Normal tissue complication probability of fibrosis in radiotherapy of breast cancer: accelerated partial breast irradiation vs conventional external-beam radiotherapy

Quantifying radiation-induced breast fibrosis by shear-wave elastography in patients with breast cancer: A 12-months-follow-up data of a prospective study

Purpose

To assess radiation-induced fibrosis (RIF) using shear-wave elastography (SWE) in patients with breast cancer who received radiotherapy (RT) after breast conserving surgery.

Methods

Forty-one patients were enrolled in a prospective study before RT. SWE and B-mode ultrasonography were performed to measure elasticity. For quantitative measurement, the maximum elasticity value was measured in the tumor bed and non-tumor bed of the treated breast, and contralateral breast before RT and at 3, and 12 months after RT. and RIF was recorded using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Results

The mean ± standard deviation elasticity values for the tumor bed, non-tumor bed, and contralateral breast were 71.2 ± 74.9 kPa, 19.4 ± 9.8 kPa and 20.3 ± 10.0 kPa before RT; 28.7 ± 26.3 kPa, 15.1 ± 7.0 kPa, and 14.7 ± 6.3 kPa at 12 months after RT, respectively. The elasticity values for all three measurement areas before and 12 months after RT were significantly different (p < 0.001 for tumor bed, p = 0.002 for non-tumor bed, p = 0.001 for contralateral breast). At 12 months follow-up, the distribution of grades of RIF evaluated by CTCAE grade was grade 0 in 43.9 %, grade 1 in 48.8 %, and grade 2 in 7.3 %.

Conclusion

We demonstrated that SWE enables the evaluation of tissue stiffness to provide quantified information for the RIF of breast cancer. Further studies with long-term follow-up should provide more quantitative data.

Contouring variation affects estimates of normal tissue complication probability for breast fibrosis after radiotherapy

BACKGROUND

Normal tissue complication probability (NTCP) models can be useful to estimate the risk of fibrosis after breast-conserving surgery (BCS) and radiotherapy (RT) to the breast. However, they are subject to uncertainties. We present the impact of contouring variation on the prediction of fibrosis.

MATERIALS AND METHODS

280 breast cancer patients treated BCS-RT were included. Nine Clinical Target Volume (CTV) contours were created for each patient: i) CTV_crop (reference), cropped 5 mm from the skin and ii) CTV_skin, uncropped and including the skin, iii) segmenting the 95% isodose (Iso95%) and iv) 3 different auto-contouring atlases generating uncropped and cropped contours (Atlas_skin/Atlas_crop). To illustrate the impact of contour variation on NTCP estimates, we applied two equations predicting fibrosis grade ≥ 2 at 5 years, based on Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) models, respectively, to each contour. Differences were evaluated using repeated-measures ANOVA. For completeness, the association between observed fibrosis events and NTCP estimates was also evaluated using logistic regression.

RESULTS

There were minimal differences between contours when the same contouring approach was followed (cropped and uncropped). CTV_skin and Atlas_skin contours had lower NTCP estimates (-3.92%, IQR 4.00, p < 0.05) compared to CTV_crop. No significant difference was observed for Atlas_crop and Iso95% contours compared to CTV_crop. For the whole cohort, NTCP estimates varied between 5.3% and 49.5% (LKB) or 2.2% and 49.6% (RS) depending on the choice of contours. NTCP estimates for individual patients varied by up to a factor of 4. Estimates from "skin" contours showed higher agreement with observed events.

CONCLUSION

Contour variations can lead to significantly different NTCP estimates for breast fibrosis, highlighting the importance of standardising breast contours before developing and/or applying NTCP models.

One-step intraoperative radiotherapy optimizes conservative treatment of breast cancer with advantages in quality of life and work resumption

BACKGROUND

Intraoperative radiotherapy (IORT) could be not-inferior to external beam radiotherapy (EBRT) in selected patients, but toxicities, self-perception of body image, quality of life, and resumption of work or daily activities have been poorly explored. The aim of the present study was to compare these outcomes between EBRT, IORT full-dose (IORT-f) and IORT boost (IORT-b).

METHODS

443 consecutive patients, candidates for breast-conserving surgery, were included: EBRT was performed in 220 patients (49.7%), IORT-f in 140 patients (31.6%), and IORT-b in 83 patients (18.7%). Radiotherapy-related toxicities were registered. Patients were evaluated at 6 months for Body Image after Breast Cancer Questionnaire (BIBCQ) to assess possible changes in self-perception of body image and limitations. A second questionnaire explored the impact of EBRT, IORT-f and IORT-b on resumption of work and normal daily activities.

RESULTS

EBRT had a higher risk of breast fibrosis and retraction (OR 3.58, 95% CI 1.024-12.526, p = 0.046) and breast edema (OR 6, 95% CI 2.077-17.335, p = 0.001) compared to IORT-f, but a lower risk of seroma compared to IORT-b (OR 0.36, 95% CI 0.166-0.785, p = 0.01). The BIBCQ scores showed a better outcome in arm concerns with IORT-f (-3.3) vs. IORT-b (-1.3, p = 0.002) and EBRT (-1.7, p = 0.006), although biased by the lower rate in axillary dissections. Return to daily activities occurred after 70.6 days with EBRT vs. 41 days with IORT-f (p < 0.0001) and 53.3 days with IORT-b (p = 0.07), without any effect of age or axillary dissection.

CONCLUSION

IORT could reduce adverse effects, allowing faster resumption of job and houseworks.

Partial breast irradiation with CyberKnife after breast conserving surgery: a pilot study in early breast cancer

BACKGROUND

Local recurrences after breast conserving treatment are mainly close to the original tumor site, and as such shorter fractionation strategies focused on and nearest mammary gland, i.e. accelerated partial breast irradiation (APBI), have been developed. Stereotactic APBI has been attempted, although there is little experience using CyberKnife (CK) for early breast cancer.

METHODS

This pilot study was designed to assess the feasibility of CK-APBI on 20 evaluable patients of 29 eligible, followed for 2 years. The primary endpoint was acute/sub-acute toxicity; secondary endpoints were late toxicity and the cosmetic result.

RESULTS

Mean pathological tumor size was 10.5 mm (±4.3, range 3-18), 8 of these patients were classified as LumA-like, 11 as LumB-like, and 1 as LumB-HER2-enriched. Using CK-APBI with Iris, the treatment time was approximately 60 min (range~ 35 to ~ 120). All patients received 30 Gy in five fractions delivered to the PTV. The median number of beams was 180 (IQR 107-213; range:56-325) with a median PTV isodose prescription of 86.0% (IQR 85.0-88.5; range:82-94). The median PTV was 88.1 cm3 (IQR 63.8-108.6; range:32.3-238.8). The median breast V100 and V50 was 0.6 (IQR 0.1-1.5; range:0-13) and 18.6 (IQR 13.1-21.7; range:7.5-37), respectively. The median PTV minimum dose was 26.2 Gy (IQR 24.7-27.6; range 22.3-29.3). Mild side effects were recorded during the period of observation. Cosmetic evaluations were performed by three observers from the start of radiotherapy up to 2 years. Patients' evaluation progressively increase from 60% to 85% of excellent rating; this trend was similar to that of external observer.

CONCLUSIONS

These preliminary results showed the safe feasibility of CK-APBI in early breast cancer, with mild acute and late toxicity and very good cosmetic results.

TRIAL REGISTRATION

The present study is registered at Clinicaltrial.gov ( NCT02896322 ). Retrospectively egistered August 4, 2016.

Preclinical evaluation of cisplatin-incorporated bio-nanocapsules as chemo-radiotherapy for human hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) has continued to increase worldwide, and advanced HCC is difficult to treat using the currently available therapeutics. Chemoradiotherapy with cisplatin (cis-diamminedichloroplatinum, CDDP) is expected to confer a curative benefit on HCC patients; however, its application is limited due to side-effects such as acute nephrotoxicity as well as the conventionally limited application of chemoradiotherapy for HCC. For the practical application of this drug in the clinical setting, we formulated a novel drug carrier-comprising bio-nanocapsule (BNC) and liposomal CDDP (BNC-LP-CDDP) that recognizes the human liver and releases CDDP. BNC-LP-CDDP showed selectively high cytotoxicity for HCC cells, and markedly reduced the survival fractions of HCC when combined with ionizing radiation (IR) treatment in in vitro assays. In particular, the treatment of mice bearing human HCC with BNC-LP-CDDP and 3 Gy IR showed 95.68% growth inhibition, whereas IR treatment alone showed 65.6% growth inhibition. Moreover, BNC-LP-CDDP led to the withdrawal of CDDP-induced nephrotoxicity. These results indicate that BNC-LP-CDDP in combination with IR markedly enhanced the chemo-radiotherapeutic efficacy and eliminated CDDP induced nephrotoxicity, thus, suggesting the potential for its clinical application as human HCC therapy.

Supervised physical therapy in women treated with radiotherapy for breast cancer

OBJECTIVE

to evaluate the effect of physical therapy on the range of motion of the shoulders and perimetry of the upper limbs in women treated with radiotherapy for breast cancer.

METHODS

a total of 35 participants were randomized into two groups, with 18 in the control group (CG) and 17 in the study group (SG). Both of the groups underwent three evaluations to assess the range of motion of the shoulders and perimetry of the upper limbs, and the study group underwent supervised physical therapy for the upper limbs.

RESULTS

the CG had deficits in external rotation in evaluations 1, 2, and 3, whereas the SG had deficits in flexion, abduction, and external rotation in evaluation 1. The deficit in abduction was recovered in evaluation 2, whereas the deficits in all movements were recovered in evaluation 3. No significant differences in perimetry were observed between the groups.

CONCLUSION

the applied supervised physical therapy was effective in recovering the deficit in abduction after radiotherapy, and the deficits in flexion and external rotation were recovered within two months after the end of radiotherapy. Registration number of the clinical trial: NCT02198118.

OBJETIVO

avaliar o efeito da fisioterapia na amplitude de movimento do ombro e na perimetria do membro superior, aplicada durante o período da radioterapia nas mulheres em tratamento para o câncer de mama.

MÉTODOS

35 voluntárias foram randomizadas em dois grupos, 18 para o grupo controle e 17 para o grupo de estudo. Os dois grupos foram submetidos a três avaliações da amplitude de movimento do ombro e perimetria do membro superior, sendo o grupo de estudo também submetido à fisioterapia supervisionada para os membros superiores.

RESULTADOS

o grupo controle apresentou déficit entre os membros para o movimento de rotação externa nas avaliações 1, 2 e 3. O grupo de estudo apresentou déficit entre os membros para os movimentos de flexão, abdução e rotação externa na avaliação 1. Houve recuperação do déficit de movimento de abdução na avaliação 2 e, na avaliação 3, os déficits de todos os movimentos estavam recuperados. Na análise da perimetria não foi observada diferença significativa.

CONCLUSÃO

o protocolo fisioterapêutico supervisionado aplicado foi efetivo na recuperação do déficit de abdução pós-radioterapia e de flexão e rotação externa quando avaliados até 2 meses após o término da radioterapia. Número do registro do ensaio clínico: NCT02198118.

OBJETIVO

evaluar el efecto de la terapia física en el rango de movimiento de los hombros y la perimetría de las extremidades superiores en mujeres tratadas con radioterapia debido a cáncer de mama.

MÉTODOS

un total de 35 participantes fueron aleatorizadas en dos grupos, 18 en el grupo control y 17 en el grupo de estudio. Ambos grupos fueron sometidos a tres evaluaciones para evaluar el rango de movimiento de los hombros y la perimetría de las extremidades superiores, y el grupo de estudio fue sometido a terapia física supervisada de las extremidades superiores.

RESULTADOS

el grupo de control tuvo déficits en la rotación externa en la evaluación 1, 2, y 3, mientras que el grupo de estudio tuvo déficits en la flexión, abducción y rotación externa en la evaluación 1. El déficit en la abducción fue recuperado en la evaluación 2, mientras que los déficits en todos los movimientos fueron recuperados en la evaluación 3. No se observaron diferencias significativas en la perimetría.

CONCLUSIÓN

la terapia física supervisada aplicada fue efectiva en la recuperación del déficit en la abducción después de la radioterapia y los déficits en flexión y rotación externa fueron recuperados dos meses después de terminada la radioterapia. Número de registro del ensayo clínico: NCT02198118.

Hypofractionation of partial breast irradiation using radiobiological models

PURPOSE

To reduce the fraction number in Partial Breast Irradiation (PBI) with initial prescription of 40 Gy in 10 fractions using radiobiological models with specific focus on risk of moderate/severe radiation-induced fibrosis (RIF) and report clinical results.

METHODS AND MATERIALS

68 patients (patient group A) were treated with 40 Gy in 10 fractions delivered by field-in-field, forward-planned IMRT. Isotoxic regimens with decreasing number of fractions were calculated using Biological Effective Dose (BED) to the breast. Risk for RIF in hypofractionated treatment was predicted by calculating NTCP from DVHs of group A rescaled to fractions and dose of novel regimens. Moderate/severe RIF was prospectively scored during follow-up. Various NTCP models, with and without incomplete repair correction, were assessed from difference to observed incidence of RIF. In order to verify the value for α/β of 3 Gy assumed for breast, we fitted α/β to observed incidences of moderate/severe RIF.

RESULTS

Treatments with 35 Gy/7f and 28 Gy/4f were selected for the fraction reduction protocol. 75 patients (group B) were treated in 35 Gy/7f. Incidence of moderate/severe RIF was 5.9% in group A, 5.3% in group B. The NTCP model with correction for incomplete repair had lowest difference from observed RIF. The α/β obtained from fitting was 2.8 (95%CIs 1.1-10.7) Gy.

CONCLUSIONS

The hypofractionated regimen was well tolerated. The model for NTCP corrected for incomplete repair was the most accurate and an assumed α/β value of 3 Gy is consistent with our patient data. The hypofractionation protocol is continuing with patients treated with 28 Gy/4f.

The photon dose calculation algorithm used in breast radiotherapy has significant impact on the parameters of radiobiological models

The comparison of the pencil beam dose calculation algorithm with modified Batho heterogeneity correction (PBC-MB) and the analytical anisotropic algorithm (AAA) and the mutual comparison of advanced dose calculation algorithms used in breast radiotherapy have focused on the differences between the physical dose distributions. Studies on the radiobiological impact of the algorithm (both on the tumor control and the moderate breast fibrosis prediction) are lacking. We, therefore, investigated the radiobiological impact of the dose calculation algorithm in whole breast radiotherapy. The clinical dose distributions of 30 breast cancer patients, calculated with PBC-MB, were recalculated with fixed monitor units using more advanced algorithms: AAA and Acuros XB. For the latter, both dose reporting modes were used (i.e., dose-to-medium and dose-to-water). Next, the tumor control probability (TCP) and the normal tissue complication probability (NTCP) of each dose distribution were calculated with the Poisson model and with the relative seriality model, respectively. The endpoint for the NTCP calculation was moderate breast fibrosis five years post treatment. The differences were checked for significance with the paired t-test. The more advanced algorithms predicted a significantly lower TCP and NTCP of moderate breast fibrosis then found during the corresponding clinical follow-up study based on PBC calculations. The differences varied between 1% and 2.1% for the TCP and between 2.9% and 5.5% for the NTCP of moderate breast fibrosis. The significant differences were eliminated by determination of algorithm-specific model parameters using least square fitting. Application of the new parameters on a second group of 30 breast cancer patients proved their appropriateness. In this study, we assessed the impact of the dose calculation algorithms used in whole breast radiotherapy on the parameters of the radiobiological models. The radiobiological impact was eliminated by determination of algorithm specific model parameters.

Dosimetric and geometric evaluation of a novel stereotactic radiotherapy device for breast cancer: the GammaPod™

PURPOSE

A dedicated stereotactic gamma irradiation device, the GammaPod™ from Xcision Medical Systems, was developed specifically to treat small breast cancers. This study presents the first evaluation of dosimetric and geometric characteristics from the initial prototype installed at University of Maryland Radiation Oncology Department.

METHODS

The GammaPod™ stereotactic radiotherapy device is an assembly of a hemi-spherical source carrier containing 36 (60)Co sources, a tungsten collimator, a dynamically controlled patient support table, and the breast immobilization system which also functions as a stereotactic frame. The source carrier contains the sources in six columns spaced longitudinally at 60° intervals and it rotates together with the variable-size collimator to form 36 noncoplanar, concentric arcs focused at the isocenter. The patient support table enables motion in three dimensions to position the patient tumor at the focal point of the irradiation. The table moves continuously in three cardinal dimensions during treatment to provide dynamic shaping of the dose distribution. The breast is immobilized using a breast cup applying a small negative pressure, where the immobilization cup is embedded with fiducials also functioning as the stereotactic frame for the breast. Geometric and dosimetric evaluations of the system as well as a protocol for absorbed dose calibration are provided. Dosimetric verifications of dynamically delivered patient plans are performed for seven patients using radiochromic films in hypothetical preop, postop, and target-in-target treatment scenarios.

RESULTS

Loaded with 36 (60)Co sources with cumulative activity of 4320 Ci, the prototype GammaPod™ unit delivers 5.31 Gy/min at the isocenter using the largest 2.5 cm diameter collimator. Due to the noncoplanar beam arrangement and dynamic dose shaping features, the GammaPod™ device is found to deliver uniform doses to targets with good conformity. The spatial accuracy of the device to locate the radiation isocenter is determined to be less than 1 mm. Single shot profiles with 2.5 cm collimator are measured with radiochromic film and found to be in good agreement with respect to the Monte Carlo based calculations (congruence of FWHM less than 1 mm). Dosimetric verifications corresponding to all hypothetical treatment plans corresponding to three target scenarios for each of the seven patients demonstrated good agreement with gamma index pass rates of better than 97% (99.0% ± 0.7%).

CONCLUSIONS

Dosimetric evaluation of the first GammaPod™ stereotactic breast radiotherapy unit was performed and the dosimetric and spatial accuracy of this novel technology is found to be feasible with respect to clinical radiotherapy standards. The observed level of agreement between the treatment planning system calculations and dosimetric measurements has confirmed that the system can deliver highly complex treatment plans with remarkable geometric and dosimetric accuracy.

Initial efficacy results of RTOG 0319: three-dimensional conformal radiation therapy (3D-CRT) confined to the region of the lumpectomy cavity for stage I/ II breast carcinoma

PURPOSE

This prospective study (Radiation Therapy Oncology Group 0319) examines the use of three-dimensional conformal external beam radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Initial data on efficacy and toxicity are presented.

METHODS AND MATERIALS

Patients with Stage I or II breast cancer with lesions < or =3 cm, negative margins and with < or =3 positive nodes were eligible. The 3D-CRT was 38.5 Gy in 3.85 Gy/fraction delivered 2x/day. Ipsilateral breast, ipsilateral nodal, contralateral breast, and distant failure (IBF, INF, CBF, DF) were estimated using the cumulative incidence method. Mastectomy-free, disease-free, and overall survival (MFS, DFS, OS) were recorded. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3, was used to grade acute and late toxicity.

RESULTS

Fifty-eight patients were entered and 52 patients are eligible and evaluable for efficacy. The median age of patients was 61 years with the following characteristics: 46% tumor size <1 cm; 87% invasive ductal histology; 94% American Joint Committee on Cancer Stage I; 65% postmenopausal; 83% no chemotherapy; and 71% with no hormone therapy. Median follow-up is 4.5 years (1.7-4.8). Four-year estimates (95% CI) of efficacy are: IBF 6% (0-12%) [4% within field (0-9%)]; INF 2% (0-6%); CBF 0%; DF 8% (0-15%); MFS 90% (78-96%); DFS 84% (71-92%); and OS 96% (85-99%). Only two (4%) Grade 3 toxicities were observed.

CONCLUSIONS

Initial efficacy and toxicity using 3D-CRT to deliver APBI appears comparable to other experiences with similar follow-up. However, additional patients, further follow-up, and mature Phase III data are needed to evaluate the extent of application, limitations, and value of this particular form of APBI.

Four-year efficacy, cosmesis, and toxicity using three-dimensional conformal external beam radiation therapy to deliver accelerated partial breast irradiation

PURPOSE

This prospective study examines the use of three-dimensional conformal external beam radiation therapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Four-year data on efficacy, cosmesis, and toxicity are presented.

METHODS

Patients with Stage O, I, or II breast cancer with lesions </=3 cm, negative margins, and negative nodes were eligible. The 3D-CRT delivered was 38.5 Gy in 3.85 Gy/fraction. Ipsilateral breast, ipsilateral nodal, contralateral breast, and distant failure (IBF, INF, CBF, DF) were estimated using the cumulative incidence method. Disease-free, overall, and cancer-specific survival (DFS, OS, CSS) were recorded. The National Cancer Institute Common Terminology Criteria for Adverse Events (version 3) toxicity scale was used to grade acute and late toxicities.

RESULTS

Ninety-four patients are evaluable for efficacy. Median patient age was 62 years with the following characteristics: 68% tumor size <1 cm, 72% invasive ductal histology, 77% estrogen receptor (ER) (+), 88% postmenopausal; 88% no chemotherapy and 44% with no hormone therapy. Median follow-up was 4.2 years (range, 1.3-8.3). Four-year estimates of efficacy were IBF: 1.1% (one local recurrence); INF: 0%; CBF: 1.1%; DF: 3.9%; DFS: 95%; OS: 97%; and CSS: 99%. Four (4%) Grade 3 toxicities (one transient breast pain and three fibrosis) were observed. Cosmesis was rated good/excellent in 89% of patients at 4 years.

CONCLUSIONS

Four-year efficacy, cosmesis, and toxicity using 3D-CRT to deliver APBI appear comparable to other experiences with similar follow-up. However, additional patients, further follow-up, and mature Phase III data are needed to evaluate thoroughly the extent of application, limitations, and complete value of this particular form of APBI.