Gallbladder toxicity and high-dose ablative-intent radiation for liver tumors: Should we constrain the dose?

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines

This systematic review and meta-analysis reports on outcomes and hepatic toxicity rates after stereotactic body radiation therapy (SBRT) for liver-confined hepatocellular carcinoma (HCC) and presents consensus guidelines regarding appropriate patient management. Using the Preferred Reporting Items for Systemic Review and Meta-Analyses guidelines, a systematic review was performed from articles reporting outcomes at ≥5 years published before October 2022 from the Embase, MEDLINE, Cochrane, and Scopus databases with the following search terms: ("stereotactic body radiotherapy" OR "SBRT" OR "SABR" OR "stereotactic ablative radiotherapy") AND ("hepatocellular carcinoma" OR "HCC"). An aggregated data meta-analysis was conducted to assess overall survival (OS) and local control (LC) using weighted random effects models. In addition, individual patient data analyses incorporating data from 6 institutions were conducted as their own subgroup analyses. Seventeen observational studies, comprising 1889 patients with HCC treated with ≤9 SBRT fractions, between 2003 and 2019, were included in the aggregated data meta-analysis. The 3- and 5-year OS rates after SBRT were 57% (95% confidence interval [CI], 47%-66%) and 40% (95% CI, 29%-51%), respectively. The 3- and 5-year LC rates after SBRT were 84% (95% CI, 77%-90%) and 82% (95% CI, 74%-88%), respectively. Tumor size was the only prognostic factor for LC. Tumor size and region were significantly associated with OS. Five-year LC and OS rates of 79% (95% CI, 0.74-0.84) and 25% (95% CI, 0.20-0.30), respectively, were observed in the individual patient data analyses. Factors prognostic for improved OS were tumor size <3 cm, Eastern region, Child-Pugh score ≤B7, and the Barcelona Clinic Liver Cancer stage of 0 and A. The incidence of severe hepatic toxicity varied according to the criteria applied. SBRT is an effective treatment modality for patients with HCC with mature follow-up. Clinical practice guidelines were developed on behalf of the International Stereotactic Radiosurgery Society (ISRS).

Safety of Radioembolization via the Cystic Artery in Patients with Hepatocellular Carcinoma and Parasitized Arterial Supply

PURPOSE

To evaluate the safety and effectiveness of radioembolization through the cystic artery supplying hepatocellular carcinoma (HCC) adjacent to the gallbladder.

MATERIALS AND METHODS

This retrospective, single-center study included 24 patients who underwent radioembolization via the cystic artery between March 2017 and October 2022. The median tumor size was 8.3 cm (range, 3.4-20.4 cm). Twenty-two (92%) patients had Child-Pugh Class A disease, and 2 (8%) patients had Class B cirrhosis. Technical issues, adverse events, and tumor response were analyzed.

RESULTS

Infusion of radioactive microspheres was performed from the main cystic artery (n = 6), the deep cystic artery (n = 9), and small feeders from the cystic artery (n = 9). The cystic artery supplied the primary index tumor in 21 patients. The median radiation activity delivered via the cystic artery was 0.19 GBq (range, 0.02-0.43 GBq). The median total radiation activity administered was 4.1 GBq (range, 0.9-10.8 GBq). There was no case of symptomatic cholecystitis requiring invasive intervention. One patient experienced abdominal pain during injection of radioactive microspheres via the cystic artery. Eleven (46%) patients received pain medication during or within 2 days of the procedure. Twelve (50%) patients had gallbladder wall thickening on a 1-month follow-up computed tomography scan. Based on follow-up imaging, 23 (96%) patients showed an objective response (complete or partial response) of the tumor supplied by the cystic artery.

CONCLUSION

Radioembolization via the cystic artery may be safe in patients with HCC partially supplied by the cystic artery.

The Role of Stereotactic Body Radiation Therapy in the Management of Liver Metastases

The liver is a common site for metastatic spread for various primary tumor histologies. Stereotactic body radiation therapy (SBRT) is a non-invasive treatment technique with broad patient candidacy for the ablation of tumors in the liver and other organs. SBRT involves focused, high-dose radiation therapy delivered in one to several treatments, resulting in high rates of local control. Use of SBRT for ablation of oligometastatic disease has increased in recent years and emerging prospective data have demonstrated improvements in progression free and overall survival in some settings. When delivering SBRT to liver metastases, clinicians must balance the priorities of delivering ablative tumor dosing while respecting dose constraints to surrounding organs at risk (OARs). Motion management techniques are crucial for meeting dose constraints, ensuring low rates of toxicity, maintaining quality of life, and can allow for dose escalation. Advanced radiotherapy delivery approaches including proton therapy, robotic radiotherapy, and real-time MR-guided radiotherapy may further improve the accuracy of liver SBRT. In this article, we review the rationale for oligometastases ablation, the clinical outcomes with liver SBRT, tumor dose and OAR considerations, and evolving strategies to improve liver SBRT delivery.

Incidence of and risk factors for late cholecystectomy in survivors of childhood cancer: A report from the Childhood Cancer Survivor Study

BACKGROUND

Gallbladder disease and need for cholecystectomy are common and significant contributors to patient morbidity and healthcare costs. Childhood cancer survivors are at elevated risk for developing cholelithiasis. However, their incidence of and risk factors for late (>5 years from diagnosis) cholecystectomy have not been studied.

METHODS

A total of 25,549 survivors (median age at diagnosis 6.9 years, range 0-21.0; current age 30.7 years, range 5.6-65.9) diagnosed between 1970 and 1999 and 5037 siblings were queried for self-reported cholecystectomy occurring five or more years from primary cancer diagnosis. Piecewise exponential models evaluated associations between cancer treatment exposures and late cholecystectomy.

RESULTS

Over a median follow-up period of 21.9 and 26.0 years, respectively, 789 survivors and 168 siblings underwent late cholecystectomy (cumulative incidence 7.2%, 95% confidence interval [CI] = 6.5-7.8% and 6.6%, 95% CI = 5.4-7.6%, respectively; rate ratio [RR] = 1.3, 95% CI = 1.1-1.5). Compared with siblings, survivors of acute lymphoblastic leukaemia (RR = 1.4, 95% CI = 1.2-1.8), soft tissue sarcoma (RR = 1.4, 95% CI = 1.0-1.8) and bone cancer (RR = 1.3, 95% CI = 1.0-1.8) were at the greatest risk. In addition to attained age, female sex and increasing body mass index, exposure to high-dose (≥750 mg/m²) platinum chemotherapy (RR = 2.6, 95% CI = 1.5-4.5), vinca alkaloid chemotherapy (RR = 1.4, 95% CI = 1.1-1.8) or total body irradiation (TBI; RR = 2.2, 95% CI = 1.2-4.2) were each associated with late cholecystectomy.

CONCLUSIONS

Independent of traditional risk factors for gallbladder disease, exposure to high-dose platinum chemotherapy, vinca alkaloid chemotherapy or TBI increased risk for late cholecystectomy. These findings should inform current long-term follow-up guidelines and education regarding risk for late cholecystectomy.

Normal tissue complication probability (NTCP) models for modern radiation therapy

Mathematical models of normal tissue complication probability (NTCP) able to robustly predict radiation-induced morbidities (RIM) play an essential role in the identification of a personalized optimal plan, and represent the key to maximizing the benefits of technological advances in radiation therapy (RT). Most modern RT techniques pose, however, new challenges in estimating the risk of RIM. The aim of this report is to schematically review NTCP models in the framework of advanced radiation therapy techniques. Issues relevant to hypofractionated stereotactic body RT and ion beam therapy are critically reviewed. Reirradiation scenarios for new or recurrent malignances and NTCP are also illustrated. A new phenomenological approach to predict RIM is suggested.