The American Society for Radiation Oncology Workforce Taskforce Review of the United States Radiation Oncology Workforce Analysis

Over the past decade, concerns have arisen in radiation oncology regarding potential workforce supply and demand imbalance. The American Society for Radiation Oncology commissioned an independent analysis in 2022, looking at supply and demand in the United States radiation oncology workforce and projecting future trends for 2025 and 2030. The final report entitled, "Projected Supply and Demand for Radiation Oncologists in the U.S. in 2025 and 2030" is now available. The analysis included evaluating radiation oncologist supply (new graduates, exits from the specialty), potential changes in demand (growth of Medicare beneficiaries, hypofractionation, loss of indications, new indications) as well as radiation oncologist productivity (growth of work RVUs produced) and demand per beneficiary. The results demonstrated a relative balance between radiation oncology supply and demand for radiation services; the growth in radiation oncologists was balanced by the rapid growth of Medicare beneficiaries over the same time period. The primary factors driving the model were found to be growth of Medicare beneficiaries, and change in work RVU productivity with hypofractionation and loss of indication having only a moderate impact; while the most likely scenario was a balance of workforce supply and demand, scenarios did demonstrate the possibility of over and under supply. Oversupply may become a concern if radiation oncologist wRVU productivity reaches the highest region; beyond 2030, this is also possible if growth in radiation oncologist supply does not parallel Medicare beneficiary growth. Limitations of the analysis included the lack of inclusion of most technical reimbursement and its impact as well as failing to account for SBRT. A modeling tool is available to allow individuals to evaluate different scenarios. Moving forward, continued study will be needed to evaluate trends (particularly work RVU productivity and Medicare beneficiary growth) to allow for continued assessment of workforce supply and demand in radiation oncology.

Making the Most of a Crisis: A Proposal for Network-Based Palliative Radiation Therapy to Reduce Travel Toxicity

A multipronged model is proposed to improve the delivery of palliative radiotherapy by increasing access to care and reducing travel burden for patients.

Development of a Comprehensive, Contour-Based, Peer Review Workflow at a Community Proton Center

Purpose

Quality assurance and continuing quality improvement are integral parts of any radiation oncology practice. With increasingly conformal radiation treatments, it has become critical to focus on every slice of the target contour to ensure adequate tumor coverage and optimal normal tissue sparing. Proton therapy centers open internationally with increasing frequency, and radiation oncologists with varying degrees of subspecialization apply proton therapy in daily practice. Precise treatment with proton therapy allows us to limit toxicity but requires in-depth knowledge of the unique properties of proton beam delivery. To address this need at our proton therapy center, we developed a comprehensive peer review program to help improve the quality of care that we were providing for our patients.

Materials and Methods

We implemented a policy of comprehensive peer review for all patients treated at our community proton facility starting in January 2013. Peer review begins at the time of referral with prospective cases being reviewed for appropriateness for proton therapy at daily rounds. There is then biweekly review of target contouring and treatment plans.

Results

During a 6-month period from June 2013 to November 2013, a total of 223 new patients were treated. Documentation of peer review at chart rounds was completed for 222 of the 223 patients (99.6%). An average of 10.7 cases were reviewed in each biweekly chart rounds session, with a total of 560 case presentations. The average time required for contour review was 145 seconds (±71 seconds) and plan review was 120 seconds (±64 seconds). Modifications were suggested for 21 patients (7.9%) during contour review and for 19 patients (6.4%) during treatment plan review. An average of 4 physicians were present at each session.

Conclusions

We demonstrated that the implementation of a comprehensive, prospective peer review program is feasible in the community setting. This article can serve as a framework for future quality assurance programs.

Hemithoracic intensity modulated radiation therapy after pleurectomy/decortication for malignant pleural mesothelioma: toxicity, patterns of failure, and a matched survival analysis

PURPOSE

To investigate safety, efficacy, and recurrence after hemithoracic intensity modulated radiation therapy after pleurectomy/decortication (PD-IMRT) and after extrapleural pneumonectomy (EPP-IMRT).

METHODS AND MATERIALS

In 2009-2013, 24 patients with mesothelioma underwent PD-IMRT to the involved hemithorax to a dose of 45 Gy, with an optional integrated boost; 22 also received chemotherapy. Toxicity was scored with the Common Terminology Criteria for Adverse Events v4.0. Pulmonary function was compared at baseline, after surgery, and after IMRT. Kaplan-Meier analysis was used to calculate overall survival (OS), progression-free survival (PFS), time to locoregional failure, and time to distant metastasis. Failures were in-field, marginal, or out of field. Outcomes were compared with those of 24 patients, matched for age, nodal status, performance status, and chemotherapy, who had received EPP-IMRT.

RESULTS

Median follow-up time was 12.2 months. Grade 3 toxicity rates were 8% skin and 8% pulmonary. Pulmonary function declined from baseline to after surgery (by 21% for forced vital capacity, 16% for forced expiratory volume in 1 second, and 19% for lung diffusion of carbon monoxide [P for all = .01]) and declined still further after IMRT (by 31% for forced vital capacity [P=.02], 25% for forced expiratory volume in 1 second [P=.01], and 30% for lung diffusion of carbon monoxide [P=.01]). The OS and PFS rates were 76% and 67%, respectively, at 1 year and 56% and 34% at 2 years. Median OS (28.4 vs 14.2 months, P=.04) and median PFS (16.4 vs 8.2 months, P=.01) favored PD-IMRT versus EPP-IMRT. No differences were found in grade 4-5 toxicity (0 of 24 vs 3 of 24, P=.23), median time to locoregional failure (18.7 months vs not reached, P not calculable), or median time to distant metastasis (18.8 vs 11.8 months, P=.12).

CONCLUSIONS

Hemithoracic intensity modulated radiation therapy after pleurectomy/decortication produced little high-grade toxicity but led to progressive declines in pulmonary function; OS and PFS were better in PD-IMRT compared with EPP-IMRT.

Anatomic distribution of fluorodeoxyglucose-avid para-aortic lymph nodes in patients with cervical cancer

PURPOSE

Conformal treatment of para-aortic lymph nodes (PAN) in cervical cancer allows dose escalation and reduces normal tissue toxicity. Currently, data documenting the precise location of involved PAN are lacking. We define the spatial distribution of this high-risk nodal volume by analyzing fluorodeoxyglucose (FDG)-avid lymph nodes (LNs) on positron emission tomography/computed tomography (PET/CT) scans in patients with cervical cancer.

METHODS AND MATERIALS

We identified 72 PANs on pretreatment PET/CT of 30 patients with newly diagnosed stage IB-IVA cervical cancer treated with definitive chemoradiation. LNs were classified as left-lateral para-aortic (LPA), aortocaval (AC), or right paracaval (RPC). Distances from the LN center to the closest vessel and adjacent vertebral body were calculated. Using deformable image registration, nodes were mapped to a template computed tomogram to provide a visual impression of nodal frequencies and anatomic distribution.

RESULTS

We identified 72 PET-positive para-aortic lymph nodes (37 LPA, 32 AC, 3 RPC). All RPC lymph nodes were in the inferior third of the para-aortic region. The mean distance from aorta for all lymph nodes was 8.3 mm (range, 3-17 mm), and from the inferior vena cava was 5.6 mm (range, 2-10 mm). Of the 72 lymph nodes, 60% were in the inferior third, 36% were in the middle third, and 4% were in the upper third of the para-aortic region. In all, 29 of 30 patients also had FDG-avid pelvic lymph nodes.

CONCLUSIONS

A total of 96% of PET positive nodes were adjacent to the aorta; PET positive nodes to the right of the IVC were rare and were all located distally, within 3 cm of the aortic bifurcation. Our findings suggest that circumferential margins around the vessels do not accurately define the nodal region at risk. Instead, the anatomical extent of the nodal basin should be contoured on each axial image to provide optimal coverage of the para-aortic nodal compartment.

Current clinical coverage of Radiation Therapy Oncology Group-defined target volumes for postmastectomy radiation therapy

PURPOSE

The Radiation Therapy Oncology Group (RTOG) has published consensus guidelines for contouring relevant anatomy for postmastectomy radiation therapy (RT). How these contours relate to current treatment practices is unknown. We analyzed the dose-volume histograms (DVHs) for these contours using current clinical practice at University of Texas MD Anderson Cancer Center and compared them with the proposed treatment plans to treat RTOG-defined targets to full dose.

METHODS AND MATERIALS

We retrospectively analyzed treatment plans for 20 consecutive women treated with postmastectomy RT for which the treatment targets were the chest wall (CW), level III axilla (Ax3), supraclavicular (SCV), and internal mammary (IM) nodes. The RTOG consensus definitions were used to contour the following anatomic structures: CW; level I, II, and III axillary nodes (Ax1, Ax2, Ax3); SCV; IM; and heart (H). DVHs for these contours and the ipsilateral lung were generated from clinically designed treatment that had actually been delivered to each patient. For comparison regarding dose to normal tissue, new treatment plans were generated with the goal of covering 95% of the anatomic contours to 45 Gy.

RESULTS

The prescribed dose was 50 Gy in each case. The mean percent of volumes that received 45 Gy (V45) for the RTOG guideline-based contours were CW 74%, Ax1 84%, Ax2 88%, Ax3 96%, SCV 84%, and IM 80%. Mean heart V10 values were 11% for treatment of left-sided tumors and 6% for right-sided tumors. Mean ipsilateral lung V20 values were 28% for left-sided tumors and 34% for right-sided tumors. For the contour-based plans, mean V45 values were CW 94%, Ax1 95%, Ax2 97%, Ax3 98%, SCV 98%, and IM 85%. Mean heart V10 values were 14% for treatment of left-sided tumors and 12% for right-sided tumors. Mean ipsilateral lung V20 values were 32% for left-sided tumors and 45% for right-sided tumors.

CONCLUSIONS

Clinically derived treatment plans, which have proven efficacy and are the current standard, cover 74% to 96% of the anatomy-based RTOG consensus volumes to the prescription dose. This discrepancy should be considered if treatment planning protocol guidelines are designed to incorporate these new definitions.

Role of definitive radiation therapy in carcinoma of unknown primary in the abdomen and pelvis

OBJECTIVES

Carcinoma of unknown primary (CUP) in the abdomen and pelvis is a heterogeneous group of cancers with no standard treatment. Considered by many to be incurable, these patients are often treated with chemotherapy alone. In this study, we determined the effectiveness of radiation therapy in combination with chemotherapy in patients with CUP in the abdomen and pelvis.

PATIENTS AND METHODS

Medical records were reviewed for 37 patients with CUP treated with radiation therapy for disease located in the soft tissues and/or nodal basins of the abdomen and pelvis at the University of Texas M.D. Anderson Cancer between 2002 and 2009. All patients underwent chemotherapy, either before or concurrent with radiation therapy. Patients were selected for radiation therapy on the basis of histologic type, disease extent, and prior therapy response. Twenty patients underwent definitive radiation therapy (defined as radiation therapy targeting all known disease sites with at least 45 Gy) and 17 patients underwent palliative radiation therapy. Only 6 patients had surgical resection of their disease. Patient and treatment characteristics were extracted and the endpoints of local disease control, progression-free survival (PFS), overall survival (OS), and treatment-related toxicity incidence were analyzed.

RESULTS

The 2-year PFS and OS rates for the entire cohort were 32% and 57%, respectively. However, in patients treated with definitive radiation therapy, the rates were 48% and 76%, and 7 patients lived more than 3 years after treatment with no evidence of disease progression. Nevertheless, radiation-associated toxicity was significant in this cohort, as 40% experienced Grade 2 or higher late toxicities.

CONCLUSIONS

The use of definitive radiation therapy should be considered in selected patients with CUP in the soft tissues or nodal basins of the abdomen and pelvis.

Anatomic distribution of [(18)F] fluorodeoxyglucose-avid lymph nodes in patients with cervical cancer

PURPOSE

Current information about the anatomic distribution of lymph node (LN) metastases from cervical cancer is not precise enough for optimal treatment planning for highly conformal radiation therapy. To accurately define the anatomic distribution of these LN metastases, we mapped [(18)F] fluorodeoxyglucose positron emission tomography (FDG PET)-positive LNs from 50 women with cervical cancer.

METHODS AND MATERIALS

Records of patients with cervical cancer treated from 2006 to 2010 who had pretreatment PET/computed tomography (CT) scans available were retrospectively reviewed. Forty-one consecutive patients (group 1) with FDG-avid LNs were identified; because there were few positive paraortic LNs in group 1, 9 additional patients (group 2) with positive paraortic LNs were added. Involved LNs were contoured on individual PET/CT images, mapped to a template CT scan by deformable image registration, and edited as necessary by a diagnostic radiologist and radiation oncologists to most accurately represent the location on the original PET/CT scan.

RESULTS

We identified 190 FDG-avid LNs, 122 in group 1 and 68 in group 2. The highest concentrations of FDG-avid nodes were in the external iliac, common iliac, and paraortic regions. The anatomic distribution of the 122 positive LNs in group 1 was as follows: external iliac, 78 (63.9%); common iliac, 21 (17.2%); paraortic, 9 (7.4%); internal iliac, 8 (6.6%); presacral, 2 (1.6%); perirectal, 2 (1.6%); and medial inguinal, 2 (1.6%). Twelve pelvic LNs were not fully covered when the clinical target volume was defined according to Radiation Therapy Oncology Group guidelines for intensity modulated radiation therapy for cervical cancer.

CONCLUSIONS

Our findings clarify nodal volumes at risk and can be used to improve target definition in conformal radiation therapy for cervical cancer. Our findings suggest several areas that may not be adequately covered by contours described in available atlases.

Automating RTOG-defined target volumes for postmastectomy radiation therapy

PURPOSE

Consistency in defining and contouring target structures in radiation therapy (RT) is critical for highly conformal RT, for evaluating treatment plans, and for quality assurance in multi-institutional RT trials. The Radiation Therapy Oncology Group (RTOG) has published consensus guidelines for contouring targets for postmastectomy RT. To aid in contouring such structures, we evaluated the potential use of an automated contouring technique, known as deformable image registration-based breast segmentation (DEF-SEG).

METHODS AND MATERIALS

The RTOG definitions were used to contour the chest wall (CW); levels I, II, and III axillary nodes (Ax1, Ax2, Ax3); supraclavicular (SCV) nodes; internal mammary (IM) nodes; and the heart. Left-sided and right-sided templates were created. The DEF-SEG was then used to generate auto-segmented contours from the appropriate template to computed tomographic scans of 20 test cases (10 left, 10 right). To assess the accuracy of this method, those contours were manually modified as necessary to match the RTOG definitions, and the extent of the overlap was compared. The dosimetric impact of the difference in contours was then evaluated by comparing dose-volume histograms for modified and unmodified contours.

RESULTS

Mean volume-overlap ratios between the unmodified DEF-SEG-generated contours and modified contours were as follows: CW, 0.91; Ax1, 0.68; Ax2, 0.64; Ax3, 0.68; SCV node, 0.66; IM node, 0.32, and the heart, 0.93. Mean differences in volume receiving 45 Gy (V45) for the modified versus unmodified contours were as follows: CW, 2.1%; SCV node, 4.8%; Ax1, 5.1%; Ax2, 5.6%; Ax3, 3.0%; and IM node, 10.1%. Mean differences in V10 between the modified heart and the unmodified heart were 0.4% for right-sided treatment and 0.5% for left-sided treatment.

CONCLUSIONS

The DEF-SEG can be helpful for delineating structures according to the RTOG consensus guidelines, particularly for the CW and the heart. No clinically significant dosimetric differences were found between the modified and unmodified contours. The DEF-SEG may be useful for evaluating treatment plans for postmastectomy RT in multi-institutional trials.