Initial Report of a Randomized Trial Comparing Conventional vs. Novel Treatment Planning Technique to Ameliorate Immunosuppression from Lung SBRT

PURPOSE/OBJECTIVE(S)

SBRT is highly effective against early-stage non-small cell lung cancer. Radiation Therapy (RT) is known to modulate the immune system and contribute to the generation of anti-tumor T cells and stimulate T cell infiltration into tumors. However, this anti-tumor activity is offset by radiation-induced immunosuppression (RIIS) which results in lower tumor control and survival. Lymphocytes are highly radiosensitive and RIIS means destroying existing as well as newly created cytotoxic and helper T lymphocytes. We hypothesized that optimizing RT treatment planning by considering circulating blood and lymphatics as a critical Organ at Risk (OAR) may mitigate RIIS.

MATERIALS/METHODS

We conducted an IRB approved NCI funded clinical trial for 50 early-stage lung cancer patients treated with SBRT alone, from 2020 to 2023, to investigate the ability to reduce RIIS by reducing dose to circulating blood and lymphatics with the aid of a predictive algorithm. All SBRT plans adhered to treatment parameters from RTOG 0813 (central) or RTOG 0915 (peripheral). Patients were randomized to two arms: experimental optimization for RIIS (to reduce dose to blood and lymphatic rich organs) versus standard SBRT planning (without optimization for RIIS). Peripheral blood samples were collected at baseline, end of Tx, 4 weeks and 6 months post Tx. Patients with baseline absolute lymphocyte counts (ALC) less than 0.5x109 cells/L were ineligible for the trial. Data acquired for all blood cell types as well as lymphocyte sub populations CD3+, CD4+, CD8+, CD19+, CD56+. Two sample t-test was used to determine the statistical significance between the cohorts at the time points.

RESULTS

The standard arm had an ALC reduction of 28% at one week post Tx and a nadir at 4 weeks with a 34% reduction. Absolute percentage reductions in ALC from baseline in the optimized arm compared to the standard arm are: end of treatment point (13%, p = 0.03), 4 weeks (12%, p = 0.08), 6 months (15%, p = 0.1), and all three time points together 13% (p = 0.001). ALC recovery appears to be faster in the optimized arm. Radiation induced suppression of all blood cell types are also reduced in the optimized arm with respect to standard arm (relative percentages): ALC (34%), WBC (47%), RBC (46%), platelets (40%), monocytes (100%), and neutrophils (62%) at 4-week mark. Average percentage reductions on integral doses, and V5 (volume receiving a 5 Gy dose) of optimized compared to standard plans are: aorta: 26%, 41% heart: 8%, 33%, vena cava: 32%, 52%, T spine: 51%, 81%, lymph nodes: 35%, 57%, total lung- ITV: 1.6%, 1%, body: 10%, 14%.

CONCLUSION

For the first time, we have shown that it is possible to reduce RIIS in a statistically significant manner, compared to standard of care, via optimized RT planning using a predictive model. This has implications in increasing the efficacy of immunotherapy by preserving the existing tumor reactive T cells in the immune system to enhance anti-tumor activity, and in reducing hospitalizations and improving survival.

Long-Term Adherence to Adjuvant Endocrine Therapy Following Various Radiotherapy Modalities in Early Stage Hormone Receptor Positive Breast Cancer

INTRODUCTION

We compared the rates of long-term adjuvant endocrine therapy (AET) adherence after various radiation therapy (RT) modalities among patients with early stage breast cancer.

MATERIALS AND METHODS

Medical records from patients with stage 0, I, or IIA (tumors ≤3 cm), hormone receptor (HR) positive breast cancer that received adjuvant radiation therapy (RT) from 2013 to 2015 at a single institution were retrospectively reviewed. All patients received breast conserving surgery (BCS) followed by adjuvant RT via one of the following modalities: whole breast radiotherapy (WBI), partial breast irradiation (PBI) with either external beam radiation therapy (EBRT) or fractionated intracavitary high-dose rate (HDR) brachytherapy, or single fraction HDR-brachytherapy intraoperative-radiation therapy (IORT).

RESULTS

One hundred fourteen patients were reviewed. Thirty patients received WBI, 41 PBI, and 43 IORT with a median follow up of 64.2, 72.0, and 58.6 months, respectively. For the entire cohort, AET adherence was approximately 64% at 2 years and 56% at 5 years. Among patients in the IORT clinical trial, adherence to AET was approximately 51% at 2 years and 40% at 5 years. After controlling for additional factors, DCIS histology (vs invasive disease) and IORT (compared to other radiation modalities) were associated with decreased endocrine therapy adherence (P < 0.05).

CONCLUSION

DCIS histology and receipt of IORT were associated with lower rates of adherence to AET at 5 years. Our findings suggest that examination of the efficacy of RT interventions such as PBI and IORT in patients who do not receive AET is warranted.

Multicenter analysis of stereotactic radiosurgery for multiple brain metastases from EGFR and ALK driven non-small cell lung cancer

INTRODUCTION

Patients with brain metastases (BrMs) arising from EGFR and ALK driven non-small cell lung cancer (NSCLC) have favorable prognoses and evolving treatment options. We evaluated multicenter outcomes for stereotactic radiosurgery (SRS) to multiple (≥4) BrMs, where randomized data remain limited.

METHODS

Data were collected retrospectively from 5 academic centers on EGFR and ALK NSCLC who received SRS to ≥4 BrMs with their first SRS treatment between 2008 and 2018. Analyzed endpoints included overall survival (OS), freedom from CNS progression (FFCNSP), and freedom from whole-brain radiotherapy (FFWBRT).

RESULTS

Eighty-nine patients (50 EGFR, 39 ALK) received a total of 159 SRS treatments to 1,080 BrMs, with a median follow up of 51.3 months. The median number of BrMs treated with SRS treatment-1 was 6 (range 4-26) and median for all treatments was 9 (range 4-47). Sixteen patients (18 %) had received WBRT prior to SRS treatment-1. The median OS was 24.2, 21.2, and 33.2 months for all patients, EGFR, and ALK subsets, respectively. After multivariable adjustment, only receipt of a next-generation tyrosine kinase inhibitor was associated with OS (HR 0.40, p = 0.005). No differences in OS were observed based on number of BrMs treated. The median FFCNSP was 9.4, 11.6, and 7.5 months, for all patients, EGFR, and ALK subsets, respectively. After multivariable adjustment, the number of BrMs (continuous) treated during treatment-1 was the only negative prognostic factor associated with FFCNSP (HR 1.071, p = 0.045). The 5-year FFWBRT was 73.6 %.

CONCLUSIONS

This multicenter analysis over a >10-year period demonstrated favorable OS, FFCNSP, and FFWBRT, in patients with EGFR and ALK driven NSCLC receiving SRS to ≥4 BrMs. These data support SRS as an option in the upfront and salvage setting for higher burden CNS disease in this population.

A comparative study using time-driven activity-based costing in single-fraction breast high-dose rate brachytherapy: An integrated brachytherapy suite vs. decentralized workflow

INTRODUCTION

Precision breast intraoperative radiation therapy (PB-IORT) is a novel approach to adjuvant radiation therapy for early-stage breast cancer performed as part of a phase II clinical trial at two institutions. One institution performs the entire procedure in an integrated brachytherapy suite which contains a CT-on-rails imaging unit and full anesthesia capabilities. At the other, breast conserving surgery and radiation therapy take place in two separate locations. Here, we utilize time-driven activity-based costing (TDABC) to compare these two models for the delivery of PB-IORT.

METHODS

Process maps were created to describe each step required to deliver PB-IORT at each institution, including personnel, equipment, and supplies. Time investment was estimated for each step. The capacity cost rate was determined for each resource, and total costs of care were then calculated by multiplying the capacity cost rates by the time estimate for the process step and adding any additional product costs.

RESULTS

PB-IORT costs less to deliver at a distributed facility, as is more commonly available, than an integrated brachytherapy suite ($3,262.22 vs. $3,996.01). The largest source of costs in both settings ($2,400) was consumable supplies, including the brachytherapy balloon applicator. The difference in costs for the two facility types was driven by personnel costs ($1,263.41 vs. $764.89). In the integrated facility, increased time required by radiation oncology nursing and the anesthesia attending translated to the greatest increases in cost. Equipment costs were also slightly higher in the integrated suite setting ($332.60 vs. $97.33).

CONCLUSIONS

The overall cost of care is higher when utilizing an integrated brachytherapy suite to deliver PB-IORT. This was primarily driven by additional personnel costs from nursing and anesthesia, although the greatest cost of delivery in both settings was the disposable brachytherapy applicator. These differences in cost must be balanced against the potential impact on patient experience with these approaches.

Knowledge-based quality control of organ delineations in radiation therapy

PURPOSE

To reduce the likelihood of errors in organ delineations used for radiotherapy treatment planning, a knowledge-based quality control (KBQC) system, which discriminates between valid and anomalous delineations is developed.

METHOD AND MATERIALS

The KBQC is comprised of a group-wise inference system and anomaly detection modules trained using historical priors from 296 locally advanced lung and prostate cancer patient computational tomographies (CTs). The inference system discriminates different organs based on shape, relational, and intensity features. For a given delineated image set, the inference system solves a combinatorial optimization problem that results in an organ group whose relational features follow those of the training set considering the posterior probabilities obtained from support vector machine (SVM), discriminant subspace ensemble (DSE), and artificial neural network (ANN) classifiers. These classifiers are trained on nonrelational features with a 10-fold cross-validation scheme. The anomaly detection module is a bank of ANN autoencoders, each corresponding with an organ, trained on nonrelational features. A heuristic rule detects anomalous organs that exceed predefined organ-specific tolerances for the feature reconstruction error and the classifier's posterior probabilities. Independent data sets with anomalous delineations were used to test the overall performance of the KBQC system. The anomalous delineations were manually manipulated, computer-generated, or propagated based on a transformation obtained by imperfect registrations. Both peer-review-based scoring system and shape similarity coefficient (DSC) were used to label regions of interest (ROIs) as normal or anomalous in two independent test cohorts.

RESULTS

The accuracy of the classifiers was ≥ $\ge$ 99.8%, and the minimum per-class F1-scores were 0.99, 0.99, and 0.98 for SVM, DSE, and ANN, respectively. The group-wise inference system reduced the miss-classification likelihood for the test data set with anomalous delineations compared to each individual classifier and a fused classifier that used the average posterior probability of all classifiers. For 15 independent locally advanced lung patients, the system detected > $>$ 79% of the anomalous ROIs. For 1320 auto-segmented abdominopelvic organs, the anomaly detection system identified anomalous delineations, which also had low Dice similarity coefficient values with respect to manually delineated organs in the training data set.

CONCLUSION

The KBQC system detected anomalous delineations with superior accuracy compared to classification methods that judge only based on posterior probabilities.

Local control of 1-5 fraction radiotherapy regimens for spinal metastases: an analysis of the impacts of biologically effective dose and primary histology

BACKGROUND

This analysis evaluates the impacts of biologically effective dose (BED) and histology on local control (LC) of spinal metastases treated with highly conformal radiotherapy to moderately-escalated doses.

MATERIALS AND METHODS

Patients were treated at two institutions from 2010-2020. Treatments with less than 5 Gy per fraction or 8 Gy in 1 fraction were excluded. The dataset was divided into three RPA classes predictive of survival (1). The primary endpoint was LC.

RESULTS

223 patients with 248 treatments met inclusion criteria. Patients had a median Karnofsky Performance Status (KPS ) of 80, and common histologies included breast (29.4%), non-small cell lung cancer (15.7%), and prostate (13.3%). A median 24 Gy was delivered in 3 fractions (BED: 38.4 Gy) to a median planning target volume (PTV) of 37.3 cc. 2-year LC was 75.7%, and 2-year OS was 42.1%. Increased BED was predictive of improved LC for primary prostate cancer (HR = 0.85, 95% CI: 0.74-0.99). Patients with favorable survival (RPA class 1) had improved LC with BED ≥ 40 Gy (p = 0.05), unlike the intermediate and poor survival groups. No grade 3-5 toxicities were reported.

CONCLUSIONS

Moderately-escalated treatments were efficacious and well-tolerated. BED ≥ 40 Gy may improve LC, particularly for prostate cancer and patients with favorable survival.

Intensity Modulated Proton Therapy Treatment Planning for Postmastectomy Patients with Metallic Port Tissue Expanders

Purpose

Proton beam therapy can significantly reduce cardiopulmonary radiation exposure compared with photon-based techniques in the postmastectomy setting for locally advanced breast cancer. For patients with metallic port tissue expanders, which are commonly placed in patients undergoing a staged breast reconstruction, dose uncertainties introduced by the high-density material pose challenges for proton therapy. In this report, we describe an intensity modulated proton therapy planning technique for port avoidance through a hybrid single-field optimization/multifield optimization approach.

Methods and Materials

In this planning technique, 3 beams are utilized. For each beam, no proton spot is placed within or distal to the metal port plus a 5 mm margin. Therefore, precise modeling of the metal port is not required, and various tissue expander manufacturers/models are eligible. The blocked area of 1 beam is dosimetrically covered by 1 or 2 of the remaining beams. Multifield optimization is used in the chest wall target region with blockage of any beam, while single-field optimization is used for remainder of chest wall superior/inferior to the port.

Results

Using this technique, clinical plans were created for 6 patients. Satisfactory plans were achieved in the 5 patients with port-to-posterior chest wall separations of 1.5 cm or greater, but not in the sixth patient with a 0.7 cm separation.

Conclusions

We described a planning technique and the results suggest that the metallic port-to-chest wall distance may be a key parameter for optimal plan design.

Protons versus photons for the treatment of chordoma

BACKGROUND

Chordoma is a rare primary bone tumour with a high propensity for local recurrence. Surgical resection is the mainstay of treatment, but complete resection is often morbid due to tumour location. Similarly, the dose of radiotherapy (RT) that surrounding healthy organs can tolerate is frequently below that required to provide effective tumour control. Therefore, clinicians have investigated different radiation delivery techniques, often in combination with surgery, aimed to improve the therapeutic ratio.

OBJECTIVES

To assess the effects and toxicity of proton and photon adjuvant radiotherapy (RT) in people with biopsy-confirmed chordoma.

SEARCH METHODS

We searched CENTRAL (2021, Issue 4); MEDLINE Ovid (1946 to April 2021); Embase Ovid (1980 to April 2021) and online registers of clinical trials, and abstracts of scientific meetings up until April 2021.

SELECTION CRITERIA

We included adults with pathologically confirmed primary chordoma, who were irradiated with curative intent, with protons or photons in the form of fractionated RT, SRS (stereotactic radiosurgery), SBRT (stereotactic body radiotherapy), or IMRT (intensity modulated radiation therapy). We limited analysis to studies that included outcomes of participants treated with both protons and photons.

DATA COLLECTION AND ANALYSIS

The primary outcomes were local control, mortality, recurrence, and treatment-related toxicity. We followed current standard Cochrane methodological procedures for data extraction, management, and analysis. We used the ROBINS-I tool to assess risk of bias, and GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included six observational studies with 187 adult participants. We judged all studies to be at high risk of bias. Four studies were included in meta-analysis. We are uncertain if proton compared to photon therapy worsens or has no effect on local control (hazard ratio (HR) 5.34, 95% confidence interval (CI) 0.66 to 43.43; 2 observational studies, 39 participants; very low-certainty evidence). Median survival time ranged between 45.5 months and 66 months. We are uncertain if proton compared to photon therapy reduces or has no effect on mortality (HR 0.44, 95% CI 0.13 to 1.57; 4 observational studies, 65 participants; very low-certainty evidence). Median recurrence-free survival ranged between 3 and 10 years. We are uncertain whether proton compared to photon therapy reduces or has no effect on recurrence (HR 0.34, 95% CI 0.10 to 1.17; 4 observational studies, 94 participants; very low-certainty evidence). One study assessed treatment-related toxicity and reported that four participants on proton therapy developed radiation-induced necrosis in the temporal bone, radiation-induced damage to the brainstem, and chronic mastoiditis; one participant on photon therapy developed hearing loss, worsening of the seventh cranial nerve paresis, and ulcerative keratitis (risk ratio (RR) 1.28, 95% CI 0.17 to 9.86; 1 observational study, 33 participants; very low-certainty evidence). There is no evidence that protons led to reduced toxicity. There is very low-certainty evidence to show an advantage for proton therapy in comparison to photon therapy with respect to local control, mortality, recurrence, and treatment related toxicity.

AUTHORS' CONCLUSIONS

There is a lack of published evidence to confirm a clinical difference in effect with either proton or photon therapy for the treatment of chordoma. As radiation techniques evolve, multi-institutional data should be collected prospectively and published, to help identify persons that would most benefit from the available radiation treatment techniques.

Para-Aortic Nodal Radiation in the Definitive Management of Node-Positive Cervical Cancer

Objectives

To investigate the safety and outcomes of elective para-aortic (PA) nodal irradiation utilizing modern treatment techniques for patients with node positive cervical cancer.

Methods

Patients with pelvic lymph node positive cervical cancer who received radiation were included. All patients received radiation therapy (RT) to either a traditional pelvic field or an extended field to electively cover the PA nodes. Factors associated with survival were identified using a Cox proportional hazards model, and toxicities between groups were compared with a chi-square test.

Results

96 patients were identified with a mean follow up of 40 months. The incidence of acute grade ≥ 2 toxicity was 31% in the elective PA nodal RT group and 15% in the pelvic field group (Chi-square p = 0.067. There was no significant difference in rates of grade ≥ 3 acute or late toxicities between the two groups (p>0.05). The KM estimated 5-year OS was not statistically different for those receiving elective PA nodal irradiation compared to a pelvic only field, 54% vs. 73% respectively (log-rank p = 0.11).

Conclusions

Elective PA nodal RT can safely be delivered utilizing modern planning techniques without a significant increase in severe (grade ≥ 3) acute or late toxicities, at the cost of a possible small increase in non-severe (grade 2) acute toxicities. In this series there was no survival benefit observed with the receipt of elective PA nodal RT, however, this benefit may have been obscured by the higher risk features of this population. While prospective randomized trials utilizing a risk adapted approach to elective PA nodal coverage are the only way to fully evaluate the benefit of elective PA nodal coverage, these trials are unlikely to be performed and instead we must rely on interpretation of results of risk adapted approaches like those used in ongoing clinical trials and retrospective data.

Clinical Outcomes and Predictors of Lung Toxicity After Multiple Courses of Lung Stereotactic Body Radiotherapy for Early-Stage Non-Small Cell Lung Cancer

BACKGROUND

The clinical outcomes of multicourse lung stereotactic body radiotherapy (SBRT) have yet to be validated in a prospective study, and there are a lack of data on allowable composite dosimetry.

PATIENTS AND METHODS

Forty-four patients underwent multicourse lung SBRT for recurrent or metachronous NSCLC. The median biologically effective dose (BED₁₀) for the first course and subsequent courses were 132 and 100 Gy, respectively. Patient and treatment characteristics were evaluated to determine the correlation with the development of radiation pneumonitis (RP).

RESULTS

The local control rate was 91%. A total of 13.6% developed a grade 2+ RP, and 4.5% developed a grade 3+ RP, including one grade 5. On univariable analysis, multiple composite dosimetric factors (V₅ [proportion of lung structure receiving at least 5 Gy], V₁₀, V₂₀, V₄₀, and mean lung dose) were correlated with the development of RP. When comprised of the first and second course of SBRT, a composite lung V₅ of < 30% and > 50% was associated with a 0 and 75% incidence of grade 2+ RP, respectively. We identified no significant correlation on multivariable analysis but observed a strong trend between composite lung V₅ and the development of grade 2+ RP (hazard ratio, 1.157; P = .058). Evaluation of multiple clinical factors also identified a significant correlation between the timing of repeat lung SBRT and the development of grade 2+ RP after the second course (P = .0028).

CONCLUSION

Subsequent courses of lung SBRT, prescribed to a median BED₁₀ of 100 Gy, can provide a high rate of local control with a 4.5% incidence of grade 3+ toxicity. Composite lung V₅ and the timing of the second course of lung SBRT may be correlated to the development of RP.

Time-driven activity-based costing of a novel form of CT-guided high-dose-rate brachytherapy intraoperative radiation therapy compared with conventional breast intraoperative radiation therapy for early stage breast cancer

INTRODUCTION

Intraoperative radiation therapy is an emerging option for adjuvant therapy for early stage breast cancer, although it is not currently considered standard of care in the United States. We applied time-driven activity-based costing to compare two alternative methods of breast intraoperative radiation therapy, including treatment similar to the techniques employed in the TARGIT-A clinical trial and a novel version with CT-guidance and high-dose-rate (HRD) brachytherapy.

METHODS AND MATERIALS

Process maps were created to describe the steps required to deliver intraoperative radiation therapy for early stage breast cancer at each institution. The components of intraoperative radiation therapy included personnel, equipment, and consumable supplies. The capacity cost rate was determined for each resource. Based on this, the delivery costs were calculated for each regimen. For comparison across centers, we did not account for indirect facilities costs and interinstitutional differences in personnel salaries.

RESULTS

The CT-guided, HRD form of intraoperative radiation therapy costs more to deliver ($4,126.21) than the conventional method studied in the TARGIT-A trial ($1,070.45). The cost of the brachytherapy balloon applicator ($2,750) was the primary driver of the estimated differences in costs. Consumable supplies were the largest contributor to the brachytherapy-based approach, whereas personnel costs were the largest contributor to costs of the standard form of intraoperative radiation therapy.

CONCLUSIONS

When compared with the more established method of intraoperative radiation therapy using a portable superficial photon unit, the delivery of treatment with CT guidance and HDR brachytherapy is associated with substantially higher costs. The excess costs are driven primarily by the cost of the disposable brachytherapy balloon applicator and, to a lesser extent, additional personnel costs. Future work should include evaluation of a less expensive brachytherapy applicator to increase the anticipated value of brachytherapy-based intraoperative radiation therapy.

Institutional experience with total neoadjuvant therapy for low-lying rectal tumors

123

Background: Surgery has traditionally been the primary treatment for rectal cancer with consideration of neoadjuvant and adjuvant therapies based on stage. Recent studies have shown that Total Neoadjuvant Therapy (TNT) may provide excellent outcomes, with a possibility of non-operative management in patients with rectal cancer. This study is an initial report of our institution’s watchful waiting strategy. Methods: Patients with Stage II-III, low rectal adenocarcinomas treated from 2015-2018 with TNT were retrospectively reviewed. Patients were surgical candidates with no planned surgery. All patients received definitive radiation (median dose 54 Gy, range 50-56 Gy, at 1.8-2 Gy/fx) with concurrent Xeloda, with additional chemotherapy delivered either prior to or following chemoradiation. Kaplan-Meier (KM) method was utilized to estimate the 2 year permanent ostomy and surgery free survivals. Univariate and multivariate analysis using binary logistic regression were performed to assess the odds ratio (OR) of the need for surgery, with 95% confidence interval (CI). Results: 28 patients were treated with TNT with a median age of 59 years (range 32-79 yrs) and median follow up of 24 months (range 6-51 mon). Reasons for TNT included: clinical trial (50%, n = 14), patient desire to avoid surgery (43%, n = 12), and history of LDR prostate brachytherapy (7%, n = 2). The majority of patients had Stage III disease (68%, n = 19). Median tumor distance from the anal verge was 3 cm (range 0-7 cm). 75% (n = 21) of patients were initially managed without surgery, with 5 patients requiring LAR and 2 requiring APR for residual disease. 4 patients initially treated without surgery experienced local recurrence (LR) requiring APR, with a median time to LR of 20 months (range 12-27 mon). The KM estimated 2 year permanent ostomy and surgery free survivals were 69% and 56% respectively. Distant metastases occurred in two patients at 2 and 7 months post RT. An incomplete response on post-treatment MRI predicted eventual receipt of surgery (p = 0.012, OR = 19.8, 95% CI 1.9-202, compared to complete responders). Conclusions: These results support the growing evidence that TNT may provide a non-surgical option for select patients with low lying rectal cancer.

Stereotactic body radiation therapy induced myonecrosis in a patient with prior gemcitabine administered for leiomyosarcoma

We present the case of radiation myonecrosis of the iliopsoas muscle, identified five months after stereotactic body radiation therapy (SBRT, 21 Gy in three fractions) to a metastatic lesion in the right iliac bone of a patient with leiomyosarcoma. The patient had been treated with various chemotherapeutic agents, most notably docetaxel and gemcitabine for five cycles 10 months prior to SBRT. As skeletal muscle is a radio-resistant organ, myonecrosis is rare, but previous case reports suggest that the administration of gemcitabine may increase the likelihood of radiation toxicity, including radiation myonecrosis. Physicians may consider conventional fractionation, rather than a hypofractionated course, in patients who have received or will receive gemcitabine.

Normal tissue dose and risk estimates from whole and partial breast radiation techniques

PURPOSE

To compare radiation dose to organs at risk in patients with early-stage breast cancer treated with lumpectomy and intraoperative radiation therapy with CT-guided HDR brachytherapy (precision breast IORT; PB-IORT) and those treated with external beam whole breast irradiation (WB-DIBH) or partial breast irradiation (PB-DIBH) with deep inspiratory breath hold.

METHODS

We retrospectively identified 52 consecutive patients with left-sided breast cancers treated with either PB-IORT (n = 17, 76% outer breast) on a phase I clinical trial, adjuvant PB-DIBH (n = 18, 56% outer breast, 6% cavity boost), or WB-DIBH (n = 17, 76% outer breast, 53% with lumpectomy cavity boost). Conventional (2 Gy/fraction) or moderate hypofractionation (2.66 Gy/fraction) was prescribed for the external beam cohorts and 12.5 Gy in 1 fraction to 1 cm from the balloon surface was prescribed to the HDR brachytherapy cohort. CT-based planning was used for all patients. Organ at risk doses and excess risk ratios (ERR) for secondary lung cancers, contralateral breast cancers, and cardiac toxicity were compared between treatment techniques.

RESULTS

Compared to WB-DIBH and PB-DIBH, PB-IORT resulted in lower ipsilateral lung V5, V10, V20, mean, and max dose (P < .05). Mean ipsilateral lung BED_3Gy was as follows: 1.32 Gy for PB-IORT, 4.33 Gy for WB-DIBH, 3.35 Gy for PB-DIBH. The ERR for lung cancer was lowest for PB-IORT (P < .001). There was significantly higher contralateral breast max dose but lower mean BED_3Gy for WB-DIBH compared with PB-IORT (P = .012, P = .011, respectively). Mean contralateral breast BED_3Gy was as follows: 0.10 Gy for PB-IORT, 0.06 Gy for WB-DIBH, and 0.08 Gy for PB-DIBH. The ERR for contralateral breast cancer was low for all breast techniques, but WB-DIBH showed lower ERR compared to PB-IORT (P = .019). Mean heart BED_2Gy was higher with PB-IORT at 1.26 Gy compared to 0.48 Gy and 0.24 Gy for WB-DIBH and PB-DIBH, respectively (P < .001).

CONCLUSIONS

Patients with early-stage breast cancer treated with PB-IORT and with tissue-sparing external beam techniques all received low organ at risk doses, but PB-IORT resulted in far lower ipsilateral lung dose compared with external beam techniques. Our data indicate the lowest mean contralateral breast BED in the WB-DIBH group, likely due to the simplicity of the field design in low-risk patients using tangential whole breast radiation. External beam using DIBH results in lowest heart dose, but all techniques were well within recommended heart constraints.

Pituitary Tumor Radiosurgery

Pituitary adenomas represent a common intracranial pathology, usually resulting in the systemic secretion of hormones and compression of local endocrine and optic structures, causing a wide variety of clinical sequelae. While they are typically treated with upfront endocrine and/or surgical decompressive therapy, in patients with residual, recurrent, or refractory disease, decades of data support management with stereotactic radiosurgery. This modality offers favorable local tumor control, endocrine remission rates, and infrequent toxicity. In the future, this alternative to resection will continue to gain popularity among patients and health care providers.

Radiation-related lymphopenia after pelvic nodal irradiation for prostate cancer

26

Background: Given uncertainty regarding the effectiveness of pelvic nodal irradiation (PNI) for prostate cancer, we aimed to determine whether prostate cancer patients treated with PNI are at a higher risk of developing radiation-related lymphopenia (RRL) and whether RRL is predictive for worse treatment outcomes. Methods: The electronic charts of 886 consecutive patients treated with radiation therapy (RT) for prostate cancer from 2006 to 2018 at our institution were retrospectively analyzed. Qualifying patients were those with total lymphocyte counts (TLCs) within one year prior to and 3–24 months after the start of RT. Lymphopenia was the primary outcome; overall survival (OS) and biochemical progression-free survival (bPFS) were secondary outcomes. Results: Thirty-six patients with PNI and ninety-five patients without PNI qualified. In the PNI cohort, 61.1% of patients developed RRL (median follow-up TLC < 1000 cells/µL), versus 26.3% of non-PNI patients. On univariate analysis, initial prostate specific antigen (iPSA), baseline lymphopenia, treatment modality, PNI status, increased planned target volume, and androgen deprivation therapy administration were all significant predictors of RRL ( p < 0.05). On multivariate analysis, PNI status was a significant predictor of RRL ( p < 0.001; HR 3.42; 95% CI 1.22–9.61) as well as iPSA ( p = 0.006; HR 1.05; 95% CI 1.00–1.11) and baseline lymphopenia ( p = 0.007; HR 8.32; 95% CI 2.19–31.6). RRL was not predictive for bPFS, distant metastasis, or OS on multivariate analysis, though the numbers of events were likely insufficient for these analyses. Conclusions: The higher risk of RRL among PNI patients comports with other papers that show increased treatment volumes are associated with higher rates of RRL. Mounting evidence for the adverse effects of RRL on clinical outcomes supports the significance of our findings and suggests further studies are needed on RRL as a potential harm of PNI that may affect interpretation of results from clinical trials of PNI.

Squamous cell carcinoma of the rectum: Practice trends and patient survival

625

Background: Leverage the National Cancer Database (NCDB) to evaluate trends in management of squamous cell cancer (SCC) of the rectum and their effect on survival for this uncommon tumor. Methods: Data was obtained from the NCDB for patients diagnosed with SCC of the rectum between 2004 and 2014, including cT1-4, cN0-2, cM0 (cohort A, n = 2,296) tumors. A subgroup analysis was performed on locally advanced tumors (cT1-T2, N+ or cT3, N any, subcohort B, n = 883), treated with chemoradiation (n = 706) or trimodality therapy (n = 177) including chemotherapy, radiation, and surgery. Pathological complete response rate following neoadjuvant therapy was obtained. Univariate and multivariate logistic regression analyses were performed to generate hazard ratios (HR) investigating factors associated with overall survival. Kaplan-Meier (K-M) method was used to estimate overall surviving proportion at 5 and 10 years. Results: The median age was 60 years with a strong female predilection (71% female). Among patients treated with neoadjuvant therapy, 36% achieved a complete pathological response at a median interval of 67 days from completion of radiation therapy to surgery. The K-M estimated 5 and 10 year overall survival for stage I disease was 71.3% and 57.8%, respectively; stage II disease was 57.0% and 38.9%, respectively; stage III disease was 57.8% and 41.5%, respectively. On multivariate analysis, increased age, male gender, more co-morbidities, and higher cT category ( P < 0.001 for each) resulted in worse survival. For locally advanced tumors (subcohort B), there was no difference in survival between chemoradiation alone compared to trimodality therapy ( P = 0.909 on multivariate analysis). Conclusions: Most providers manage locally advanced SCC of the rectum similar to anal cancer, which results in equivalent overall survival and spares patients from the additional morbidity associated with surgical resection. [Table: see text]

Radiation-related Lymphopenia after Pelvic Nodal Irradiation for Prostate Cancer

Purpose

Given the uncertainty with regard to the effectiveness of pelvic nodal irradiation (PNI) for prostate cancer, we aimed to determine whether patients with prostate cancer who are treated with PNI are at a higher risk of developing radiation-related lymphopenia (RRL).

Methods and materials

The electronic charts of 886 consecutive patients treated with radiation therapy for prostate cancer between 2006 and 2018 at our institution were retrospectively analyzed. Qualifying patients were those with total lymphocyte counts within 1 year before and 3 to 24 months after the start of radiation therapy. Lymphopenia was the primary outcome, and overall survival and biochemical progression-free survival were secondary outcomes.

Results

Thirty-six patients with and 95 patients without PNI qualified for inclusion. In the PNI cohort, 61.1% of patients developed RRL (median follow-up total lymphocyte count < 1000 cells/μL) versus 26.3% of non-PNI patients (P < .001). On univariate analysis, initial prostate-specific antigen level, baseline lymphopenia, treatment modality, PNI status, increased planned target volume, and androgen deprivation therapy administration were all significant predictors of RRL (P < .05). On multivariate analysis, PNI status was a significant predictor of RRL (hazard ratio [HR], 3.42; 95% confidence interval [CI], 1.22-9.61; P < .001), as were initial prostate-specific antigen values (HR, 1.05; 95% CI, 1.00-1.11; P = .006) and baseline lymphopenia (HR, 8.32; 95% CI, 2.19-31.6; P = .007). RRL was not predictive for biochemical progression-free survival, distant metastasis, or overall survival on multivariate analysis, but the number of events was likely insufficient for these analyses.

Conclusions

The higher risk of RRL among patients with PNI comports with other papers that show that increased treatment volumes are associated with higher rates of RRL. Mounting evidence for the adverse effects of RRL on clinical outcomes supports the significance of our findings and suggests that further studies are needed on RRL as a potential harm of PNI that may affect the interpretation of results from clinical trials of PNI.

Squamous cell carcinoma of the rectum: Practice trends and patient survival

Purpose

Leverage the National Cancer Database (NCDB) to evaluate trends in management of nonmetastatic squamous cell cancer (SCC) of the rectum and their effect on survival for this uncommon tumor.

Methods and Materials

Retrospective data was obtained from the NCDB for patients diagnosed with SCC of the rectum between 2004 and 2014, including cT1‐4, cN0‐2, cM0 tumors (cohort A, n = 2296). A subgroup analysis was performed on locally advanced tumors (cT1‐T2, N+ or cT3, N any, subcohort B, n = 883), treated with chemoradiation (n = 706) or trimodality therapy (n = 177) including chemotherapy, radiation, and surgery. Pathological complete response rate following neoadjuvant therapy was obtained. Univariate and multivariate logistic regression analyses were performed to generate hazard ratios (HR) investigating factors associated with overall survival. Kaplan‐Meier (K‐M) method was used to estimate overall surviving proportion at 5 and 10 years.

Results

The K‐M estimated 5 and 10 year overall survival for stage I disease was 71.3% and 57.8%, respectively; stage II disease was 57.0% and 38.9%, respectively; stage III disease was 57.8% and 41.5%, respectively. On multivariate analysis, higher cT category (P < 0.001) resulted in worse survival. For locally advanced tumors (subcohort B), there was no significant difference in survival between chemoradiation alone compared to trimodality therapy (P = 0.909 on multivariate analysis).

Conclusions

Most providers manage locally advanced SCC of the rectum similar to anal cancer, which results in equivalent overall survival and spares patients from the additional morbidity associated with surgical resection.

Stereotactic Shifts During Frame-Based Image-Guided Stereotactic Radiosurgery: Clinical Measurements

PURPOSE

To determine the magnitude and reason for discrepancies between frame- and cone beam computed tomography (CBCT)-determined stereotactic coordinates, we reviewed frame-based Gamma Knife radiosurgery procedures in which CBCT was performed before treatment.

METHODS AND MATERIALS

Clinical and treatment documentation was reviewed for 150 frame placements for which stereotactic coordinates were defined via both frame and fiducials on computed tomography imaging and CBCT. Treatment planning system-reported rotational and translational differences and standard deviations (SDs) between frame-based and CBCT-based stereotactic coordinates were recorded. Potential clinical predictors for increased differences were collected. Multiple linear regressions were performed to evaluate for associations with increased translations and rotations.

RESULTS

The absolute mean of the measured pitch, yaw, and roll shifts was 0.14 degrees (range -0.71-0.63 degrees, SD 0.19 degrees), 0.16 degrees (range -0.50 to 0.83 degrees, SD 0.21 degrees), and 0.12 degrees (range 0.37-0.51 degrees, SD 0.15 degrees), respectively. The absolute mean of the measured shifts in the left-right, anteroposterior, and superior-inferior direction was 0.29 mm (range -1.29 to 0.82 mm, SD 0.35 mm), 0.24 mm (range -0.59 to 0.33 mm, SD 0.19 mm), and 0.24 mm (range -0.69 to 0.91 mm, SD 0.27 mm), respectively. Three cases (2.0%) exceeded 1 mm in translational difference, all in the left-right direction (1.05, 1.13, and 1.29 mm). Lower Karnofsky Performance Scale status was associated with greater translational differences (vector magnitude, P = .023) and rotation (pitch, P = .044; yaw, P = .002). Usage of longer total pin length (sum of all 4 fixation pin lengths) was associated with increased rotation but not with translation (P < .001 and P = .56, respectively).

CONCLUSIONS

CBCT imaging in this cohort of frame-based cases suggests that the discrepancy in stereotactic coordinates is less than 1 mm or degree in most cases. Low Karnofsky Performance Scale status and longer total pin length correlate with larger differences between frame-defined and CBCT-defined stereotactic coordinates.

Preliminary toxicity results using partial breast 3D-CRT with once daily hypo-fractionation and deep inspiratory breath hold

BACKGROUND

To evaluate the clinical outcomes of patients treated with 3D conformal Hypo-fractionated, deep Inspiratory breath-hold (DIBH), Partial breast radiotherapy, termed "HIP." HIP was implemented to merge the schedule of once-daily breast hypofractionation with partial breast treatment.

METHODS

We identified 38 breast cancers in 37 patients from 2013 to 2014 treated at our institution with HIP following lumpectomy for early stage breast cancer. Patients received a hypo-fractionated course (≤ 20 fractions) of once daily radiation to the partial breast (lumpectomy cavity + margin) utilizing DIBH regardless of laterality. Clinical and treatment-related characteristics were obtained, including target volume and organ at risk (OAR) dosimetric characteristics. Patients were followed clinically and with at least yearly mammograms for up to 36 months (range 5-36 months). Acute and late toxicity was scored using the Common Terminology Criteria for Adverse Events (CTCAE) v4.03.

RESULTS

Patients received a median dose of 42.56 Gy in 16 Fractions (Fx) (range 40.05-53.2 Gy; and 15-20 Fx). OAR doses were low, with a mean heart dose of 0.37 Gy, an ipsilateral lung V20 mean of 4%, and a contralateral lung V5 of 1%. Acute toxicity (≤ grade 2) was present in 79% (n = 30) of the cases, with dermatitis being the most common finding (63%). Late grade 1-2 toxicity was present in 42% (n = 16) of the cases, with hyperpigmentation being the most common finding (n = 9). There were no severe acute or late toxicities (≥ grade 3). At a median follow up of 21 months, there were no local, regional, or distant failures.

CONCLUSIONS

We report limited toxicity in this low risk cohort of patients with early stage breast cancer treated with HIP, a unique and logical combination of 3-D conformal external beam radiotherapy, moderate hypo-fractionation, and DIBH.

Short-course Versus Long-course Neoadjuvant Therapy for Non-metastatic Rectal Cancer: Patterns of Care and Outcomes From the National Cancer Database

INTRODUCTION

The purpose of this study was to compare the utilization, pathologic response, and overall survival (OS) between long-course neoadjuvant chemoradiation (LC-CRT) and short-course neoadjuvant radiation (SC-RT) in the treatment of non-metastatic rectal cancer.

METHODS AND MATERIALS

Retrospective data was obtained from the National Cancer Database (NCDB) for patients diagnosed with clinical stage II or III (limited to T3, any N or T1-2, N1-2) rectal cancer between 2004 and 2014 (28,193 patients). Univariate and multivariate analyses were performed to investigate factors associated with receipt of SC-RT, pathologic complete response (pCR) rate, and OS. Patients were compared based on the neoadjuvant therapy they received prior to tumor resection. SC-RT was defined as 25 Gy given over 1 week prior to surgery (with or without chemotherapy as part of their treatment course). LC-CRT was defined as 45 to 60 Gy given over 5 to 6 weeks (with chemotherapy) prior to surgery.

RESULTS

A total of 27,988 (99%) of patients received LC-CRT, and 205 (1%) patients received SC-RT. Receipt of SC-RT was associated with older age, more comorbidities, and treatment at an academic facility (P < .001 for each). Additional days from radiation completion to surgery was associated with a higher pCR rate (P < .001 for both). LC-CRT did not lead to increased OS compared with SC-RT (P = .517).

CONCLUSIONS

In this United States database study, there was no improvement in OS for patients receiving LC-CRT compared with SC-RT; however, a longer interval between radiation therapy and surgery led to a higher pCR rate. Academic facilities were more likely to utilize SC-RT compared with other facilities.

Integration of MRI target delineation into rapid workflow cervical cancer brachytherapy: Impact on clinical outcomes

INTRODUCTION

We evaluated the impact of MRI-based target delineation on toxicity and tumour control after implementation of a protocol to incorporate MRI while minimizing impact on overall procedural time.

METHODS

We retrospectively reviewed outcomes for a cohort of 96 consecutive patients who received intracavitary brachytherapy for cervical cancer at our institution during 2012-2016. Starting in October 2014, an outpatient MRI was obtained for patients after Smit sleeve placement and first insertion to assess concurrent chemoradiotherapy tumour response. Then, for subsequent fractions, the MRI was co-registered by the Smit sleeve to the planning CT for target volume delineation. The primary and secondary outcomes were toxicity and local control, respectively.

RESULTS

Median follow-up for the pre- (n = 50) and post-MRI-based (n = 46) planning groups was 24.6 and 14.7 months, respectively. Median treatment duration for patients before and after MRI implementation was 56 and 58 days (P = 0.052), respectively. Cumulative rectal D2 cc was less for those with MRI-based target delineation (P = 0.005). On multivariable analysis, patients with MRI-based target delineation experienced fewer severe late (CTCAE grade ≥ 3) toxicities (P = 0.025, hazard ratio = 0.25). Local control was 86% and 91% of the pre- and post-MRI groups, respectively (P = 0.959).

CONCLUSIONS

Preliminary findings using this technique, which is applicable to other institutions without in-room MRI availability, are associated with lower radiation prescription doses, lower rectal doses and favourable toxicity rates while maintaining a rapid workflow. Longer follow-up is required to confirm equivalent local control.

National care among patients with WHO grade I intracranial meningioma

PURPOSE

To analyze the national treatment trends of patients diagnosed with benign intracranial meningioma.

METHODS AND MATERIALS

Data was obtained from the National Cancer Database (NCDB) for patients with WHO grade I meningioma tumors between 2004 and 2014 (190,527 patients), diagnosed by either surgical specimen or diagnostic imaging. Univariable and multivariable analyses (binary logistic models) were performed to generate odds ratios (OR) and investigate factors associated with definitive initial treatment compared to initial observation. Initial treatments considered included surgical resection and/or radiation, including either fractionated external beam radiotherapy (EBRT) or stereotactic radiosurgery (SRS).

RESULTS

The rate of observation increased over time, from 37% in 2004 to 55% in 2014 (p < 0.001). Conjointly, the rate of resection decreased from 50% to 37% from 2004 to 2014 (p < 0.001). The utilization of radiotherapy, including SRS, remained generally stable over time at 6% or less. SRS was more frequently utilized, compared to EBRT, as definitive treatment (4.6% versus 1.7%, respectively, p < 0.001). Compared to Community Cancer programs, patients at Academic/Research programs were more likely to receive definitive initial treatment over observation (OR = 2.909, each p < 0.001).

CONCLUSIONS

There is a national trend favoring initial observation for radiographically diagnosed WHO grade I meningioma. However, patients presenting to academic facilities are more likely to receive definitive initial treatment. Further research into differing approaches among treatment facilities for this common tumor may help clarify this trend.

Adult nodular lymphocyte-predominant Hodgkin lymphoma: treatment modality utilization and survival

Early-stage nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is associated with a favorable prognosis. Our aim was to evaluate the patterns of care of radiotherapy utilization in this disease and to define the relationship between treatment modality and survival. The National Cancer Database was queried for patients with stages I-II NLPHL diagnosed from 2004 to 2012. Patients were compared based on primary therapy into four categories: radiotherapy, chemotherapy, both, or neither. Covariate-adjusted and propensity score-weighted (PS) Cox proportional hazards models were used, adjusting for potential factors confounding survival. After exclusions, 1420 patients were evaluated, 571 (40%) received radiotherapy alone, 318 (22%) received chemotherapy alone, 351 (25%) received both, and 180 (13%) received neither. Younger patient age (P = 0.001), female gender (P = 0.019), and chemotherapy use (P < 0.001) were associated with decreased radiotherapy utilization. On PS, radiation alone (HR = 0.298, P < 0.001) and chemoradiotherapy (HR = 0.258, P < 0.001) were associated with improved survival compared to no upfront therapy, but the use of chemotherapy alone did not statistically differ compared to no initial therapy (HR = 0.784, P = 0.078). In this large database analysis, over one-third of patients with early-stage NLPHL did not receive radiotherapy as a component of initial therapy. The omission of upfront radiotherapy was associated with inferior survival.

Quality assurance tool for organ at risk delineation in radiation therapy using a parametric statistical approach

PURPOSE

To develop a quality assurance (QA) tool that identifies inaccurate organ at risk (OAR) delineations.

METHODS

The QA tool computed volumetric features from prior OAR delineation data from 73 thoracic patients to construct a reference database. All volumetric features of the OAR delineation are computed in three-dimensional space. Volumetric features of a new OAR are compared with respect to those in the reference database to discern delineation outliers. A multicriteria outlier detection system warns users of specific delineation outliers based on combinations of deviant features. Fifteen independent experimental sets including automatic, propagated, and clinically approved manual delineation sets were used for verification. The verification OARs included manipulations to mimic common errors. Three experts reviewed the experimental sets to identify and classify errors, first without; and then 1 week after with the QA tool.

RESULTS

In the cohort of manual delineations with manual manipulations, the QA tool detected 94% of the mimicked errors. Overall, it detected 37% of the minor and 85% of the major errors. The QA tool improved reviewer error detection sensitivity from 61% to 68% for minor errors (P = 0.17), and from 78% to 87% for major errors (P = 0.02).

CONCLUSIONS

The QA tool assists users to detect potential delineation errors. QA tool integration into clinical procedures may reduce the frequency of inaccurate OAR delineation, and potentially improve safety and quality of radiation treatment planning.

Spatial shifts in frame-based Gamma Knife radiosurgery: A case for cone beam CT imaging as quality assurance using the Gamma Knife® Icon™

BACKGROUND

Cone beam CT (CBCT) imaging has been integrated into the most recent version of the Leksell Gamma Knife for the primary purpose to facilitate fractionated therapy.

CASE DESCRIPTION

This case study presents three patients where the CBCT system of the Gamma Knife Icon discovered potentially clinically significant frame shifts. In each case, patients were imaged with volumetric MR prior to stereotactic frame placement. Immediately following frame placement, diagnostic stereotactic CT imaging was acquired with a stereotactic indicator box attached to the frame. Following treatment planning and immediately before radiosurgery, a CBCT was acquired using the on-board imaging functionality of the Gamma Knife Icon, which provides a registration of the patient's anatomy to stereotactic space independent of that provided by the stereotactic frame/fiducials. Co-registration of the CT and CBCT provides an estimate of the difference between these two estimates of stereotactic coordinates. The vector magnitudes of the differences measured at the center of stereotactic space were 0.93mm, 2.64mm and 2.18 mm for Case 1, Case 2 and Case 3 respectively.

CONCLUSIONS

Use of the CBCT functionality of the Gamma Knife Icon to verify the consistency of frame placement can prevent clinically significant targeting errors due to frame slippage or frame adapter mounting errors, and allows any required adjustments to be made without interrupting the overall treatment workflow.

Prostate cancer high dose-rate brachytherapy: review of evidence and current perspectives

INTRODUCTION

Patients with intermediate to high risk disease (prostate specific antigen (PSA) ≥ 10, Gleason score ≥ 7, or clinical stage ≥ T2b) suffer from poorer long-term biochemical control (freedom from an increasing prostate specific antigen level) when treated with external beam radiation (EBRT) alone. In order to improve biochemical control while limiting long-term complications, brachytherapy has been incorporated into radiotherapy treatment, either alone or in combination with EBRT.

AREAS COVERED

Current literature regarding the use of high dose-rate (HDR) brachytherapy for localized prostate cancer, including as a boost and monotherapy. The efficacy and toxicities of various approaches are evaluated including comparisons to low dose-rate (LDR) brachytherapy.

EXPERT COMMENTARY

Prostate HDR brachytherapy has higher conformality than EBRT, potentially improving the therapeutic ratio by allowing higher doses per fraction to tumor cells. The improved biochemical control shown in trials have resulted in EBRT plus brachytherapy to be included as a standard treatment option supported by the NCCN and ASCO guidance documents for intermediate to high risk prostate cancer.

Impact of academic facility type and volume on post-surgical outcomes following diagnosis of glioblastoma

OBJECTIVE

To identify if facility type and/or facility volume impact overall survival (OS) following diagnosis of glioblastoma (GBM). We also sought to compare early post-surgical outcomes based on these factors.

METHODS

The National Cancer Database was queried for patients with GBM diagnosed from 2004 to 2013 with known survival. Patients were grouped based on facility type and facility volume. Multivariable analyses were performed to investigate factors associated OS following diagnosis and Chi-square tests were used to compare early post-surgical outcomes.

RESULTS

89,839 patients met inclusion criteria. Factors associated with improved OS on multivariable analysis included younger patient age, female gender, race, lower comorbidity score, higher performance score, smaller tumor size, unifocal tumors, MGMT hypermethylation, fully resected tumors, radiotherapy, and chemotherapy (each p < .001). Also, OS was improved among patients treated at centers averaging at least 30.2 cases per year (HR 0.948, compared to <7.4 cases/year, p < .001), and patients treated at Academic/Research programs had improved survival compared to those treated at Comprehensive Community Cancer programs (HR 1.069, p < .001) and Integrated Network Cancer programs (HR 1.126, p < .001). Similarly, Academic/Research programs and high volume centers demonstrated improved 30- and 90-day morality as well as 30-day readmission rates (p < .001).

CONCLUSIONS

This study suggests that patients treated in Academic/Research programs and high patient-volume centers have increased survival and more favorable early-postsurgical outcomes. The extent to which differences in patient populations, socioeconomic factors, and/or provider expertise play into this cause will be areas of future research.

National trends in radiotherapy for brain metastases at time of diagnosis of non-small cell lung cancer

BACKGROUND

To analyze the national trends of patients treated radiotherapy for brain metastases from non-small cell lung cancer (NSCLC) that were found at diagnosis.

METHODS

The National Cancer Database was queried for patients with NSCLC diagnosed from 2004 to 2013 that received brain irradiation for metastases and patients grouped into having had received fractionated brain radiotherapy (5-15 fractions with or without radiosurgery) or intracranial radiosurgery alone (1-5 fractions). Univariable and multivariable (MVA) analyses were performed to investigate factors associated with the receipt of SRS alone, and temporal/regional trends.

RESULTS

47,746 patients met inclusion criteria, of which 42,148 received fractionated brain irradiation (88%) and 5,598 received radiosurgery (12%). 345 patients received fractioned brain irradiation with a radiosurgical boost (0.8%). The utilization of radiosurgery-alone increased over time owing to increases in each radiosurgery modality. On MVA, several factors were associated with increased odds of receiving intracranial radiosurgery-alone over fractionated brain radiotherapy including more recent year of diagnosis, increased median income, eastern U.S. regions, further distance to the hospital, and the receipt of chemotherapy (each p<0.001). Patients of Asian descent were less likely to receive radiosurgery alone (p=0.044).

CONCLUSIONS

In the management of brain metastases from NSCLC, overall utilization of an intracranial radiosurgery alone treatment strategy has increased over the past decade. Despite this, there appear to be significant geographic variations and disparities remain based on patient income level and race. Further study is needed to define the reasons for these disparities and appropriate actions to mitigate them.

The Effect of Receptor Status on Mastectomy and Contralateral Prophylactic Mastectomy Rates in Early Stage Invasive Breast Carcinoma

BACKGROUND

There is an established relationship between hormone receptor (HR; estrogen and/or progesterone receptors) status, HER2 status, and locoregional recurrence. The purpose of this study was to analyze how HR and HER2 receptor status have influenced the surgical management trends among patients with early stage breast cancer.

PATIENTS AND METHODS

The National Cancer Database was queried for patients with cT1 to cT3, cN0, and cM0 breast carcinoma from 2004 to 2012. Patients were grouped on the basis of receptor status and surgical management (mastectomy or breast-conserving surgery [BCS]). Multivariable analyses were performed to investigate factors associated with increased odds of receiving mastectomy over BCS. Among a subgroup of patients who underwent ipsilateral mastectomy, analyses were performed to determine any association between contralateral prophylactic mastectomy (CPM) and receptor status.

RESULTS

We found 280,241 patients who met inclusion criteria for analyzing mastectomy or BCS surgical decision. Patients with HER2-positive (HER2⁺) tumors (HR⁺/HER⁺ and HR^-/HER2⁺) were the most likely to undergo mastectomy (odds ratio [OR], 1.212 and 1.499 respectively, compared with HR⁺/HER2^- patients, each P < .001). HR status alone did not affect ipsilateral surgical management as patients with HR⁺/HER2^- and HR^-/HER2^- tumors demonstrated similar mastectomy rates (P = .391). Among the 108,018 who underwent mastectomy, 20% underwent CPM. After adjustment, patients with HR⁺/HER2⁺, HR^-/HER2⁺, and HR^-/HER2^- were all more likely to undergo CPM (OR 1.356, 1.608, and 1.358, respectively compared with HR⁺/HER2^- patients, each P < .001).

CONCLUSION

This analysis indicates that patients with early stage breast cancer are more likely to undergo a mastectomy and CPM if they have HER2⁺ tumors.

Intraoperative radiation therapy for breast cancer patients: current perspectives

Accelerated partial breast irradiation (APBI) provides an attractive alternative to whole breast irradiation (WBI) through normal tissue radiation exposure and reduced treatment duration. Intraoperative radiation therapy (IORT) is a form of APBI with the shortest time interval, as it delivers the entirety of a planned radiation course at the time of breast surgery. However, faster is not always better, and IORT has been met with healthy skepticism. Patients treated with IORT have an increased compliance and overall satisfaction when compared to patients treated with WBI. However, early randomized trial results demonstrated an increased rate of recurrence after IORT, slowing its widespread adoption. Despite these controversies, IORT utilization is increasing nationally and several novel developments are aimed at continuing to minimize the risk of recurrence and treatment-related toxicity while maximizing the patient experience.