Prostate cancer image guided radiotherapy: Why the commotion over rectal volume and motion?

Introduction

Distended rectums on pre-radiotherapy scans are historically associated with poorer outcomes in patients treated with two-dimensional IGRT. Subsequently, strict rectal tolerances and preparation regimes were implemented. Contemporary IGRT, daily online registration to the prostate, corrects interfraction motion but intrafraction motion remains. We re-examine the need for rectal management strategies when using contemporary IGRT by quantifying rectal volume and its effect on intrafraction motion.

Materials and methods

Pre and during radiotherapy rectal volumes and intrafraction motion were retrospectively calculated for 20 patients treated in 5-fractions and 20 treated in 20-fractions. Small (rectal volume at planning-CT ≤ median), and large (volume > median) subgroups were formed, and rectal volume between timepoints and subgroups compared. Rectal volume and intrafraction motion correlation was examined using Spearman's rho. Intrafraction motion difference between small and large subgroups and between fractions with rectal volume < or ≥ 90 cm3 were assessed.

Results

Median rectal volume was 74 cm3, 64 cm3 and 65 cm3 on diagnostic-MRI, planning-CT and treatment imaging respectively (ns). No significant correlation was found between patient's rectal volume at planning-CT and median intrafraction motion, nor treatment rectal volume and intrafraction motion for individual fractions. No significant difference in intrafraction motion between small and large subgroups presented and for fractions where rectal volume breached 90 cm3, motion during that fraction was not significantly greater.

Conclusion

Larger rectal volumes before radiotherapy and during treatment did not cause greater intrafraction motion. Findings support the relaxation of strict rectal diameter tolerances and do not support the need for rectal preparation when delivering contemporary IGRT to the prostate.

Outcomes of Tolerability, Acute Toxicity and Quality of Life from MR-Guided Radiation Therapy (1.5T MR-Linac) for Liver Metastases in the MOMENTUM Study

PURPOSE/OBJECTIVE(S)

Stereotactic body radiation therapy (SBRT) offers an important treatment option for metastatic liver tumors. The introduction of magnetic resonance (MR) guided SBRT has paved the way for optimal tumor visualization and daily plan adaptation. The purpose of this study is to review tolerability of MR-guided SBRT of liver metastases and to present early toxicity and quality of life outcomes.

MATERIALS/METHODS

All patients with liver metastases who were treated on a 1.5T MR-Linac and enrolled in the MOMENTUM study (NTC04075305) were included. Patients were treated between April 2019 and December 2022 in 5 different institutes across 3 countries. Descriptive statistics were used to present the tolerability of treatment, toxicity (CTCAE v5.0) and quality of life outcomes (QLQ C30 and EQ 5D-5L) at baseline and 3 months after treatment.

RESULTS

A total of 127 patients with liver metastases were included in the analysis. There were 64 females and 63 men, with a median age of 66 years (range 31 to 93). The median ECOG-score was 0 (range 0-2). The most common primary origin was colorectal cancer (66%), followed by bronchus and lung cancer (12%), with ocular melanoma, pancreatic and breast cancer being joint third (all 6-7%). Fractionation schedules ranged from 12 - 67.5 Gy in 2 - 12 fractions. The most commonly prescribed fractionation dose was 60 Gy in 3-5 fractions (53% and 13% respectively) and 50 Gy in 5 fractions (11%). Completion data was available for 116 patients. 112 patients (97%) received all fractions. 4 Patients (3%) did not complete treatment due to technical issues and 2 of the 4 receiving no treatment on the MR-Linac. Physician reported toxicity at 3 months was recorded for 82 patients (66%). No grade 4 or 5 toxicities were reported. There were 12 grade 3 toxicities reported in 6 (7%) patients with 5 deemed radiation therapy related (Table 1) and 34 grade 2 toxicities in 21 (26%) patients.

CONCLUSION

We have presented the largest cohort (to our knowledge) of 127 patients treated using 1.5 Tesla MR Guidance for metastatic liver tumors. 97% of treatments were completed successfully with all treatments being well tolerated. Acute grade 3 toxicity was reported in 7% of patients with no grade 4 or 5 toxicities present. These outcomes suggest radiotherapy on the MR-Linac is a safe and promising treatment for patients with liver metastases. Additional prospective follow up is ongoing for late toxicity events and long-term control data. Table 1: Grade ≥3 toxicity at 3 months related to radiation therapy (total No. of patients was 82) There was QLQ-C30 data on 89 patients at baseline and on 62 patients at 3 months. At 3 months the median score was worse for physical functioning, VAS score and pain.

Is the Motion Causing a Commotion? Two-Fraction Prostate SBRT on the MR-Linac

PURPOSE/OBJECTIVE(S)

In HERMES (NCT04595019) men with localized prostate cancer are treated on the Unity MR-Linac platform (MRL, Elekta AB, Stockholm) and randomized between stereotactic body radiotherapy (SBRT) with 36.25 Gy in 5 fractions and 24 Gy in 2 fractions. Patients randomized to two fractions receive 24 Gy to the high risk PTV, 20 Gy to the low risk PTV and a boost of 27 Gy to the dominant intraprostatic lesion. This study explores dose received by the target and organs at risk (OARs) when considering intrafraction motion in two fraction SBRT.

MATERIALS/METHODS

Targets and OARs were delineated and a reference plan generated on Monaco v5.40.01 (Elekta). An Adapt-to-Shape (ATS) workflow was used. Contours were propagated to the session MRI (MRIsession) and edited accordingly. Prior to delivery, a verification MRI (MRIverif) was acquired with baseline shifts corrected for using the Adapt-to-Position (ATP-of-ATS) workflow. A post treatment MRI (MRIpost) was acquired after delivery. Men in the 2-fraction arm received each fraction in 2 sub-fractions sequentially on the same day, to mitigate intrafraction motion. The plans of 5 men receiving 2 fraction SBRT were analyzed. The targets, urethra, bladder and rectum were recontoured on the MRIverif and MRIpost. Delivered plans were recalculated on the corresponding MRIverif and MRIpost. The percentage of optimal and mandatory target dose constraints met were calculated. Accumulated OAR doses were calculated by averaging their respective dose statistics across all sub-fractions, conservatively assuming that the same area of the OAR receives the maximum dose each fraction. Analysis was carried out separately for MRIverif and MRIpost as the true 'delivered dose' most likely lies between these two estimates.

RESULTS

There was good coverage across all fractions. The mandatory constraints of CTVpsv V24.0 Gy > 95% and CTVsv V20.0 Gy > 95% were met in 100% of fractions and V2700cGy > 95% in 90% on the MRIpost. Table 3 shows OAR dose.

CONCLUSION

This work demonstrates that target coverage is good, even for the GTV where no margin is applied. With our conservative dose calculation approach, we found dose constraints are exceeded for some patients. However, treatment has been well tolerated, suggesting that that our current dose constraints may be cautious. Once Elekta's True Tracking and automated gating software is implemented at our center we will be able to further improve OAR clinical goal compliance.

Characteristics of patients with diabetes hospitalised for COVID-19 infection-a brief case series report

OBJECTIVES

Diabetes has been shown to be a risk factor for corona virus disease-2019 (COVID-19) infection. The characteristics of patients with diabetes vulnerable to this infection are less specified. We aim to present the characteristics of patients with diabetes admitted to hospital with COVID-19.

DESIGN

A retrospective case series.

SETTING

A single clinical centre in the UK.

METHODS

We have retrospectively collected the demographics, medical characteristics and outcome of all patients with diabetes admitted to hospital over two-week period with COVID-19 infection. All cases were diagnosed by a reverse transcription polymerase chain reaction (RT-PCR) of pharyngeal and nasal swabs.

RESULTS

A total of 71 COVID-19 patients were admitted during the study period of whom 16 (22.5%) patients had diabetes and were included in this case series. There was no significant difference between patients with compared to those without diabetes regarding age, gender or clinical presentation. However, comorbidities were more common in patients with diabetes specially hypertension {75% v 36.4%, a difference of 38.6%, 95% confidence interval (CI) 6.5-58.3} and chronic kidney disease (37.5 v 5.5, a difference of 32% (1.6-51.6). Patients with diabetes were significantly more obese than those without diabetes (56.2% v 21.8% a difference of 34.4%, 95% CI 7.7-61.1). About one third (31.3%) of patients with diabetes were frail. Mean {standard deviation (SD)} duration of diabetes was 10 (2.8) years and mean (SD) HbA1c was 60.3 (15.6) mmol/mol. The use of angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and non-steroidal anti-inflammatory drugs (NSAIDs) was common (37.5%, 25% and 18.8% respectively). There was no significant difference in the outcomes between patients with compared to those without diabetes.

CONCLUSION

Patients with diabetes hospitalised for COVID-19 were significantly more obese and had high prevalence of comorbidities than those without diabetes. Other features of patients with diabetes and COVID-19 infection included long duration of diabetes, less tight glycaemic control and common use of ACE inhibitors, ARBs and NSAIDs.

Isolated metastatic primary peritoneal carcinoma to the breast: a rare site of disease recurrence

Primary breast carcinoma is a common pathology in the UK. It can present with metastatic deposits but it is rare that lesions in the breast are the sole primary or secondary presentation for metastatic cancer from other sources. We present a case of a primary peritoneal cancer recurring after optimal treatment with a new breast lesion and the diagnostic difficulties that this can cause.

Model for outcomes assessment of antihistamine use for seasonal allergic rhinitis

BACKGROUND

Drug selection for optimal treatment of common medical conditions may be difficult and involve many diverse factors.

OBJECTIVE

The efficacy, safety, quality of life, and cost of treatment of seasonal allergic rhinitis with cetirizine, chlorpheniramine, or terfenadine were compared in a prospective, two-phase, randomized, single-blind clinical trial conducted in a managed care setting.

METHODS

In phase I, which lasted 2 weeks, patients were randomized to receive one of the study drugs. In phase II, which lasted 4 weeks, the initial treatment was continued unless patients were dissatisfied, in which case they could be randomly assigned to receive another study drug. In both phases pseudoephedrine could be taken as needed. Patients kept daily diaries of symptoms and costs, and study drugs were evaluated at the end of each phase for efficacy, safety, and effect on quality of life by means of a validated questionnaire. A multiattribute outcomes assessment model for formulary decision making was used to rank the antihistamines.

RESULTS

Physicians' and patients' assessments in phases I and II indicated that cetirizine and chlorpheniramine were significantly more effective than terfenadine (p < 0.05). Incidence of sedation in phase I and phase II was 40.5% and 16.7% for chlorpheniramine, 11.6% and 9.8% for cetirizine, and 6.7% and 5.1% for terfenadine, respectively. At the end of phase I, 28.9% of the patients treated with chlorpheniramine, 50% of the patients treated with terfenadine, and 69.4% of the patients treated with cetirizine were satisfied with their therapy and chose not to switch their medication. Quality of life scores improved most after treatment with cetirizine and least after treatment with terfenadine.

CONCLUSION

The result of this trial indicate that antihistamine selection is best made with the use of a multiattribute evaluation that includes quality of life. In this study cetirizine was favored by patients and physicians most often, followed by chlorpheniramine and then terfenadine.