Postmastectomy hypofractionated and accelerated radiation therapy with (and without) subcutaneous amifostine cytoprotection

Hypofractionation for Regional Nodal Irradiation in Breast Cancer: Best of Both the Worlds

Locoregional radiotherapy play an important role in controlling the disease after surgery in patients with breast cancer. Radiotherapy schedules vary from conventional fraction to hypofractionation. The purpose of this review is to get an insight into the data on regional nodal irradiation (RNI) with hypofractionation in patients with breast cancer. This systematic review was constructed in accordance with Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) framework. Electronic databases such as PubMed, Cochrane and EMBASE were searched from January 1, 2023 to March 31, 2023 to identify studies published in English language on hypofractionated RNI in post mastectomy patients. The search was carried out with the National Library of Medicine's Medical Subject Heading (MeSH) terms like "regional nodal irradiation," "hypofractionated" and "hypofractionation in breast cancer" with different Boolean operators (and/or). A manual search of reference lists of included articles was also performed to make sure there were no additional cases unidentified from the primary search. Studies deemed potentially eligible were identified and assessed by same independent reviewers to confirm eligibility. RNI data are mainly from a randomized study from Beijing and pooled data from START trials. There are also data from retrospective and single institutional studies and a few phase II studies with limited number of patients using different dose fractionations and techniques of radiotherapy. Doses used in these trials ranged from 26-47.7 Gy in 5-19 fractions over 1-4 weeks. Grade ≥ 2 pulmonary fibrosis and lymphedema rate ranged from 2%-7.9% and 3%-19.8% respectively. Grade ≥ 2 shoulder dysfunction and brachial plexopathy ranged from 0.2%-28% and 0%-< 1%, respectively. Late effects with a dose range of 26-40 Gy delivered in 5 to 15 fractions over 1-3 weeks were less/similar to conventional fraction. Current data showed lower/similar rates of toxicity with hypofractionated RNI compared with conventional fractionation RNI. Doses of 26 Gy to 40 Gy delivered in 5 to 15 fractions over 1-3 weeks are safe for RNI. With limited data, ultra-hypofractionation 26 Gy/5 fractions/1 week also seems to be safe. However, long-term outcome is awaited and many trials are going on to address its efficacy and safety.

Dosimetry and Toxicity Outcomes in Patients Treated with Hypofractionated Regional Nodal Irradiation for Breast Cancer: What is the Best Dose-Volume Limit to Minimize Risks of Radiation Pneumonitis?

PURPOSE

Although published data have supported the use of hypofractionated regional nodal irradiation (HF-RNI) for breast cancer, limited dosimetric data exist to evaluate predictors of lung toxicity. The ongoing RT CHARM trial limits the percentage of ipsilateral lung volume that receives ≥18 Gy to 35 to 40%. We assessed dosimetry, toxicity, and disease outcomes in patients with breast cancer treated with HF-RNI with a particular focus on pneumonitis.

METHODS AND MATERIALS

We retrospectively reviewed all patients with breast cancer treated with HF-RNI (40-43 Gy in 15-16 fractions) after either lumpectomy or mastectomy at The University of Pittsburgh Medical Center from September 2018 to December 2021 to collect dosimetric and outcomes data. All post-radiation therapy chest computed tomography (CT) scans were manually reviewed for evidence of acute (≤6 months postradiation) or chronic (>6 months postradiation) pneumonitis.

RESULTS

One-hundred-ninety-one patients qualified with a median follow-up of 20.3 months (range, 5.1-42.2). Acute grade 1 (G1) pneumonitis was observed in 6.8% of the overall cohort (13 of 191 patients) and 39.4% of the patients (13 of 33) who received a chest CT ≤6 months postradiation therapy. Only 1 patient developed acute G2 pneumonitis. Chronic G1 pneumonitis was observed in 29.8% of the overall cohort (57 of 191 patients) and 77% of patients (57 of 74 patients) who received a chest CT >6 months postradiation therapy. No patients developed acute G3+ or chronic G2+ pneumonitis.

CONCLUSIONS

Rates of symptomatic pneumonitis were low in this cohort of patients treated with HF-RNI, even with integration of HER2/neu-directed therapy, chemotherapy, hormone therapy, and internal mammary nodal irradiation. Lung V20Gy <26% appeared safe in this cohort to limit symptomatic pneumonitis, though this is not meant to represent the safe upper limit. Given the low event rate of symptomatic pneumonitis, data from larger cohorts will be needed to assess dosimetric predictors and the safe upper limit of lung dose.

Determination of biological radioprotective characteristics of some natural organic compounds for radiation shielding applications

Ionizing radiation is used in many fields in energy, medicine, and industrial applications. Those who are in these areas or cancer patients receiving radiotherapy are at risk for acute or long-term exposure to radiation damage due to these ionizing radiations. Non-toxic new agents are needed to protect intact tissue and cells. In this study, we aimed to determine the gamma and neutron radiation attenuation characteristics of seven different natural compounds (quercetin, menadione, naphthol, caffeine, quinine sulphate, cholesterol and riboflavin) to help users in radiation applications. Gamma radiation attenuation parameters such as the mean free path, mass attenuation coefficient, effective atom number, linear attenuation coefficient, and half-value layer were calculated theoretically with WinXCom software for the energy range 0.015–15 MeV. Fast neutron attenuation criteria, such as mean free path, half-value layer, effective removal cross-sections and transmission neutron number, were theoretically determined with Monte Carlo simulation codes (Geant4). Neutron absorption measurement experiments were also applied in addition to the theoretical results. The neutron radiation absorption capacities were determined for samples with an 241Am-Be 4.5 MeV energy neutron source and portatif-type Canberra brand BF3 gas neutron detector. Neutron attenuation parameters were compared with paraffin to determine the absorption capability of the samples. It was found that the dose 1.1094 (μSv/h) from the source was absorbed by the samples to the following extent: 31.76% (Quercetin), 21.85% (Menadione), 28.85% (Naphthol), 22.94% (Caffeine), 12.51% (Quinine sulphate), 40.44% (Cholesterol) and 20.94% (Riboflavin). From the results, it can be clearly seen that all these drug samples had a good neutron radiation attenuation capacity. This revealed that the examined samples had radiation absorption abilities. It was found that the cholesterol sample had an especially excellent absorption power for both neutron and gamma radiation. The samples investigated in this study could be used to develop radiation-protective drugs.

Ten-year outcomes of hypofractionated postmastectomy radiation therapy of 26 Gy in 6 fractions

PURPOSE

To investigate the efficacy and long-term side effects of hypofractionated postmastectomy radiation therapy (HFRT-PM) of 26 Gy in 6 fractions over 5 weeks.

MATERIALS & METHODS

We retrospectively reviewed characteristics and outcomes of patients with stage I-III breast cancer treated with HFRT-PM between 2000-2009. Treatment provided four fractions of 4 Gy (day (d)1, d3, d15, d17) then two fractions of 5 Gy (d29, d31) over 5 weeks. The treatment techniques were applied by using 3D conformal radiotherapy of chest wall with regional nodal volume if required.

RESULTS

454 patients were identified, with a median follow-up of 10.6 years (range 0.5-22.9). Regional nodal irradiation was made in 84.1 % of patients. At 10 years, the cumulative incidence of locoregional relapse was 15.1 %. In multivariate analysis, regional lymph nodes involvement (≥ 4 nodes) was associated with worse locoregional control (HR 1.68; [95% CI 1.06-2.67], p = 0.03) and overall survival (HR 2.16; [95% CI 1.59-2.95], p < 0.001). The toxicities were acceptable. The incidence of cardiac disorders (3.3 %), and symptomatic lung fibrosis (1.5 %) was low during follow-up. At 10 years, the cumulative rate of arm lymphedema was 9.5 % and considered severe in 20 patients (4.4 %).

CONCLUSION

The long-term results of this study show that HFRT-PM of 26 Gy in 6 fractions over 5 weeks seems safes but locoregional recurrence seems slightly higher than those observed in the literature, highlighting that long-term follow-up is needed and the need of randomized trials for hypofractionated radiotherapy therapy in postmastectomy situation.

Hypofractionated Radiation Therapy (HFRT) of Breast/Chest Wall and Regional Nodes in Locally Advanced Breast Cancer: Toxicity Profile and Survival Outcomes in Retrospective Monoistitutional Study

AIM

To evaluate the efficacy and safety of hypofractionated radiation therapy (HFRT) of the breast/chest wall and regional nodes in patients with locally advanced breast cancer and positive lymph nodes.

MATERIALS AND METHODS

One hundred and twenty-two patients treated between October 2016 and March 2020 with HFRT were retrospectively reviewed. A total dose of 42.4 Gy was delivered to the chest wall and lymph nodes in 16 fractions of 2.65 Gy each, using the IMRT technique. Patients treated with breast-conserving surgery received an overdose (concomitant boost of 3 Gy daily) with the SIB (Simultaneous Integrated Boost) technique.

RESULTS

Median age at diagnosis was 58 years (range 34-86 years) and median follow-up was 22 months (range 6-48 months). Overall survival (OS) at 1, 2 and 3 years was 100%, 97.3% and 90%, respectively. Disease-free survival (DFS) at 1, 2, and 3 years was 91.4%, 87%, and 84.8%, respectively. Distant metastasis-free survival (MFS) at 1, 2 and 3 years was 93.1%, 88% and 85.7%, respectively. Two patients (1.6%) experienced local recurrence on the chest wall during FUP. Twenty-one patients (17%) showed a grade 2 dermal toxicity, no grade 3 acute skin toxicity was found. Sixteen patients (13%) showed early-stage arm lymphedema (grade ≤ 2). Twenty-three patients (19%) showed a grade 2 late skin toxicity. Twenty patients (16%) had grade ≤ 2 late arm lymphedema.

CONCLUSION

Given the excellent local control, survival rates and the low toxicity profile demonstrated, HFRT could be considered a valid therapeutic option in patients with locally advanced breast cancer.

Long-Term Results of Postoperative Hypofractionated Accelerated Breast and Lymph Node Radiotherapy (HypoAR) with Hypofractionated Boost

We report long-term results (median follow-up 12 years) of hypofractionated accelerated radiotherapy (HypoAR) in patients treated with breast-conserving surgery. In total, 367 women were treated with HypoAR. Axillary and supraclavicular area (ASA) were treated in patients with involved nodes. In total, 290 patients (scheme A) received 3.5 Gy/day ×10 fractions (breast/ASA) followed by two 4 Gy fractions with electrons to the affected breast quadrant within 16 days. In total, 77 patients (Scheme B) received 2.7 Gy/day for 16 consecutive fractions (breast/ASA) within 22 days, while concurrently, the affected breast quadrant received an electron booster dose of 0.8 Gy for the first 13 fractions. Amifostine was offered to 252/367 patients. Early radiation toxicity was minimal. Regarding late toxicities, symptomatic breast edema was noted in 2.2%, asymptomatic breast fibrosis in 1.9%, and arm lymphedema in 3.7% of patients. Amifostine reduced early radiation dermatitis (p = 0.001). In total, 2.2% of patients developed contralateral breast and 1.6% other carcinomas. Locoregional recurrence (LR) occurred in 3.1% of patients (0% for in situ carcinomas). Positive margins after surgery, extracapsular node invasion, and HER2-enriched/triple-negative tumors were linked with significantly worse LR-free survival. The involvement of more than three nodes and luminal type other than A were independent prognostic variables of metastasis and death events. HypoAR delivering a biological dose of 50–52 Gy to the breast/ASA is a safe and effective therapy for patients treated with conservative surgery. The risk of carcinogenesis is low. Positive surgical margins, extracapsular node invasion, and HER2-enriched/triple-negative phenotypes appear as a cluster of features linked with a higher risk for locoregional relapse.

Successful Treatment of a Locally Recurrent and Metastatic Malignant Phyllodes Tumor with Accelerated Radiotherapy and Nab-Paclitaxel, Cisplatin, and Liposomal Doxorubicin Chemotherapy

Phyllodes tumors are rare breast lesions of fibroepithelial origin. Malignant transformation with metastases is linked with poor prognosis. We present a case of a 62-year-old woman with a recurrent malignant phyllodes tumor of the breast and lung metastases. The patient was originally presented with a borderline phyllodes tumor (7.4 cm) of the left breast, treated with wide local excision. A year later, the patient returned with palpable left breast masses. On PET-CT, increased uptake of 18F-FDG by large breast tumors was evident. A right lung lesion of metastatic origin was also present. A simple left breast mastectomy was performed. Histopathological report described 2 malignant phyllodes tumors (7 cm and 6.5 cm). One month later, during the CT simulation for radiotherapy planning, encysted fluid in the chest wall and 2 additional pulmonary lesions of the right lung were identified, confirming progressive lung metastatic disease. Both the chest wall and the regional lymph node area were irradiated with hypofractionated and accelerated radiotherapy. Biweekly chemotherapy with albumin-bound paclitaxel, cisplatin, and liposomal doxorubicin was also prescribed at the start of radiotherapy for 12 cycles. At the end of chemotherapy, complete regression of lung metastases was achieved, and there was no evidence of local recurrence. Within 2 years of follow-up, the patient is free of disease and treatment-related toxicities. Accelerated hypofractionated radiotherapy is effective in the locoregional control of malignant phyllodes tumors. The combination of cisplatin with nab-paclitaxel and liposomal doxorubicin chemotherapy has acceptable toxicity and is highly effective in eradicating metastatic lesions.

Late-term effects of hypofractionated chest wall and regional nodal radiotherapy with two-dimensional technique in patients with breast cancer

PURPOSE

Hypofractionated radiotherapy (RT) is becoming a new standard in postoperative treatment of patients with early stage breast cancer after breast conservation surgery. However, data on hypofractionation in patients with advanced stage disease who undergo mastectomy followed by local and regional nodal irradiation (RNI) is lacking. In this retrospective study, we report late-term effects of 3 weeks post-mastectomy hypofractionated local and RNI with two-dimensional (2D) technique in patients with stage II and III breast cancer.

METHODS

Between January 1990 and December 2007, 1,770 women with breast cancer who were given radical treatment with mastectomy, systemic therapy and RT at least 10 years ago were included. RT dose was 35 Gy/15 fractions/3 weeks to chest wall by two tangential fields and 40 Gy in same fractions to supraclavicular fossa (SCF) and internal mammary nodes (IMNs). SCF and IMNs dose was prescribed at dmax and 3 cm depth, respectively. Chemotherapy and hormonal therapy was given in 64% and 74% patients, respectively. Late-term toxicities were assessed with the Radiation Therapy Oncology Group (RTOG) scores and LENT-SOMA scales (the Late Effects Normal Tissue Task Force-Subjective, Objective, Management, Analytic scales).

RESULTS

Mean age was 48 years (range, 19 to 75 years). Median follow-up was 12 years (range, 10 to 27 years). Moderate/marked arm/shoulder pain was reported by 254 (14.3%) patients. Moderate/marked shoulder stiffness was reported by 219 (12.3%) patients. Moderate/marked arm edema was seen in 131 (7.4%) patients. Brachial plexopathy was not seen in any patient. Rib fractures were noted in 6 (0.3%) patients. Late cardiac and lung toxicity was seen in 29 (1.6%) and 23 (1.3%) patients, respectively. Second malignancy developed in 105 (5.9%) patients.

CONCLUSION

RNI with 40 Gy/15 fractions/3 weeks hypofractionation with 2D technique seems safe and comparable to historical data of conventional fractionation (ClinicalTrial.gov Registration No. XXXX).

5-Year Update of a Multi-Institution, Prospective Phase 2 Hypofractionated Postmastectomy Radiation Therapy Trial

PURPOSE

Hypofractionation in the setting of postmastectomy radiation (PMRT) is not currently the standard of care in most countries. Here we present a 5-year update of our multi-institutional, phase 2 prospective trial evaluating a novel 15-day hypofractionated PMRT regimen.

METHODS AND MATERIALS

Patients were enrolled to receive 3.33 Gy daily to the chest wall (or reconstructed breast) and regional lymphatics in 11 fractions with an optional 4-fraction mastectomy scar boost. The primary endpoint was freedom from grade 3 or higher late non-reconstruction-related radiation toxicities. Toxicities were scored using Common Terminology Criteria for Adverse Events v4.0. Secondary endpoints included local and locoregional recurrence rates, cosmesis, and reconstruction complications.

RESULTS

After enrolling 69 patients with stage II-IIIa breast cancer, 67 women were eligible for analysis. At a median follow up of 54 months, there were no acute or late grade 3 and 4 nonreconstruction reported toxicities. The grade 2 or greater late toxicity rate was only 12% and comprised grade 2 pain, fatigue, and lymphedema that persisted beyond 6 months after completion of radiation therapy. Only 3 women (4.6%) experienced a chest wall or nodal recurrence as a first site of relapse. Freedom from local failure, including local failure after distant relapse, was 92% at 5 years, and the 5-year overall survival was 90%.

CONCLUSIONS

This is the first prospective trial conducted in the United States to demonstrate the safe and effective use of hypofractionated PMRT. We have demonstrated a low complication rate while achieving excellent local control. Toxicity was better than anticipated based on previously published series of PMRT toxicities. Although our fractionation was novel, the radiobiological equivalent dose is similar to other hypofractionation schedules. This trial was the basis for the creation of Alliance A221505 (RT CHARM), which is currently accruing patients in a phase 3 randomized design.

Comparing hypofractionated to conventional fractionated radiotherapy in postmastectomy breast cancer: a meta-analysis and systematic review

Purpose

To compare the efficacy and toxicity of hypofractionated radiotherapy versus conventional fractionated radiotherapy in postmastectomy breast cancer using meta-analysis.

Methods

The PubMed, EMbase, Cochrane Library, Google Scholar, Wan Fang and CNKI databases were searched to identify controlled clinical trials comparing hypofractionated radiotherapy versus conventional fractionated radiotherapy in postmastectomy breast cancer. Overall survival (OS) was the primary endpoint, and disease-free survival (DFS), locoregional recurrence (LRR), distant metastasis (DM), acute skin toxicity, acute lung toxicity, late skin toxicity, lymphedema,, shoulder restriction, and late cardiac related toxicity were the secondary endpoints.

Results

Twenty-five controlled clinical trials involving 3871 postmastectomy breast cancer patients were included in this meta-analysis according to the selection criteria. The meta-analysis revealed that there were no significant differences in OS (OR = 1.08, 95% CI = 0.87~1.33, P = 0.49), DFS (OR = 1.13, 95% CI = 0.91~1.40, P = 0.28), LRR (OR = 1.01, 95% CI = 0.76~1.33, P = 0.96), DM (OR = 1.16, 95% CI = 0.85~1.58, P = 0.34), acute skin toxicity (OR = 0.94, 95% CI = 0.67~1.32, P = 0.72), acute lung toxicity (OR = 0.94, 95% CI = 0.74~1.20, P = 0.62), late skin toxicity (OR = 0.98, 95% CI = 0.75~1.27, P = 0.88), lymphedema (OR = 0.99, 95% CI = 0.77~1.28, P = 0.94), shoulder restriction (OR = 0.75, 95% CI = 0.43~1.31, P = 0.31), or late cardiac related toxicity (OR = 1.17, 95% CI = 0.82~1.65, P = 0.39) between the two groups.

Conclusions

The results of this study show that compared to conventional fractionated radiotherapy, hypofractionated radiotherapy is not significantly different with respect to efficacy or toxicity in postmastectomy breast cancer. Additional large randomized clinical trials are needed to further confirm this conclusion.

Use of Amifostine for Cytoprotection during Radiation Therapy: A Review

BACKGROUND

Radiation therapy is a cornerstone of the therapeutic modalities used in modern oncology. However, it is sometimes limited in its ability to achieve optimal tumor control by radiation-induced normal tissue toxicity. In delivering radiation therapy, a balance must be achieved between maximizing the dose to the tumor and minimizing any injury to the normal tissues. Amifostine was the first Food and Drug Administration (FDA)-approved clinical radiation protector intended to reduce the impact of radiation on normal tissue, lessening its toxicity and potentially allowing for increased tumor dose/control. Despite being FDA-approved almost 20 years ago, Amifostine has yet to achieve widespread clinical use.

SUMMARY

A thorough review of Amifostine's development, mechanism of action, and current clinical status were conducted. A brief history of Amifostine is given, from its development at Walter Reid Institute of Research to its approval for clinical use. The mechanism of action of Amifostine is explored. The results of a complete literature review of all prospective randomized trials to date involving the use of Amifostine in radiation therapy are presented. The results are arranged by treatment site and salient findings discussed. Side effects and complications to consider in using Amifostine are reviewed. Key Messages: Amifostine has been explored as a radiation protectant in most radiation treatment sites. Studies have demonstrated efficacy of Amifostine in all treatment sites reviewed, but results are heterogeneous. The heterogeneity of studies looking at Amifostine as a clinical radiation protectant has precluded a definitive answer on its efficacy. Complicating its clinical use is its toxicity and delivery requirements. Amifostine has largely fallen out of use with the advent of intensity modulated radiation therapy (IMRT). However, side effects with IMRT remain a challenge and concern. The use of Amifostine in the IMRT era has been poorly explored and is worthy of future study.

Radiation Modifiers

Radiation therapy is one of the most commonly used treatments for cancer. Radiation modifiers are agents that alter tumor or normal tissue response to radiation, such as radiation sensitizers and radiation protectors. Radiation sensitizers target aspects of tumor molecular biology or physiology to enhance tumor cell killing after irradiation. Radioprotectors prevent damage of normal tissues selectively. Radiation modifiers remain largely investigational at present, with the promise that molecular characterization of tumors may enhance the capacity for successful clinical development moving forward. A variety of radiation modifiers are described.

Patterns of Practice in Radiotherapy for Breast Cancer in Korea

Adjuvant radiotherapy (RT) is a well-established treatment for breast cancer. However, there is a large degree of variation and controversy in practice patterns. A nationwide survey on the patterns of practice in breast RT was designed by the Division for Breast Cancer of the Korean Radiation Oncology Group. All board-certified members of the Korean Society for Radiation Oncology were sent a questionnaire comprising 39 questions on six domains: hypofractionated whole breast RT, accelerated partial breast RT, postmastectomy RT (PMRT), regional nodal RT, RT for ductal carcinoma in situ, and RT toxicity. Sixty-four radiation oncologists from 54 of 86 (62.8%) hospitals responded. Twenty-three respondents (35.9%) used hypofractionated whole breast RT, and the most common schedule was 43.2 Gy in 16 fractions. Only three (4.7%) used accelerated partial breast RT. Five (7.8%) used hypofractionated PMRT, and 40 (62.5%) had never used boost RT after chest wall irradiation. Indications for regional nodal RT varied; ≥pN2 (n=7) versus ≥pN1 (n=17) versus ≥pN1 with pathologic risk factors (n=40). Selection criteria for internal mammary lymph node (IMN) irradiation also varied; only four (6.3%) always treated IMN when regional nodal RT was administered and 30 (46.9%) treated IMN only if IMN involvement was identified through imaging. Thirty-one (48.4%) considered omission of whole breast RT after breast-conserving surgery for ductal carcinoma in situ based on clinical and pathologic risk factors. Fifty-two (81.3%) used heart-sparing techniques. Overall, there were wide variations in the patterns of practice in breast RT in Korea. Standard guidelines are needed, especially for regional nodal RT and omission of RT for ductal carcinoma in situ.

Effectiveness and safety of different amifostine regimens: Preliminary results of a phase II multicenter randomized controlled trial

Objective

The radioprotective effects of amifostine remain uncertain in patients with nasopharyngeal carcinoma (NPC), and adverse effects and cost limit generalization of its classical everyday regimen. This phase II multicenter randomized controlled trial aimed to explore whether amifostine could ameliorate the toxicities of NPC patients in the era of intensity-modulated radiotherapy (IMRT), and to compare different regimens of amifostine on effectiveness and safety.

Methods

Patients with stage I-IVB NPC were involved prospectively from January 1st, 2013. All patients received radical treatment based on IMRT. After a randomization stratified by their stage, these patients were allocated into 3 groups: the group treated without amifostine, the group treated with the everyday regimen of amifostine, and the group treated with the every-other-day regimen. The 3 groups of patients were compared on radiotherapy-related acute toxicities, treatment effects of NPC, and amifostine-related complications. This trial was registered on the clinicaltrials.gov (ID: NCT01762514).

Results

Until August 31st, 2017, totally 187 patients completed experimental intervention. Only amifostine of everyday regimen appeared to reduce the patient proportion of mucositis (79.1% vs. 96.8%, P=0.002). Hypocalcemia was less common in patients treated without amifostine than in those treated with amifostine (22.6% vs. 53.4% vs. 41.8%, P=0.002). Neither complete remission rates nor the survivals were affected by amifostine.

Conclusions

Amifostine of everyday regimen could reduce mucositis in NPC patients who received IMRT, though it also had the possibility to cause more hypocalcemia.

Trends and Patterns of Utilization of Hypofractionated Postmastectomy Radiotherapy: A National Cancer Database Analysis

BACKGROUND

The acceptance of hypofractionated radiotherapy in treating breast cancer in the breast conservation therapy setting has stimulated interest in hypofractionated postmastectomy radiotherapy (PMRT). We assessed national trends and patterns of utilization of hypofractionated PMRT.

PATIENTS AND METHODS

Women 18 years of age or older with breast cancer treated with mastectomy and PMRT to the chest wall with or without regional lymph nodes from 2004 to 2014 were identified from the National Cancer Database. A standard fractionation cohort was defined as patients receiving 180 to 200 cGy per fraction to a total dose of 4500 to 7000 cGy over 5 to 7 weeks, and a hypofractionation cohort was defined as those receiving 250 to 400 cGy per fraction to a total dose of 3000 to 6000 cGy over 2 to 5 weeks. Multivariable logistic regression was used to determine factors associated with hypofractionated PMRT use.

RESULTS

We identified 113,981 patients who met study criteria. Overall, hypofractionated PMRT use was low (1.1%) although utilization increased over time (P ≤ .001). Older age, greater comorbidity, further distance from treatment facility, treatment at academic facilities, less extensive disease, and recent treatment year were statistically significant predictors of hypofractionation use compared with standard fractionation. Conversely, breast reconstruction and receipt of chemotherapy were negative predictors.

CONCLUSION

Because of the absence of high-level evidence to support its use, hypofractionated PMRT was uncommonly utilized in the United States from 2004 to 2014, although a small increase in use was noted over time. Findings from this study might be useful in designing future studies, and might serve as a baseline for evaluation of future changes in practice patterns.

IPW-5371 Proves Effective as a Radiation Countermeasure by Mitigating Radiation-Induced Late Effects

There is an ongoing and significant need for radiation countermeasures to reduce morbidities and mortalities associated with exposure of the heart and lungs from a radiological or nuclear incidents. Radiation-induced late effects occur months to years after exposure, stemming from significant tissue damage and remodeling, resulting in fibrosis and loss of function. TGF-β is reported to play a role in both pulmonary and cardiac fibrosis. We investigated the ability of a small molecule TGF-β receptor 1 inhibitor, IPW-5371, to mitigate the effects of thoracic irradiation in C57L/J mice, a murine model that most closely resembles that observed in humans in the induction of fibrosis and dose response. To simulate a radiological event, radiation was administered in two doses: 5 Gy total-body irradiation (eliciting a whole-body response) and immediately after that, a thoracic "top-up" of 6.5 Gy irradiation, for a total dose of 11.5 Gy to the thorax. IPW-5371 was administered once daily, orally, starting 24 h postirradiation for 6 or 20 weeks at a dose of 10 mg/kg or 30 mg/kg. Animals were monitored for a period of 180 days for survival, and cardiopulmonary injury was assessed by echocardiography, breathing rate and arterial oxygen saturation. Exposure of the thorax (11.5 Gy) induced both pulmonary and cardiac injury, resulting in a reduced life span with median survival of 135 days. IPW-5371 treatment for 6 weeks, at both 10 mg/kg and 30 mg/kg, delayed disease onset and mortality, with median survival of 165 days. Twenty weeks of IPW-5371 treatment at 30 mg/kg preserved arterial O₂ saturation and cardiac contractile reserve and resulted in significant decreases in breathing frequency and cardiac and pulmonary fibrosis. This led to dramatic improvement in survival compared to the irradiated, vehicle-treated group (P < 0.001), and was statistically insignificant from the nonirradiated group. We observed that IPW-5371 treatment resulted in decreased pSmad3 tissue levels, confirming the effect of IPW-5371 on TGF-β signaling. These results demonstrate that IPW-5371 represents a potentially promising radiation countermeasure for the treatment of radiation-induced late effects.

Pulmonary toxicity generated from radiotherapeutic treatment of thoracic malignancies

Radiation-induced lung injury (RILI) remains a major obstacle for thoracic radiotherapy for the treatment of lung cancer, esophageal cancer and lymphoma. It is the principal dose-limiting complication, and can markedly impair the therapeutic ratio as well as a patient's quality of life. The current review presents the relevant concepts associated with RILI, including the pathogenic mechanisms and the potential treatment strategies, so as to achieve a general understanding of this issue. RILI comprises an acute radiation pneumonitis phase and subsequent late lung fibrosis. The established assessment criteria are clinical manifestations, imaging changes and the necessity for medical assistance. Risk factors are also considered in order to optimize treatment planning. Due to the underlying molecular mechanisms of RILI, the present review also discusses several targeted pharmacological approaches for its treatment, as well as corticosteroid therapy.

Hypofractionated Regional Nodal Irradiation for Women With Node-Positive Breast Cancer

PURPOSE

To evaluate the effect of hypofractionated radiation therapy (HFRT) of the breast/chest wall and regional nodes on overall survival (OS), disease-free survival (DFS), locoregional control and on treatment-related toxicity in patients with breast cancer and nodal involvement.

METHODS AND MATERIALS

Two hundred fifty-seven patients treated between October 2009 and June 2011 with hypofractionated locoregional radiation therapy (42 Gy in 15 fractions) were retrospectively reviewed, 51 (19.8%) after breast-conserving surgery and 206 (80.2%) after radical surgery. Patients treated with breast-conserving surgery received a boost dose to the tumor bed (delivered by photons, electrons, or interstitial high-dose-rate brachytherapy). Two hundred fifty-six (99.6%) patients underwent chemotherapy, 209 (81.3%) had hormonal treatment, and 65 (25.3%) had anti-HER2 targeted therapy.

RESULTS

The median follow-up time was 64 months (range, 11-88 months). The rates of 5-year OS, DFS, locoregional recurrence (LRR)-free survival, and distant metastasis (DM)-free survival were 86.6%, 84.4%, 93.9%, and 83.1%, respectively. In multivariate analysis (MVA), lymph node ratio >65%, lymphovascular invasion, and negative hormone receptor status predicted for OS, DSF, and DM. T3 to 4 stage was also associated with worse DFS and DM. Finally, for LRR the independent prognostic factors on MVA were N2 to 3 stage and grade 3. Hyperpigmentation was observed in 19.2% of patients, telangiectasia in 12.3%, and fibrosis in 30.7%. Grade ≥2 lymphedema was recorded in 5.8% of cases. During the study follow-up, no cardiac or symptomatic pneumonitis was observed, nor were plexopathy or rib fractures.

CONCLUSION

According to the findings from this retrospective study, HFRT seems to be an acceptable alternative for patients with breast cancer who need regional nodal irradiation. However, prospective randomized trials are necessary to confirm these preliminary results.

Prospective evaluation of radiation-induced skin toxicity in a race/ethnically diverse breast cancer population

We evaluated predictors of radiation‐induced skin toxicity in a prospective study of a tri‐racial/ethnic breast cancer population. We evaluated patient demographics, tumor characteristics, and treatment variables in the first 392 patients in a prospective study assessing radiation‐induced skin toxicity. Logistic regression analyses were conducted to evaluate potential predictors of skin toxicity. The study consists of 59 non‐Hispanic whites (NHW; 15%), 241 Hispanic Whites (HW; 62%), 79 black or African Americans (AA; 20%), and 13 others (3%). Overall, 48% developed grade 0–1 skin toxicity, 49.8% grade 2, and 2.2% grade 3 by the National Cancer Institute's Common Toxicity Criteria for Adverse Events (CTCAE) scale. Twenty‐one percent developed moist desquamation. In multivariate analysis, higher body mass index (BMI; OR = 2.09; 95%CI = 1.15, 3.82), higher disease stage (OR = 1.82; 95%CI = 1.06, 3.11), ER‐positive/PR‐negative status (OR = 2.74; 95%CI = 1.26, 5.98), and conventionally fractionated regimens (OR = 3.25; 95%CI = 1.76, 6.01) were significantly associated with higher skin toxicity grade after adjustment for age, race, ethnicity, ER status, and breast volume. BMI specifically predicted for moist desquamation, but not degree of erythema. In this racially and ethnically diverse cohort of breast cancer patients receiving radiation to the intact breast, risk factors including BMI, disease stage, and conventionally fractionated radiation predicted for higher skin toxicity grade, whereas age, race, ethnicity, and breast volume did not. BMI specifically predicted for moist desquamation, suggesting that preventive measures to address this particular outcome should be investigated.

Breast, chest wall, and nodal irradiation with prone set-up: Results of a hypofractionated trial with a median follow-up of 35 months

PURPOSE

To test clinical feasibility, safety, and toxicity of prone hypofractionated breast, chest wall, and nodal radiation therapy.

METHODS AND MATERIALS

Following either segmental or total mastectomy with axillary node dissection, patients were treated in an institutional review board-approved prospective trial of prone radiation therapy to the breast, chest wall, and supraclavicular and level III axillary lymph nodes. A dose of 40.5 Gy/15 fractions with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose, 48 Gy) was prescribed. In postmastectomy patients, the same treatment was prescribed, but without a tumor bed boost. The primary endpoint was incidence of >grade 2 acute skin toxicity. The secondary endpoints were feasibility of treatment using prone set-up, compliance with protocol-defined dosimetric constraints, and incidence of late toxicity. A dosimetric comparison was performed between protocol plans (prone) and nonprotocol plans (supine), targeting the same treatment volumes.

RESULTS

Sixty-nine patients with stage IB-IIIA breast cancer enrolled in this trial. Surgery was segmental mastectomy (n = 45), mastectomy (n = 23), and bilateral mastectomy (n = 1), resulting in 70 cases. None experienced >grade 2 acute skin toxicity according to the Common Terminology Criteria for Adverse Events, v 3.0, meeting our primary endpoint. Ninety-six percent of patients could be treated with this technique prone. However, 17 plans (24%) exceeded protocol constraints to the brachial plexus. Maximum long-term toxicity was 1 grade 2 arm lymphedema, 1 grade 3 breast retraction, and no occurrence of brachial plexopathy. Dosimetric comparison of protocol with nonprotocol plans demonstrated significantly decreased lung and heart doses in prone plans.

CONCLUSIONS

Prone hypofractionated breast, chest wall, and nodal radiation therapy is safe and well tolerated in this study. Although the initial pattern of local and regional control is encouraging, longer follow-up is warranted for efficacy and late toxicity assessment, particularly to the brachial plexus.

New approaches to radiation protection

Radioprotectors are compounds that protect against radiation injury when given prior to radiation exposure. Mitigators can protect against radiation injury when given after exposure but before symptoms appear. Radioprotectors and mitigators can potentially improve the outcomes of radiotherapy for cancer treatment by allowing higher doses of radiation and/or reduced damage to normal tissues. Such compounds can also potentially counteract the effects of accidental exposure to radiation or deliberate exposure (e.g., nuclear reactor meltdown, dirty bomb, or nuclear bomb explosion); hence they are called radiation countermeasures. Here, we will review the general principles of radiation injury and protection and describe selected examples of radioprotectors/mitigators ranging from small-molecules to proteins to cell-based treatments. We will emphasize agents that are in more advanced stages of development.

Comparative efficacy and the window of radioprotection for adrenergic and serotoninergic agents and aminothiols in experiments with small and large animals

This review gives a comparative evaluation of the radioprotective properties and the therapeutic index (TI) of radioprotectors from various pharmacological group in experiments on both small and large animals. It presents a hypothesis explaining the decrease in the TI of cystamine and 5-methoxytryptamine (mexamine), and the retention of that of α1-adrenomimetic indralin, and also compares the effects on large and small animals. The considerable differences in the therapeutic indices of catecholamines, serotonin and cystamine are a consequence of specific features of their mechanisms of radioprotective action. Radioprotectors acting via receptor mediation tend to provide a more expanded window of protection. The reduction in the TI of cystamine in larger animals, such as dogs, may be caused by the greater increase in toxicity of aminothiols in relation to the decrease in their optimal doses for radioprotective effect in going from mice to dogs, which is a consequence of the slower metabolic processes in larger animals. The somatogenic phase of intoxication by cystamine is significantly longer than the duration of its radioprotective effect, and increases with irradiation. The decrease in the radioprotective effect and the TI of mexamine in experiments with dogs may be caused by their lower sensitivity to the acute hypoxia induced by the mexamine. This is because of lower gradient in oxygen tension between tissue cells and blood capillaries under acute hypoxia that is determined by lower initial oxygen consumption in a large animal as compared with a small animal. Indralin likely provides optimal radioprotective effects and a higher TI for large animals via the increased specificity of its adrenergic effect on tissue respiration, which supports the development of acute hypoxia in the radiosensitive tissues of large animals. The stimulatory effect of indralin on early post-irradiation haematopoietic recovery cannot provide a high level of radioprotective action for large animals, but it may promote recovery.

Comments on the mechanisms of action of radiation protective agents: basis components and their polyvalence

Purpose

These comments suggest a division of radiation protective agents on the grounds of their mechanism of action that increase the radio resistance of an organism.

Conclusion

Given below is the division of radiation protective agents on the basis of their mechanism of action into 3 groups: 1) Radiation protective agents, with the implementation of radiation protective action taking place at the cellular level in the course of rapidly proceeding radiation-chemical reactions. At the same time, when the ionizing radiation energy is absorbed, these agents partially neutralize the “oxygen effect” as a radiobiological phenomenon, especially in the radiolysis of DNA; 2) Radiation protective agents that exert their effect at the system level by accelerating the post-radiation recovery of radiosensitive tissues through activation of a number of pro-inflammatory signaling pathways and an increase in the secretion of hematopoietic growth factors, including their use as mitigators in the early period after irradiation prior to the clinical development of acute radiation syndrome (ARS). 3) Radiomodulators including drugs and nutritional supplements that can elevate the resistance of the organism to adverse environmental factors, including exposure to ionization by means of modulating the gene expression through a hormetic effect of small doses of stressors and a “substrate” maintenance of adaptive changes, resulting in an increased antioxidant protection of the organism. Radiation protective agents having polyvalence in implementation of their action may simultaneously induce radioprotective effect by various routes with a prevalence of basis mechanisms of the action.

Mechanisms of cellular fibrosis associated with cancer regimen-related toxicities

Fibrosis is a common, persistent and potentially debilitating complication of chemotherapy and radiation regimens used for the treatment of cancer. The molecular mechanisms underlying fibrosis have been well studied and reveal overall processes that are largely ubiquitous. However, it is important to note that although the processes are similar, they result in cellular phenotypes that are highly tissue specific. These tissue specific differences may present opportunities for therapeutic interventions to prevent or treat this often irreversible condition. Data generated from animal models of cancer therapy-related tissue toxicities have revealed that the signaling pathways involved in fibrosis are the same as those involved in the normal injury response and include the transforming growth factor β superfamily and a range of pro-inflammatory cytokines. The critical difference between normal wound healing and fibrosis development appears to be, that in fibrosis, these signaling pathways escape normal cellular regulation. As a result, an injury state is maintained and processes involved in normal healing are usurped. There are a few, if any, therapeutics that effectively prevent or treat fibrosis in patients. Consequently, cancer survivors may be chronically plagued with a variety of life-altering fibrosis-related symptoms. Uncovering the signaling pathways that drive cellular fibrosis is paramount to the development of specific therapeutics that will mitigate this potentially devastating condition.

[Hypofractionated radiotherapy, a standard in breast cancer?]

In the era of high-tech radiotherapy, hypofractionated schema is more and more widely used regardless of tumour sites. In this article, we expose the role, techniques and indications of hypofractionated radiotherapy in adjuvant breast radiotherapy.

Molecular mechanisms and treatment of radiation-induced lung fibrosis

Radiation-induced lung fibrosis (RILF) is a severe side effect of radiotherapy in lung cancer patients that presents as a progressive pulmonary injury combined with chronic inflammation and exaggerated organ repair. RILF is a major barrier to improving the cure rate and well-being of lung cancer patients because it limits the radiation dose that is required to effectively kill tumor cells and diminishes normal lung function. Although the exact mechanism is unclear, accumulating evidence suggests that various cells, cytokines and regulatory molecules are involved in the tissue reorganization and immune response modulation that occur in RILF. In this review, we will summarize the general symptoms, diagnostics, and current understanding of the cells and molecular factors that are linked to the signaling networks implicated in RILF. Potential approaches for the treatment of RILF will also be discussed. Elucidating the key molecular mediators that initiate and control the extent of RILF in response to therapeutic radiation may reveal additional targets for RILF treatment to significantly improve the efficacy of radiotherapy for lung cancer patients.

Design and evaluation of biodegradable enteric microcapsules of amifostine for oral delivery

Amifostine is the first FDA approved cytoprotective and chemoprotective agent in the treatment of cancer. However, it is not used widely because of its ineffectiveness when administered orally. The objective of this study was to prepare and evaluate the radioprotective efficacy of orally active amifostine enteric microcapsules (amifostine mc). The microcapsules were prepared by spray drying technique using Eudragit L100-55, and the yield was more than 80%. The particle size and surface morphology were determined by particle analyzer and scanning electron microscopy. Thermal characterization and infrared spectroscopy were evaluated as well. In vitro release assay found that more than 60% amifostine was released during the first 4h and the cumulative release ratio was up to approximately 90% in 24h at 37°C. The radioprotective efficacy was determined by 30-day survival study in mice acutely exposed to 6 Gy γ-ray irradiation. The results showed that all dose groups of amifostine microcapsules could significantly improve survival animal numbers and time. Furthermore, tissue distribution studies indicated the concentrations of the active metabolite WR-1065 in mice tissues of microcapsule group were higher than that of oral amifostine group at 180 min (p<0.01). These results demonstrated that oral administration of amifostine microcapsules provided effective radioprotection compared to the bulk drug.