Effectiveness and Safety of Tissue Expander for Adjuvant Helical Tomotherapy in Curatively Resected Retroperitoneal Sarcoma

BACKGROUND/AIM

We investigated the effectiveness and safety of using a tissue expander (TE) for adjuvant helical tomotherapy (HT) for curatively resected retroperitoneal sarcoma (RPS).

MATERIALS AND METHODS

This study was conducted with 60 RPS patients who underwent curative resection with or without TE insertion followed by HT from June 2009 to December 2016. Among the patients, TE was inserted in 37 (61.7%). The quality of TE insertion was evaluated. Median follow-up after surgery was 19.4 months (range=4.5-93.2 months).

RESULTS

A higher biologically-equivalent dose (α/β=10) was used with patients who had TE insertion (median, 72.0 gray [Gy] vs. 67.1 Gy, p=0.02). The quality of TE insertion was excellent in 18 patients (48.6%), good in 10 (27.0%), fair in seven (18.9%), and poor in two (5.4%). Toxicity was not significantly different according to TE insertion. Local recurrence-free survival (LRFS) was 78.2%, and overall survival was 95.6% at 3 years. TE insertion was not a significant factor for LRFS (91.1% in TE vs. 62.9% in non-TE group at 3 years, p=0.62). In the subgroup of patients with R1 or unknown tumor margin status, however, LRFS was marginally higher in the TE insertion group (100.0% in TE vs. 62.9% non-TE group at 3 years, p=0.05).

CONCLUSION

HT with TE insertion as adjuvant RT for curatively resected RPS was feasible with acceptable toxicity. In the patients with R1 or unknown tumor margin status, LRFS was marginally higher in the TE insertion group after HT.

High-dose radiation therapy alone by moderate hypofractionation for patients with thoracic esophageal squamous cell carcinoma

We conducted retrospective analyses to investigate the clinical outcome of thoracic esophageal cancer patients who were treated with high-dose radiation therapy (RT) alone by moderate hypofractionation due to medical unfitness or refusal to receive either surgery or chemo-radiotherapy.Between May 2003 and April 2013, 70 patients were treated with high-dose RT alone with curative aim. The planned total RT dose was 60 Gy in daily 3.0 Gy per fraction. We evaluated the survival outcome, toxicities, and prognostic factors affecting patients' survival.At the time of analysis, 32 patients experienced disease progression. The 2-year overall survival (OS), cancer-specific survival (CSS) and local control (LC) rates were 52.1%, 57.8%, and 68.2%, respectively. Among them, 25 patients had superficial (cT1a-b) esophageal cancers, and the 2-year OS, CSS, and LC rates were 80.0%, 87.3%, and 81.6%, respectively. Multivariate analysis revealed that cT disease (P < 0.001) and tumor location (P = 0.022) were the significant factors for OS. The incidence of grade 3 or higher toxicities were 9.9%, including grade 3 esophagitis (2 patients, 2.8%) and grade 4 or 5 trachea-esophageal fistula (5 patients, 7.1%).High-dose RT alone by moderate hypofractionation had led to reasonable clinical outcomes at acceptable toxicity risk in thoracic esophageal cancer patients who are medically unfit or refuse surgery or chemotherapy, especially for the patients having superficial lesion.

Clinical outcomes of tissue expanders on adjuvant radiotherapy of resected retroperitoneal sarcoma

We investigated the efficacy and safety of a tissue expander (TE) for adjuvant radiotherapy (RT) of resected retroperitoneal sarcoma (RPS).This study was conducted with 37 patients with RPS who received resection with or without TE insertion followed by RT from August 2006 to June 2012 at Samsung Medical Center. Among the 37 patients, TE was inserted in 19. The quality of TE insertion was evaluated according to the correlation of clinical target volume and retroperitoneal surface volume covered by TE and was defined as follows: excellent, ≥85%; good, 70% to 85%; fair, 50% to 70%; and poor, <50%. The median follow-up period after surgery was 47.9 months (range, 5.5-85.5 months).The quality of TE insertion was excellent in 7 (36.8%), good in 5 (26.3%), fair in 4 (21.0%), and poor in 3 (16.7%) patients. A significantly higher biologically equivalent dose (BED, α/β = 10) was used in patients who had TE insertion (median, 64.8 vs. 60.0 Gy, P = 0.01). Local control was 39.7%, and overall survival was 76.4% at 5 years. Local control was significantly higher in patients who received ≥65 Gy of BED, 100.0% in contrast to 22.8% (P = 0.01). One patient with a history of multiple tumor resections showed abdominal infection with duodenal perforation of uncertain cause but had the potential of being related to TE and/or RT. Otherwise there were no ≥grade III acute or late toxicities.TE for adjuvant RT in RPS is feasible for delivering a higher RT dose with acceptable toxicity.

Effect of the gel elasticity of model skin matrices on the distance/depth-dependent transmission of vibration energy supplied from a cosmetic vibrator

OBJECTIVE

The purpose of this study was to determine how the energies supplied from a cosmetic vibrator are deeply or far transferred into organs and tissues, and how these depths or distances are influenced by tissue elasticity.

METHODS

External vibration energy was applied to model skin surfaces through a facial cleansing vibrator, and we measured a distance- and depth-dependent energy that was transferred to model skin matrices. As model skin matrices, we synthesized hard and soft poly(dimethylsiloxane) (PDMS) gels, as well as hydrogels with a modulus of 2.63 MPa, 0.33 MPa and 21 kPa, respectively, mostly representing those of skin and other organs. The transfer of vibration energy was measured either by increasing the separation distances or by increasing the depth from the vibrator.

RESULTS

The energies were transmitted deeper into the hard PDMS than into the soft PDMS and hydrogel matrices. This finding implies that the vibration forces influence a larger area of the gel matrices when the gels are more elastic (or rigid). There were no appreciable differences between the soft PDMS and hydrogel matrices. However, the absorbed energies were more concentrated in the area closest to the vibrator with decreasing elasticity of the matrix. Softer materials absorbed most of the supplied energy around the point of the vibrator. In contrast, harder materials scattered the external energy over a broad area.

CONCLUSIONS

The current results are the first report in estimating how the external energy is deeply or distantly transferred into a model skins depending on the elastic moduli of the models skins. In doing so, the results would be potentially useful in predicting the health of cells, tissues and organs exposed to various stimuli.

Clinical outcomes in cervical cancer patients treated by FDG-PET/CT-based 3-dimensional planning for the first brachytherapy session

The aim of the study was to evaluate the treatment outcomes in cervical cancer patients treated with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT)-guided 3-dimensional brachytherapy (3D-BT) planning for the first brachytherapy session.We retrospectively analyzed 87 patients with cervical cancer who received definitive radiotherapy (RT). Primary tumor size was ≤4 cm in 22 patients (25.3%), >4 cm and ≤6 cm in 45 patients (51.7%), and >6 cm in 20 patients (23.0%). The median total dose of external beam RT was 50.4 (50.4-60.4) Gy. FDG-PET/CT-guided 3D-BT with an iridium-192 source was performed. The clinical target volume (CTV) for 3D-BT included the entire cervix and the abnormal FDG-uptake with a 1-cm expansion. A planned total dose was 24 Gy at 4 Gy per insertion 3 times per week using a tandem and 2 ovoids.The mean D95 and D90 for the CTV were 73.4 (±5.9) Gy and 77.9 (±6.9) Gy, respectively (EQD2, α/β=10). The D2cc for the rectum and bladder was 374 (±97.4) cGy and 394 (±107.6) cGy per fraction, respectively. The EQD2 (α/β=3) for the D2cc was 74.5 (±12.4) Gy for the rectum and 77.3 (±14.6) Gy for the bladder. The median follow-up period was 40 (8-61) months. The 3-year overall survival (OS), progression-free survival (PFS), and local control (LC) rates were 84.7%, 72.1%, and 89.2%, respectively. The 3-year LC rate was 100% for tumors ≤ 4 cm, 91.1% for tumors > 4 cm and ≤ 6 cm, and 70.5% for tumors > 6 cm (P = 0.014). Local failure developed in 9 patients. Three patients had local failures outside of the CTV. Grade 1, 2, and 3 rectal bleeding developed in 5, 4, and 2 patients, respectively. One patient experienced rectovaginal fistula.FDG-PET/CT-guided 3D-BT planning is a feasible approach, which showed favorable clinical outcomes.

Distribution of catecholaminergic presympathetic-premotor neurons in the rat lower brainstem

We previously characterized the organization of presympathetic-premotor neurons (PSPMNs), which send descending poly-synaptic projections with collaterals to skeletal muscle and the adrenal gland. Such neurons may play a role in shaping integrated adaptive responses, and many of them were found within well-characterized regions of noradrenergic cell populations suggesting that some of the PSPMNs are catecholaminergic. To address this issue, we used retrograde trans-synaptic tract-tracing with attenuated pseudorabies virus (PRV) recombinants combined with multi-label immunofluorescence to identify PSPMNs expressing tyrosine hydroxylase (TH). Our findings indicate that TH-immunoreactive (ir) PSPMNs are present throughout the brainstem within multiple cell populations, including the A1, C1, C2, C3, A5 and A7 cell groups along with the locus coeruleus (LC) and the nucleus subcoeruleus (SubC). The largest numbers of TH-ir PSPMNs were located within the LC and SubC. Within SubC and the A7 cell group, about 70% of TH-ir neurons were PSPMNs, which was a significantly greater fraction of neurons than in the other brain regions we examined. These findings indicate that TH-ir neurons near the pontomesencephalic junction that are distributed across the LC, SubC, and the A7 may play a prominent role in somatomotor-sympathetic integration, and that the major functional role of the A7 and SubC noradrenergic cell groups maybe in the coordination of concomitant activation of somatomotor and sympathetic outflows. These neurons may participate in mediating homeostatic adaptations that require simultaneous activation of sympathetic and somatomotor nerves in the periphery.

Clinical outcomes of stereotactic body radiotherapy for spinal metastases from hepatocellular carcinoma

Purpose

To investigate the outcomes of patients with spinal metastases from hepatocellular carcinoma (HCC), who were treated by stereotactic body radiotherapy (SBRT).

Materials and Methods

This retrospective study evaluated 23 patients who underwent SBRT from October 2008 to August 2012 for 36 spinal metastases from HCC. SBRT consisted of approximately 2 fractionation schedules, which were 18 to 40 Gy in 1 to 4 fractions for group A lesions (n = 15) and 50 Gy in 10 fractions for group B lesions (n = 21).

Results

The median follow-up period was 7 months (range, 2 to 16 months). Seven patients developed grade 1 or 2 gastrointestinal toxicity, and one developed grade 2 leucopenia. Compression fractures occurred in association with 25% of the lesions, with a median time to fracture of 2 months. Pain relief occurred in 92.3% and 68.4% of group A and B lesions, respectively. Radiologic response (complete and partial response) occurred in 80.0% and 61.9% of group A and B lesions, respectively. The estimated 1-year spinal-tumor progression-free survival rate was 78.5%. The median overall survival period and 1-year overall survival rate were 9 months (range, 2 to 16 months) and 25.7%, respectively.

Conclusion

SBRT for spinal metastases from HCC is well tolerated and effective at providing pain relief and radiologic response. Because compression fractures develop at a high rate following SBRT for spinal metastases from primary HCC, careful follow up of the patient is required.

Efficacy and safety of ifosfamide in combination with carboplatin and etoposide in small cell lung cancer

PURPOSE

Ifosfamide, a potent alkylating agent, is rarely incorporated into small cell lung cancer (SCLC) treatment. The aim of this study was to assess the efficacy and safety of ifosfamide in combination with carboplatin and etoposide (ICE) in previously untreated patients with SCLC.

METHODS

From January 2002 to January 2014, we consecutively enrolled 69 patients with SCLC who were treated with ICE as initial chemotherapy at Kangbuk Samsung Hospital. The modified ICE regimen consists of ifosfamide 1200 mg/m(2)/day on days 1, 2, and 3 with mesna, etoposide 80 mg/m(2)/day on days 1, 2, and 3, and carboplatin AUC 6 on day 1. Treatment was repeated every 3 weeks and continued for up to nine cycles. Response assessments were performed every three cycles with computed tomography.

RESULTS

Among 69 patients with SCLC, the median age was 69 years (range 51-88 years). Sixteen (23 %) patients had limited disease (LD), and 53 (77 %) had extensive disease (ED). The overall response rate was 73 %. Stable disease rate was 20 %. The median overall survival was 11.3 months [95 % confidence interval (CI) 8.9-14.1] in the overall population, 20.6 months (95 % CI 14.2-21.2) for LD and 9.1 months (95 % CI 7.8-11.6) for ED. The median number of administered cycles was 6 (range 1-9). Grade ≥3 hematological toxicities included neutropenia (34 %), anemia (59 %), and thrombocytopenia (31 %). Grade ≥3 non-hematological toxicities included peripheral neuropathy in 2 %.

CONCLUSION

In chemonaïve patients with SCLC, modified ICE is well tolerated and shows favorable efficacy.

Effects of adjuvant radiotherapy on completely resected gastric cancer: A radiation oncologist's view of the ARTIST randomized phase III trial

PURPOSE

We investigated which subgroups might benefit from adjuvant radiotherapy (RT) and suggested optimal RT targets by analyzing the results of the Adjuvant Chemoradiation Therapy in Stomach Cancer (ARTIST) trial.

METHODS

We conducted randomized controlled trial in 458 gastric cancer patients. Patients were randomly assigned to XP (6 cycles of capecitabine and) or XPRT (2 cycles of XP+RT 45Gy/25 fraction with capecitabine+2 cycles of XP) groups after D2 resection. Minimum follow-up was 5years.

RESULTS

During follow-up, 77 patients (33.8%) in the XP arm and 60 (26.1%) in the XPRT arm experienced recurrence. Among these patients, locoregional recurrence (LRR) developed in 44 (9.6%; 29 in XP, 15 in XPRT; P=0.03). The local recurrence rate (4.8%) did not vary between arms. Regional recurrence was the most important difference between the two groups (23 in the XP arm, 5 in the XPRT arm, P<0.001). LRR-free survival (LRRFS) was significantly different between study arms (P=0.03), especially in patients with LN metastasis (P=0.009).

CONCLUSIONS

Adjuvant RT after D2 resection in gastric cancer reduced LRR, especially in group 3 LNs, and improved LRRFS. Patients with LN metastasis benefited more from the adjuvant RT treatment than the other subgroups.

Tumor Volume Reduction Rate during Adaptive Radiation Therapy as a Prognosticator for Nasopharyngeal Cancer

Purpose

The purpose of this study is to evaluate the prognostic significance of the tumor volume reduction rate (TVRR) measured during adaptive definitive radiation therapy (RT) for nasopharyngeal cancer (NPC).

Materials and Methods

We reviewed the RT records of 159 NPC patients treated with definitive RT with or without concurrent chemotherapy between January 2006 and February 2013. Adaptive re-planning was performed in all patients at the third week of RT. The pre- and mid-RT gross tumor volumes (GTVs) of the primary tumor and the metastatic lymph nodes were measured and analyzed for prognostic implications.

Results

After a median follow-up period of 41.5 months (range, 11.2 to 91.8 months) for survivors, there were 43 treatment failures. The overall survival and progression-free survival (PFS) rates at 5 years were 89.6% and 69.7%, respectively. The mean pre-RT GTV, mid-RT GTV, and TVRR were 45.9 cm³ (range, 1.5 to 185.3 cm³), 26.7 cm³ (1.0 to 113.8 cm³), and –41.9% (range, –87% to 78%), respectively. Patients without recurrence had higher TVRR than those with recurrence (44.3% in the no recurrence group vs. 34.0% in the recurrence group, p=0.004), and those with TVRR > 35% achieved a significantly higher rate of PFS at 5 years (79.2% in TVRR > 35% vs. 53.2% in TVRR ≤ 35%; p < 0.001). In multivariate analysis, TVRR was a significant factor affecting PFS (hazard ratio, 2.877; 95% confidence interval, 1.555 to 5.326; p=0.001).

Conclusion

TVRR proved to be a significant prognostic factor in NPC patients treated with definitive RT, and could be used as a potential indicator for early therapeutic modification during the RT course.

Dosimetric effects of multileaf collimator leaf width on intensity-modulated radiotherapy for head and neck cancer

PURPOSE

The authors evaluated the effects of multileaf collimator (MLC) leaf width (2.5 vs. 5 mm) on dosimetric parameters and delivery efficiencies of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) for head and neck (H&N) cancers.

METHODS

The authors employed two types of mock phantoms: large-sized head and neck (LH&N) and small-sized C-shape (C-shape) phantoms. Step-and-shoot IMRT (S&S_IMRT) and VMAT treatment plans were designed with 2.5- and 5.0-mm MLC for both C-shape and LH&N phantoms. Their dosimetric characteristics were compared in terms of the conformity index (CI) and homogeneity index (HI) for the planning target volume (PTV), the dose to organs at risk (OARs), and the dose-spillage volume. To analyze the effects of the field and arc numbers, 9-field IMRT (9F-IMRT) and 13-field IMRT (13F-IMRT) plans were established for S&S_IMRT. For VMAT, single arc (VMAT1) and double arc (VMAT2) plans were established. For all plans, dosimetric verification was performed using the phantom to examine the relationship between dosimetric errors and the two leaf widths. Delivery efficiency of the two MLCs was compared in terms of beam delivery times, monitor units (MUs) per fraction, and the number of segments for each plan.

RESULTS

2.5-mm MLC showed better dosimetric characteristics in S&S_IMRT and VMAT for C-shape, providing better CI for PTV and lower spinal cord dose and high and intermediate dose-spillage volume as compared with the 5-mm MLC (p < 0.05). However, no significant dosimetric benefits were provided by the 2.5-mm MLC for LH&N (p > 0.05). Further, beam delivery efficiency was not observed to be significantly associated with leaf width for either C-shape or LH&N. However, MUs per fraction were significantly reduced for the 2.5-mm MLC for the LH&N. In dosimetric error analysis, absolute dose evaluations had errors of less than 3%, while the Gamma passing rate was greater than 95% according to the 3%/3 mm criteria. There were no significant differences in dosimetric error between the 2.5- and 5-mm MLCs.

CONCLUSIONS

As compared with MLC of 5-mm leaf widths, MLC with finer leaf width (2.5-mm) can provide better dosimetric outcomes in IMRT for C-shape. However, the MLC leaf width may only have minor effects on dosimetric characteristics in IMRT for LH&N. The results of the present study will serve as a useful assessment standard when assigning or introducing equipment for the treatment of H&N cancers.

Overexpression of the Brassica rapa transcription factor WRKY12 results in reduced soft rot symptoms caused by Pectobacterium carotovorum in Arabidopsis and Chinese cabbage

Chinese cabbage (Brassica rapa L. ssp. pekinensis), an important vegetable crop, can succumb to diseases such as bacterial soft rot, resulting in significant loss of crop productivity and quality. Pectobacterium carotovorum ssp. carotovorum (Pcc) causes soft rot disease in various plants, including Chinese cabbage. To overcome crop loss caused by bacterial soft rot, a gene from Chinese cabbage was isolated and characterised in this study. We isolated the BrWRKY12 gene from Chinese cabbage, which is a group II member of the WRKY transcription factor superfamily. The 645-bp coding sequence of BrWRKY12 translates to a protein with a molecular mass of approximately 24.4 kDa, and BrWRKY12 was exclusively localised in the nucleus. Transcripts of BrWRKY12 were induced by Pcc infection in Brassica. Heterologous expression of BrWRKY12 resulted in reduced susceptibility to Pcc but not to Pseudomonas syringae pv. tomato in Arabidopsis. Defence-associated genes, such as AtPDF1.2 and AtPGIP2, were constitutively expressed in transgenic lines overexpressing BrWRKY12. The expression of AtWKRY12, which is the closest orthologue of BrWRKY12, was down-regulated by Pcc in Arabidopsis. However, the Atwrky12-2 mutants did not show any difference in response to Pcc, pointing to a difference in function of WRKY12 in Brassica and Arabidopsis. Furthermore, BrWRKY12 in Chinese cabbage also exhibited enhanced resistance to bacterial soft rot and increased the expression of defence-associated genes. In summary, BrWRKY12 confers enhanced resistance to Pcc through transcriptional activation of defence-related genes.

Pretreatment clinical mediastinal nodal bulk and extent do not influence survival in N2-positive stage IIIA non-small cell lung cancer patients treated with trimodality therapy

BACKGROUND

Treatment for patients with N2-positive stage IIIA non-small cell lung cancer has been a controversial issue. The current study evaluated the outcomes in patients treated with trimodality therapy, which consisted of neoadjuvant radiation therapy concurrent with chemotherapy followed by surgical resection, with emphasis on clinical and pathologic nodal status.

METHODS

We reviewed the records of 355 patients who were treated with trimodality therapy between 1997 and 2011.

RESULTS

After completion of neoadjuvant chemoradiation, overall down-staging and complete response rates were 50.4 % (179 patients), and 13.2 % (47 patients), respectively. With median follow-up of 35.3 months, median times of progression-free survival (PFS) and overall survival (OS) were 16.3 months and 45.5 months, respectively. Seventeen patients (4.8 %) died of postoperative complications, and the remaining 338 patients were analyzed on prognostic factors. Old age (p = 0.032), pneumonectomy (p < 0.001), and ypN+ (p < 0.001) were found to be the significant prognosticators for worse PFS, and old age (p = 0.013), pneumonectomy (p < 0.001), and ypN+ (p < 0.001) were related to worse OS. Clinical N2 status did not influence either OS or PFS: the number of involved stations (single station vs. multi-station; p = 0.187 for PFS; p = 0.492 for OS), and bulk (clinically evident vs. microscopic; p = 0.902 for PFS; p = 0.915 for OS).

CONCLUSION

ypN stage was the most important prognosticator for both PFS and OS; however, neither initial bulk nor extent of cN2 disease influenced prognosis. Surgery following neoadjuvant chemoradiation should have contributed to improved clinical outcomes regardless of clinical nodal bulk and extent.

Prognostic significance of tumor response as assessed by sequential 18F-fluorodeoxyglucose-positron emission tomography/computed tomography during concurrent chemoradiation therapy for cervical cancer

PURPOSE

To investigate the prognostic role of metabolic response by the use of serial sets of positron emission tomography/computed tomography (PET/CT) in patients with cervical cancer who were treated with concurrent chemoradiation therapy (CCRT).

METHODS AND MATERIALS

A total of 60 patients who were treated with CCRT between February 2009 and December 2010 were analyzed. Three sequential PET/CT images were acquired for each patient: pre-CCRT, during-CCRT at 4 weeks of CCRT, and 1 month post-CCRT PET/CT. Metabolic responses were assessed qualitatively. The percentage changes in the maximum values of standardized uptake value (ΔSUV(max)%) from the PET/CT images acquired pre-CCRT and during-CCRT were calculated. Receiver operating characteristic (ROC) curve analysis was performed to evaluate whether ΔSUV(max)% could predict complete response (CR) on the post-CCRT PET/CT and to identify the best cutoff value. Prognostic factors of progression-free survival (PFS) were analyzed.

RESULTS

During-CCRT PET/CT showed that 8 patients (13%) had CR, and the other 52 patients (87%) had partial response (PR). On the post-CCRT PET/CT, 43 patients (73%) had CR, 12 patients (20%) had PR, and 4 patients (7%) had progressive disease. The average SUV(max) in primary tumors was 16.3 (range, 6.4-53.0) on the pre-CCRT PET/CT images and 5.3 (range, 0-19.4) on the during-CCRT PET/CT images. According to ROC curve analysis, ΔSUV(max)% could predict CR response on post-CCRT PET/CT (P<.001, cutoff value of 59.7%). In all patients, the PFS rate was 71.9% at 2 years. Multivariate analysis showed that ΔSUV(max)% ≥60% (P=.045) and CR response on the post-CCRT PET/CT (P=.012) were statistically significant predictors of PFS.

CONCLUSION

Metabolic responses on the during-CCRT images at 4 weeks of treatment and 1-month post-CCRT PET/CT images may predict treatment outcomes in patients with cervical cancer. ΔSUV(max)% ≥60% at 4 weeks of CCRT may predict CR response on 1-month post-CCRT PET/CT and also PFS.

Tumor volume reduction rate measured during adaptive definitive radiation therapy as a potential prognosticator of locoregional control in patients with oropharyngeal cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic significance of the tumor volume reduction rate (TVRR) measured during adaptive definitive radiation therapy (RT) in patients with oropharyngeal cancer.

METHODS

We reviewed the RT records of 59 patients with oropharyngeal cancer who were treated with definitive RT with or without concurrent chemotherapy between January 2006 and October 2010. Adaptive replanning was performed in all patients during RT. The pre-RT and mid-RT gross tumor volumes (GTVs) of the primary and the metastatic lymph nodes were measured and analyzed for their possible impacts on locoregional control.

RESULTS

After the median follow-up period of 41.3 months (range, 9.3-73.5 months) for survivors, there were 10 treatment failures (8 locoregional recurrences and 2 distant metastases). The locoregional control rate at 3 years in all the patients was 84.1%. The mean pre-RT and mid-RT total GTVs were 27.5 cm(3) (±17.9 cm(3) ) and 16.9 cm(3) (±12.1 cm(3) ), and the mean GTV reduction rate was 37.9% (±22.6%), respectively. The patients who achieved locoregional control had a higher TVRR than those with locoregional failure (p = .010), and those with the TVRR >35% achieved significantly higher locoregional control at 3 years (94.4% vs 72.4%; p = .018). On multivariate analysis when adjusted with other clinical prognostic factors, the TVRR was found to be a significant factor affecting the locoregional control (hazard ratio = 0.136; 95% confidence interval = 0.022-0.852; p = .033).

CONCLUSION

The TVRR measured during adaptive RT proved a significant prognosticator on locoregional disease control in patients with oropharyngeal cancer, based on which a few therapeutic modifications may be considered.