Naoyuki Kanayama

Efficacy and Safety of Endoscopic Resection Followed by Chemoradiotherapy for Superficial Esophageal Squamous Cell Carcinoma: A Retrospective Study.

OBJECTIVES: The reported 1‐ and 3‐year overall survival rates after esophagectomy for stage I superficial esophageal squamous cell carcinoma (SESCC) are 95–97% and 86%, and those after definitive chemoradiotherapy (CRT) are 98% and 89%, respectively. This study was performed to elucidate the efficacy and safety of another treatment option for SESCC: endoscopic resection (ER) followed by CRT. METHODS: We retrospectively reviewed the overall survival, recurrence, and grade ≥3 adverse events of consecutive patients who refused esophagectomy and underwent ER followed by CRT for SESCC from 1 January 2006 to 31 December 2012. RESULTS: In total, 66 patients with SESCC underwent ER followed by CRT during the study period, and complete follow‐up data were available for all patients. The median age was 67 (range, 45–82) years, and the median observation period was 51 (range, 7–103) months. Local and metastatic recurrences occurred in 2 (3%) and 6 (9%) patients, respectively, and 17 (26%) patients died. The 1‐, 3‐, and 5‐year overall survival rates were 98%, 87%, and 75%, respectively. One of the 23 patients with mucosal cancer and 5 of 43 with submucosal cancer developed metastatic recurrences (P=0.65). Five of the 61 patients with negative vertical resection margin and 1 of 5 with positive vertical resection margin developed metastatic recurrences (P=0.39). None of the 30 patients without lymphovascular involvement developed metastatic recurrences; however, 6 of 36 patients with lymphovascular involvement developed metastatic recurrences (P=0.0098). Grade ≥3 adverse events occurred in 21 (32%) patients and all adverse events were associated with CRT, hematological adverse events in 13 (20%), and non‐hematological adverse events in 9 (14%). CONCLUSIONS: ER followed by CRT provides survival comparable with that of esophagectomy or definitive CRT and has a low local recurrence rate. A particularly favorable outcome is expected for cancers without lymphovascular involvement.

Definitive radiotherapy for primary vaginal cancer: correlation between treatment patterns and recurrence rate

Abstract The purpose of this study was to determine the outcomes and optimal practice patterns of definitive radiotherapy for primary vaginal cancer. Between 1993 and 2012, 49 patients were treated with definitive radiotherapy for primary vaginal cancer in three hospitals. Of these, 15 patients (31%) had clinically positive regional lymph node metastasis. A total of 34 patients (70%) received external beam radiotherapy with high-dose-rate brachytherapy (interstitial or intracavitary), and 8 (16%) (with small superficial Stage I tumors) were treated with local radiotherapy. The median follow-up was 33 months (range: 1–169 months). The 3-year overall survival (OS), disease-free survival (DFS), and loco-regional control (LRC) rates were 83%, 59% and 71%, respectively. In multivariate analysis, the histological type (P = 0.044) was significant risk factors for LRC. In Federation of Gynecology and Obstetrics (FIGO) Stage I cases, 3 of 8 patients (38%) who did not undergo prophylactic lymph node irradiation had lymph node recurrence, compared with 2 of 12 patients (17%) who underwent prophylactic pelvic irradiation. For Stage III–IV tumors, the local recurrence rate was 50% and the lymph node recurrence rate was 40%. Patients with FIGO Stage I/II or clinical Stage N1 had a higher recurrence rate with treatment using a single modality compared with the recurrence rate using combined modalities. In conclusion, our treatment outcomes for vaginal cancer were acceptable, but external beam radiotherapy with brachytherapy (interstitial or intracavitary) was needed regardless of FIGO stage. Improvement of treatment outcomes in cases of FIGO Stage III or IV remains a significant challenge.

External validation of a multifactorial normal tissue complication probability model for tube feeding dependence at 6 months after definitive radiotherapy for head and neck cancer

BACKGROUND AND PURPOSE The purpose of this study was to externally validate a previously published normal tissue complication probability (NTCP) model for tube feeding dependence at 6 months (TUBEM6) after completion of (chemo) radiotherapy. MATERIALS AND METHODS This study evaluated 122 head and neck cancer patients treated by definitive (chemo) radiotherapy. The closed testing procedure was used to select the appropriate method for updating the NTCP model. In this procedure, the likelihood ratio test was used to compare the updated model against the original model. RESULTS Mean predicted NTCP was 12.2% (95% CI: 9.9%-14.5%) when using the original NTCP model for TUBEM6. TUBEM6 at our institute was 5.7% (95% CI: 1.8-9.6%) for the 122 patients evaluated. The test for the model revision against the original NTCP model was statistically significant (p = 0.032). The test for the model revision against the model adjusting intercept only was not statistically significant (p = 0.240). According to the closed testing procedure, the model required adjusting the intercept only. CONCLUSIONS TUBEM6 at our institute was lower than that predicted by the original NTCP model. The closed testing procedure indicated that only an adjustment of the intercept was needed indicating the importance of external validation.

Clinical implementation of contrast-enhanced four-dimensional dual-energy computed tomography for target delineation of pancreatic cancer

BACKGROUND AND PURPOSE The accurate delineation of pancreatic tumor with respiratory motion is challenging. This study demonstrates the application of contrast-enhanced four-dimensional dual-energy computed tomography (CE-4D-DECT) for tumor delineation and assesses the objective and subjective image quality. MATERIAL AND METHODS Twelve patients underwent CE-4D-DECT, and quantitative spectral analysis was performed on the resulting virtual monochromatic images (VMI) to determine the optimal VMI (O-VMI) with the highest contrast-to-noise ratio (CNR). The objective value of the CNR between pancreatic parenchyma and tumor, and the subjective measurement with five-point scale were compared between O-VMI, standard VMI (S-VMI, 77 keV) and single energy CT (SECT, 120 kVp). RESULTS The CNR was the highest in the VMI at 60 keV, and the corresponding CNR in the O-VMI (3.4) was significantly higher (p < 0.05) than that in the S-VMI (2.4) and the SECT (2.7). The overall mean subjective measurements among 4 radiation oncologists were higher for the O-VMI over the S-VMI and SECT with respect to overall image quality (4.0, 3.3 and 3.7, respectively), tumor enhancement (3.4, 2.6 and 3.2, respectively), and vessel delineation (4.2, 3.6 and 4.2, respectively). CONCLUSIONS The O-VMI derived from the CE-4D-DECT demonstrated its superiority over the S-VMI and SECT in depicting pancreatic tumor.

Radiation Dose Escalation in Accelerated Hyperfractionated Radiotherapy for Stage III Non-small-cell Lung Cancer

Aim: To identify clinical benefits of dose escalation in accelerated hyperfractionated radiotherapy (AH-RT) for stage III non-small-cell lung cancer (NSCLC) using propensity score-matched (PSM) analysis. Materials and Methods: Our study retrospectively examined 294 patients undergoing definitive radiotherapy [131 patients, conventional once-daily radiotherapy (OD-RT); and 163, AH-RT] who were followed-up for a median of 40.4 months. The impact of overall survival (OS), progression-free survival (PFS), and locoregional control (LRC) was investigated. Results: Pre-PSM, the median OS, PFS, and LRC durations were 23.1 vs. 39.9 (p=0.03), 8.9 vs. 13.5 (p<0.01), and 12.9 vs. 50.3 (p<0.01) months in the OD-RT and AH-RT groups, respectively. After-PSM (two matched groups of 144 patients), AH-RT was associated with better LRC [adjusted hazard ratio (aHR)=0.59, 95% confidence interval (CI)=0.33-0.99, p=0.04] and marginally better PFS (aHR=0.65, 95% CI=0.41-1.03; p=0.06), but not OS (aHR=0.75, 95% CI=0.46-1.24; p=0.26). Conclusion: After PSM analysis, dose escalation using AH-RT improved LRC and PFS in patients with locally advanced NSCLC. AH-RT can be a promising option for patients with advanced NSCLC.

How Well Does Dual-energy CT with Fast Kilovoltage Switching Quantify CT Number and Iodine and Calcium Concentrations?

RATIONALE AND OBJECTIVES Because it is imperative for understanding the performance of dual-energy computed tomography scanner to determine clinical diagnosis, we aimed to assess the accuracy of quantitative measurements using dual-energy computed tomography with fast kilovoltage switching. MATERIALS AND METHODS Quantitative measurements were performed for 16 reference materials (physical density, 0.965-1.550 g/cm3; diameter of rod, 2.0-28.5 mm; iodine concentration, 2-15 mg/mL; and calcium concentration, 50-300 mg/mL) with varying scanning settings, and the measured values were compared to their theoretical values. RESULTS For high-density material, the maximum differences in Hounsfield unit values in the virtual monochromatic images at 50, 70, and 100 keV were -176.2, 61.0, and -35.2 HU, respectively, and the standard deviations over short- and long-term periods were 11.1, 6.1, and 3.5 HU at maximum. The accuracy of the Hounsfield unit measurement at 50 and 70 keV was significantly higher (P < 0.05) with higher radiation output and smaller phantom size. The difference in the iodine and calcium measurements in the large phantom were up to -2.6 and -60.4 mg/mL for iodine (5 mg/mL with 2-mm diameter) and calcium (300 mg/mL) materials, and the difference was improved with a small phantom. Metal artifact reduction software improved subjective image quality; however, the quantitative values were significantly underestimated (P < 0.05) (-49.5, -26.9, and -15.3 HU for 50, 70, and 100 keV, respectively; -1.0 and -17 mg/mL for iodine and calcium concentration, respectively) compared to that acquired without a metal material. CONCLUSIONS The accuracy of quantitative measurements can be affected by material density and the size of the object, radiation output, phantom size, and the presence of metal materials.

Selective neck irradiation for supraglottic cancer: focus on Sublevel IIb omission

OBJECTIVE To estimate selective neck irradiation omitting surgical Sublevel IIb. METHODS Bilateral necks of 47 patients (94 necks) were subjected to definitive radiotherapy for supraglottic cancer. Sixty-nine and 25 necks were clinically node negative (cN-) and clinically node positive (cN+), respectively. We subdivided Sublevel IIb by the international consensus guideline for radiotherapy into Sublevel IIb/a, directly posterior to the internal jugular vein, and Sublevel IIb/b, which was behind Sublevel IIb/a and coincided with surgical Sublevel IIb. Bilateral (Sub)levels IIa, III, IV and IIb/a were routinely irradiated, whereas Sublevel IIb/b was omitted from the elective clinical target volume in 73/94 treated necks (78%). RESULTS Two patients presented with ipsilateral Sublevel IIb/a metastases. No Sublevel IIb/b metastasis was observed. Five patients experienced cervical lymph node recurrence; Sublevel IIb/a recurrence developed in two patients, whereas no Sublevel IIb/b recurrence occurred even in the cN- necks of cN+ patients or cN0 patients. The 5-year regional control rates were 91.5% for Sublevel IIb/b-omitted patients and 77.8% for Sublevel IIb/b treated patients. CONCLUSIONS Selective neck irradiation omitting Sublevel IIb/b did not compromise regional control and could be indicated for cN- neck of supraglottic cancer.