Estimating risks of radiotherapy complications as part of informed consent: the high degree of variability between radiation oncologists may be related to experience

Incidence of alopecia in brain tumour patients treated with pencil scanning proton therapy and validation of existing NTCP models

BACKGROUND AND PURPOSE

Radiation-induced alopecia (RIA) is one of the most frequent and upsetting cosmetic side effects after radiotherapy (RT) for brain cancer. We report the incidence of RIA in a cohort of brain tumours patients treated with Proton Therapy (PT) and externally validate published NTCP models of grade 2 (G2) RIA for their implementation in clinical practice.

METHODS

Data for patients treated for brain tumours with scanning beam PT between 2018 and 2022 were extracted. Acute, late and permanent RIA events were evaluated according to CTCAE 5.0. Lyman-Kutcher-Burman (LKB) and multivariable logistic regression (MLR) published models were computed from the relative dose-surface histogram of the scalp. External validity of models was assessed in terms of discrimination and calibration.

RESULTS

In the 264 patients analysed, rates of any grade acute (≤90 days after PT completion), late (>90 days) and permanent RIA (persisting for> 12 months) were 61.8 %, 24.7 % and 14.4 %, respectively. In our independent cohort, LKB- and MLR-NTCP showed a good discrimination for G2 RIA (0.71≤ROC-AUC≤0.83) while model calibration was unsatisfactory possibly due to a different outcome evaluation between training and validation cohorts, as well as differences in clinical and treatment related variables between the two groups.

CONCLUSIONS

Despite the reasonable sensitivity and specificity of the NTCP models for RIA in the validation cohort, our study emphasizes the significance of differences between the cohorts utilized for model development and validation. Specifically, variations in the reporting of clinical outcomes inevitably jeopardize the validation of NTCP models. A standardize and objective RIA scoring system is essential.

Practical Guideline for Prevention of Patchy Hair Loss following CyberKnife Stereotactic Radiosurgery for Calvarial or Scalp Tumors: Retrospective Analysis of a Single Institution Experience

INTRODUCTION

Patchy alopecia is a common adverse effect of stereotactic radiosurgery (SRS) on the calvarium and/or scalp, yet no guidelines exist for its prevention. This study aims to investigate the incidence and outcomes of patchy alopecia following SRS for patients with calvarial or scalp lesions and establish preventive guidelines.

METHODS

The study included 20 patients who underwent CyberKnife SRS for calvarial or scalp lesions, resulting in a total of 30 treated lesions. SRS was administered as a single fraction for 8 lesions and hypofractionated for 22 lesions. The median SRS target volume was 9.85 cc (range: 0.81-110.7 cc), and the median prescription dose was 27 Gy (range: 16-40 Gy), delivered in 1-5 fractions (median: 3). The median follow-up was 15 months.

RESULTS

Among the 30 treated lesions, 11 led to patchy alopecia, while 19 did not. All cases of alopecia resolved within 12 months, and no patients experienced other adverse radiation effects. Lesions resulting in alopecia exhibited significantly higher biologically effective dose (BED) and single-fraction equivalent dose (SFED) on the overlying scalp compared to those without alopecia. Patients with BED and SFED exceeding 60 Gy and 20 Gy, respectively, were 9.3 times more likely to experience patchy alopecia than those with lower doses. The 1-year local tumor control rate for the treated lesions was 93.3%. Chemotherapy was administered for 26 lesions, with 11 lesions receiving radiosensitizing agents. However, no statistically significant difference was found.

CONCLUSION

In summary, SRS is a safe and effective treatment for patients with calvarial/scalp masses regarding patchy alopecia near the treated area. Limiting the BED under 60 Gy and SFED under 20 Gy for the overlying scalp can help prevent patchy alopecia during SRS treatment of the calvarial/scalp mass. Clinicians can use this information to inform patients about the risk of alopecia and the contributing factors.

ACR-ARS Practice Parameter on Informed Consent Radiation Oncology

OBJECTIVES

Consent is a communication process between the patient and a health care provider, in which both parties have the opportunity to ask questions and exchange information relevant to the patient's diagnosis and treatment. The process of informed consent is designed to protect a patient's autonomy in their medical decision-making in the context of an asymmetric relationship with the health care system. A proper consent process assures a patient's individual autonomy, reduces the opportunity for abusive conduct or conflicts of interest, and raises trust levels among participants. This document was developed as an educational tool to facilitate these goals.

METHODS

This practice parameter was produced according to the process described under the heading "The Process for Developing ACR Practice Parameters and Technical Standards" on the ACR website ( https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards ) by the Committee on Practice Parameters-Radiation Oncology of the ACR Commission on Radiation Oncology in collaboration with the ARS. Committee members were charged with reviewing the prior version of the informed consent practice parameter published in 2017 and recommending additions, modifications, or deletions. The committee met through remote access and subsequently through an online exchange to facilitate the development of the revised document. Focus was given on identifying new considerations and challenges with informed consent given the evolution of the practice of radiation oncology in part driven by the COVID-19 pandemic and other external factors.

RESULTS

A review of the practice parameter published in 2017 confirmed the ongoing relevance of recommendations made at that time. In addition, the evolution of the practice of radiation oncology since the publication of the prior document resulted in the need for new topics to be addressed. These topics include remote consent either through telehealth or telephone and with the patient or their health care proxy.

CONCLUSIONS

Informed consent is an essential process in the care of radiation oncology patients. This practice parameter serves as an educational tool designed to assist practitioners in optimizing this process for the benefit of all involved parties.

Dosimetric Predictors of Acute and Chronic Alopecia in Primary Brain Cancer Patients Treated With Volumetric Modulated Arc Therapy

Purpose: To determine dose constraints that correlate with alopecia in patients treated with photon-based Volumetric Modulated Arc Therapy (VMAT) for primary brain tumors.

Methods: During the treatment planning process, the scalp was drawn as a region of interest. Dose received by 0.1 cc (D_0.1cc), mean dose (D_mean), absolute volumes receiving different doses (V_16Gy, V_20Gy, V_25Gy, V_30Gy, V_35Gy, V_40Gy, and V_43Gy) were registered for the scalp. Alopecia was assessed according to Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Receiver operating characteristics (ROC) curve analysis was used to identify parameters associated with hair-loss.

Results: One-hundred and one patients were included in this observational study. At the end of radiotherapy (RT), 5 patients did not develop alopecia (D_mean scalp 3.1 Gy). The scalp of the patients with G1 (n = 11) and G2 (n = 85) alopecia received D_mean of 10.6 Gy and 11.8 Gy, respectively. At ROC analysis, V_16Gy20Gy ≥ 5.2 cc were the strongest predictors of acute alopecia risk. Chronic hair-loss assessment was available for 74 patients: median time to recovery from G2 alopecia was 5, 9 months. The actuarial rate of hair regrowth was 98.1% at 18 months after the end of RT. At ROC analysis, V_40Gy43Gy ≥2.2 cc were the strongest predictors of chronic G2-alopecia risk. V_20Gy, V_40Gy, and D_0,1cc were shown to be independent variables according to correlation coefficient r.

Conclusions: V_20Gy and V_40Gy were the strongest predictors for acute and chronic G2 hair-loss, respectively. The low-dose bath typical of VMAT corresponds to large areas of acute but transient alopecia. However, the steep dose gradient of VMAT allows to reduce the areas of the scalp that receive higher doses, minimizing the risk of permanent alopecia.

The application of our dosimetric findings for the scalp may help in reducing the alopecia risk and also in estimating the probability of hair-loss during patient counseling before starting radiotherapy.

How informed is our consent? Patient awareness of radiation and radical prostatectomy complications

OBJECTIVE

To evaluate patient's recall of pretreatment counseling for radical prostatectomy and radiation therapy for the treatment of prostate cancer.

MATERIAL AND METHODS

A retrospective review of all patients presenting to our reconstructive urology clinic for the management of the complications of prostate cancer treatment was conducted over 24 months. Patients treated with only surgery or radiotherapy were included in the study. Patients were asked a standard series of questions to assess their recall of their pre-prostate cancer treatment counseling.

RESULTS

We identified 206 patients that met inclusion criteria. Of those, 153 underwent radical prostatectomy and 53 patients received radiation therapy. Median age at presentation was 72 years in the surgery group and 75 in the radiation therapy group. Mean time since treatment was 8.8 years in those that recalled being counseled and 9.9 years in those who did not (p=0.21). In the surgery group, the adverse effects experienced by 119 (77.8%) patients recalled, and counselled were related to the risk of treatment. In the surgical patients that had records with documentation of pretreatment counseling, 41/48 (85.4%) endorsed recall. In the surgery group, 117 (76.5%) stated that their treating physician was aware of their complication. In the radiation group, 5 patients (9.4%) endorsed recall (p<0.0001). In the subgroup of radiation patients with documentation of pre-treatment counseling, no patients endorsed recall. In the surgery group, 117 (76.5%) patients stated that their treating physicians were aware of their complication, while in the radiation group, only 16 (30.2%) of treating physicians were aware of the complications (p<0.0001).

CONCLUSION

Patient recall of potential complications of prostate cancer treatment is poor. It's unclear if this is secondary to poor recall, selective memory loss or inadequate counseling.

Radiation- and Chemotherapy-Induced Permanent Alopecia: Case Series

Background:

Radiation- and chemotherapy-induced alopecia is mostly temporary. However, permanent scalp alopecia is reported, albeit infrequently.

Objective:

The objective of this observational case series was to determine the kind and doses of chemotherapeutic agents and radiation in inducing permanent alopecia of the scalp.

Methods and Results:

Eleven patients referred to our department over a period of 3 years for permanent alopecia after chemotherapy/radiotherapy or combination therapy were included. A detailed medical and therapeutic history was obtained from each patient and from medical records. Photography was done, and the scalp biopsies were taken. Patients were divided into three groups according to the type of therapy. The first group received conditioning chemotherapy prior to bone marrow transplantation. The second group had radiation for brain tumors, and the third group received both.

Conclusion:

A comprehensive multicenter and multidisciplinary study is required to determine the definite causative agents, doses, and other cofactors that induce permanent alopecia following chemotherapy/radiotherapy, as well as the means to avoid this distressing outcome in surviving patients.

Comparison of permanent hair loss in children with standard risk PNETS of the posterior fossa following radiotherapy alone or chemotherapy and radiotherapy after surgical resection

Hair loss was compared between surgery followed by craniospinal radiotherapy (CSRT) or chemotherapy then CSRT (C-CSRT) for medulloblastoma. The proportion of patients exhibiting hair loss in the cranial field was 70.0% (C-CSRT) versus 30.0% (CSRT) (95% CI: 14.7% to 58.9%; P = 0.002). The C-CSRT group also experienced more virtual/complete hair loss over the posterior fossa boost. Age was a significant contributor to hair loss in the cranial field. Persistent significant hair loss is an under-reported late effect of treatment that could influence quality of survival and should be considered in future trial design.

Utility of daily image guidance with intensity-modulated radiotherapy for tumors of the base of skull

BACKGROUND

This study was carried out to report our experience using intensity-modulated radiotherapy (IMRT) with daily image-guided radiotherapy (IGRT) for tumors involving the base of skull.

METHODS

In all, 100 patients were prospectively treated with IMRT to a median dose of 64 Gy (range, 45-70 Gy). Daily helical megavoltage computed tomography (MVCT) scans were obtained as part of an IGRT registration protocol for patient alignment.

RESULTS

The 2-year local-regional control was 91%. A total of 3295 daily MVCT scans were obtained. The mean shift to account for interfraction motion was 1.18 ± 1.75 mm, 1.81 ± 1.34 mm, and 1.33 ± 1.19 mm for the medial-lateral (ML), superior-inferior (SI), and anterior-posterior (AP) directions, respectively. Pretreatment shifts of >3 mm occurred in 10%, 26%, and 18%, in the ML, SI, and AP directions, respectively.

CONCLUSIONS

The feasibility and efficacy of daily IGRT as a complement to IMRT for skull base were demonstrated.

Dose distribution in the thyroid gland following radiation therapy of breast cancer--a retrospective study

Purpose

To relate the development of post-treatment hypothyroidism with the dose distribution within the thyroid gland in breast cancer (BC) patients treated with loco-regional radiotherapy (RT).

Methods and materials

In two groups of BC patients postoperatively irradiated by computer tomography (CT)-based RT, the individual dose distributions in the thyroid gland were compared with each other; Cases developed post-treatment hypothyroidism after multimodal treatment including 4-field RT technique. Matched patients in Controls remained free for hypothyroidism. Based on each patient's dose volume histogram (DVH) the volume percentages of the thyroid absorbing respectively 20, 30, 40 and 50 Gy were then estimated (V20, V30, V40 and V50) together with the individual mean thyroid dose over the whole gland (MeanTotGy). The mean and median thyroid dose for the included patients was about 30 Gy, subsequently the total volume of the thyroid gland (VolTotGy) and the absolute volumes (cm³) receiving respectively < 30 Gy and ≥ 30 Gy were calculated (Vol < 30 and Vol ≥ 30) and analyzed.

Results

No statistically significant inter-group differences were found between V20, V30, V40 and V50Gy or the median of MeanTotGy. The median VolTotGy in Controls was 2.3 times above VolTotGy in Cases (ρ = 0.003), with large inter-individual variations in both groups. The volume of the thyroid gland receiving < 30 Gy in Controls was almost 2.5 times greater than the comparable figure in Cases.

Conclusions

We concluded that in patients with small thyroid glands after loco-radiotherapy of BC, the risk of post-treatment hypothyroidism depends on the volume of the thyroid gland.

A novel mouse model of cutaneous radiation injury

BACKGROUND

Radiation therapy is a cornerstone of oncologic treatment. Skin tolerance is often the limiting factor in radiotherapy. To study these issues and create modalities for intervention, the authors developed a novel murine model of cutaneous radiation injury.

METHODS

The dorsal skin was isolated using a low-pressure clamp and irradiated. Mice were followed for 8 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy specimens were taken and examined histologically. Tensiometry was performed and Young's modulus calculated.

RESULTS

High-dose radiation isolated to dorsal skin causes progressive changes in skin perfusion, resulting in dermal thickening, fibrosis, persistent alopecia, and sometimes ulceration. There is increased dermal Smad3 expression, and decreased elasticity and bursting strength.

CONCLUSIONS

This model of cutaneous radiation injury delivers reproducible localized effects, mimicking the injury pattern seen in human subjects. This technique can be used to study radiation-induced injury to evaluate preventative and therapeutic strategies for these clinical issues.

Surgical interventions for the treatment of radiation-induced alopecia in pediatric practice

Permanent alopecia can occur following treatment for pediatric malignant disease, especially cranial irradiation, resulting in identity and self-image problems. This late effect is usually addressed through external cosmesis and psychological adjustment. Surgical options are less commonly utilized. The experience of reconstructive procedures in patients at RLC NHS Trust, Alder Hey with alopecia is presented. Four patients had scalp tissue expansion and one had hair transplantation. The reconstructive options available are discussed as well as the potential opportunities and difficulties in this population. Post-radiotherapy alopecia can be successfully addressed by reconstructive surgery, and should be considered more often in this population.

Informed consent in radiation oncology: is consenting easier than informing?

The patient's right to be informed has been universally recognized and reflected in the legal system of many countries. This right to correct and complete information on behalf of the patient and his admission to proceed with the recommended diagnostic or therapeutic procedure is formalized in the document commonly known as informed consent. Although the legal and bioethical considerations regarding this document have been exhaustively discussed and consensuated, its content continues to create certain doubts and uncertainties. The formal content and the manner in which the consent is obtained are the most difficult aspects. In this article, we analyze what should be included in the written informed consent, with regard to the totality of the information which the patient receives, who should inform, and how the consent should be obtained, as well as how to reflect the different aspects of the variety of radiotherapeutic procedures in the informed consent.

Étude de l'estimation du risque en chirurgie esthétique : enquête nationale auprès des chirurgiens

AIM

The aim of this study was to establish the status of the means of information and to search for the variability in risk estimation.

MATERIALS AND METHODS

A questionnaire has been mailed to a hundred plastic surgeons randomly sorted among the habilitation list to be returned in an anonymous enclosed envelope. This random sample comprised 50 liberal practioners and 50 plastic surgeons working at hospital. The first part of this questionnaire dealed with basic data such as the type of activity (reconstructive or aesthetic), years of experience and means of information. The second part dealed in seven items with the most important preoperative information to be given to the patient and the most feared complications according to each surgeon before a reduction mammaplasty and abdominoplasty.

RESULTS

A total of 50 (50%) of the 100 questionnaires were returned. Years of experience influenced significantly the importance given to information and the way of transmitting it. Important variability existed between the surgeons' answers. Moreover, current complications were in many cases never mentioned. Risk estimation depended on the experience of the surgeon and the information procedures were influenced by the surgeon's type of activity.

CONCLUSION

Important variability in risk estimation exists among the plastic surgeons leading to an important variability in the kind and way of delivering information.

Systematic review of the effect of radiation dose on tumor control and morbidity in the treatment of prostate cancer by 3D-CRT

PURPOSE

A higher radiation dose is believed to result in a larger probability of tumor control and a higher risk of side effects. To make an evidence-based choice of dose, the relation between dose and outcome needs to be known. This study focuses on the dose-response relation for prostate cancer.

METHODS AND MATERIALS

A systematic review was carried out on the literature from 1990 to 2003. From the selected studies, the radiation dose, the associated 5-year survival, 5-year bNED (biochemical no evidence of disease), acute and late gastrointestinal (GI) and genitourinary (GU) morbidity Grade 2 or more, and sexual dysfunction were extracted. With logistic regression models, the relation between dose and outcome was described.

RESULTS

Thirty-eight studies met our criteria, describing 87 subgroups and involving up to 3000 patients per outcome measure. Between the (equivalent) dose of 70 and 80 Gy, various models estimated an increase in 5-year survival (ranging from 10% to 11%), 5-year bNED for low-risk patients (5-7%), late GI complications (12-16%), late GU complications (8-10%), and erectile dysfunction (19-24%). Only for the overall 5-year bNED, results were inconclusive (range, 0-18%).

CONCLUSIONS

The data suggest a relationship between dose and outcome measures, including survival. However, the strength of these conclusions is limited by the sometimes small number of studies, the incompleteness of the data, and above all, the correlational nature of the data. Unambiguous proof for the dose-response relationships can, therefore, only be obtained by conducting randomized trials.

Volumetric Uncertainty in Radiotherapy

The technologies available to identify anatomical structures (including radiotherapy target and normal tissue 'volumes'), and to deliver dose accurately to these volumes, have improved significantly in the past decade. However, the ability of clinicians to identify volumes accurately and consistently in patients still suffers from uncertainties that arise from human error, inadequate training, lack of consensus on the derivation of volumes and inadequate characterisation of the accuracy and specificity of imaging technologies. Inadequate volume definition of a target can result in treatment failure and, consequently, disease progression; excessive volume may also lead to unnecessary patient injury. This is a serious problem in routine clinical care. In the context of large multi-centre clinical trials, uncertainty and inconsistency in tissue-volume reporting will be carried through to the analysis of treatment effect on outcome, which will subsequently influence the treatment of future patients. Strategies need to be set in place to ensure that the abilities and consistency of clinicians in defining volumes are aligned with the ability of new technologies to present volumetric information. This review seeks to define the concept of volumetric uncertainty and propose a conceptual model that has these errors evaluated and responded to separately. Specifically, we will explore the major causes, consequences of, and possible remediation of volumetric uncertainty, from the point of view of a multidisciplinary radiotherapy clinical environment.

Permanent alopecia after cranial irradiation: Dose–response relationship

PURPOSE

To develop a dose-response relationship for the occurrence of permanent alopecia after cranial irradiation and to analyze potential confounding variables that may contribute to this unwanted and often unavoidable complication of treatment.

METHODS AND MATERIALS

Twenty-six patients were enrolled in this study. Three reviewers independently assessed 61 scalp regions and assigned a score for the degree of alopecia in each region using a 4-point scale. Patient and treatment data were collected using a patient questionnaire and outpatient medical chart review. The hair follicle dose was calculated for each scalp region and correlated with the alopecia score for that region. A dose-response relationship was established using the data from these correlations.

RESULTS

Permanent alopecia correlated significantly with the follicle dose only (p < 0.001). A personal history of alopecia and the use of chemotherapy correlated with permanent alopecia with borderline statistical significance (p = 0.059 and p = 0.068, respectively). Patient age, family history of baldness, gender, tobacco use, diabetes, and beam energy did not correlate with alopecia.

CONCLUSION

We report the first human dose-response relationship describing the effect of the follicle dose on the subsequent development of permanent scalp alopecia after cranial irradiation. This information will assist the radiation oncologist, physicist, and dosimetrist in designing a treatment plan that might minimize the risk of this untoward side effect of cranial irradiation.

Do written consent forms provide medicolegal protection from litigation in radiotherapy?

Two methods were used in an attempt to determine whether written consent forms serve a useful medicolegal purpose in Australian radiotherapy departments. First a survey was posted to all practising radiation oncologists to ask about their use of written consent forms and whether they had ever been useful in any claims made against them. Second, the largest medical defence organization in Australia was contacted for de-identified details about every claim ever made against a radiation oncologist. The survey yielded a response rate of 50.3%. Only one respondent indicated that any consent form had ever played a role in any claim and was not prepared to discuss it. Many radiation oncologists did not routinely use a consent form and its use could not be considered standard practice. The submitted consent forms generally did not contain warnings to the patient about specific risks of treatment. The details of the previous claims provided by the medical defence organization indicated that more often claims arose from circumstances in which a written consent form could not provide any useful protection such as radiation dose calculation errors. The medicolegal value of written consent forms in radiotherapy seems low, although further research may be necessary before dispensing with them completely.

Radiotherapy-induced thyroid disorders

Despite their specific functional consequences, radiotherapy-induced thyroid abnormalities remain under-estimated and underreported. These sequelae may include primary or central hypothyroidism, thyroiditis, Graves' disease, euthyroid Graves' ophthalmopathy, benign adenomas, multinodular goitre and radiation-induced thyroid carcinoma. Primary hypothyroidism, the most common radiation-induced thyroid dysfunction, affects 20-30% of patients administered following curative radiotherapy to the neck region, with approximately half of the events occurring within the first 5 years after therapy. The relative risk of radiation-induced cancer (mainly well-differentiated tumours) is 15-53-fold higher than in non-irradiated population. The aetiology of radiation-induced thyroid injury includes vascular damage, parenchymal cell damage and auto-immune reactions. Total radiotherapy dose, irradiated volume of the thyroid gland, and the extent of prior thyroid resection are among the most important factors associated with the risk of hypothyroidism. The contribution of other treatment modalities (chemotherapy, endocrine therapy) as well as patient- and tumour-related factors is less clear. Reduction in radiation dose to the thyroid gland and hypothalamic/pituitary complex should be attempted whenever possible. New radiotherapy techniques, such as stereotactic radiosurgery, three-dimensional conformal irradiation, intensity modulated radiotherapy and proton therapy allow generally better dose distribution with lower dose to the non-target organs. The diagnostic approach to thyroid radiation injury includes baseline thyroid function assays in all patients undergoing thyroid or parasellar irradiation. Recommended follow-up procedures include at least annual evaluation with a history for symptoms of thyroid dysfunction, clinical examination, and measurement of thyroid hormones and thyrotropin. Management of overt hypothyroidism is based on hormone replacement therapy. Thyroid hormone therapy is also recommended in cases of subclinical hypothyroidism. Treatment of other radiation-induced thyroid disorders (thyroiditis, Graves' disease, thyroid cancer) is similar to that employed in spontaneously occurring conditions. Further improvements in radiotherapy techniques and progress in endocrine diagnostics and therapy may allow better prevention and management of radiation-related thyroid injury.