• Radiation Oncology Journal
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• v.34 no.1
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• pp.26-33
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• 2016

Purpose: To compare the dose distribution between carotid sparing intensity modulated radiotherapy (IMRT) and opposed lateral field technique (LAFT), and to determine the effects of carotid sparing IMRT in early glottic cancer patients who have risk factors for atherosclerosis. Materials and Methods: Ten early glottic cancer patients were treated with carotid sparing IMRT. For each patient, the conventional LAFT plan was developed for comparison. IMRT and LAFT plans were compared in terms of planning target volume (PTV) coverage, conformity index, homogeneity index, and the doses to planning organ at risk volume (PRV) for carotid arteries, spinal cord and pharyngeal constrictor muscle. Results: Recurrence was not observed in any patients during the follow-up period. $V_{95%}$ for PTV showed no significant difference between IMRT and LAFT plans, while $V_{100%}$ was significantly higher in the IMRT plan (95.5% vs. 94.6%, p = 0.005). The homogeneity index (11.6%) and conformity index (1.4) in the IMRT plan were significantly better than those in the LAFT plans (8.5% and 5.1, respectively) (p = 0.005). The median $V_{5Gy}$ (90.0%), $V_{25Gy}$ (13.5%), and $V_{50Gy}$ (0%) for carotid artery PRV in the IMRT plan were significantly lower than those in the LAFT plan (99.1%, 89.0%, and 77.3%, respectively) (p = 0.005). Conclusion: Our study suggests that carotid sparing IMRT can significantly decrease the dose to carotid arteries compared to LAFT, and it would be considered for early glottic cancer patient with high risk of atherosclerosis.

• Radiation Oncology Journal
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• v.34 no.1
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• pp.18-25
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• 2016

Purpose: Radiotherapy of the neck is known to cause carotid artery stenosis. We compared the carotid artery dose received between volumetric modulated arc therapy (VMAT) and conventional fixed-field intensity-modulated radiotherapy (IMRT) plans in patients with early glottic cancer. Materials and Methods: Twenty-one early glottic cancer patients who previously underwent definitive radiotherapy were selected for this study. For each patient, double arc VMAT, 8-field IMRT, 3-dimensional conformal radiotherapy (3DCRT), and lateral parallel-opposed photon field radiotherapy (LPRT) plans were created. The 3DCRT plan was generated using lateral parallel-opposed photon fields plus an anterior photon field. VMAT and IMRT treatment plan optimization was performed under standardized conditions to obtain adequate target volume coverage and spare the carotid artery. Dose-volume specifications for the VMAT, IMRT, 3DCRT, and LPRT plans were calculated with radiotherapy planning system. Monitor units (MUs) and delivery time were measured to evaluate treatment efficiency. Results: Target volume coverage and homogeneity results were comparable between VMAT and IMRT; however, VMAT was superior to IMRT for carotid artery dose sparing. The mean dose to the carotid arteries in double arc VMAT was reduced by 6.8% compared to fixed-field IMRT (p < 0.001). The MUs for VMAT and IMRT were not significantly different (p = 0.089). VMAT allowed an approximately two-fold reduction in treatment delivery time in comparison to IMRT (3 to 5 minutes vs. 5 to 10 minutes). Conclusion: VMAT resulted in a lower carotid artery dose compared to conventional fixed-field IMRT, and maintained good target coverage in patients with early glottic cancer.

• Radiation Oncology Journal
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• v.8 no.1
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• pp.51-57
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• 1990

Retrospective analyses were done of 48 patients with early glottic cancer, 31 with T1NOMO and 17 with T2NOMO, who received radiation therapy from March 1979 to August 1984 at Seoul National University Hospital with the prescribed full dosage. The median follow-up period was 67 months (range: 34 months$\~$126 months), and the percent follow-up for longer than five years was $85.4\%$ The five-year actuarial overall and recurrence-free survival rates of the whole patient group were $83.2\%\;and\;69.4\%$, respectively. The five-year actuarial overall and recurrence-free survival rates of the T1 group were $87.1\%\;and\;76.0\%$, and those of the T2 group were $76.5\%\;and\;58.2\%$, respectively. Possible causes of the failures to radiation therapy, the dose-response relationship, association with the second malignant tumors, and some recommendations for better treatment outcome are analyzed and discussed.

• Korean Journal of Head & Neck Oncology
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• v.10 no.2
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• pp.178-184
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• 1994

Laryngeal cancer is one of the most frequent cancers in the head and neck area. Clinical analysis was performed on 30 cases of treated $T_1$ glottic cancer patients. Early glottic cancer occured most frequently in male in their sixties and all were well or moderately well differentiated squamous cell carcinoma. Overall five year survival rate was 81.5% and there was no significant difference between stages or the differentiation of the diseases. Recurrence at the primary site, especially anterior commissure, was common, thus careful pre- and postoperative follow up evaluation is recommended.

• Korean Journal of Head & Neck Oncology
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• v.12 no.1
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• pp.26-31
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• 1996

Radiation therapy in T1 glottic cancer offers an excellent cure rate with preservation of voice. From 1983 to 1992 eighty nine patients with TNM staged T1N0M0 invasive squamous cell carcinoma of the glottis were treated at the Dept. of Radiation Oncology, Yonsei Cancer Center, Yonsei University. There were 84 men and 5 women with median age of 59 years. All patients were treated either with Co-60 teletherapy unit or 4MV linear accelerator with an median dose of 6400 cGy(6000-7000 cGy), 200 cGy per day, 5 days in a week. Fourteen local failures have been observed and the median time to local recurrence was 17 months. There were no nodal failure without local recurrence or distant metastases. The 5 year local control rate was 84.3%. The 5 year actuarial surivival rate and the 5 year disease free survival rate were 89.2%, 87.5%, respectively. The 5 year actuarial survival rate and the 5 year disease free survival rate of the nineteen patients with anterior commissure involvement were 77.8% and 74.5% which were lower than those of seventy patients without anterior commissure involvement(91.6%, 90.6%)(p < 0.05). Among the several influencing factors, anterior commissure involvement was the significant prognostic foctor. Final local control rate, taking into account the salvage surgery, was 89.9% at 5 years.

• Korean Journal of Head & Neck Oncology
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• v.12 no.2
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• pp.206-211
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• 1996

On 147 patients with early laryngeal cancer undertaken surgery or radiation therapy at Seoul National University Hospital from January 1987 through December 1994, retrospective analysis with reviewing the medical record was performed. The number of recurred cases was twenty six. The recurrence rate was higher in the cases with radiation therapy than in those with surgical therapy. And the recurrence rate was remarkable in the cases with T2 in supraglottic cancer and in those with T1 in glottic cancer. Of the patients undertaken surgery, recurrence rate was higher in the patients with laser operation than in those with other procedures. It was, however, lower in the patients with laryngofissure with cordectomy than in those with other surgical techniques. The overall three year disease free survival rate was 72 % in early laryngeal carcinoma.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.29-34
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• 2009

Purpose: This study was designed to evaluate long-term results in terms of failure, survival and voice preservation after radiation therapy for early glottic cancer. Materials and Methods: From February 1988 to December 2003, 70 patients with early glottic cancer were treated with radiation therapy at Keimyung University Dongsan Medical Center. Patient age distribution was from 39 to 79 years, with a median age of 62 years. All patients had squamous cell carcinoma. According to the TNM stage, 58 patients had stage I disease, 12 patients had stage II disease; 67 patients were male. The laryngeal area was irradiated with the use of bilateral opposing fields with/without a wedge filter with 6 MV photons at a total dose of $54{\sim}70.2$ Gy in $1.8{\sim}2.2$ Gy fractions over $6{\sim}8$ weeks. We delivered a median radiation dose of 60 Gy for stage I patients and a median radiation dose of 66 Gy for stage II patients. Salvage surgery was performed in patients with local recurrence. The voice preservation rate was analyzed after all treatments including salvage surgery. Follow-up periods were from 13 to 180 months, with a median follow-up period of 77.5 months. The survival rate was analyzed by the use of the Kaplan Meier method and log rank test. A comparison of two groups was performed with the use of the chi-squared test. Results: The local control rate was 98.5% (69/70). The five-year-overall survival rate was 93.9%. The five-year disease free survival rate (5YDFS) was 84.1% and the 5YDFS after radiation and salvage surgery was 92.8%. According to stage, the 5YDFS was 93.1% and 91.7% for stage I and stage II respectively. Thirteen patients (18.5%) had local failure with 24 months of median time to local failure and nine patients received salvage surgery; however, four patients were lost to follow-up after a diagnosis of recurrence. Only two patients died due to a distant metastasis at 33 months and 71 months after radiation therapy, respectively. Nine patients died due to other diseases with a median time of 73 months. There were no severe acute or chronic complications after radiation therapy. Voice preservation was ultimately achieved in 88.5% (62/70) of patients. Conclusion: We considered that radiation therapy was effective and we achieved excellent survival and voice preservation in early laryngeal cancer. The use of radiation therapy should be the first choice for the treatment of early glottic cancer.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.226-232
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• 2000

Purpose :This study was performed to find out the prognostic factors affecting local control in early glottic cancer treated with radiation therapy alone. Materials and Methods :We analysed 37 patients of histologically confirmed early glottic cancer treated at Chonnam National University Hospital between July Im and December 1995, retrospectively. Age of patients ranged from 30 to 73 years (median; 59 years). Thirty-five (95$\%$) patients were male. Histological type was all squamous cell carcinoma. According to the staging system of 1997 American Joint Committee on Cancer, 37 patients were restaged as follows: Tla; U (73$\%$), Tlb; 3 (8$\%$), 72: 7 (19$\%$). Radiation therapy was done using 6 MV X-ray of linear accelerator The range of total radiation dose delivered to the glottic lesion was between 5,040 cGy and 7,020 cGy (median; 6,600 cGy). Median follow-up period was U months. local control rates were calculated by Kaplan-Meier method. Generalized Wilcoxon test was used to evaluate the difference of control rates between comparable groups. Multivariate analysis using Cox proportional hazard model was done to find out prognostic factors affecting local control. Results:5 year survival rate of 37 patients was 89$\%$. Local control rate of 37 patients was 74$\%$ in 5 years. We included age, 7-stage, anterior commissure involvement, fraction size, total radiation dose, treatment time of radiotherapy as potential prognostic factors in univariate and multivariate analysis. As a result, treatment time had statistical significance in local control rate in both univariate (p=0.026) and multivariate (p=0.017) analysis. Complication was not recorded except one patient with hypothyroidism. Conclusion :This study revealed that overall treatment time of radiation was a significant factor affecting local control rate.

• Radiation Oncology Journal
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• v.10 no.2
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• pp.181-186
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• 1992

A retrospective analysis was undertaken for 22 patients with early glottic cancer ($T_1N_0M_0$; 17, $T_2N_0M_0$; 5) who completed curative radiotherapy at the Department of Therapeutic Radiology, Chonnam University Hospital between November 1985 and December 1990. Median follow-up period was 39 months. The 3 year actuarial survival rate of T1, T2 was $81\%$ and $80\%$. respectively. Three patients ($13\%$) showed second malignant tumors and the site of the new primary was esophagus in two patients and lung in the other one. They were excluded from the local control analysis. The local control rate of T1. T2 group was $66\%$ and $50\%$. respectively. The surgical salvage rate and the ultimate local control rate of T1 group was $80\%$ (4/5) and $93\%$. and that of T2 group was $100\%\;(2/2)\;and\;75\%$. respectively. The local control rates of T1 stage were evaluated according to the various parameters. The local control rate of the superficial and exophytic lesion was better than that of the ulcerative and infiltrative one, and the involvement of anterior commissure was not seemed to be adverse prognostic factor. But the protracted treatment time showed the adverse effect on the local control of the disease. All of the eleven patients controlled by primary radiation therapy have maintained their voice well without any significant complication.

• Radiation Oncology Journal
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• v.19 no.4
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• pp.301-305
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• 2001

Purpose : This study was peformed for the evaluation of the feasibility and toxicity of hypofractionated radiation therapy for early glottic cancer Methods and Materials : From February 1999 to February 2000, 20 patients with Histologically confirmed Stage I, II glottic cancer were enrolled into this study. There were 18 males and 2 females, the median age of the patients was 59 years. The distribution of stage distribution was as fellows; T1aN0-16 patients, T1bN0-1 patient, T2N0-3 patients. Eighteen patients underwent laryngomicroscopic biopsy only, and two patients underwent laser cordectomy. All patients received radical radiation therapy (2.5 Gy per fraction, 24 fractions, total 60 Gy). Median duration of treatment was 36 days (range $31\~45\;days$). Results : Radiation therapy were well tolerated. Most common acute reactions were odynophagia and hoarseness, and these reactions resolved after radiation therapy. There were one case of RTOG grade 3 odynophagia $(5\%)$, six cases of grade 3 hoarseness $(30\%)$. Response of radiation therapy was evaluated one month after completion of treatment. All patients revealed complete response. During follow up, total three cases of treatment failure were detected. two cases were local recurrence in 10 and 13 months of radiation therapy and one case was local recurrence and distant metastasis in 2 months of radiation therapy. Conclusion : This hypofractionated radiation therapy schedule was feasible and effective for control of early glottic cancer But longer follow up time would be required to assess the long-term disease control and the late complication by shortening radiation therapy duration.