Is postmastectomy radiotherapy necessary for breast cancer patients with clinically node-positive downstaging to ypN0 after neoadjuvant chemotherapy?

PURPOSE

The significance of postmastectomy radiotherapy (PMRT) in breast cancer patients who initially have clinically node-positive (cN +) status but achieve downstaging to ypN0 following neoadjuvant chemotherapy (NAC) remains uncertain. This study aims to assess the impact of PMRT in this patient subset.

METHODS

Patients were enrolled from West China Hospital, Sichuan University from 2008 to 2019. Overall survival (OS), Locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and breast cancer-specific survival (BCSS) were estimated using the Kaplan-Meier method and assessed with the log-rank test. The impact of PMRT was further analyzed by the Cox proportional hazards model. Propensity score matching (PSM) was performed to reduce the selection bias.

RESULTS

Of the 333 eligible patients, 189 (56.8%) received PMRT, and 144 (43.2%) did not. At a median follow-up period of 71 months, the five-year LRFS, DMFS, BCSS, and OS rates were 99.1%, 93.4%, 96.4%, and 94.3% for the entire cohort, respectively. Additionally, the 5-year LRFS, DMFS, BCSS, and OS rates were 98.9%, 93.8%, 96.7%, and 94.5% with PMRT and 99.2%, 91.3%, 94.9%, and 92.0% without PMRT, respectively (all p-values not statistically significant). After multivariate analysis, PMRT was not a significant risk factor for any of the endpoints. When further stratified by stage, PMRT did not show any survival benefit for patients with stage II-III diseases.

CONCLUSION

In the context of comprehensive treatments, PMRT might be exempted in ypN0 breast cancer patients. Further large-scale, randomized controlled studies are required to investigate the significance of PMRT in this patient subset.

The trade-off of post-mastectomy radiotherapy usage for the breast cancer patients aged 70 years or older: a study based on SEER database

BACKGROUND

This study aimed to investigate the role of post-mastectomy radiotherapy (PMRT) in the female aged 70 years or older diagnosed with breast cancer, which is still controversial.

METHODS

This retrospective study enrolled female breast cancer women aged 70 + years following mastectomy from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was performed to reduce covariable imbalance. A nomogram was created to predict the 1,3,5-years overall survival (OS) and divide patients into three risk groups.

RESULTS

After matching, PMRT were associated with significant improvement in breast cancer-specific survival (BCSS) and OS (p < 0.001). By contrast, the BCSS and OS benefit from PMRT were not significant in patients with T1N1 tumor (BCSS: HR = 0.716, p = 0.249;OS:HR = 0.908, p = 0.572), and T2N1 tumor (BCSS:HR = 0.866, p = 0.289;OS:HR = 0.879, p = 0.166). Stratified by subtype, the HR+/HER-2- subtype and the HR-/HER-2- subtype (all p < 0.001) have a significant prolonged survival, yet not significant BCSS difference are shown in the HER-2 + tumor. In the low-risk group as determined by the nomogram, the use of PMRT did not significantly improve OS (p = 0.203).

CONCLUSIONS

This study demonstrated that PMRT improves the survival of females with elderly breast cancer, while for T1-2N1 breast cancer patients, the omission of PMRT could be considered. Furthermore, the nomogram we constructed could be used as a decision tool for the omission of PMRT in low-risk elderly patients.

Postmastectomy radiotherapy in patients with T1-2N1 breast cancer: a single center experience and a meta-analysis

PURPOSE

Postmastectomy radiotherapy (PMRT) in patients with T1-2N1 breast cancer is still controversial. This study was to evaluate the survival prognosis of T1-2N1 patients with or without PMRT.

PATIENTS AND METHODS

From January 2006 to May 2017, 2606 female breast cancer patients underwent mastectomy in our medical center, among whom 402 patients of T1-2N1 stage with or without PMRT were finally analyzed. The median follow-up duration was 59.5 months. The primary endpoint was overall survival (OS). The secondary endpoint was disease-free survival (DFS).

RESULTS

In the study of our center, no statistically significant difference was observed between the T1-2N1 PMRT and non-PMRT subgroups for the 5-year OS (94.4% vs 95.4%, p = 0.667) and DFS (90.1% vs. 91.1%, p = 0.798). By the date of the last follow-up, 8.96% (n = 36) of the patients experienced any recurrence. Univariate analysis revealed that PMRT was not a prognostic factor for either OS (p = 0.667) or DFS (p = 0.798) in T1-2N1 patients. We then did a meta-analysis on the current treatment patterns, in which 2606 PMRT and 4281 non-PMRT T1-2N1 breast cancer patients with mastectomy were included. The meta-analysis showed that PMRT didn't improve the OS of the patients (HR = 0.85, p = 0.11), but patients with PMRT had better DFS than those in the non-PMRT group (HR = 0.62, p < 0.001).

CONCLUSION

PMRT did not affect the survival of T1-2N1 breast cancer patients who underwent mastectomy, suggesting that radiotherapy may be safely omitted for them.

Optimal fractionation and timing of weekly cone-beam CT in daily surface-guided radiotherapy for breast cancer

PURPOSE

Surface-guided radiotherapy (SGRT) has been demonstrated to be a promising supplement to cone-beam computed tomography (CBCT) in adjuvant breast cancer radiotherapy, but a rational combination mode is lacking in clinical practice. The aim of this study was to explore this mode and investigate its impact on the setup and dose accuracy.

METHODS AND MATERIALS

Daily SGRT and weekly CBCT images were acquired for 23 patients with breast cancer who received conventional fractionated radiotherapy after lumpectomy. Sixteen modes were acquired by randomly selecting one (CBCT₁), two (CBCT_ij), three (CBCT_ijk), four (CBCT_ijkl), and five (CBCT₁₂₃₄₅) images from the CBCT images for fusion with the SGRT. The CTV-PTV margins, OAR doses, and dose coverage (V95%) of PTV and CTV was calculated based on SGRT setup errors with different regions of interest (ROIs). Dose correlations between these modalities were investigated using Pearson and Spearman's methods. Patient-specific parameters were recorded to assess their impact on dose.

RESULTS

The CTV-PTV margins decreased with increasing CBCT frequencies and were close to 5 mm for CBCT_ijkl and CBCT₁₂₃₄₅. For the ipsilateral breast ROI, SGRT errors were larger in the AP direction, and target doses were higher in all modes than in the whole breast ROI (P < 0.05). In the ipsilateral ROI, the target dose correlations between all modes increased with increasing CBCT time intervals, decreased, and then increased with increasing CBCT frequencies, with the inflection point being CBCT participation at week 5. The dose deviations in CBCT₁₂₃, CBCT₁₂₄, CBCT₁₂₅, CBCT_ijkl, and CBCT₁₂₃₄₅ were minimal and did not differ significantly (P > 0.05). There was excellent agreement between CBCT₁₂₄ and CBCT₁₂₃₄, and between (CBCT_ijkl, CBCT₁₂₃₄₅) and CBCT₁₂₅ in determining the classification for the percentage of PTV deviation (Kappa = 0.704-0.901). In addition, there were weak correlations between the patient's D_{ips_b} (ipsilateral breast diameter with bolus) and CTV doses in modes with CBCT participation at week 4 (R = 0.270 to 0.480).

CONCLUSIONS

Based on weekly CBCT, these modes with ipsilateral ROI and a combination of daily SGRT and a CBCT frequency of ≥ 3 were recommended, and CBCT was required at weeks 1 and 2 for CBCT_ijk.

Application of thermoplastic elastomer (TPE) bolus in postmastectomy radiotherapy

PURPOSE

To assess the planned dose, in vivo dosimetry, acute skin toxicity, pain, and distress using Thermoplastic Elastomer (TPE) bolus for postmastectomy radiotherapy (PMRT).

MATERIAL AND METHODS

Thirty-two PMRT patients with TPE bolus (17 patients for 25 fractions, 15 patients for the first 20 fractions) were selected for the study. The acute skin toxicity, pain, and psychological distress were assessed from the first treatment week to the fourth week after the end of treatment. At the first treatment, the MOSFET was used in vivo dosimetry measurement.

RESULTS

In vivo dosimetry with the bolus, the dose deviation ranged from -6.22% to -1.56% for 5 points. The presence of grade 1 and 2 skin toxicity reached its peak (70.0% and 13.3%) in the sixth week. Two patients (6.6%) with 25 fractions bolus experienced moist desquamation in the fifth and seventh week, with pain score 2 and 3, and interruptions of 3 and 5 days, respectively. The incidence of pain score 1, 2, and 3 peaked in the fifth (33.3%), fourth (33.3%), and seventh (10.0%) week. No patients experienced grade 3 skin toxicity and severe pain. One patient had significant anxiety, and two patients had significant depression.

CONCLUSION

The TPE bolus can accurately fit skin and improve the surface dose to more than 90%. Twenty fractions with TPE bolus had similar skin toxicity and pain to those without bolus and did not increase patients' distress and clinical workload, compared with the literature's data, which is an alternative to the 3D printing bolus for PMRT.

The therapeutic effect of adipose-derived stem cells on soft tissue injury after radiotherapy and their value for breast reconstruction

Background

Postmastectomy radiotherapy is considered to be a necessary treatment in the therapy of breast cancer, while it will cause soft tissue damage and complications, which are closely related to the success rate and effectiveness of breast reconstruction. After radiotherapy, cutaneous tissue becomes thin and brittle, and its compliance decreases. Component fat grafting and adipose-derived stem cell therapy are considered to have great potential in treating radiation damage and improving skin compliance after radiotherapy.

Main body

In this paper, the basic types and pathological mechanisms of skin and soft tissue damage to breast skin caused by radiation therapy are described. The 2015–2021 studies related to stem cell therapy in PubMed were also reviewed. Studies suggest that adipose-derived stem cells exert their biological effects mainly through cargoes carried in extracellular vesicles and soluble secreted factors. Compared to traditional fat graft breast reconstruction, ADSC therapy amplifies the effects of stem cells in it. In order to obtain a more purposeful therapeutic effect, proper stem cell pretreatment may achieve more ideal and safe results.

Conclusion

Recent research works about ADSCs and other MSCs mainly focus on curative effects in the acute phase of radiation injury, and there is little research about treatment of chronic phase complications. The efficacy of stem cell therapy on alleviating skin fibrosis and its underlying mechanism require further research.

Optimal timing of postmastectomy radiotherapy in two-stage prosthetic breast reconstruction: An updated meta-analysis

BACKGROUND

There is no consensus on the timing of postmastectomy radiotherapy (PMRT) in relation to the exchange procedure in breast cancer patients undergoing the immediate two-stage prosthetic breast reconstruction. This meta-analysis investigated the reconstruction failure, complications, and cosmesis between PMRT to the tissue expander (TE) and PMRT to the permanent implant (PI).

METHODS

A literature search was conducted in PubMed and Embase databases until February 2022. Studies presenting at least one aspect relating to reconstruction failure, complications, and cosmesis between two cohorts were included. Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias in included studies.

RESULTS

Eleven studies presenting 1447 patients were enrolled. Three studies were prospective controlled research. The risk for implant loss was higher in PMRT to TE cohort (RR 1.75; 95% CI, 1.03 to 2.98; p = 0.04); meanwhile, the PMRT to TE cohort had a significantly lower risk of capsular contracture (RR 0.47; 95% CI, 0.29 to 0.78; p = 0.003). However, the synthesized result should be interpreted sensibly due to heterogeneity in statistical methods and definitions.

CONCLUSION

Delivering PMRT to PI may reduce the risk of implant loss, while delivering PMRT to TE can reduce the risk of severe capsular contracture. More high-quality studies are warranted for the refinement of clinical practice.

A 30-year long-term report from the Danish breast cancer cooperative group DBCG 82bc trial

BACKGROUND

Between 1982 and 1990 the Danish Breast Cancer Cooperative Group (DBCG) conducted a randomized trial in high-risk pre- and postmenopausal (<70 years) breast cancer patients comparing mastectomy plus adjuvant systemic therapy alone versus the same treatment plus postoperative irradiation.

AIM

To present a comprehensive analysis of the complete DBCG 82bc study with a 30-year long-term follow-up of the cancer therapeutic effect and survival, together with an additional focus on the potential long-term life-threatening morbidity related to cardiac irradiation and/or the risk of secondary cancer induction.

METHODS

A total of 3083 patients with pathological stage II and stage III breast cancer were after mastectomy randomly assigned to receive adjuvant systemic therapy and postoperative irradiation to the chestwall and regional lymph nodes (1538 pts), or adjuvant systemic therapy alone (1545 pts). Pre- and menopausal patients (DBCG 82b) received 8-9 cycles of CMF with an interval of 4 weeks, whereas postmenopausal patients (DBCG 82c) received tamoxifen 30 mg daily for one year. The median follow-up time was 34 years. The primary endpoints were loco-regional recurrence (LRR) and overall mortality, and the secondary endpoints were distant metastasis, breast cancer mortality, and irradiation related late morbidity.

RESULTS

Overall the 30-year cumulative incidence of loco-regional recurrence was 9% in irradiated patients versus 37% in non-irradiated patients who received adjuvant systemic therapy alone (HR: 0.21 [95% cfl 0.18-0.26]). Distant metastasis probability at 30 years was 49% in irradiated patients compared to 60% in non-irradiated (HR: 0.77 [0.70-0.84]). Consequently, these figures resulted in a reduced breast cancer mortality: 56% vs 67% (HR: 0.75 [0.69-0.82], and overall mortality (81% vs 86% at 30 years (p < 0.0001), HR: 0.83 [0.77-0.90] in favor of irradiation. Radiotherapy did not result in any significant excess death of other courses, such as ischemic heart disease, HR: 0.82 [0.58-1.18]; nor secondary lung cancer HR: 1.44 [0.92-2.24], or other non-cancer related death HR: 1.15 [0.92-1.45].

CONCLUSION

The study definitely demonstrate that optimal long-term treatment benefit of high-risk breast cancer can only be achieved if both loco-regional and systemic tumor control are aimed for. Therefore, radiotherapy has an important role in the multidisciplinary treatment of breast cancer. The PMRT treatment did not result in excess ischemic heart damage, nor in other non-breast cancer related death.

Effects of postmastectomy radiotherapy on survival in different age groups for patients with T3N0M0 breast cancer

BACKGROUND

Postmastectomy radiotherapy (PMRT), as an important regional treatment, improves the survival rate of patients with T3N0M0 breast cancers. However, the therapeutic effect of PMRT on T3N0M0 patients in different age groups is unclear.

METHODS

Using Surveillance, Epidemiology, and End Results database, we identified 4840 T3N0M0 patients between 2000 and 2015. The primary and secondary outcomes were overall survival (OS) and breast cancer-specific survival (BCSS). Survival outcomes were compared using Kaplan-Meier survival test, COX regression analysis, propensity score matching and forest plot, which present the relationship between age and PMRT.

RESULTS

Survival analysis demonstrated that for young patients (aged 18-45 and 46-55), there was no significant difference in OS between with and without PMRT. However, for patients older than 65 years, PMRT could significantly improve survival time (P < 0.001). Multivariate Cox analysis of OS showed older patients with PMRT had a lower hazard ratio (HR) than those without PMRT (aged 56-65: HR = 0.67, P = 0.014; aged >65: HR = 0.60, P < 0.001), and little benefit for young patients. The consistent results were also observed in 1:1 matched cohort. Subgroup analysis revealed the survival HRs of with versus without PMRT for patients older than 65 years were significant in most subgroups.

CONCLUSION

The effect of PMRT in T3N0M0 patients is related to the age. PMRT is associated with improved survival in older patients with T3N0M0 breast cancer, especially those older than 65 years. While the benefit of PMRT is limited in T3N0M0 patients of young age. The observation suggests the importance of age for T3N0M0 patients when individualized treatment is made.

POstmastectomy radioThErapy in Node-posiTive breast cancer with or without Internal mAmmary nodaL irradiation (POTENTIAL): a study protocol for a multicenter prospective phase III randomized controlled trial

BACKGROUND

Various randomized trials have demonstrated that postmastectomy radiotherapy (RT) to the chest wall and comprehensive regional nodal areas improves survival in patients with axillary node-positive breast cancer. Controversy exists as to whether the internal mammary node (IMN) region is an essential component of regional nodal irradiation. Available data on the survival benefit of IMN irradiation (IMNI) are conflicting. The patient populations enrolled in previous studies were heterogeneous and most studies were conducted before modern systemic treatment and three-dimensional (3D) radiotherapy (RT) techniques were introduced. This study aims to assess the efficacy and safety of IMNI in the context of modern systemic treatment and computed tomography (CT)-based RT planning techniques.

METHODS

POTENTIAL is a prospective, multicenter, open-label, parallel, phase III, randomized controlled trial investigating whether IMNI improves disease-free survival (DFS) in high-risk breast cancer with positive axillary nodes (pN+) after mastectomy. A total of 1800 patients will be randomly assigned in a 1:1 ratio to receive IMNI or not. All patients are required to receive ≥ six cycles of anthracycline and/or taxane-based chemotherapy. Randomization will be stratified by institution, tumor location (medial/central vs. other quadrants), the number of positive axillary nodes (1-3 vs. 4-9 vs. ≥10), and neoadjuvant chemotherapy (yes vs. no). Treatment will be delivered with CT-based 3D RT techniques, including 3D conformal RT, intensity-modulated RT, or volumetric modulated arc therapy. The prescribed dose is 50 Gy in 25 fractions or 43.5 Gy in 15 fractions. Tiered RT quality assurance is required. After RT, patients will be followed up at regular intervals. Oncological and toxilogical outcomes, especially cardiac toxicities, will be assessed.

DISCUSSION

This trial design is intended to overcome the limitations of previous prospective studies by recruiting patients with pN+ breast cancer, using DFS as the primary endpoint, and prospectively assessing cardiac toxicities and requiring RT quality assurance. The results of this study will provide high-level evidence for elective IMNI in patients with breast cancer after mastectomy.

TRIAL REGISTRATION

ClinicalTrails.gov , NCT04320979 . Registered 25 Match 2020, https://clinicaltrials.gov/ct2/show/NCT04320979.

Postmastectomy radiotherapy for all node positive patients: The case against

Postmastectomy radiotherapy (PMRT) is accepted as the standard of care for women with early breast cancer with 4 or more involved axillary nodes. However the role of PMRT in women with 1-3 involved nodes remains controversial and guidelines vary. We present the arguments against advocating postmastectomy radiotherapy for all women with node positive breast cancer.

Chronological Skin Changes Through Postmastectomy Radiotherapy Based on Radiotherapy Techniques: Using Quantitative Dermatological Measurements

BACKGROUND

There has been few research on how to measure skin status quantitatively throughout the course of radiotherapy (RT). We evaluated the changes in the skin induced by 2 different RT techniques using objective measurements in breast cancer patients.

METHODS

In this prospective study, between August 2015 and March 2019, serial measurements of the dermatological factors during and after postmastectomy radiotherapy (PMRT) were made in 40 breast cancer patients. PMRT was performed using the conventional photon tangential technique (PTT) or patient-tailored bolus technique (PTB). We analyzed these measurements using a mixed effect model and compared the clinically evaluated radiation dermatitis and patient-reported outcomes (PROs).

RESULTS

The trend of changes in melanin and erythema was significantly different between the PTB and PTT groups (p = 0.045 and 0.016, respectively). At the 3-month follow-up erythema intensity and melanin were higher in the PTB group than in PTT group (both p < 0.001). Eight patients (40% in the PTB group) reported grade 2 radiation dermatitis and 1 patient (5% in the PTB group) reported grade 3 radiation dermatitis. No grade 2 or higher radiation dermatitis was found in the PTT group. Ten patients (50%) in the PTB group and 3 patients (15%) in the PTT group reported severe erythema likely due to questionable clinical evaluation, but hyperpigmentation was rarely reported at the follow-up visits.

CONCLUSION

The PTB group showed higher intensity of erythema at the end of RT than the PTT group and the increase in melanin lasted until the 3-month follow-up visits in the PTB group. Moreover, patients subjectively appealed more severe symptoms following PTB in PROs.

A prospective feasibility study of a 1-mm bolus for postmastectomy radiotherapy

BACKGROUND

The optimal chest wall bolus regimen for postmastectomy radiotherapy (PMRT) remains unknown. We aimed to prospectively evaluate the use of a 1-mm-thick daily tissue-equivalent bolus in patients who received PMRT using thermoluminescent dosimeters (TLDs) and skin toxicity assessment.

METHODS

Patients with a 1-mm-thick daily bolus during PMRT were prospectively enrolled at The Juntendo University Hospital. The surface dose was measured in vivo under the 1-mm-thick bolus on the chest wall. We assessed the acute skin toxicity weekly during PMRT, and 1, 2, 4, and 12 weeks after the completion of PMRT.

RESULTS

A total of 19 patients aged 32-79 years old received PMRT from July 2019 to January 2020. All patients completed the protocol treatment without interruptions, and the median follow-up was 32 weeks. In vivo dosimetry analysis revealed surface doses between 77 and 113% of the prescribed dose, with a mean of 92% of the prescribed radiation dose, and a standard deviation of 7% being delivered. Grade 2 dermatitis was found in 10 patients (53%), and Grade 3 dermatitis was found in one patient (5%). All cases of Grade 2 and 3 dermatitis were improved 4 weeks after PMRT. There were no cases of Grade 4 dermatitis and no chest wall recurrences during the treatment or follow-up period.

CONCLUSIONS

Results confirmed the feasibility of using a 1-mm-thick daily bolus for PMRT, exhibiting an appropriate dose buildup and acceptable skin toxicity without treatment interruptions.

TRIAL REGISTRATION

The University Hospital Medical Information Network Clinical Trials Registry, UMIN000035773 . Registered 1 July 2019.

Dosimetric assessment of bolus for postmastectomy radiotherapy

There remains wide variation in the use of chest wall boluses for postmastectomy radiotherapy, which may result from the need for 2 treatment plans with the commonly used half-time tissue-equivalent 5-mm-thick bolus to achieve a full surface dose. To establish a bolus method requiring one treatment plan, we assessed the surface dose of a thinner daily bolus for all treatment fractions and compared it against the half-time 5-mm-thick bolus. In this basic study, we specifically investigated dosage achieved when using the following: (1) the existing bolus protocol, a half-time 5-mm-thick tissue-equivalent Clearfit bolus (Fujidenolo Inc., Aichi, JP); (2) no bolus; and (3) daily 1-, 2-, and 3-mm-thick Clearfit boluses at 4 and 6 MV photons. Dosimetric measurements were then taken in an anthropomorphic phantom to study the effect of each regimen on the surface doses, and the mean surface doses of the daily thinner boluses were compared with the existing bolus protocol by the Welch 2-sample t test. The mean surface doses for the existing bolus protocol, no bolus, and daily 1-, 2-, and 3-mm-thick boluses were 68% (range, 59% to 77%), 53% (41% to 66%), 73% (60% to 83%), 77% (66% to 87%), and 82% (75% to 91%) of the prescription dose at 4 MV, respectively; the corresponding values at 6 MV were 71% (63% to 79%), 50% (39% to 60%), 72% (56% to 83%), 81% (68% to 90%), and 89% (80 to 97%) of the prescription dose. The mean surface doses were comparable between the existing bolus protocol and the 1-mm-thick daily bolus at 4 and 6 MV. In conclusion, the mean surface dose of a 1-mm-thick bolus approximate that of a half-time 5-mm-thick bolus at 4 and 6 MV. As such, we have started a prospective clinical study on the safety and efficacy of a 1-mm-thick bolus for postmastectomy radiotherapy.

The survival benefit of postmastectomy radiotherapy for breast cancer patients with T1-2N1 disease according to molecular subtype

OBJECTIVE

To evaluate the significance of postmastectomy radiotherapy (PMRT) in female breast cancer patients with T1-2N1M0 disease according to molecular subtypes and other risk factors.

METHOD

We conducted a retrospective cohort-based study utilizing the Surveillance, Epidemiology, and End Results database. Patients who were diagnosed with T1-2N1M0 invasive breast cancer and received mastectomy between 2010 and 2014 were enrolled in our study. Overall survival (OS) was calculated with Kaplan-Meier method, and multivariant Cox hazard model was conducted to identify the impact of PMRT according to molecular subtypes and other risk factors. Propensity score matching (PSM) was applied to balance measurable confounders.

RESULTS

Of all the 16,521 enrolled patients, 5775 (35.0%) cases received PMRT. The distribution of molecular subtype is 71.4% for Luminal A, 13.2% for Luminal B, 5.1% for HER2 enriched, and 10.3% for TNBC. The OS was significantly better for patients in PMRT group than the Non-PMRT group (P < 0.0001). Stratified by molecular subtype, PMRT significantly prolonged survival in Luminal A patients (HR: 0.759, 95% CI: 0.651-0.884, P < 0.001), Yet it brought no significant survival advantage in Luminal B, TNBC or HER2 enriched subtype (P = 0.914, P = 0.124, P = 0.103, respectively). Also, PMRT bore prognostic significance among those patients who were older than 56 years old, single, white, exempt from reconstruction and chemotherapy, and were with ductal, GradeⅡtumor (all P < 0.05). After PSM, the survival benefit of PRMT sustained in Luminal A patients with T1 tumor concomitant with one positive lymph node.

CONCLUSION

Our study demonstrates a beneficial impact for PMRT on overall survival among Luminal A subtype breast cancer patients with T1-2N1 disease. The selection of PMRT should be stratified by molecular subtype and other risk factors.

Postmastectomy radiation therapy in early breast cancer: Utility or futility?

Postmastectomy radiation therapy (PMRT) has been shown to reduce the risk of locoregional recurrence (LRR), in patients with locally advanced breast cancer who are considered of high-risk because of large tumors (>5 cm) or presence of axillary lymph-node involvement, as well as to reduce breast cancer mortality. However, controversy still remains with respect to indication of PMRT in case of early-stages invasive tumors. This review aims to analyze the impact that PMRT has on final results in women with breast tumors in different scenarios that would otherwise be considered as early breast cancer, such as extensive DCIS, tumors without axillary lymph-node involvement or with minimal microscopic nodal-involvement. The existence of risk factors including young age, premenopausal status, and presence of lymphovascular invasion (LVI), high grade or tumor size >2 cm has been associated with an increased risk of LRR in these patients at early-stages and advises to consider PMRT in selected cases.

Higher reconstruction failure and less patient-reported satisfaction after post mastectomy radiotherapy with immediate implant-based breast reconstruction compared to immediate autologous breast reconstruction

PURPOSE

To improve shared decision making, clinical- and patient-reported outcomes between immediate implant-based and autologous breast reconstruction followed by postmastectomy radiotherapy (PMRT) were compared.

METHODS

All women with in situ and/or invasive breast cancer who underwent skin sparing mastectomy with immediate breast reconstruction (IBR) (autologous- or implant based, one- or two staged) followed by PMRT in the Utrecht region between 2012 and 2016 were selected from the Netherlands Cancer Registry, of which 112 (59%) agreed to participate. The primary outcome was reconstruction failure after the start of radiotherapy, and secondary outcomes were patient-reported outcomes measured with BREAST-Q.

RESULTS

109 patients underwent skin-sparing mastectomy, of which 29 (27%) underwent immediate autologous reconstruction and 80 (73%) received immediate implant-based reconstruction. After PMRT, reconstruction failure occurred in 17 patients (21%) with implant-based reconstruction, while no failure was seen in the autologous group (p = 0.04). Mean patient-reported 'Satisfaction with Breasts' (50.9 vs. 63.7, p = 0.001) and 'Sexual Well-being' (46.0 vs. 55.5, p = 0.037) were lower after implant-based reconstruction compared to autologous reconstruction. Thirteen patients with autologous flaps underwent surgical cosmetic corrections compared to ten patients in the implant group (45 vs. 13%, p = 0.001). IBR and PMRT in this study resulted in a high rate of severe capsular contraction in implant-based reconstruction (16.9%) and fibrosis in autologous reconstruction (13.8%).

CONCLUSIONS

Patients treated with PMRT and one or two stage immediate implant-based reconstruction were at greater risk of developing reconstruction failure and were less satisfied when compared to one or two stage immediate autologous reconstruction. Since fairly high complication rates in both reconstruction methods after PMRT are observed, it raises the question whether immediate breast reconstruction should be considered at all when PMRT is indicated. Patients considering or potential candidates for IBR should be informed about the consequences of PMRT and especially when opting for autologous reconstruction one should possibly perform reconstruction in a secondary setting.

Conventional versus hypofractionated postmastectomy radiotherapy: a report on long-term outcomes and late toxicity

Objective

We evaluated the long-term outcomes and late toxicity of conventional fractionated (CF) and hypofractionated (HF) postmastectomy radiotherapy (PMRT) in terms of locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and late toxicity.

Methods

A cohort of 1640 of breast cancer patients receiving PMRT between January 2004 and December 2014 were enrolled. Nine hundred eighty patients were treated with HF-PMRT: 2.65 Gy/fraction to a total of 42.4–53 Gy and 660 patients were treated with CF-PMRT: 2 Gy/fraction to a total of 50–60 Gy.

Results

The median follow-up time was 71.8 months (range 41.5–115.9 months). No significant difference was found in the rates of 5-year LRRFS, DFS, and OS of HF-PMRT vs CF-PMRT; 96% vs. 94% (p = 0.373), 70% vs. 72% (p = 0.849), and 73% vs. 74% (p = 0.463), respectively. We identified a cohort of 937 eligible breast cancer patients who could receive late toxicities assessment. With a median follow-up time of this patient cohort of 106.3 months (range 76–134 months), there was a significant higher incidence of grade 2 or more late skin (4% vs 1%) and subcutaneous (7% vs 2%) toxicity in patients treated with HF-PMRT vs CF-PMRT. Patients who received additional radiation boost were significantly higher in the HF-PMRT group. Grade 2 or more late RTOG/EORTC lung toxicity was significant lesser in HF-PMRT vs CF-PMRT (9% vs 16%). Grade 1 brachial plexopathy was also significant lesser in HF-PMRT vs CF-PMRT (2% vs 8%). Heart toxicity and lymphedema were similar in both groups.

Conclusions

HF-PMRT is feasible to deliver with comparable long-term efficacy to CF-PMRT. HF-PMRT had higher grade 2 or more skin and subcutaneous toxicity but less lung and brachial plexus toxicity.

Individualized Prediction of Survival Benefit from Postmastectomy Radiotherapy for Patients with Breast Cancer with One to Three Positive Axillary Lymph Nodes

PURPOSE

There still exist some arguments regarding the use of postmastectomy radiotherapy (PMRT) for patients with breast cancer carrying one to three positive axillary lymph nodes considering the heterogeneity of this cohort. Here, we developed a prognostic nomogram to estimate the probability of long-term outcome in patients receiving or not receiving PMRT in order to assist in making individually locoregional treatment decisions for this particular cohort.

METHODS

Altogether, 20,336 women, aged 18 to 80 years, diagnosed with breast cancer, and carrying one to three positive nodes were identified in the Surveillance, Epidemiology, and End Results (SEER) database. We applied multivariant Cox hazard model to determine the impact of covariates on disease-specific survival (DSS) and overall survival (OS). Then, the nomogram was built accordingly. Internal and external validations were performed to examine the accuracy of nomograms.

RESULTS

Age of diagnosis, tumor grade, size, estrogen and progesterone receptor status, and number of positive nodes were independent factors of DSS and OS in the multivariate analysis. Incorporating these factors into the constructed nomogram showed high accuracy when predicting 5- and 10-year survival, with internally and externally bootstrap-corrected concordance indexes in the range of 0.6 to 0.8.

CONCLUSION

Besides the number of involved nodes, extra variables existed as predictors of survival outcomes in this cohort; therefore, the recommendation of PMRT or no PMRT requires comprehensive consideration. This clinically validated nomogram provided a useful tool that could aid decision making by estimating DSS and OS benefits from PMRT, useful in predicting 5- and 10-year DSS and OS for patients with one to three positive nodes after mastectomy.

IMPLICATIONS FOR PRACTICE

This study evaluated population-based data to identify prognostic factors associated with patients with breast cancer with one to three lymph nodes and help clinicians to weigh the benefit of postmastectomy radiotherapy (PMRT). Surveillance, Epidemiology, and End Results (SEER) data were used to develop a prognostic nomogram to predict the likelihood of long-term survival with and without PMRT in order to optimize the individual locoregional control strategy for this particular cohort. This clinically validated nomogram provides a useful tool to predict 5- and 10-year disease-specific survival and overall survival for patients with one to three positive nodes and can aid tailored clinical decision making by estimating predicted benefit from PMRT.

Postmastectomy radiotherapy for left-sided breast cancer patients: Comparison of advanced techniques

Postmastectomy radiotherapy (PMRT) has been shown to improve the overall survival for invasive breast cancer patients, and many advanced radiotherapy technologies were adopted for PMRT. The purpose of our study is to compare various advanced PMRT techniques including fixed-beam intensity-modulated radiotherapy (IMRT), non-coplanar volumetric modulated arc therapy (NC-VMAT), multiple arc VMAT (MA-VMAT), and tomotherapy (TOMO). Results of standard VMAT and mixed beam therapy that were published by our group previously were also included in the plan comparisons. Treatment plans were produced for nine PMRT patients previously treated in our clinic. The plans were evaluated based on planning target volume (PTV) coverage, dose homogeneity index (DHI), conformity index (CI), dose to organs at risk (OARs), normal tissue complication probability (NTCP) of pneumonitis, lifetime attributable risk (LAR) of second cancers, and risk of coronary events (RCE). All techniques produced clinically acceptable PMRT plans. Overall, fixed-beam IMRT delivered the lowest mean dose to contralateral breast (1.56 ± 0.4 Gy) and exhibited lowest LAR (0.6 ± 0.2%) of secondary contralateral breast cancer; NC-VMAT delivered the lowest mean dose to lungs (7.5 ± 0.8 Gy), exhibited lowest LAR (5.4 ± 2.8%) of secondary lung cancer and lowest NTCP (2.1 ± 0.4%) of pneumonitis; mixed beam therapy delivered the lowest mean dose to heart (7.1 ± 1.3 Gy) and exhibited lowest RCE (8.6 ± 7.1%); TOMO plans provided the most optimal target coverage while delivering higher dose to OARs than other techniques. Both NC-VMAT and MA-VMAT exhibited lower values of all OARs evaluation metrics compare to standard VMAT. Fixed-beam IMRT, NC-VMAT, and mixed beam therapy could be the optimal radiation technique for certain breast cancer patients after mastectomy.

Postmastectomy radiation therapy using VMAT technique for breast cancer patients with expander reconstruction

Postmastectomy radiotherapy (PMRT) following immediate breast reconstruction is increasingly adopted in the management of breast cancer patients. We retrospectively evaluate the complication rates of PMRT using VMAT technique to immediate tissue expander-based reconstructions and the possible impact of tissue expander volume on radiotherapy planning. We reviewed the data of patients who underwent immediate expander breast reconstruction and received PMRT with VMAT (50 Gy in 25 fractions) on the reconstructed breast and axillary levels III-IV. Neoadjuvant or adjuvant systemic therapy was administered in most of the patients. Autologous fat grafting was routinely performed at the time of second-stage reconstruction. Between 2015 and 2017, PMRT was delivered to 46 consecutive patients (median age 50 years) with expander reconstruction. Median follow-up was 27 months (range 10-41). Two patients (4.3%) had a reconstruction failure, as expander rupture and infection, following the first- and the second-stage reconstruction, respectively. In most cases expanders were completely inflated before PMRT (65.2%). Median expander volume before PMRT was 425 cm³ (range 150-700 cm³). The amount of expander inflation did not significantly affect dosimetry, except for skin dose, with a surface receiving more than 30 Gy of 36.6 ± 0.9 cm² and 47.0 ± 2.5 cm² for a volume expander below or above the median, respectively. However, this variable was not predictor for complications. Disease progression was recorded in 15.2% of patients. PMRT using VMAT technique for breast cancer patients with expander reconstruction is associated with a very low complication rate. The expander volume before PMRT does not significantly compromise radiotherapy dose distribution.

An in silico comparative dosimetric study of postmastectomy locoregional irradiation using intensity-modulated vs 3-dimensional conventional radiotherapy

An in silico dosimetric evaluation of intensity-modulated radiation therapy (IMRT) vs 3-dimensional conventional radiation therapy (3D-CRT) treatment plans in postmastectomy radiation therapy (PMRT) to the chest wall and regional lymphatics was conducted. Twenty-five consecutive patients with breast cancer referred for locoregional PMRT, stages T_2-4 with N_1-3, were planned to receive 50 Gy in 25 fractions with IMRT. Additionally, a 3D-CRT plan was generated using identical contours for the clinical target volumes (CTV), planning target volumes (PTV), and organs at risk (OAR). Treatment plans were assessed using dose-volume histogram (DVH) parameters of D₉₈, D₉₅, D₅₀, D₂, and homogeneity index for individual CTVs and PTVs. OARs evaluated were ipsilateral and contralateral lungs, heart, spinal cord, and opposite breast. Most DVH parameters pertaining to CTVs and PTVs significantly favored IMRT. V₂₀ for ipsilateral and contralateral lungs, D₃₃ of heart and maximum dose to spinal cord favored IMRT (all p < 0.001). The mean dose to the opposite breast was significantly lesser with 3D-CRT (5.8 ± 1.8 Gy vs 2.0 ± 1.0 Gy, p < 0.001). Thus, except for the mean dose to the opposite breast, the compliance to DVH constraints applied to PTV and OARs were significantly better with IMRT. At a median follow-up of 76 months (7-91), none had locoregional failure or pulmonary or cardiac morbidity. For PMRT, requiring comprehensive irradiation to both chest wall and regional lymphatics, IMRT offers superior dosimetric advantages over 3D-CRT. This was also corroborated by long-term outcomes in these patients treated with IMRT.

Outcome of postmastectomy radiotherapy after primary systemic treatment in patients with clinical T1-2N1 breast cancer

PURPOSE

The role of postmastectomy radiotherapy following primary systemic treatment in patients with clinical T1-2N1 breast cancer remains a controversial issue. The purpose of this study was to evaluate the benefit of postmastectomy radiotherapy following primary systemic treatment.

PATIENTS AND METHODS

Between 2005 and 2012, in two independent institutions, female patients with T1-2N1 breast cancer receiving primary systemic treatment followed by mastectomy and lymph node dissection because bad response, then treated with or without chest wall and regional lymph node irradiation have been studied retrospectively. The patients received normofractionated radiotherapy using 3D conformal photons or electron techniques. Locoregional recurrence-free survival, distant metastasis-free survival and disease-free survival were calculated using Kaplan-Meier method. Univariate analysis of potential prognostic factors was performed using log-rank test.

RESULTS

Eighty-eight patients have been studied. Of them, 75 patients received postmastectomy radiotherapy. At surgery, 53 patients achieved ypN0. Median follow-up was 67 months. Postmastectomy radiotherapy significantly improved locoregional recurrence-free survival, with a 5-year rate of 96.9% versus 78.6% in the group that did not have postmastectomy radiotherapy. In the subgroup of 53 patients achieving ypN0, postmastectomy radiotherapy improved locoregional recurrence-free survival (a 5-year rate of 94.7% vs. 72.9%), distant metastasis-free survival (a 5-year rate of 92.8% vs. 75%) and disease-free survival (a 5-year rate of 92.9% vs. 62.5%). By univariate analysis, postmastectomy radiotherapy was the only significant prognostic factor affecting locoregional recurrence-free survival.

CONCLUSIONS

For patients with clinical T1-2N1 disease, postmastectomy radiotherapy could significantly improve locoregional recurrence-free survival after primary systemic treatment and be even more therapeutic in the subgroup of patients with good response for primary systemic treatment by improving locoregional recurrence-free, distant metastasis-free and disease-free survival. Larger prospective studies are needed to confirm our findings.

Radiation Therapy and Immediate Breast Reconstruction: Novel Approaches and Evidence Base for Radiation Effects on the Reconstructed Breast

Patients who undergo breast reconstruction experience higher complication rates if they have had a history of radiotherapy. However, implant-based reconstruction confers significantly higher complication and reconstruction failure rates compared with autologous reconstruction. This article analyses the factors that contribute to the complications of the different breast reconstruction modalities and the strategies described to mitigate these problems.

Outcomes and utilization of postmastectomy radiotherapy for T3N0 breast cancers

BACKGROUND

The role of postmastectomy radiotherapy (PMRT) for women with pT3N0M0 breast cancer is controversial. We sought to determine the benefit of PMRT in this cohort using the National Cancer Database (NCDB).

METHODS

We analyzed women with pT3N0M0 breast cancer who received mastectomy with or without PMRT between 2004 and 2012. We excluded men, women ≤18 years, neoadjuvant or unknown radiation or chemotherapy status, unknown estrogen or progesterone receptor status, unknown surgical margin status, histology other than invasive ductal or lobular carcinoma, and if death occurred <3 months after diagnosis. A total of 4291 patients was included for analysis. Chi-squared analysis was used to compare patient characteristics. Univariate (UVA) and multivariate (MVA) Cox proportional hazards modeling was used to identify factors associated with survival. Propensity score matching was performed to address confounding variables. Survival analysis was performed using Kaplan-Meier and shared frailty models.

RESULTS

Of the 4291 women analyzed, 2030 (47%) received PMRT. On MVA, PMRT (HR 0.72, p < 0.001), chemotherapy (HR 0.51, p < 0.001), and hormone therapy (HR 0.63, p < 0.001) were associated with improved overall survival (OS). After propensity score matching, a matched cohort of 2800 women was analyzed. At 5 years, OS was 83.7% and 79.8% with and without PMRT, respectively (p < 0.001). This difference in OS benefit increased with time. At 10 years, OS was 67.4% and 59.2% with and without PMRT, respectively.

CONCLUSIONS

PMRT was associated with improved OS in women with pT3N0M0 breast cancer, which strongly suggests PMRT may provide a survival advantage and should be considered.

Breast reconstruction and postmastectomy radiotherapy: complications by type and timing and other problems in radiation oncology

Breast reconstruction (BR) represents a suitable option for women who are not expected to require postmastectomy radiotherapy (PMRT). As recent evidence has led to an extension of the indications for PMRT, this has also appeared to increase the incidence of reconstructive complications. Nevertheless, in the USA at least, trends towards BR are changing. The frequency of immediate reconstruction continues to increase, even in the setting of PMRT. In immediate implant-based reconstruction, a staged approach is preferred. The failure rate of PMRT in implant patients is lower than that with expander patients. In delayed implant-based construction, tissue expansion of irradiated skin leads to a significantly increased risk of complications. In contrast, autologous tissue appears to tolerate radiation damage better than implant-based reconstructions. No significant differences have been described when complication rates of immediate autologous tissue BR with PMRT were compared with delayed autologous tissue BR following PMRT. In previously radiated patients, autologous tissue BR is preferred, and it may be safer when carried out ≥ 12 months after PMRT. Several other problems are associated with radiation delivery after BR and the clues to solve them are reviewed in this paper.

Postmastectomy radiotherapy benefit in Chinese breast cancer patients with T1-T2 tumor and 1-3 positive axillary lymph nodes by molecular subtypes: an analysis of 1369 cases

The aim of this study was to examine the association between molecular subtype (MST) and prognosis and research the postmastectomy radiotherapy (PMRT) effect in T1-T2 tumors with 1-3 positive axillary lymph nodes (ALNs). This retrospective study studied breast cancer patients with T1-T2 tumors and 1-3 positive ALNs according to MST: Luminal A, Luminal B, human epidermal growth factor receptor-2 (Her-2) positive, and Triple negative. The impact of adjuvant PMRT in T1-T2 tumors with 1-3 positive ALNs was also assessed. This study included 1369 patients: 33.0 % Luminal A, 42.9 % Luminal B, 11.9 % Her-2 positive, and 12.2 % Triple negative. On univariate and multivariate analyses, MST was associated with locoregional relapse (LRR). Kaplan-Meier analysis showed that PMRT significantly decreased LRR risk (p = 0.017) and distant metastasis (DM) risk (p < 0.0001). In subgroup analysis, PMRT showed significant benefits of improvement in LRR in patients with younger age, positive lymphovascular invasion (LVI), and ratio of positive lymph nodes (LNs) >25 %. Moreover, the nomogram could more accurately predict LRR (c-index 0.75) in T1-2N1 breast cancer patients. MST associated with patient outcomes in breast cancer patients with T1-T2 tumors and 1-3 positive ALN. It makes sense to offer PMRT for patients aged<40 years old, LVI, 2 and 3 positive lymph nodes, and ratio of positive LNs >25 %.

Accuracy of a multidisciplinary team-led discussion in predicting postmastectomy radiotherapy

INTRODUCTION

Immediate breast reconstruction (IBR) is performed increasingly following mastectomy for breast cancer. The literature suggests higher reconstructive failure and poorer cosmesis in the subgroup of patients receiving postmastectomy radiotherapy (PMRT) following IBR. We set out to determine the accuracy of a multidisciplinary team (MDT) discussion in predicting PMRT.

METHODS

Preoperative MDT discussions were recorded prospectively over a 12-month period (from February 2011) in a symptomatic breast unit. The estimated need for PMRT was stratified into 'PMRT not required', 'PMRT possibly required', 'PMRT probably required' and 'PMRT required' groups.

RESULTS

Of 156 referrals included in the study, 76 patients (49%) underwent mastectomy: 61 simple mastectomy, 10 skin sparing mastectomy (SSM) and delayed-immediate breast reconstruction, 3 SSM and implant-based IBR, and 2 mastectomy IBR with an autologous flap. The IBR rate was therefore 19.7%. The proportion of patients who received PMRT was 14% (3/21) in the 'PMRT not required', 30% (7/23) in the 'PMRT possibly required', 65% (9/14) in the 'PMRT probably required' and 94% (17/18) in the 'PMRT required' groups. Assigning a linear numerical score (1-4) to these groups (higher score representing greater likelihood of receiving PMRT), the predicted need for PMRT correlated with the proportion of patients who ultimately received PMRT (linear regression r(2)=0.98, p=0.01).

CONCLUSIONS

This study has examined the factors influencing MDT discussions regarding IBR, demonstrating that the MDT is reasonably accurate at predicting need for PMRT. Whether such accuracy is clinically adequate and/or reproducible across units is debatable.

Postmastectomy radiotherapy: indications and implications

BACKGROUND

Although breast conservation surgery, when combined with radiotherapy, has been shown to provide excellent locoregional control for breast cancer, approximately one third of women with breast cancer require mastectomy. Many of these women are offered immediate reconstruction. Postmastectomy radiotherapy (PMRT) is indicated in some cases, but is associated with side-effects, including its impact on the reconstructed breast.

OBJECTIVE

To review the pertinent issues surrounding PMRT, including patient selection for radiotherapy and the effect of radiotherapy on reconstructive decisions.

METHODS

A literature review was performed using the Medline database.

CONCLUSIONS

PMRT is indicated in patients who are deemed to have a high risk of loco-regional recurrence. Although PMRT is strongly recommended for patients with four or more positive lymphnodes, other indications for PMRT remain controversial. Immediate reconstruction post mastectomy has been shown to have favorable outcomes. However, PMRT may increase the need for revision surgery post immediate reconstruction. There are few randomized trials looking at these key issues, and the evidence is largely derived from observational retrospective studies. Patients should be carefully counseled before a decision is made to proceed with immediate reconstruction, where there is a high chance that PMRT may be indicated.