume histogram (DVH) parameters, WBI and MIBT plans were retrospectively analyzed, and ipsilateral skin and breast biologically equivalent dosimetric indices were recorded (α/β = 3 Gy). A multivariate ordinal logistic regression model was used for statistical analysis.

Results

Twenty-eight consecutive patients were enrolled into this study. The median time from completion of radiation therapy to cosmesis scoring was 18 months. In evaluation with BCCT.core software, no patient was scored as excellent. Cosmesis was good in 18%, fair in 50%, and poor in 32% of patients. According to Harvard's scale, 10.5% of patients had excellent cosmesis, and 43%, 28.5%, and 18% of patients had good, fair, and poor scores, respectively. In univariate analysis, patients with higher absolute MIBT V29Gy (cc), those treated with irradiation of regional lymphatics (odds ratio ≈ 5), and patients with larger breast volumes had statistically significant lower Harvard's scores. In the multivariate model, none of the mentioned factors remained statistically significant, except for a trend for poorer cosmesis in patients with higher absolute MIBT V29Gy (p-value = 0.066).

Conclusions

Based on the results of this study, MIBT breast V29Gy, regional nodal irradiation, and larger breast volumes are the potential factors, which could predict cosmesis.

Thermal Boost Combined with Interstitial Brachytherapy in Early Breast Cancer Conserving Therapy—Initial Group Long-Term Clinical Results and Late Toxicity

(1) In breast-conserving therapy (BCT), adjuvant radiation, including tumor bed boost, is mandatory. Safely delivered thermal boost (TB) based on radio-sensitizing interstitial microwave hyperthermia (MWHT) preceding standard high-dose-rate (HDR) brachytherapy (BT) boost has the potential for local control (LC) improvement. The study is to report the long-term results regarding LC, disease-free survival (DFS), overall survival (OS), toxicity, and cosmetic outcome (CO) of HDR-BT boost ± MWHT for early breast cancer (BC) patients treated with BCT. (2) In the years 2006 and 2007, 57 diverse stages and risk (IA-IIIA) BC patients were treated with BCT ± adjuvant chemotherapy followed by 42.5–50.0 Gy whole breast irradiation (WBI) and 10 Gy HDR-BT boost. Overall, 25 patients (group A; 43.9%) had a BT boost, and 32 (group B; 56.1%) had an additional pre-BT single session of interstitial MWHT on a tumor bed. Long-term LC, DFS, OS, CO, and late toxicity were evaluated. (3) Median follow-up was 94.8 months (range 1.1–185.5). LC was 55/57, or 96.5% (1 LR in each group). DFS was 48/57, or 84.2% (4 failures in group A, 5 in B). OS was 46/57, or 80.7% (6 deaths in group A, 5 in B). CO was excellent in 60%, good in 36%, and satisfactory in 4% (A), and in 53.1%, 34.4%, and 9.4% (B), respectively. One poor outcome was noted (B). Late toxicity as tumor bed hardening occurred in 19/57, or 33.3% of patients (9 in A, 10 in B). In one patient, grade 2 telangiectasia occurred (group A). All differences were statistically insignificant. (4) HDR-BT boost ± TB was feasible, well-tolerated, and highly locally effective. LC, DFS, and OS were equally distributed between the groups. Pre-BT MWHT did not increase rare late toxicity.

Accelerated hypofractionated breast radiotherapy with simultaneous integrated boost: a feasibility study

Purpose

To assess the feasibility of accelerated hypofractionated radiotherapy with simultaneous integrated boost (SIB) in patients with breast cancer.

Materials and Methods

A total of 27 patients after breast-conserving surgery were included in this study. Patients were planned on a four-dimensional computerized tomogram, and contouring was done using RTOG guidelines. The dose was 34 Gy/10#/2 week to the breast and 40 Gy/10#/2 week to the tumor bed as SIB with volumetric modulated arc technique. The primary endpoint was grade 2 acute skin toxicity. Doses to the organs-at-risk were calculated. Toxicities and cosmesis were assessed using RTOG/LENT/SOMA and HARVARD/NSABP/RTOG grading scales, respectively. Disease-free survival (DFS) and overall survival (OS) were calculated with Kaplan-Meier curves.

Results

The mean age of the patients was 42 years. Left and right breast cancers were seen in 17 (63%) and 10 (37%) patients, respectively. The mean values of ipsilateral lung V₁₆ and contralateral lung V₅ were 16.01% and 3.74%, respectively. The mean heart doses from the left and right breast were 7.25 Gy and 4.37 Gy, respectively. The mean doses to the contralateral breast, oesophagus, and D_max to brachial plexus were 2.64 Gy, 3.69 Gy, and 26.95 Gy, respectively. The mean value of thyroid V₂₅ was 19.69%. Grade 1 and 2 acute skin toxicities were observed in 9 (33%) and 5 (18.5%) patients, respectively. Grade 2 hyperpigmentation, edema, and induration were observed in 1 (3.7%), 2 (7.4%), and 4 (14.8%) patients, respectively. Mild breast pain and arm/shoulder discomfort were reported by 1 (3.4%) patient. The median follow-up was 51 months (range, 12 to 61 months). At four years, breast induration, edema, and fibrosis were observed in 1 (3.7%) patient. Cosmesis was excellent and good in 21 (78%) and 6 (22%) patients, respectively. Local recurrence and distant metastases occurred in 1 (3.7%) and 2 (7.4%) patients, respectively. DFS and OS at four years were 88% and 92%, respectively.

Conclusion

With this radiotherapy schedule, acute and late toxicity rates were acceptable with no adverse cosmesis. Local control, DFS, and OS were good.

The Role of Interstitial Brachytherapy for Breast Cancer Treatment: An Overview of Indications, Applications, and Technical Notes

Simple Summary

Breast cancer is the most common cancer in the female population. Adjuvant radiotherapy has become increasingly important as conservative treatment. Muticatheter interstitial brachytherapy is a type of radiation technique wherein the radioactive sources are directly implanted into or close to the target tissue and may be considered an extremely precise, versatile, and variable radiation technique. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy, with particular focus on the implant description, limits, and advantages of the technique.

Abstract

Breast cancer represents the second leading cause of cancer-related death in the female population, despite continuing advances in treatment options that have significantly accelerated in recent years. Conservative treatments have radically changed the concept of healing, also focusing on the psychological aspect of oncological treatments. In this scenario, radiotherapy plays a key role. Brachytherapy is an extremely versatile radiation technique that can be used in various settings for breast cancer treatment. Although it is invasive, technically complex, and requires a long learning curve, the dosimetric advantages and sparing of organs at risk are unequivocal. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy, with longer follow-up than new, emerging radiation techniques, whose effectiveness is proven by over 20 years of experience. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy to perform breast lumpectomy boost, breast-conserving accelerated partial breast irradiation, and salvage reirradiation for ipsilateral breast recurrence, with particular focus on the implant description, limits, and advantages of the technique.

Thermal Boost to Breast Tumor Bed—New Technique Description, Treatment Application and Example Clinical Results

(1) Current breast-conserving therapy for breast cancer consists of a combination of many consecutive treatment modalities. The most crucial goal of postoperative treatment is to eradicate potentially relapse-forming residual cancerous cells within the tumor bed. To achieve this, the HDR brachytherapy boost standardly added to external beam radiotherapy was enhanced with an initial thermal boost. This study presents an original thermal boost technique developed in the clinic. (2) A detailed point-by-point description of thermal boost application is presented. Data on proper patient selection, microwave thermal boost planning, and interstitial hyperthermia treatment delivery are supported by relevant figures and schemes. (3) Out of 1134 breast cancer patients who were administered HDR brachytherapy boost in the tumor bed, 262 were also pre-heated interstitially without unexpected complications. The results are supported by two example cases of hyperthermia planning and delivery. (4) Additional breast cancer interstitial thermal boost preceding HDR brachytherapy boost as a part of combined treatment in a unique postoperative setting was feasible, well-tolerated, completed in a reasonable amount of time, and reproducible. A commercially available interstitial hyperthermia system fit and worked well with standard interstitial brachytherapy equipment.

Chronic toxicity and long-term outcome in intraoperative electron radiotherapy as boost followed by whole-breast irradiation

PURPOSE

The administration of a dose boost to the tumor bed after breast-conserving surgery has proven to reduce local recurrence. Intra-operative electron radiotherapy (IOERT) offers an alternative method to deliver a boost with several advantages, such as direct visualization of the tumor bed, less inter- and intrafraction motion and a reduction in the number of medical appointments. The objective of our study is to assess chronic toxicity and long-term outcome for our patients after IOERT boost.

MATERIAL AND METHODS

Forty-six patients treated at our institution between July 2013 and June 2020 with IOERT boost during Breast-Conserving Surgery and consecutive whole breast irradiation were prospectively analyzed. A 10-12 Gy boost was prescribed to 42 patients and 4 patients received a 20 Gy boost. An analysis for overall survival, local relapse and distant progression was performed. Acute and chronic toxicity was assessed by CTCAE 4.0.

RESULTS

The median age was 64.5 years (40-90). The median follow-up was 62 months (4-86). We had no local recurrences but 2 patients (4.3%) presented a distant recurrence. Mean pathological tumor size was 16 mm (6-52). 84.8% (39) of the patients had invasive ductal carcinoma. 52.2% (24) presented histological grade II. 52.2% (24) were Luminal A like, 21.7% (10) Luminal B like, 13% (6) HER2 positive, 13% (6) triple negative. No Grade 3-4 chronic toxicity was observed. Grade 1-2 fibrosis was evidenced in 13% (6) of the patients, 4.3% (2) patients presented fat necrosis, 6.5% (3) presented seroma, 4.3% (2) had localized pain, 2.2% (1) presented localized hematoma and 2.2% (1) presented localized edema.

CONCLUSIONS

IOERT boost in breast cancer treatment during BCS is a safe option with low chronic toxicity. The recurrence rates are comparable to published data and emphasize that IOERT as boost is an effective treatment.

Biological dose summation of external beam radiotherapy for the whole breast and image-guided high-dose-rate interstitial brachytherapy boost in early-stage breast cancer

Purpose

To develop an alternative method for summing biologically effective doses of external beam radiotherapy (EBRT) with interstitial high-dose-rate (HDR) brachytherapy (BT) boost in breast cancer. The total doses using EBRT boost were compared with BT boost using our method.

Material and methods

Twenty-four EBRT plus interstitial HDR-BT plans were selected, and additional plans using EBRT boost were created. The prescribed dose was 2.67/40.05 Gy to whole breast and 4.75/14.25 Gy BT or 2.67/10.7 Gy EBRT to planning target volume (PTV) boost. EBRT and BT computed tomography (CT) were registered twice, including fitting the target volumes and using the lung, and the most exposed volume of critical organs in BT were identified on EBRT CT images. The minimal dose of these from EBRT was summed with their BT dose, and these EQD2 doses were compared using BT vs. EBRT boost. This method was compared with uniform dose conception (UDC).

Results

D₉₀ of PTV boost was significantly higher with BT than with EBRT boost: 67.1 Gy vs. 56.7 Gy, p = 0.0001. There was no significant difference in the dose of non-target and contralateral breast using BT and EBRT boost. D₁ to skin, lung, and D_0.1 to heart were 58.6 Gy vs. 66.7 Gy (p = 0.0025), 32.6 Gy vs. 50.6 Gy (p = 0.0002), and 52.2 Gy vs. 58.1 Gy (p = 0.0009), respectively, while D_0.1 to ribs was 44.3 Gy vs. 37.7 Gy (p = 0.0062). UDC overestimated D₁ (lung) by 54% (p = 0.0001) and D₁ (ribs) by 28% (p = 0.0003).

Conclusions

Based on our biological dose summation method, the total dose of PTV in the breast is higher using BT boost than with EBRT. BT boost yields lower skin, lung, and heart doses, but higher dose to ribs. UDC overestimates lung and ribs doses.

Health-related quality of life of breast cancer patients after accelerated partial breast irradiation using intraoperative or external beam radiotherapy technique

PURPOSE

To compare health-related quality of life (HRQL) in elderly breast cancer patients between two types of Accelerated Partial Breast Irradiation: intraoperative radiotherapy (IORT) and external beam APBI (EB-APBI).

METHODS

Between 2011 and 2016 women ≥60 years undergoing breast conserving therapy for early stage breast cancer were included in a prospective multi-centre cohort study. Patients were treated with electron IORT (1 × 23.3 Gy) or photon EB-APBI (10 × 3.85 Gy daily). HRQL was measured by the EORTC-QLQ C30 and BR23 questionnaires before surgery and at several time points until 1 year.

RESULTS

HRQoL data was available of 204 IORT and 158 EB-APBI patients. In longitudinal analyses emotional functioning and future perspective were significantly, but not clinically relevantly, worse in IORT-treated patients, and improved significantly during follow-up in both groups. All other aspects of HRQL slightly worsened after treatment and recovered within 3 months with an improvement until 1 year. Cross-sectional analysis showed that postoperatively fatigue and role functioning were significantly worse in IORT patients compared to EB-APBI patients who were not yet irradiated, but the difference was not clinically relevant. At other timepoints there were no significant differences. Multivariable analysis at 1 year identified comorbidity and systemic therapy as risk factors for a worse global health score (GHS).

CONCLUSIONS

EB-APBI and IORT were well tolerated. Despite a temporary deterioration after treatment, all HRQL scales recovered within 3 months resulting in no clinically relevant differences until 1 year between groups nor compared to baseline levels.

Bone in the breast? Long term toxicity 21 years after interstitial brachytherapy as a boost

An 81-year-old patient developed an exulcerous tumor in her left breast 21 years after breast cancer treatment with lumpectomy and adjuvant radiotherapy. At the time of the initial treatment 21 years ago, whole breast irradiation was performed with a prescribed dose of 48 Gy and a maximal dose of 69 Gy. In addition, the patient received a 14.7 Gy boost with multicatheter brachytherapy as partial breast irradiation. In general, fat necrosis after radiotherapy, surgery or trauma is a minor problem for patients, but can lead to diagnostic difficulties. The incidence varies: the literature indicates that it occurs in up to 34% of cases. The direct pathogenesis is not clear; it can be due to high radiation dose to the breast, dosimetric inhomogeneities or surgical complications (seromas and inflammation). The tumor in the case described here, occurring more than two decades after the primary treatment, is a rarity in this extent and is an unusual clinical, radiological, and histological finding. It provides a good example of the need for an individualized approach to treatment.

The Role of Brachytherapy in the Treatment of Breast Cancer

Radiotherapy plays an important part in the management of breast cancer. Especially after breast-conserving surgery, external whole breast irradiation, occasionally with an additional local boost, is an integral part of breast conservation. Besides external radiation techniques, brachytherapy (BT) has long been among the treatment options, especially with regard to local boost application. With the emerging implementation of accelerated partial breast irradiation (APBI), BT in general and interstitial multi-catheter BT in particular, are gaining an increasing role in the management of a selected group of early breast cancer patients. APBI is an approach to reduce the irradiated area to the former tumor bed rather than treating the whole breast tissue in patients with a low baseline local recurrence risk. After a variety of phase I-III clinical studies, it is clearly evident that APBI will play a role in the treatment of this selected patient group. In this review, we focus on the clinical development and different available techniques of breast BT and provide a preview of prospects for its use.

Transition from Paris dosimetry system to 3D image-guided planning in interstitial breast brachytherapy

PURPOSE

The purpose of this study is to evaluate our first experience with 3D image-guided breast brachytherapy and to compare dose distribution parameters between Paris dosimetry system (PDS) and image-based plans.

MATERIAL AND METHODS

First 49 breast cancer patients treated with 3D high-dose-rate interstitial brachytherapy as a boost were selected for the study. Every patient underwent computed tomography, and the planning target volume (PTV) and organs at risk (OAR) were outlined. Two treatment plans were created for every patient. First, based on a Paris dosimetry system (PDS), and the second one, imaged-based plan with graphical optimization (OPT). The reference isodose in PDS implants was 85%, whereas in OPT plans the isodose was chosen to obtain proper target coverage. Dose and volume parameters (D90, D100, V90, V100), doses at OARs, total reference air kerma (TRAK), and quality assurance parameters: dose nonuniformity ratio (DNR), dose homogeneity index (DHI), and conformity index (COIN) were used for a comparison of both plans.

RESULTS

The mean number of catheters was 7 but the mean for 20 first patients was 5 and almost 9 for the next 29 patients. The mean value of prescribed isodose for OPT plans was 73%. The mean D90 was 88.2% and 105.8%, the D100 was 59.8% and 75.7%, the VPTV90 was 88.6% and 98.1%, the VPTV100 was 79.9% and 98.9%, and the TRAK was 0.00375 Gym(-1) and 0.00439 Gym(-1) for the PDS and OPT plans, respectively. The mean DNR was 0.29 and 0.42, the DHI was 0.71 and 0.58, and the COIN was 0.68 and 0.76, respectively.

CONCLUSIONS

The target coverage in image-guided plans (OPT) was significantly higher than in PDS plans but the dose homogeneity was worse. Also, the value of TRAK increased because of change of prescribing isodose. The learning curve slightly affected our results.

The use of an interstitial boost in the conservative treatment of breast cancer: how to perform it routinely in a radiotherapy department

Purpose

To demonstrate the utility of a boost with interstitial brachytherapy (BT) in breast-conserving therapy (BCT) by doing a thorough review of the literature and describing in detail our technique for delivering this boost.

Material and methods

Our department has been delivering the boost with interstitial BT since 1989, in most cases with rigid needles and a theoretical dosimetry. In the early years, we used low-dose-rate (LDR) with iridium-192 wires. The dose administered was 15 Gy if there were no risk factors for local relapse or 20-25 Gy in the presence of risk factors. The risk factors considered were the presence of a close margin (less than 10 mm) and an extensive intraductal component (more than 25%). After 2002, we switched to high-dose-rate (HDR); using the linear quadratic model we changed the low dose to 3 fractions of 4.5 Gy in the case of no risk factors for local relapse or to 3 fractions of 5 Gy in the presence of risk factors.

Results

In 79 consecutive boost patients treated in our department between 2010 and 2011, with a median follow-up of 46 months, the local control rate was 97.47%. With respect to cosmesis, fibrosis occurred in 17 cases (21.5%) and hyperpigmentation in 26 cases (32.9%). Our hospital's results are comparable in terms of local control and cosmesis to those of other authors.

Conclusions

This educational article describes our department's boost technique with rigid needles and comments briefly on our results using this technique in a group of consecutively treated patients in our department. A review of the literature and the published results on local control and cosmesis is also described.

Dose estimation for different skin models in interstitial breast brachytherapy

PURPOSE

Skin is a major organ at risk in breast-conserving therapy (BCT). The American Brachytherapy Society (ABS) recommendations require monitoring of maximum dose received, however, there is no unambiguous way of skin contouring provided. The purpose of this study was to compare the doses received by the skin in different models.

MATERIAL AND METHODS

Standard treatment plans of 20 patients who underwent interstitial breast brachytherapy were analyzed. Every patient had a new treatment plan prepared according to Paris system and had skin contoured in three different ways. The first model, Skin 2 mm, corresponds to the dermatological breast skin thickness and is reaching 2 mm into an external patient contour. It was rejected in a further analysis, because of distinct discontinuities in contouring. The second model, Skin 4 mm, replaced Skin 2 mm, and is reaching 2 mm inside and 2 mm outside of the External contour. The third model, Skin EXT, is created on the External contour and it expands 4 mm outside. Doses received by the most exposed 0.1 cc, 1 cc, 2 cc, and the maximum doses for Skin 4 mm and Skin EXT were compared.

RESULTS

Mean, median, maximum, and standard deviation of percentage dose difference between Skin EXT and Skin 4 mm for the most exposed 0.1 cc (D0.1cc) of skin were 18.01%, 17.20%, 27.84%, and 4.01%, respectively. All differences were statistically significant (p < 0.05).

CONCLUSIONS

Monitoring of doses received by skin is necessary to avoid complications and obtain a satisfactory cosmetic effect. It is difficult to assess the compatibility of treatment plans with recommendations, while there is no unambiguous way of skin contouring. Especially, if a mean difference of doses between two models of skin contouring is 18% for the most exposed 0.1 cc and can reach almost 28% in some cases. Differences of this magnitude can result in skin complications during BCT.

Brachytherapy in breast cancer: an effective alternative

Breast conserving surgery (BCS) with following external beam radiation therapy (EBRT) of the conserved breast has become widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of EBRT after BCS is to treat the whole breast up to a total dose of 42.5 to 50 Gy. An additional dose is given to treated volume as a boost to a portion of the breast. In the early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent the cancer from local recurrence is the breast tissue that surrounds the area where the initial cancer was removed. Accelerated partial breast irradiation (APBI) is an approach that treats only the lumpectomy bed plus a 1-2 cm margin rather than the whole breast and as a result allows accelerated delivery of the radiation dose in four to five days. There has been a growing interest for APBI and various approaches have been developed under phase I-III clinical studies; these include multicatheter interstitial brachytherapy, balloon catheter brachytherapy, conformal external beam radiation therapy (3D-EBRT) and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include MammoSite, Axxent electronic brachytherapy, Contura, hybrid brachytherapy devices. Another indication for breast brachytherapy is reirradiation of local recurrence after mastectomy. Published results of brachytherapy are very promising. We discuss the current status, indications, and technical aspects of breast cancer brachytherapy.

HDR-plesiotherapy for the treatment of anogenital extramammary Paget's disease

BACKGROUND

Extramammary Paget disease (EMPD) is a rare condition that most commonly affects the anogenital region in the elderly. It may be associated with an underlying invasive carcinoma. Surgical excision is nowadays considered a standard treatment for extramammary Paget's disease, although this approach might not be suitable for all patients. Good rates of local control and cosmetic outcome have been achieved by using high-dose-rate (HDR) plesiotherapy in the treatment of skin tumors arising in different locations.

MATERIAL AND METHODS

We present the results observed in a patient with EMPD treated by HDR plesiotherapy with a custom-made mold up to a final dose of 54 Gy in 12 fractions of 450 cGy over 4 weeks.

RESULTS

After a follow-up of 18 months, the patient is alive and without evidence of local or distant relapse. Acute toxicity was acceptable and cosmetic result was considered as excellent.

CONCLUSION

This technique represents an attractive alternative for those patients who are not candidates for surgical procedures because of unacceptable risk of disfigurements or functional impairment, medical contraindications or patient preference.

Radiation techniques used in patients with breast cancer: Results of a survey in Spain

AIM

To evaluate the resources and techniques used in the irradiation of patients with breast cancer after lumpectomy or mastectomy and the status of implementation of new techniques and therapeutic schedules in our country.

BACKGROUND

The demand for cancer care has increased among the Spanish population, as long as cancer treatment innovations have proliferated. Radiation therapy in breast cancer has evolved exponentially in recent years with the implementation of three-dimensional conformal radiotherapy, intensity modulated radiotherapy, image guided radiotherapy and hypofractionation.

MATERIAL AND METHODS

An original survey questionnaire was sent to institutions participating in the SEOR-Mama group (GEORM). In total, the standards of practice in 969 patients with breast cancer after surgery were evaluated.

RESULTS

The response rate was 70% (28/40 centers). In 98.5% of cases 3D conformal treatment was used. All the institutions employed CT-based planning treatment. Boost was performed in 56.4% of patients: electrons in 59.8%, photons in 23.7% and HDR brachytherapy in 8.8%. Fractionation was standard in 93.1% of patients. Supine position was the most frequent. Only 3 centers used prone position. The common organs of risk delimited were: homolateral lung (80.8%) and heart (80.8%). In 84% histograms were used. An 80.8% of the centers used isocentric technique. In 62.5% asymmetric fields were employed. CTV was delimited in 46.2%, PTV in 65% and both in 38.5%. A 65% of the centers checked with portal films. IMRT and hypofractionation were used in 1% and in 5.5% respectively.

CONCLUSION

In most of centers, 3D conformal treatment and CT-based planning treatment were used. IMRT and hypofractionation are currently poorly implemented in Spain.

Evaluation of clinical benefits achievable by using different optimization algorithms during real-time prostate brachytherapy

BACKGROUND AND PURPOSE

High dose rate (HDR) brachytherapy is a clinically used procedure in prostate cancer treatment. The purpose of this study was to present the influence of using different optimization algorithms in 3D-CBRT planning on the treatment plan quality.

MATERIALS AND METHODS

Treatment plans were calculated for 15 patients--three plans for each patient using: geometrical optimization (GO), inverse optimization (IO) and blind inverse optimization (BIO). For each patient, PTV and OAR volumes, number of needles and geometry of the implant were set equal. Differences between dose distributions were tracked using: D90, V100, V200, Dmax (for prostate); D10, Dmax (for urethra); D10, V100, Dmax (for rectum).

RESULTS

The analysis of mean values of D90 and V100 in the prostate showed that inverse algorithms gave the best results (mean D90 was 12.1% for BIO and 9.3% for IO better than for GO, mean V100 was 8.2% for BIO and 6.3% for IO better than for GO). From a clinical point of view, GO diminished the doses in the PTV and urethra in all analyzed parameters. The lowest mean doses in the rectum were achieved for plans optimized with IO and BIO (mean D10: 61.2% for GO, 58.1% for IO, 58.0% for BIO; mean Dmax: 92.8% for GO, 85.1% for IO, 83.6% for BIO).

CONCLUSIONS

Application of the blind inverse optimization (BIO) algorithm led to clinically best dose parameters for PTV and the rectum. Use of geometrical optimization (GO) led to smaller doses in the urethra, which was however associated with a certain dose decrease also in PTV.

Assessment of dose homogeneity in conformal interstitial breast brachytherapy with special respect to ICRU recommendations

Purpose

To present the results of dose homogeneity analysis for breast cancer patients treated with image-based conformal interstitial brachytherapy, and to investigate the usefulness of the ICRU recommendations.

Material and methods

Treatment plans of forty-nine patients who underwent partial breast irradiation with interstitial brachytherapy were analyzed. Quantitative parameters were used to characterize dose homogeneity. Dose non-uniformity ratio (DNR), dose homogeneity index (DHI), uniformity index (UI) and quality index (QI) were calculated. Furthermore, parameters recommended by the ICRU 58 such as minimum target dose (MTD), mean central dose (MCD), high dose volume, low dose volume and the spread between local minimum doses were determined. Correlations between the calculated homogeneity parameters and usefulness of the ICRU parameters in image-based brachytherapy were investigated.

Results

Catheters with mean number of 15 (range: 6-25) were implanted in median 4 (range: 3-6) planes. The volume of the PTV ranged from 15.5 cm³ to 176 cm³. The mean DNR was 0.32, the DHI 0.66, the UI 1.49 and the QI 1.94. Related to the prescribed dose, the MTD was 69% and the MCD 135%. The mean high dose volume was 8.1 cm³ (10%), while the low dose volume was 63.8 cm³ (96%). The spread between minimum doses in central plane ranged from −14% to +20%. Good correlation was found between the DNR and the DHI (R²=0.7874), and the DNR correlated well with the UI (R²=0.7615) also. No correlation was found between the ICRU parameters and any other volumetric parameters.

Conclusions

To characterize the dose uniformity in high-dose rate breast implants, DVH-related homogeneity parameters representing the full 3D dose distributions are mandatory to be used. In many respects the current recommendations of the ICRU Report 58 are already outdated, and it is well-timed to set up new recommendations, which are more feasible for image-guided conformal interstitial brachytherapy.

Thermal boost combined with interstitial brachytherapy in breast conserving therapy - Assessment of early toxicity

BACKGROUND

Hyperthermia (HT) causes a direct damage to cancerous cells and/or sensitize them to radiotherapy with usually minimal injury to normal tissues. Adjuvant HT is probably one of the most effective radiation sensitizers known and works best when delivered simultaneously with radiation. In breast conserving therapy, irradiation has to minimize the risk of local relapse within the treated breast, especially in an area of a tumor bed. Brachytherapy boost reduces 5-year local recurrence rate to mean 5,5%, so there still some place for further improvement. The investigated therapeutic option is an adjuvant single session of local HT (thermal boost) preceding standard CT-based multicatheter interstitial HDR brachytherapy boost in order to increase the probability of local cure.

AIM

To report the short-term results in regard to early toxicity of high-dose-rate (HDR) brachytherapy (BT) boost with or without interstitial microwave hyperthermia (MV HT) for early breast cancer patients treated with breast conserving therapy (BCT).

MATERIALS AND METHODS

Between February 2006 and December 2007, 57 stage IA-IIIA breast cancer patients received a 10 Gy HDR BT boost after conservative surgery and 42.5-50 Gy whole breast irradiation (WBI) ± adjuvant chemotherapy. 32 patients (56.1%) were treated with additional pre-BT single session of interstitial MW HT to a tumor bed (multi-catheter technique). Reference temperature was 43 °C and therapeutic time (TT) was 1 h. Incidence, severity and duration of radiodermatitis, skin oedema and skin erythema in groups with (I) or without HT (II) were assessed, significant p-value ≤ 0.05.

RESULTS

Median follow-up was 40 months. Local control was 100% and distant metastasis free survival was 91.1%. HT sessions (median): reference temperature 42.2 °C, therapeutic time (TT) 61.4 min, total thermal dose 42 min and a gap between HT and BT 30 min. Radiodermatitis grades I and II occurred in 24 and 6 patients, respectively, differences between groups I and II were not significant. Skin oedema and erythema occurred in 48 (85.7%) and 36 (64.3%) cases, respectively, and were equally distributed between the groups. The incidence and duration of skin oedema differed between the subgroups treated with different fractionation protocols of WBI, p = 0.006. Skin oedema was present up to 12 months. No difference in pattern of oedema regression between groups I and II was observed, p = 0.933.

CONCLUSION

Additional thermal boost preceding standard HDR BT boost has a potential of further improvement in breast cancer local control in BCT. Pre-BT hyperthermia did not increase early toxicity in patients treated with BCT and was well tolerated. All side effects of combined treatment were transient and were present for up to 12 months. The increase in incidence of skin oedema was related to hypofractionated protocols of WBI. The study has to be randomized and continued on a larger group of breast cancer patients to verify the potential of local control improvement and to assess the profile of late toxicity.