Radiation Therapy Techniques and Treatment-Related Toxicity in the PORTEC-3 Trial: Comparison of 3-Dimensional Conformal Radiation Therapy Versus Intensity-Modulated Radiation Therapy

Abandonment of Routine Radiotherapy for Nonlocally Advanced Rectal Cancer and Oncological Outcomes

Importance

Neoadjuvant short-course radiotherapy was routinely applied for nonlocally advanced rectal cancer (cT1-3N0-1M0 with >1 mm distance to the mesorectal fascia) in the Netherlands following the Dutch total mesorectal excision trial. This policy has shifted toward selective application after guideline revision in 2014.

Objective

To determine the association of decreased use of neoadjuvant radiotherapy with cancer-related outcomes and overall survival at a national level.

Design, Setting, and Participants

This multicenter, population-based, nationwide cross-sectional cohort study analyzed Dutch patients with rectal cancer who were treated in 2011 with a 4-year follow-up. A similar study was performed in 2021, analyzing all patients that were surgically treated in 2016. From these cohorts, all patients with cT1-3N0-1M0 rectal cancer and radiologically unthreatened mesorectal fascia were included in the current study. The data of the 2011 cohort were collected between May and October 2015, and the data of the 2016 cohort were collected between October 2020 and November 2021. The data were analyzed between May and October 2022.

Main Outcomes and Measures

The main outcomes were 4-year local recurrence and overall survival rates.

Results

Among the 2011 and 2016 cohorts, 1199 (mean [SD] age, 68 [11] years; 430 women [36%]) of 2095 patients (57.2%) and 1576 (mean [SD] age, 68 [10] years; 547 women [35%]) of 3057 patients (51.6%) had cT1-3N0-1M0 rectal cancer and were included, with proportions of neoadjuvant radiotherapy of 87% (2011) and 37% (2016). Four-year local recurrence rates were 5.8% and 5.5%, respectively (P = .99). Compared with the 2011 cohort, 4-year overall survival was significantly higher in the 2016 cohort (79.6% vs 86.4%; P < .001), with lower non-cancer-related mortality (13.8% vs 6.3%; P < .001).

Conclusions and Relevance

The results of this cross-sectional study suggest that an absolute 50% reduction in radiotherapy use for nonlocally advanced rectal cancer did not compromise cancer-related outcomes at a national level. Optimizing clinical staging and surgery following the Dutch total mesorectal excision trial has potentially enabled safe deintensification of treatment.

Prompt Pain Relief From Bone Metastases: The Virtual Simulation Program

Purpose

Rapid pain relief for patients with bone metastases can be a challenge due to the lengthy and complex radiation therapy workflow. The purpose of this study was to evaluate the time (in days) between initial radiation oncology consultation and start of palliative radiation treatment after implementing an alternative virtual simulation palliative workflow.

Methods and Materials

Patients meeting strict criteria were selected for virtual simulation, which included only those with painful bone metastases who were recommended palliative radiation therapy using standard anterior-posterior/posterior-anterior or opposed lateral fields. A recent (within 30 days) diagnostic computed tomography (CT) scan clearly visualizing the target volume was required for treatment planning. For comparison, a reference group of 40 consecutive patients with bone metastases who underwent in-person CT simulation before virtual simulation implementation was reviewed.

Results

Forty-five patients were treated for painful bone metastases as part of the virtual simulation program from May 2021 to October 2022. Regarding travel distance, 23 patients lived locally (<50 miles from the treatment center) and 22 patients were distant (≥50 miles from the treatment center). Average time from consultation to treatment for all patients undergoing virtual simulation was 3.7 days, compared with 7.5 days for patients undergoing in-person CT simulation (3.8 days sooner, on average; P ≤ .001). Before full implementation of the virtual simulation program, 5 eligible patients participated in a virtual simulation pilot from April 2021 to May 2021, in which each patient was contoured and planned on both a pre-existing diagnostic CT scan and a standard CT simulation scan. For virtual simulation-based plans, the average V90, V95, and V99 were 99.99%, 99.87%, and 96.70%. No significant planning target volume (PTV) coverage difference was found on subsequent in-person CT simulation scans.

Conclusions

The virtual simulation program decreased the time from consultation to start of treatment by more than 50% for patients recommended palliative radiation therapy for painful bone metastases. This benefit was most significant for outpatients traveling ≥50 miles for treatment. Virtual simulation-based planning can be considered for patients anxious to proceed with radiation therapy quickly or in underserved settings with limited transportation options to regional treatment centers.

Impact of reduced margin pelvic radiotherapy on gastrointestinal toxicity and outcome in gynecological cancer

Purpose

To investigate the effect of reduced margin pelvic radiotherapy on gastrointestinal toxicity and outcomes in gynecological cancer.

Materials and methods

This retrospective study analyzed data of 590 patients who underwent hysterectomy and adjuvant pelvic radiotherapy between 2010 and 2020 at two tertiary centers. The pelvic nodal region was delineated based on a reduced margin definition or the Radiation Therapy Oncology Group (RTOG) guidelines. All patients were treated with intensity-modulated radiotherapy with imaging guidance. Gastrointestinal toxicity was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) and the Patient-Reported Outcome version (PRO-CTCAE).

Results

Overall, 352 (59.7%) and 238 (40.3%) patients underwent RTOG and reduced margin pelvic radiotherapy, respectively. Median follow-up was 6.4 years (IQR: 3.7-9.6). Reduced margin pelvic radiotherapy significantly lowered the radiation dose to the small bowel. For CTCAE grade ≥ 2 or 3, acute gastrointestinal toxicity was lower in the reduced margin group than in the RTOG group (16.4% vs. 33.5%, p < 0.001; 2.9% vs. 8.5%, p < 0.001). The reduced margin group reported less severe acute gastrointestinal toxicity (PRO-CTCAE score ≥ 3) than the RTOG group (12.5% vs. 28.7%, p < 0.001). Late grade 3 gastrointestinal toxicity was lower in the reduced margin group than in the RTOG group (0.8% vs. 4.8%, p = 0.006). The 5-year pelvic recurrence-free survival and disease-free survival in the RTOG and reduced margin pelvic radiotherapy groups were 97.4% and 97.9% (p = 0.55) and 80.7% and 83.5% (p = 0.18), respectively.

Conclusion

Reduced margin pelvic radiotherapy decreased acute and late gastrointestinal toxicity and achieved favorable outcomes.

Changes in physical function in older women with endometrial cancer with or without adjuvant therapy

OBJECTIVE

To evaluate changes in physical function (PF) for older women with endometrial cancer (EC) + / - adjuvant therapy in the Women's Health Initiative Life and Longevity after Cancer cohort.

MATERIALS AND METHODS

This study examined women ≥ 70 years of age with EC with available treatment records. Change in PF was measured using the RAND-36 and compared between groups using Wilcoxon rank-sum tests. Multivariable median regression was used to compare the changes in scores while adjusting for confounding variables.

RESULTS

Included in the study were 287 women, 150 (52.3%) women who did not receive adjuvant therapy and 137 (47.7%) who received adjuvant therapy. When comparing PF scores, there was a statistically significant difference in the median percent change in functional decline, with a greater decline in those who received adjuvant therapy (- 5.9% [- 23.5 to 0%]) compared to those who did not (0 [- 18.8 to + 6.7%]), p = 0.02). Results were not statistically significant after multivariable adjustment, but women who underwent chemotherapy had a greater percent change (median ∆ - 13.8% [- 35.5 to 0%]) compared to those who received radiation alone (median ∆ - 5.9% [- 31.3 to 0%]) or chemotherapy and radiation (median ∆ - 6.5% [- 25.8 to + 5.7%].

CONCLUSIONS

Older women with EC who received adjuvant therapy experienced greater change in PF than those who did not receive adjuvant therapy, particularly women who received chemotherapy. These results were not statistically significant on multivariate analysis.

IMPLICATIONS FOR CANCER SURVIVORS

EC survivors may experience changes in PF because of chemotherapy and/or radiation therapy. Additional supportive care may need to be provided to older women to mitigate functional decline.

Hypothyroidism following Radiotherapy for Head and Neck Cancer: A Systematic Review of the Literature and Opportunities to Improve the Therapeutic Ratio

(1) Background: Radiotherapy (RT) is a central component for the treatment of many head and neck cancers. In this systematic review of the literature, we aimed to characterize and quantify the published evidence on RT-related hypothyroidism, including estimated incidence, clinical risk factors, and dosimetric parameters that may be used to guide clinical decision making. Furthermore, we aimed to identify potential areas of improvement in the prevention and clinical management of RT-induced hypothyroidism, including the role of modern advanced therapeutic techniques. (2) Methods: We conducted a systemic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed and Google Scholar were searched to identify original research articles describing the incidence, mechanism, dosimetry, treatment, or prevention of radiation-related hypothyroidism for adults receiving RT for the treatment of head and neck cancers. The snowball method was used to identify additional articles. For identified articles, we tabulated several datapoints, including publication date, patient sample size, estimated hypothyroidism incidence, cancer site/type, follow-up period, radiation modality and technique, use of multimodality therapy, method of thyroid function evaluation, and proposed dosimetric predictors of hypothyroidism. (3) Results: One hundred and eleven articles met inclusion criteria, reflecting a range of head and neck cancer subtypes. There was a large variation in the estimated incidence of RT-related hypothyroidism, with a median estimate of 36% (range 3% to 79%). Reported incidence increased in later publication dates, which was likely related to improved screening and longer follow up. There were a wide variety of predictive metrics used to identify patients at high risk of hypothyroidism, the most common of which were volumetric and mean dosimetrics related to the thyroid gland (Vxx%, Dmean). More recently, there has been increasing evidence to suggest that the thyroid gland volume itself and the volume of the thyroid gland spared from high-dose radiation (VSxx) may better predict thyroid function after RT. There were no identified studies investigating the role of advanced radiotherapeutic techniques such as MRI-guided RT or particle therapy to decrease RT-related hypothyroidism. Conclusions: Hypothyroidism is a common toxicity resulting from therapeutic radiation for head and neck cancer with recent estimates suggesting 40-50% of patients may experience hypothyroidism after treatment. Dosimetric predictive models are increasingly able to accurately identify patients at risk of hypothyroidism, especially those utilizing thyroid VS metrics. Further investigation regarding the potential for advanced radiotherapeutic therapies to decrease RT-induced thyroid dysfunction is needed.

Health-related quality of life and patient-reported symptoms after postoperative proton beam radiotherapy of cervical and endometrial cancer: 2-year results of the prospective phase II APROVE-trial

INTRODUCTION

The APROVE-trial investigated the tolerability of postoperative proton beam therapy in women with cervical or endometrial cancer. The present analysis evaluated the secondary endpoints of health-related quality of life (HRQOL) and patient-reported symptoms.

METHODS

25 patients were included in this prospective phase-II-trial and treated with postoperative radiotherapy using protons alone or in combination with chemotherapy. To attain general and gynecologic-specific HRQOL measures, the EORTC-QLQ-C30 questionnaires combined with -QLQ-CX24 for cervical and -QLQ-EN24 for endometrial cancer were assessed at baseline, at the end of RT and up to 2 years after radiotherapy. The results were compared to an age-matched norm reference population. Symptoms were assessed using Common Terminology Criteria for Adverse Events (CTCAE) and institutional patient-reported symptoms grading.

RESULTS

Scores regarding global health status were markedly impaired at baseline (mean: 58.0 ± 20.1) compared to reference population data, but significantly (p = 0.036) improved and evened out to comparable norm values 2 years after proton therapy (mean: 69.9 ± 19.3). Treatment caused acute and long-term worsening of pain (p = 0.048) and gastrointestinal symptoms (p = 0.016) for women with endometrial cancer, but no higher-grade CTCAE ≥ 3° toxicity was observed. Dosimetric evaluation of rectum, sigmoid, large and small bowel showed no correlation with the reported gastrointestinal symptoms. After 2 years, fatigue had significantly improved (p = 0.030), whereas patients with cervical cancer experienced more often lymphedema (p = 0.017). Scores for endometrial cancer pertaining to sexual activity (p = 0.048) and body image (p = 0.022) had improved post treatment; in the latter this effect persisted after 2 years.

CONCLUSION

Proton beam therapy in the adjuvant setting was well tolerated with only low-grade side effects concerning gastrointestinal symptoms, lymphedema and pain. Overall quality of life was impaired at baseline, but patients were able to recover to values comparable to norm population 2 years after proton therapy. Larger studies are needed to confirm whether the benefit of proton therapy translates into a clinical effect. Sexual dysfunction remains an important issue.

TRIAL REGISTRATION

The trial was registered at https://clinicaltrials.gov (ClinicalTrials.gov Identifier: NCT03184350, 09th June 2017).

Comparison of Breast Cancer Radiotherapy Techniques Regarding Secondary Cancer Risk and Normal Tissue Complication Probability - Modelling and Measurements Using a 3D-Printed Phantom

Background

Radiotherapy after breast-conserving therapy is a standard postoperative treatment of breast cancer, which can be carried out with a variety of irradiation techniques. The treatment planning must take into consideration detrimental effects on the neighbouring organs at risk-the lung, the heart, and the contralateral breast, which can include both short- and long-term effects represented by the normal tissue complication probability and secondary cancer risk.

Patients and Methods

In this planning study, we investigate intensity-modulated (IMRT) and three-dimensional conformal (3D-CRT) radiotherapy techniques including sequential or simultaneously integrated boosts as well as interstitial multicatheter brachytherapy boost techniques of 38 patients with breast-conserving surgery retrospectively. We furthermore develop a 3D-printed breast phantom add-on to allow for catheter placement and to measure the out-of-field dose using thermoluminescent dosimeters placed inside an anthropomorphic phantom. Finally, we estimate normal tissue complication probabilities using the Lyman-Kutcher-Burman model and secondary cancer risks using the linear non-threshold model (out-of-field) and the model by Schneider et al. (in-field).

Results

The results depend on the combination of primary whole-breast irradiation and boost technique. The normal tissue complication probabilities for various endpoints are of the following order: 1%-2% (symptomatic pneumonitis, ipsilateral lung), 2%-3% (symptomatic pneumonitis, whole lung), and 1%-2% (radiation pneumonitis grade ≥ 2, whole lung). The additional relative risk of ischemic heart disease ranges from +25% to +35%. In-field secondary cancer risk of the ipsilateral lung in left-sided treatment is around 50 per 10,000 person-years for 20 years after exposure at age 55. Out-of-field estimation of secondary cancer risk results in approximately 5 per 10,000 person-years each for the contralateral lung and breast.

Conclusions

In general, 3D-CRT shows the best risk reduction in contrast to IMRT. Regarding the boost concepts, brachytherapy is the most effective method in order to minimise normal tissue complication probability and secondary cancer risk compared to teletherapy boost concepts. Hence, the 3D-CRT technique in combination with an interstitial multicatheter brachytherapy boost is most suitable in terms of risk avoidance for treating breast cancer with techniques including boost concepts.

Using a Weekly Patient-Reported Outcome Questionnaire to Track Acute Toxicity in Patients Undergoing Pelvic Radiotherapy for Gynecologic Cancers

There are limited patient-reported outcome (PRO) data tracking changes in toxicity in patients actively undergoing radiotherapy. Between 2015−2019, acute toxicity was prospectively measured in 698 patients undergoing a 5-week course of pelvic radiotherapy for gynecologic cancers using a weekly PRO questionnaire. Our questionnaire was able detect a pattern of onset and resolution of acute gastrointestinal (GI) and genitourinary (GU) toxicity in 27 out of 32 questions. Logistic regression analysis showed that increasing GI and GU toxicity at week 2 could predict for severe toxicity at week 5. However, due to a low number of severe events, univariate results could not be productively added to a multivariate model. We observed a >70% response rate for all sections of the questionnaire, except for questions on sexual and vaginal health, which had a 13% average response rate. By demonstrating that PRO data can be used to track acute toxicity during radiotherapy, there is a need to further examine how this tool may be implemented in the clinic to provide complex, adaptive care, such as early side effect management, and modifying radiation delivery in real-time.

Postoperative Radiotherapy for Endometrial Cancer in Elderly (≥80 Years) Patients: Oncologic Outcomes, Toxicity, and Validation of Prognostic Scores

Endometrial cancer is a common malignancy in elderly women that are more likely to suffer from limiting medical comorbidities. Given this narrower therapeutic ratio, we aimed to assess the oncologic outcomes and toxicity in the adjuvant setting. Out of a cohort of 975 women, seventy patients aged ≥ 80 years, treated with curative postoperative radiotherapy (RT) for endometrial cancer between 2005 and 2021, were identified. Outcomes were assessed using Kaplan-Meier-analysis and comorbidities using the Charlson Comorbidity Index and G8 geriatric score. The overall survival at 1-, 2- and 5-years was 94.4%, 82.6%, and 67.6%, respectively, with significant correlation to G8 score. At 1- and 5-years, the local control rates were 89.5% and 89.5% and distant control rates were 86.3% and 66.9%, respectively. Severe (≥grade 3) acute toxicity was rare with gastrointestinal (2.9%), genitourinary (1.4%), and vaginal disorders (1.4%). Univariate analysis significantly revealed inferior overall survival with lower RT dose, G8 score, hemoglobin levels and obesity, while higher grading, lymphangiosis, RT dose decrease and the omission of chemotherapy reduced distant control. Despite older age and additional comorbidities, elderly patients tolerated curative treatment well. The vast majority completed treatment as planned with very low rates of acute severe side-effects. RT offers durable local control; however, late distant failure remains an issue.