Search

Purpose: Hyaluronate gel has been injected as a spacer into the rectovaginal fossa and vesicouterine fossa during brachytherapy for patients with cervical cancer at our institution. The effect of hyaluronate gel injection (HGI) on dose-volume parameters was investigated in this study. Methods and Materials: Between July 2008 to January 2020, a total of 104 patients (non-HGI group: 52 patients; HGI group: 52 patients) who underwent curative radiation therapy for cervical cancer were selected. The total doses of external beam radiation therapy and brachytherapy for high-risk clinical target volume (CTVHR) D90, bladder D2cc, and rectal D2cc were converted to the equivalent dose in 2 Gy fractions (EQD2) and were analyzed for association with HGI. Results: Median CTVHR D90 (EQD2) in the non-HGI group was 76.0 Gy (63.7-99.5 Gy), and in the HGI group it was 79.4 Gy (52.6-97.5 Gy) (P = .017). The median bladder D2cc and rectal D2cc (EQD2) were 62.9 Gy and 56.0 Gy in the non-HGI group and 63.7 Gy and 54.8 Gy in the HGI group, which had no significant difference. Conclusions: In cases with HGI, a significant CTVHR D90 dose increase was obtained with sufficient bladder and rectal doses suppression.

Purpose: The purpose of this study was to investigate the overlaps between gross target volume (GTV) and the celiac artery (CA) and superior mesenteric artery (SMA) lymph node regions and to examine the dose incidentally irradiated to the CA and SMA lymph node regions by involved-field radiation therapy (IFRT) for locally advanced pancreatic cancer (LAPC). Methods and Materials: Fifty-nine patients who had LAPC without distant metastasis were included. They received IFRT at 50.4 Gy in 28 fractions with 3-dimensional conformal radiation therapy. We calculated the percentages of overlap of GTV in the CA and SMA lymph node regions and examined what cases tend to have an overlap. We also investigated the dose metrics of CA and SMA lymph node regions by IFRT and the frequency of CA or SMA lymph node metastasis after IFRT. Results: The median GTV volume was 52.2 mL. Median overlap percentages in the CA and SMA lymph node regions were 39.2% and 28.6%, respectively. There was a significant correlation between GTV volume and SMA overlap percentage (P < .001). Although the SMA overlap percentage was higher in the pancreas head (P = .028), the CA overlap percentage was higher in the pancreas body or tail (P = .002). Median mean dose, D95, and minimum dose in the CA lymph node region were 50.1 Gy, 48.7 Gy, and 45.9 Gy, respectively, and those in the SMA lymph node region 49.9 Gy, 47.3 Gy, and 39.2 Gy, respectively. CA lymph node metastases after IFRT were detected in 4 patients (6.8%). Conclusions: An overlap between GTV and CA-SMA lymph node regions was detected in many patients, and the CA and SMA lymph node regions were irradiated incidentally even by IFRT. Prophylactic lymph node regions might not be necessary in radiation therapy planning of LAPC.

Purpose: We investigated the synchronization of respiration-induced motions at the primary tumor and organs at risk at radiation planning for pancreatic cancer. Methods and Materials: Four-dimensional computed tomography images were acquired under the condition of shallow free breathing in patients with pancreatic cancer. The gross tumor volume (GTV), duodenum (DU), and stomach (ST) were contoured. The center of mass was computed for each 4-dimensional volume of interest. The respiration dependence of coordinates for the center of each volume of interest was computed relative to its location at the 50% (maximum exhalation) phase. Based on the shift of the GTV, we investigated the synchronization of respiration-induced motions between each contouring target. We examined the differences in the volume averaged dose to the ST and DU in each respiratory phase. Results: Nine patients with pancreatic cancer were analyzed in this study. The mean maximum 3-dimensional excursions at the GTV, DU, and ST were 9.6, 9.8, and 11.4 mm, respectively. At phase 0% and 90% (inhale phases), mean distance changes in the positional relationship with the GTV were 0.3 and 0.7 mm respectively for the DU and −2.5 and −2.4 mm respectively for the ST. There was no significant respiration associated change (RAC) between each respiratory phase in the DU (P = .568), and there was a significant RAC in the ST (P < .001). There was a significant RAC of the volume averaged dose to the ST (P = .023). Conclusions: Our results indicate that the DU but not the ST might move synchronously with GTV due to respiration.

Purpose: Adjuvant durvalumab has become a standard treatment after chemoradiation therapy for patients with locally advanced non-small cell lung cancer (LA-NSCLC). Accordingly, predicting radiation pneumonitis (RP) requiring steroidal treatment (steroid-RP) is of utmost importance because steroidal administration is reported to weaken the effectiveness of immunotherapy. However, grade 2 RP was used as an index of RP in previous studies, but it is an ambiguous definition because it includes not only steroid-RP but also a mild cough requiring only a cough medicine. Therefore, in this study, steroid-RP was used for evaluating RP, and the purpose of this study was to investigate predictive factors of steroid-RP, including original simple interstitial lung abnormality scores (ILASs). Methods and Materials: A total of 145 patients with LA-NSCLC who received definitive radiation therapy (DRT) in our institution from January 2014 to May 2017 were identified. Original ILASs, performance status, age, respiratory function, Brinkman index, concurrent administration of chemotherapy, and dose–volume histogram metrics of the lung were analyzed to evaluate their association with steroid-RP. Additionally, 3 diagnostic radiologists evaluated the patients’ pre-DRT chest computed tomography images and determined the simple ILASs. ILASs were rated as follows: 0: none; 1: abnormality without honeycombing (ground-glass attenuation, fine reticular opacity, and microcysts); and 2: honeycombing. Results: The median follow-up period was 729 days. Thirty-one patients (21.4%) experienced steroid-RP. In the univariate analysis, lung V5/V10/VS5, Brinkman index, and ILASs were significant predictive factors of steroid-RP. Additionally, multivariate analysis including Brinkman index ≥840, lung V5 ≥37%, and an ILAS ≥1 revealed that only an ILAS (P = .001) was an independent predictive factor of steroid-RP. Conclusions: The original simple ILAS was an easy-to-use tool and a significant predictive factor of steroid-RP in DRT in patients with LA-NSCLC.