Single-Session Ablative Transarterial Radioembolization for Patients with Hepatocellular Carcinoma to Streamline Care: An Initial Experience.

PURPOSE: Transarterial radioembolization (TARE) for hepatocellular carcinoma (HCC) is performed after a mapping angiogram involving infusion of radiolabeled macroaggregated albumin to assess for non-target embolization and pulmonary shunting. The purpose of this case series was to evaluate the safety and feasibility of single-session TARE without the initial procedure. MATERIALS AND METHODS: A single-institution case series of 16 consecutive procedures on 15 patients with 18 tumors who underwent an attempted single-session TARE procedures with glass microspheres are presented. A lung shunt fraction (LSF) of 5% was assumed for planning purposes. RESULTS: Sixty-seven percent (10/15) of patients were male with a median age of 72 years. Median tumor size was 2.5 cm (IQR 2.0-3.2 cm). Sixteen of the 18 targeted tumors were untreated prior to the single-session TARE. Rate of technical success was 88% (14/16). Two patients did not ultimately receive a single-session TARE due to intraprocedural findings. The mean administered activity was 2.0 GBq, and the mean MIRD dose was 464 Gy based on pre-treatment anatomic imaging and 800 Gy based on cone-beam CT. There were no cases of radiation pneumonitis. Mean post-procedural calculated lung dose was 4.9 Gy (range 3.1-9.3) based on SPECT. CONCLUSIONS: An initial experience with single-session TARE using Y-90 glass microspheres without pre-procedural mapping angiography and lung shunt estimation demonstrates that it is a feasible and safe treatment option for select patients with small (< 5 cm) HCC. LEVEL OF EVIDENCE IV: Level 4 case series.

Voxel-based tumor dose correlates to complete pathologic necrosis after transarterial radioembolization for hepatocellular carcinoma.

PURPOSE: The transarterial radioembolization (TARE) dose is traditionally calculated using the single-compartment Medical Internal Radiation Dose (MIRD) formula. This study utilized voxel-based dosimetry to correlate tumor dose with explant pathology in order to identify dose thresholds that predicted response. METHODS: All patients with HCC treated with TARE using yttrium-90 [90Y] glass microspheres at a single institution between January 2015 - June 2023 who underwent liver transplantation were eligible. The [90Y] distribution and dose-volume histograms were determined using Simplicity90 (Mirada Medical, Oxford UK) with a Bremsstrahlung SPECT/CT. A complete response was assigned if explant pathology showed complete necrosis and the patient had not undergone additional treatments to the same tumor after TARE. Logistic regression and receiver operator characteristic (ROC) curves were constructed to evaluate dose thresholds correlated with response. RESULTS: Forty-one patients were included. Twenty-six (63%) met criteria for complete response. Dose to 95% (D95), 70% (D70), and 50% (D50) of the tumor volume were associated with likelihood of complete response by logistic regression (all p < 0.05). For lesions with complete response versus without, the median D95 was 813 versus 232 Gy, D70 was 1052 versus 315 Gy, and D50 was 1181 versus 369 Gy (all p < 0.01). A D95 > 719 Gy had the highest accuracy at 68% (58% sensitivity, 87% specificity) for predicting complete response. Median percent of tumor volume receiving at least 100 Gy (V100), 200 Gy (V200), 300 Gy (V300), and 400 Gy (V400) also differed by pathologic response: the median V100, V200, V300, and V400 was 100% versus 99%, 100% versus 97%, 100% versus 74%, and 100% versus 43% in the complete response versus non-complete response groups, respectively (all p < 0.05). CONCLUSION: Voxel-based dosimetry was well-correlated with explant pathology. The D95 threshold had the highest accuracy, suggesting the D95 may be a relevant target for multi-compartment dosimetry.

Current trends in nonoperative management for rectal adenocarcinoma: An unequal playing field?

BACKGROUND AND OBJECTIVES: Increasing evidence suggests patient-oriented benefits of nonoperative management (NOM) for rectal cancer. However, vigilant surveillance requires excellent access to care. We sought to examine patient, socioeconomic, and facility-level factors associated with NOM over time. METHODS: Using the National Cancer Database (2006-2017), we examined patients with Stage II-III rectal adenocarcinoma, who received neoadjuvant chemoradiation and received NOM versus surgery. Factors associated with NOM were assessed using multivariable logistic regression with backward stepwise selection. RESULTS: There were 59,196 surgical and 8520 NOM patients identified. NOM use increased from 12.9% to 15.9% between 2006 and 2017. Patients who were Black (adjusted odds ratio [aOR]: 1.36, 95% confidence interval [CI]: 1.26-1.47), treated at community cancer centers (aOR: 1.22, 95% CI: 1.12-1.30), without insurance (aOR: 1.87, 95% CI: 1.68-2.09), and with less education (aOR: 1.53, 95% CI: 1.42-1.65) exhibited higher odds of NOM. Patients treated at high-volume centers (aOR: 0.79, 95% CI: 0.74-0.84) and those who traveled >25.6 miles for care (aOR: 0.59, 95% CI: 0.55-0.64) had lower odds of NOM. CONCLUSIONS: Vulnerable groups who traditionally have difficulty accessing comprehensive cancer care were more likely to receive NOM, suggesting that healthcare disparities may be driving utilization. More research is needed to understand NOM decision-making in rectal cancer treatment.

Factors associated with refusing surgery versus planned nonoperative management for rectal cancer.

BACKGROUND: Increasingly, patients with rectal cancer receive nonoperative management. A growing body of retrospective evidence supporting the safety of this approach has likely contributed to its growing popularity. However, patients may also undergo nonoperative management because of refusal of surgical resection. We hypothesize that patients who refuse surgery are more likely to be from groups who traditionally face barriers accessing care. METHODS: We used the National Cancer Database (2006-2017) to analyze patients with nonmetastatic rectal adenocarcinoma who underwent nonoperative management following radiation. We identified 2 groups: (1) planned nonoperative management and (2) nonoperative management because of refusal of surgery. We performed logistic regression to compare the groups along patient, socioeconomic, and facility-level factors. RESULTS: In total, 9,613 and 2,039 patients were included in the planned nonoperative management and refused nonoperative management groups, respectively. Of the total study cohort (ie, planned nonoperative management + refused nonoperative management), 21% of these patients diagnosed in 2017 underwent refused nonoperative management, versus 12% in 2006. Patients who were Black (adjusted odds ratio 1.47, 95% confidence interval 1.26-1.71) or Asian/Pacific Islander (adjusted odds ratio 1.51, 95% confidence interval 1.18-1.92), age ≥65 years (adjusted odds ratio 1.55, 95% confidence interval 1.37-1.77), with more advanced disease stage (stage III adjusted odds ratio 1.30, 95% confidence interval 1.10-1.53), and government insurance (adjusted odds ratio 1.19, 95% confidence interval 1.04-1.36) were associated with increased utilization of refused nonoperative management. Conversely, lower education (adjusted odds ratio 0.62, 95% confidence interval 0.50-0.76) and female sex (adjusted odds ratio 0.88, 95% confidence interval 0.79-0.97) were associated with planned nonoperative management. CONCLUSION: Our findings suggest that the refused nonoperative management group is demographically distinct. Outreach efforts to better understand the rationale behind patient decision making in rectal cancer will be paramount to ensuring appropriate implementation of nonoperative management.