Better compliance with hypofractionation vs. conventional fractionation in adjuvant breast cancer radiotherapy : Results of a single, institutional, retrospective study

Second Malignancy Probabilities in Patients With Breast Cancer Treated With Conventional Versus Hypofractionated External Beam Radiation Therapy in the Adjuvant Setting

AIMS

For women with breast cancer, seminal studies have shown that adjuvant hypofractionated external beam radiation therapy (hEBRT) maintains similar outcomes and may reduce overall costs compared with conventionally fractionated external beam radiation therapy (cEBRT). However, it is unclear whether hEBRT may be associated with differential risk of development of radiation-induced second malignancies compared with cEBRT. Because the occurrence of second malignancies is small, large databases may improve our understanding of the relative risk of second malignancies between hEBRT and cEBRT.

MATERIALS AND METHODS

Using the National Cancer Database, we carried out a retrospective cohort analysis of women diagnosed with non-metastatic, stage 0-III breast cancer from 2004 to 2017. All patients had a lumpectomy or mastectomy and a follow-up time of at least 60 months after diagnosis. The probability of second malignancies in women receiving adjuvant cEBRT or hEBRT was compared using multivariable logistic regression adjusting for sociodemographic, geographical, clinical and treatment factors, allowing for relative (but not absolute) comparison of second malignancy risk. Temporal sensitivity analyses stratified by year of diagnosis and length of follow-up time were also conducted.

RESULTS

Of the 125 228 women in our study, 115 576 (92.3%) received cEBRT and 9652 (7.71%) received hEBRT. The median age of the cohort was 60 (interquartile range 51-68) years at diagnosis and the median follow-up time was 99.61 (interquartile range 77.5-128.49) months. Upon adjusting for sociodemographic and clinical factors, patients who received hEBRT had no difference in relative risk than patients who received cEBRT (odds ratio 0.937, 95% confidence interval 0.869-1.010, P = 0.091). In analyses stratified by year of diagnosis, and stratified by length of follow-up, there was no difference in second malignancy probability between patients who completed hEBRT and patients who completed cEBRT.

CONCLUSIONS

In this analysis of over 120 000 women with non-metastatic breast cancer, hEBRT was not associated with different odds of developing second malignancies compared with cEBRT. Our findings may inform patient counselling in the choice of radiation regimens for breast cancer and further support the safety of hypofractionated regimens for breast cancer.

Effects of X-ray cranial irradiation on metabolomics and intestinal flora in mice

Cranial radiotherapy is an important treatment for intracranial and head and neck tumors. To investigate the effects of cranial irradiation (C-irradiation) on gut microbiota and metabolomic profile, the feces, plasma and cerebral cortex were isolated after exposing mice to cranial X-ray irradiation at a dose rate of 2.33 Gy/min (5 Gy/d for 4 d consecutively). The gut microorganisms and metabolites were detected by 16 S rRNA gene sequencing method and LC-MS method, respectively. We found that compared with sham group, the gut microbiota composition changed at 2 W and 4 W after C-irradiation at the genus level. The fecal metabolomics showed that compared with Sham group, 44 and 66 differential metabolites were found to be annotated into metabolism pathways at 2 W and 4 W after C-irradiation, which were significantly enriched in the arginine and proline metabolism. Metabolome analysis of serum and cerebral cortex showed that, at 4 W after C-irradiation, the expression pattern of metabolites in serum samples of mice was similar to that of sham group, and the cerebral cortex metabolites of the two groups were completely separated. KEGG functional analysis showed that serum and brain tissue differential metabolites were respectively enriched in tryptophan metabolism, and arginine proline metabolism. The correlation analysis showed that the changes of gut microbiota genera were significantly correlated with the changes of metabolism, especially Helicobacter, which was significantly correlated with many different metabolites at 4 W after C-irradiation. These data suggested that C-irradiation could affect the gut microbiota and metabolism profile, even at relatively long times after C-irradiation.

Novel Form of Breast Intraoperative Radiation Therapy with CT-Guided High-Dose-Rate Brachytherapy: Interim Results of a Prospective Phase-II Clinical Trial

BACKGROUND

Precision breast intraoperative radiation therapy (PB-IORT) is a novel method of IORT that uses customized CT-based treatment plans and high-dose-rate (HDR) brachytherapy. We conducted a phase-II multi-institution trial to evaluate the efficacy of PB-IORT.

STUDY DESIGN

Between 2015 and 2022, 3 centers enrolled women aged 45 years and older with invasive or in situ carcinoma measuring 3 cm or smaller and N0 status (n = 358). Breast-conserving surgery was performed, and a multilumen balloon catheter was placed in the lumpectomy bed. CT images were used to create customized HDR brachytherapy plans that delivered 12.5 Gy to the tumor bed. The primary outcome assessed was the 5-year rate of index quadrant tumor recurrence. An interim analysis was conducted after one-third of eligible participants completed 5 years of follow-up. This trial is registered with clinicaltrials.gov (NCT02400658).

RESULTS

The cohort comprised 153 participants with a median age of 64 years and median follow-up time of 5.9 years. The estimated 5-year index quadrant tumor recurrence rate and overall survival were 5.08% (95% CI 2.23 to 9.68) and 95.1%, respectively. Locoregional (ipsilateral breast and axilla) and distant recurrence rates were each 1.96%. Seven deaths occurred during the first 5 years of follow-up, with only 1 attributable to breast cancer. Overall, 68.6% of patients experienced any adverse effects, and 4 cases of breast-related severe toxicities were observed.

CONCLUSIONS

This study presents the results of a planned interim analysis of a phase-II trial investigating PB-IORT and demonstrates the efficacy and safety of single-fraction, CT-based, HDR brachytherapy after breast-conserving surgery. These findings provide valuable insights into the use of PB-IORT as a treatment modality.

Analysis of multicatheter interstitial brachytherapy: Accelerated partial breast irradiation in a retrospective cohort of early-stage breast cancer patients

PURPOSE

To determine cardiac dose received by patients treated with high dose rate interstitial brachytherapy. Patients with early-stage, node negative breast cancer can be treated using multi-catheter interstitial brachytherapy accelerated partial breast irradiation (MIB-APBI), with the benefit of reduced treatment volumes and favorable toxicity.

METHODS AND MATERIALS

We conducted a retrospective review of left-sided breast cancer patients treated using MIB-APBI at our institution since 2014. The mean heart dose (MHD) was calculated using the Oncentra 3.2 planning system. The minimum distance between the planning target volume (PTVeval) and heart contour was measured manually.

FINDINGS

81 patients were included. The upper outer quadrant was the most common site. The MHD was 97.8 cGy (EQD2a/b=2) (range 22-229 cGy). MHD significantly correlated with the closest distance between PTVeval and heart contour (correlation coefficient -0.823, p <0.001); size of PTVeval (cc) and quadrant location did not.

CONCLUSIONS

Appropriately selected women with early-stage, low-risk, left-sided breast cancer who received MIB-APBI had acceptable MHD. There was a strong correlation between the distance of PTVeval and MHD. Quadrant breast tumor is in cannot be used as a surrogate for MHD in brachytherapy. Our findings contribute to the growing evidence of the utility and safety of MIB-APBI.

Safety of hypofractionated volumetric modulated arc therapy for early breast cancer: A preliminary report

The present study attempts to evaluate the acute and subacute toxicities of hypofractionated volumetric modulated arc therapy (HFX-VMAT) in patients with early breast cancer (EBC). It is a retrospective analysis of 23 patients treated with HFX-VMAT after breast-conserving surgery between September 2021 and February 2022. A total dose of 50.05 to 52.55 Gy was delivered, consisting of 40.05 Gy to the ipsilateral whole breast in 15 fractions of 2.67 Gy and a tumor bed boost dose of 10-12.5 Gy in 4-5 fractions. The primary endpoint was acute/subacute radiation pneumonitis (RP). The secondary endpoint was poor cosmesis, indicating acute/subacute radiation dermatitis. Chest computed tomography (CT) and the Common Terminology Criteria for Adverse Events v.5.0 were used to assess acute and subacute RP and dermatitis, respectively, during radiotherapy (RT) and at 3- and 6-months post-RT. The median follow-up duration was 3.8 months (range, 2.3-4.2). A total of seven patients developed RP. None of these patients presented RP-related symptoms; the diagnosis was based on radiologic findings observed on follow-up chest CT. Among the seven patients with RP, five had right-sided, and two had left-sided breast tumors (71.4 vs. 28.6%; P=0.026). Grade 1 erythema was observed in 19 patients (82.6%) and grade 2 erythema in four (17.4%). The mean target dose, D_105% (the dose received by 105% of the target volume), homogeneity index, mean lung dose, ipsilateral lung V₂₀ (the percentage volume receiving 20 Gy), and V₃₀ (the percentage volume receiving 30 Gy) for ipsilateral whole breast RT were significantly associated with RP (P=0.039, 0.047, 0.018, 0.015, 0.018 and 0.003, respectively.). HFX-VMAT showed tolerable acute/subacute toxicities. Therefore, HFX-VMAT is an effective and safe treatment option for EBC.

Facing problems in radiotherapy for breast cancer patients in Yogyakarta, Indonesia: A cohort retrospective study

BACKGROUND

The aim of this study is to explore problems in radiotherapy for breast cancer patients in Yogyakarta, Indonesia, focusing on overall treatment time (OTT) and completion rate.

METHODS

A retrospective cohort study was conducted based on data from the Insurance Unit at a tertiary hospital in Yogyakarta, Indonesia. The study included all female outpatients with breast cancer who were treated with radiotherapy from January to December 2017 and met the inclusion criteria. The primary outcomes were OTT and completion rate. The secondary outcomes included the number of radiotherapy fractions, radiotherapy doses, number of radiotherapy interruption days, and reasons for radiotherapy interruption. The chi-squared and Mann-Whitney U tests were used to assess the differences in outcomes between two insurance schemes (JKN-PBI (Beneficiaries of Health Insurance Contribution Assistance) and JKN-NON-PBI (Non-Beneficiaries of Health Insurance Contribution Assistance)).

RESULTS

The sample included 285 breast cancer patients (mean age: 53 years). The median OTT was 38 days (IQR: 17-48 days), with 123 (43.2%) patients having prolonged OTT. The completion rate was 57.9%. No significant differences in OTT (44.4% vs. 35.7%, p = 0.445) and completion rate (57.2% vs. 61.9%, p = 0.569) were found between the JKN-NON-PBI and JKN-PBI groups, respectively. In all, the data reported 3,022 interrupted days of radiotherapy across a total of 227 patients. The most common reason for radiotherapy interruption was unknown.

CONCLUSION

There are problems in timely delivery and low completion rate of radiotherapy among breast cancer patients in Indonesia. There are no significant differences in OTT and completion rate between the insurance schemes.

Compliance of Radiotherapy Treatment at a Tertiary Cancer Center in India—A Clinical Audit

Introduction Noncompliance to planned radiotherapy (RT) treatment is associated with inferior outcomes and also serves as an indicator of quality of care offered to the patients. Identification of the rate of noncompliance and its causative factors can help us develop an insight toward implementing mitigation measures thereby improving the quality of treatment.

Objective To ascertain the incidence of noncompliance and the factors affecting the same in patients offered RT appointments.

Materials and Methods We retrospectively reviewed the records of patients from January 1, 2019, to December 31, 2019, who were noncompliant (defaulted RT simulation or defaulted initiation of RT or defaulted planned RT during the course of RT but excluding planned/unplanned treatment breaks or early conclusions prescribed by the treating radiation oncologist) for the planned RT treatment.

Results Of the 8,607 appointments (7,699 external beam RT and 908 brachytherapy) given to the patients attending the radiation oncology outpatient department in the year 2019, a total of 197 (2.28%) patients were found to be noncomplaint. Ninety-seven patients defaulted RT simulation (49.2%), 53 defaulted RT starting (26.9%), and 47 defaulted while on RT (23.9%). Half of these had either head–neck (29.9%) or gynecological (20.8%) malignancies. Patients with breast cancers had the least noncompliance rates (0.02%). The cause for noncompliance was ascertained in 135 patients (68.5%). The common causes of noncompliance were the desire to continue treatment closer to home (21.5%) followed by logistic (17%), lack of confidence in the curative potential of the planned therapy (17%), and financial reasons (11.8%). Patients with head–neck and gynecological malignancies were more often with advanced staged disease and were planned multimodal treatment protocols. The majority of the 23 patients who defaulted palliative RT were planned for fractionated treatments (73.9%).

Conclusion The incidence of noncompliance in patients planned for RT in our institute can be considered optimum. Appropriate counseling of patients at the time of scheduling appointment, upfront identification of patients at high risk of noncompliance, and assisting patients with financial and logistic challenges are imperative to ensure adherence to planned treatment schedule.

The Abscopal Effects of Cranial Irradiation Induce Testicular Damage in Mice

To investigate whether the abscopal effects of cranial irradiation (C-irradiation) cause testicular damage in mice, male C57BL/6 mice (9weeks of age) were randomly divided into a sham irradiation group, a shielded group and a C-irradiation group and administered sham/shielded irradiation or C-irradiation at a dose rate of 2.33Gy/min (5Gy/d for 4 d consecutively). All mice were sacrificed at 4weeks after C-irradiation. We calculated the testis index, observed testicular histology by haematoxylin-eosin (HE) staining and observed testicular ultrastructure by transmission electron microscopy. Western blotting was used to determine the protein levels of Bax, Bcl-2, Cleaved caspase 3, glial cell line-derived neurotrophic factor (GDNF) and stem cell factor (SCF) in the testes of mice. Immunofluorescence staining was performed to detect the expression of Cleaved caspase 3 and 3β hydroxysteroid dehydrogenase (3βHSD), and a TUNEL assay was used to confirm the location of apoptotic cells. The levels of testosterone (T), GDNF and SCF were measured by ELISA. We also evaluated the sperm quality in the cauda epididymides by measuring the sperm count, abnormality, survival rate and apoptosis rate. The results showed that there was no significant difference in testicular histology, ultrastructure or sperm quality between the shielded group and sham group. Compared with the sham/shielded group, the C-irradiation group exhibited a lower testis index and severely damaged testicular histology and ultrastructure at 4weeks after C-irradiation. The levels of apoptosis in the testes increased markedly in the C-irradiation group, especially in spermatogonial stem cells. The levels of serum T and testicular 3βHSD did not obviously differ between the sham group and the C-irradiation group, but the levels of GDNF and SCF in the testes increased in the C-irradiation group, compared with the sham group. In addition, the sperm count and survival rate decreased in the C-irradiation group, while the abnormality and apoptosis rate increased. Under these experimental conditions, the abscopal effects of C-irradiation induced testicular damage with regard to both structure and function and ultimately decreased sperm quality in mice. These findings provide novel insights into prevention and treatment targets for male reproductive damage induced by C-irradiation.

Impact of a SBRT/SRS longitudinal telehealth training pilot course in Latin America

PURPOSE

To assess the impact of longitudinal telehealth training in stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) for clinicians in Latin America.

MATERIALS AND METHODS

Professionals from two Peruvian centers received an initial SBRT/SRS on-site training course and subsequently received follow-up telehealth training (interventional group) or not (negative control arm). Twelve live video conference sessions were scheduled. Surveys pre- and post-curriculum measured participants' confidence in seven practical domains of SBRT/SRS, based on Likert scales of 1-5, and post-curriculum surveys assessed educators' experiences.

RESULTS

Sixty-one participants were registered, with an average of 24 attendees per session. Pre- and post- surveys were completed by 22 participants. For interventional and negative-control groups, mean changes in Likert scale were satisfactory for the former and remained unmodified for the latter.

CONCLUSIONS

Conducting telehealth educational programs via virtual classroom sessions could be a reliable method to augment training for SBRT and SRS.

Predictors of Whole Breast Radiation Therapy Completion in Early Stage Breast Cancer Following Lumpectomy

BACKGROUND

Whole breast radiation therapy (RT) has become standard of care in early stage breast cancer treatment following lumpectomy. Predictors of RT completion have been sparsely studied, with no previous nationwide examination of the impact of fractionation regimen on completion rate.

PATIENTS AND METHODS

The National Cancer Database identified patients with early stage breast cancer having undergone lumpectomy and RT from 2004 through 2015. Fraction size of 1.8-2.0 Gray (Gy) was defined as standard fractionation (SFRT); 2.66-2.70 Gy/fraction as hypofractionation (HFRT). RT completion was defined as receipt of at least 46 Gy for SFRT and 40 Gy for HFRT. A multivariable logistic regression model characterized RT completion predictors.

RESULTS

A total of 100,734 patients were identified where fraction size could be reliably characterized as above; more than 87% completed RT. Of these, 66.8% received SFRT, yet HFRT use significantly increased over time (5.2% increase/year; P < .0001). RT completion rates were significantly greater following HFRT (99.3%) versus SFRT (79.7%); patients receiving SFRT had higher odds of not completing RT (odds ratio, 41.5; 95% confidence interval, 36.6-47.1; P < .0001). Multivariable analysis revealed that African-American and Caucasian patients treated with SFRT versus HFRT had 22 and 43 times the odds of not completing RT, respectively (P < .0001).

CONCLUSIONS

SFRT remained the majority of RT fractionation in the studied time period, although HFRT use has increased over time. Patients residing > 10 miles from a treatment facility or of African-American race had lower odds of completing RT, as were patients treated with SFRT versus HFRT. These findings suggest compliance advantages of HFRT for patients with early stage breast cancer having undergone lumpectomy.

Effect of hypofractionation on the incidental axilla dose during tangential field radiotherapy in breast cancer

Objective

Tangential field irradiation in breast cancer potentially treats residual tumor cells in the axilla after sentinel lymph node biopsy (SLNB). In recent years, hypofractionated radiotherapy has gained importance and currently represents the recommended standard in adjuvant breast cancer treatment for many patients. So far, the impact of hypofractionation on the effect of incidental lymph node irradiation has not be addressed.

Materials and methods

Biological effective dose (BED) and tumor control probability (TCP) were estimated for four different hypofractionated radiation schemes (42.50 Gy in 16 fractions [Fx]; 40.05 Gy in 15 Fx; 27 Gy in 5 Fx; and 26 in 5 Fx) and compared to conventional fractionation (50 Gy in 25 Fx). For calculation of BED and TCP, a previously published radiobiological model with an α/β ratio of 4 Gy was used. The theoretical BED and TCP for incidental irradiation between 0 and 100% of the prescribed dose were evaluated. Subsequently, we assessed BED and TCP in 431 axillary lymph node metastases.

Results

The extent of incidental lymph node irradiation and the fractionation scheme have a direct impact on BED and TCP. The estimated mean TCP in the axillary nodes ranged from 1.5 ± 6.4% to 57.5 ± 22.9%, depending on the patient’s anatomy and the fractionation scheme. Hypofractionation led to a significant reduction of mean TCP of lymph node metastases for all schedules.

Conclusion

Our data indicate that hypofractionation might affect the effectiveness of incidental radiotherapy in the axilla. This is particularly relevant for patients with positive sentinel lymph nodes who receive SLNB only.

Optimization of autogenerated chest-wall radiation treatment plans developed for postmastectomy breast cancer patients in underserved clinics

Over the past decade, several strides have been made to improve the management of breast cancer in developing countries; however, there are still obstacles present. In the area of radiation therapy, these hurdles include limited access to radiotherapy treatment and scarcity of oncology specialists. In an effort to reduce inequities in cancer care while improving patient outcomes, our research is focused on developing automated postmastectomy radiation therapy (PMRT) plans for breast cancer patients in these underserved communities that can be further improved upon through treatment planning system (TPS) specific optimization guidelines. The automated planning tool utilized algorithms integrated with Varian's Eclipse TPS. The tool created PMRT plans that used monoisocentric tangents and supraclavicular (SCV) fields with a mix of high and low energy photon beams along with field-in-field (FIF) segments. The completed autogenerated PMRT plans were imported into Phillip's Pinnacle 9.10 and Varian's Eclipse 13.6 TPSs to be further improved through manual optimization; the time required to complete this step was measured and assessed. A senior dosimetrist, physicist, and physician evaluated the optimized plans for clinical acceptability. Guidelines were developed for the planning systems that can be implemented by personnel with either limited experience in radiation treatment planning or those with limited time to produce treatment plans. The autogenerated plans in conjunction with our guidelines have shown to significantly reduce the time required to produce a clinically acceptable PMRT plan from approximately 120 ± 60 minutes to just 13 ± 11 (Pinnacle) and 12 ± 7 (Eclipse) minutes, reducing the total uninterrupted treatment planning time by an average of 108 ± 51 minutes. The results from this research indicate that the autogenerated PMRT plans along with the optimization guidelines are a viable option to provide quality and clinically acceptable PMRT plans that are more efficient and consistent for postmastectomy breast cancer patients in severely underserved communities.

Endocrine therapy with or without whole breast irradiation in low-risk breast cancer patients after breast-conserving surgery: 10-year results of the Austrian Breast and Colorectal Cancer Study Group 8A trial

PURPOSE

To investigate long-term results of patients with hormonal receptor-positive breast cancer treated with breast-conserving surgery (BCS) and consecutive endocrine therapy (ET) with or without whole breast irradiation (WBI).

METHODS AND MATERIALS

Within the 8 A trial of the Austrian Breast and Colorectal Cancer Study Group, a total of 869 patients received ET after BCS which was randomly followed by WBI (n = 439, group 1) or observation (n = 430, group 2). WBI was applied up to a mean total dosage of 50 Gy (+/- 10 Gy boost) in conventional fractionation.

RESULTS

After a median follow-up of 9.89 years, 10 in-breast recurrences (IBRs) were observed in group 1 and 31 in group 2, resulting in a 10-year local recurrence-free survival (LRFS) of 97.5% and 92.4%, respectively (p = 0.004). This translated into significantly higher rates for disease-free survival (DFS): 94.5% group 1 vs 88.4% group 2, p = 0.0156. For distant metastases-free survival (DMFS) and overall survival (OS), respective 10-year rates amounted 96.7% and 86.6% for group 1 versus 96.4% and 87.6%, for group 2 (ns). WBI (hazard ratio [HR]: 0.27, p < 0.01) and tumour grading (HR: 3.76, p = 0.03) were found as significant predictors for IBR in multiple cox regression analysis.

CONCLUSIONS

After a median follow-up of 10 years, WBI resulted in a better local control and DFS compared with ET alone. The omission of WBI and tumour grading, respectively, were the only negative predictors for LRFS.

Factors influencing non-adherence to radiotherapy: a retrospective audit of 1,548 patients from a tertiary cancer centre

Purpose:

To determine the frequency, factors and reasons of patient non-adherence to radiotherapy (RT) in a tertiary cancer centre.

Background:

Inadvertent treatment interruptions often lead to prolongation of planned treatment time. In the case of RT with a curative intent, prolongation of planned treatment has been associated with inferior clinical outcomes. Delay or prolongation of treatment is associated with a relative risk of local recurrence by up to 2% per day for specific malignancies. Thus, it is critical to understand key factors that influence non-adherence to RT.

Methods and Materials:

A retrospective observation audit was conducted comprising patients treated with radical, adjuvant or palliative RT at our centre from January 2018 to December 2018. Non-adherence was defined as premature permanent termination of planned treatment by the patient without recommendation or consultation from the treating clinician. All data were collected and analysed (retrospectively) with the help of Statistical Package for the Social Sciences (SPSS) version 22.

Results:

A total of 1,548 patients were included in the study of which 105 (6·7%) were non-adherent to planned RT. Of the total 105 patients, 44 (42%) were elderly (60 years and above). Treatment non-adherence was predominant in males (male:female = 1·85:1). More than 90% of non-adherent patients had stage III and IV cancer. A total of 77 patients (74%) out of 105 were more than 50 km away from our centre. A total of 66 (63%) out of 105 patients had completed more than 2 weeks of radiation (40% of planned RT) and then defaulted for radiation due to acute toxicities.

Conclusion:

Treatment adherence is a major factor in determining successful outcomes among cancer patients treated with RT. This study reveals several factors that contribute to non-adherence to treatment.

The Association Between Use of Hypofractionation and Treatment Completion Among Recipients of Radiation Therapy Post-Mastectomy

PURPOSE

Although there is some evidence to support the use of hypofractionated (HF) radiation therapy (RT) postmastectomy, it is not currently the standard of care. RT noncompletion and delayed completion have been shown to lead to inferior outcomes. This study assesses the association between the choice of an HF versus conventionally fractionated regimen and completion.

METHODS AND MATERIALS

RT orders placed in 2016 and 2017 for patients with a national health plan, along with the associated claims, were extracted. Each order was assigned a target date for timely completion, as well as a date 30 days after the target, which was used to assess delayed completion. Univariate analyses and logistic regressions were conducted to test for an association between regimen and completion. A Poisson regression was used to examine the association between regimen and length of treatment delay among patients completing RT.

RESULTS

Of the 743 orders meeting inclusion criteria, 56 (7.5%) were for HF. Unadjusted analyses found that the timely and delayed completion rates were significantly (P < .001) higher for patients receiving HF. The adjusted odds ratios (HF order versus CF order) were 3.96 (95% confidence interval, 2.23-7.01) for timely completion and 2.64 (95% confidence interval, 1.43-5.15) for completion within 30 days of the target. Among completers, an order for HF was significantly (P < .001) associated with less delay.

CONCLUSIONS

When an HF regimen was ordered, patients were more likely to complete therapy without a delay, to complete therapy overall, and, if experiencing a delay, to experience a shorter delay.

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.