Radiation Oncology Journal最新文献

Purpose: We aimed to determine whether patients with esophageal cancer with a low baseline body mass index (BMI) have a poor prognosis following radiotherapy (RT).

Materials and methods: We retrospectively analyzed data from 50 patients with esophageal cancer to determine whether a low starting BMI (before RT) was associated with a poor outcome. All study participants were diagnosed with non-metastatic esophageal squamous cell carcinoma (SCC).

Results: The number of patients at each T stage were as follows: 7 (14%) patients at T1, 18 (36%) at T2, 19 (38%) at T3, and 6 (12%) at T4. Based on BMI, 7 (14%) patients were defined as underweight. A low BMI was common in patients with T3/T4 stage esophageal cancer (7/43, p = 0.01). Overall, the 3-year progression-free survival (PFS) and overall survival (OS) rates were 26.3% and 69.2%, respectively. In univariate analysis, clinical factors associated with poor PFS included being underweight (BMI <18.5 kg/m2; p = 0.011) and a positive N status (p = 0.017). Univariate analysis also revealed that being underweight was associated with a decrease in OS (p = 0.003). However, being underweight was not an independent prognostic factor for PFS and OS.

Conclusion: Patients with esophageal SCC with a low starting BMI (BMI <18.5 kg/m2) are more prone to have a negative survival outcome following RT than patients who are considered to be normal weight or overweight. For this reason, it is important that clinicians pay more attention to BMI when treating patients with esophageal SCC.

Purpose: The target delineation of whole ventricle radiotherapy (WVRT) in germinoma varies among radiation oncologists, especially regarding the inclusion of the prepontine cistern (PC). We evaluated the outcome of PC-sparing WVRT in localized germinoma.

Materials and methods: We identified 87 localized intracranial germinoma patients who received radiotherapy (RT) following chemotherapy between 1999 and 2020. By institutional policy, RT for localized germinoma excluded PC from the target volume. WVRT was delivered to 65 patients (74.7%) and involved field radiotherapy (IFRT) to 22 patients (25.3%). The median dose was 45.0 Gy (range, 23.4 to 55.8 Gy) for the primary tumor and 19.8 Gy (rangem 14.4 to 36.0 Gy) for the whole ventricle. We analyzed the dosimetric differences of the organs at risk between the PC-excluding plans and the PC-including ones.

Results: The median follow-up duration was 7.8 years (range, 1.0 to 22.5 years). The 10-year recurrence-free survival and overall survival rates were 86.3% and 90.9%, respectively. The recurrences occurred in eight patients (8.7%), including five patients after IFRT and three after WVRT. Five of them showed recurrences at lateral ventricles and only one patient experienced spinal cord relapse. However, no relapse in the PC occurred. Endoscopic third ventriculostomy was not a significant prognostic factor. The dosimetric comparisons showed significantly lower mean doses to the brainstem and the cochleae when the PC was excluded.

Conclusion: WVRT for localized germinoma can safely exclude the PC in the target volume, reducing radiation dose to the brain stem. The target protocol needs to reach a consensus regarding the PC in prospective trials.

Rectal resection surgery after neoadjuvant treatment has been the mainstay treatment of locally advanced rectal cancer. However, functional outcomes and quality of life after radical resection of the rectum remain suboptimal. The excellent oncologic outcomes in patients who achieved pathologic complete response after neoadjuvant treatment questioned the need for radical surgery. The watch-and-wait approach is a noninvasive therapeutic alternative for organ preservation and avoiding operative morbidity. In the watch-and-wait approach, patients with locally advanced rectal cancer who achieve excellent clinical response after neoadjuvant treatment undergo active surveillance rather than rectal cancer surgery. In this practical review, we summarized the main results of studies on the watch-and-wait approach and provided a practical method for implementing the watch-and-wait approach.

Purpose: This study explored the potential feasibility of cell-free DNA (cfDNA) in monitoring treatment response through the measurement of chromosomal instabilities using I-scores in the context of radiation therapy (RT) for other solid tumors.

Materials and methods: This study enrolled 23 patients treated with RT for lung, esophageal, and head and neck cancer. Serial cfDNA monitoring was performed before RT, 1 week after RT, and 1 month after RT. Low-depth whole-genome sequencing was done using Nano kit and NextSeq 500 (Illumina Inc.). To measure the extent of genome-wide copy number instability, I-score was calculated.

Results: Pretreatment I-score was elevated to more than 5.09 in 17 patients (73.9%). There was a significant positive correlation between the gross tumor volume and the baseline I-score (Spearman rho = 0.419, p = 0.047). The median I-scores at baseline, post-RT 1 week (P1W), and post-RT 1 month (P1M) were 5.27, 5.13, and 4.79, respectively. The I-score at P1M was significantly lower than that at baseline (p = 0.002), while the difference between baseline and P1W was not significant (p = 0.244).

Conclusion: We have shown the feasibility of cfDNA I-score to detect minimal residual disease after RT in patients with lung cancer, esophageal cancer, and head and neck cancer. Additional studies are ongoing to optimize the measurement and analysis of I-scores to predict the radiation response in cancer patients.

Purpose: To perform the analysis of the peripheral blood lymphocyte changes after stereotactic ablative radiotherapy (SABR) in patients with oligometastatic cancers.

Materials and methods: The dynamics of the immune status in peripheral blood was prospectively evaluated in 46 patients with lung (17 cases) or liver (29 cases) metastases treated by SABR. Flow cytometry of peripheral blood lymphocyte subpopulations was performed before SABR, 3-4 weeks and 6-8 weeks after the end of SABR: 3 fractions of 15-20 Gy or 4 fractions of 13.5 Gy. The number of treated lesions varied from 1 (32 patients) to 2-3 (14 patients).

Results: SABR induced a significant increase of T-lymphocytes (CD3+CD19-) (p = 0.001), T-helper (CD3+CD4+) (p = 0.004), activated cytotoxic T-lymphocytes (CD3+CD8+HLA-DR+) (p = 0.001), activated T-helpers (CD3+CD4+HLA-DR+) (p < 0.001). A significant decrease of T-regulated immune suppressive lymphocytes (CD4+CD25brightCD127low) (p = 0.002) and NKT-cells (CD3+CD16+CD56+) (p = 0.007) was recorded after the SABR. The comparative analysis demonstrated that lower doses of SABR (EQD2Gy(α/β=10) = 93.7-105.7 Gy) induced significant increase of T-lymphocytes, activated cytotoxic T-lymphocytes, and activated CD4+CD25+ T-helpers, while SABR with higher doses (EQD2Gy(α/β=10) = 150 Gy) was not associated with these effects. A more efficient activations of T-lymphocytes (p = 0.010), activated T-helpers (p < 0.001), and cytotoxic T-lymphocytes (p = 0.003) were associated with SABR to a single lesion. A significant increase of T-lymphocytes (p = 0.002), T-helpers (p = 0.003), and activated cytotoxic T-lymphocytes (p = 0.001) was observed after SABR for hepatic metastases in contrast to SABR for lung lesions.

Conclusion: Changes in peripheral blood lymphocytes after SABR could be influenced by the location or the number of irradiated metastasis, and the dose of SABR.

Purpose: There has been limited work assessing the use of re-irradiation (re-RT) for local failure following stereotactic spinal radiosurgery (SSRS). We reviewed our institutional experience of conventionally-fractionated external beam radiation (cEBRT) for salvage therapy following SSRS local failure.

Materials and methods: We performed a retrospective review of 54 patients that underwent salvage conventional re-RT at previously SSRS-treated sites. Local control following re-RT was defined as the absence of progression at the treated site as determined by magnetic resonance imaging.

Results: Competing risk analysis for local failure was performed using a Fine-Gray model. The median follow-up time was 25 months and median overall survival (OS) was 16 months (95% confidence interval [CI], 10.8-24.9 months) following cEBRT re-RT. Multivariable Cox proportional-hazards analysis revealed Karnofsky performance score prior to re-RT (hazard ratio [HR] = 0.95; 95% CI, 0.93-0.98; p = 0.003) and time to local failure (HR = 0.97; 95% CI, 0.94-1.00; p = 0.04) were associated with longer OS, while male sex (HR = 3.92; 95% CI, 1.64-9.33; p = 0.002) was associated with shorter OS. Local control at 12 months was 81% (95% CI, 69.3-94.0). Competing risk multivariable regression revealed radioresistant tumors (subhazard ratio [subHR] = 0.36; 95% CI, 0.15-0.90; p = 0.028) and epidural disease (subHR = 0.31; 95% CI, 0.12-0.78; p =0.013) were associated with increased risk of local failure. At 12 months, 91% of patients maintained ambulatory function.

Conclusion: Our data suggest that cEBRT following SSRS local failure can be used safely and effectively. Further investigation is needed into optimal patient selection for cEBRT in the retreatment setting.

Purpose: Nasopharyngeal cancer (NPC) has a higher prevalence of regional nodal metastasis than other head and neck cancers; however, level IB lymph node involvement is rare. We evaluated the safety and feasibility of level IB-sparing radiotherapy (RT) for NPC patients.

Materials and methods: We retrospectively reviewed 236 patients with NPC who underwent definitive intensity-modulated RT with or without chemotherapy between 2004 and 2018. Of them, 212 received IB-sparing RT, and 24 received non-IB-sparing RT. We conducted a propensity score matching analysis to compare treatment outcomes according to IB-sparing status. In addition, dosimetric analysis of the salivary glands was performed to identify the relationship between xerostomia and the IB-sparing RT.

Results: The median follow-up duration was 78 months (range, 7 to 194 months). Local, regional, and distant recurrences were observed in 11.9%, 6.8%, and 16.1% of patients, respectively. Of the 16 patients with regional recurrence, 14 underwent IB-sparing RT. The most common site categorization of regional recurrence was level II (75%), followed by retropharyngeal lymph nodes (43.8%); however, there was no recurrence at level IB. In the matched cohorts, IB-sparing RT was not significantly related to treatment outcomes. However, IB-sparing RT patients received a significantly lower mean ipsilateral and contralateral submandibular glands doses (all, p < 0.001) and had a lower incidence of chronic xerostomia compared with non-IB-sparing RT patients (p = 0.006).

Conclusion: Our results demonstrated that IB-sparing RT is sufficiently safe and feasible for treating NPC. To reduce the occurrence of xerostomia, IB-sparing RT should be considered without compromising target coverage.

Purpose: This study aimed to evaluate the clinical infrastructure and utilization of radiotherapy (RT) services in Korea between 2017 and 2019.

Materials and methods: We extracted the data of patients who underwent RT between 2017 and 2019 from the Health Insurance Review and Assessment Service. We further analyzed this data according to the diagnosis and treatment modalities of patients diagnosed with International Classification of Disease 10 (ICD-10) diagnostic codes C00-C97 and D00-D48. In addition, we collected statistics on RT facilities in Korea using a nationwide survey.

Results: The total number of patients who received RT in 2017, 2018, and 2019 were 77,901, 81,849, and 87,460, respectively. The number of patients diagnosed with ICD 10 C- and D-codes in 2019 was 86,339, of whom 39,467 were men and 46,872 women. The rate of utilization of RT among cancer patients was 30.4% in 2017 and 2018 and 30.9% in 2019. In 2019, the most common types of cancers treated with RT were breast, lung, prostate, colorectal, and liver cancers. Regarding the RT infrastructure in Korea, there were 95 radiation oncology centers, 237 megavoltage (MV) teletherapy units, 35 brachytherapy units, and two proton accelerators in 2019. There were 4.5 MV teletherapy machines per million.

Conclusion: The number of patients treated with RT has increased consistently from 2017 to 2019. As the number of patients with cancer increases, it is expected that the RT infrastructure will be further expanded in Korea.