Do overall treatment time, field size, and treatment energy influence local control of T1-T2 squamous cell carcinomas of the glottic larynx?

Radiation for Early Glottic Cancer

Multidisciplinary evaluation of early-stage glottic cancer facilitates optimal treatment with either surgery or radiation therapy. Standard of care radiation treatment of early-stage glottic cancer continues to be three-dimensional opposed lateral fields to include the whole larynx. Modern radiation treatment techniques are allowing studies to examine the efficacy and toxicity of altered doses and treatment volumes. Advanced techniques, such as stereotactic body radiation therapy or single-vocal cord irradiation, are not yet considered standard of care for early-stage glottic cancer and should be performed at institutions with clinical trials to ensure adequate expertise and quality assurance.

Prospective Observational Comparative Study of Response and Toxicities in Early Glottic Cancer Using Telecobalt Versus 3D-CRT

The study was performed with 50 patients, 24 patients in Arm A and 26 patients in Arm B. Arm A-Conventional Telecobalt RT 66 Gy/33 fraction in stage T1N0M0 and stage T2N0M0 and Arm B-3D-CRT 66 Gy/33 fraction in T1N0M0 and T2N0M0 used. At the end of RT, 6 weeks, 3 months acute and late toxicities were noted by RTOG/EORTC morbidity scoring criteria for skin reaction, dysphagia and laryngeal toxicity. Fiber optic Laryngoscopy clinical assessment criteria were used to assess response after 6 weeks, 3 months of treatment completion. At 6 weeks of follow-up-Both Arm A and B complete response rate were 83.3% and 88.5% respectively and at 3 months rate were 85.0% and 95.7% respectively. There was no superiority of results with 3D-CRT over 2DRT. At the end of RT dysphagia grade 3 toxicity seen 1 patient (4.2%) but in Arm B (total 26 patients) no grade 3 toxicity found. At the end of 6 week and 3 month, one patient (4.3%) had grade 3 toxicity on Arm B only at 3 month. All these results are comparable. At the end of RT, one patient (3.8%) had incidentally dermatitis grade 3 toxicity in Arm B only. But all the results are comparable. On follow up, 6 week and 3 months, no grade 3 toxicity noted. At the end of RT, grade 3 laryngeal toxicity noted in 3 (12.5%) in Arm A and 2 (7.7%) in Arm B, not statistically significant. At 6 week, grade 3 toxicity found in 3/24 (12.5%) in Arm A and 2/26 (7.7%) in Arm B, at 3 months, 1/26 (4.3%) patient had incidental grade 3 toxicity only in Arm B. As conformal radiotherapy is more time consuming, less available in India and more costly than 2DRT, we can consider Conventional 2D planning for patients in India where most of people belong to low economic profile. Due to limitation in sample size and long-term follow-up further randomized studies are needed to validate the results.

Early glottic cancer recurrence: A critical review on its current management

INTRODUCTION

Recurrent early glottic cancer (rEGC) poses several issues in terms of timely diagnosis, correct re-staging, and treatment. We want to critically review the latest evidence about rEGC considering its epidemiology, biology, diagnostic challenges, and treatment strategies.

METHODS

A systematic search of the literature using PubMed from 1990 to October 31, 2020 was performed.

RESULTS

There are many different treatment options available (open surgery, transoral mini-invasive surgery, radiotherapy), and many factors related to the patient's status and previous treatments must be considered when planning the best management strategy for rEGC. While its overall prognosis remains satisfactory, it is of the utmost importance to appreciate all the clinical implications derived from the choice of the initial therapeutic modality, and from a correct primary and recurrent staging.

CONCLUSION

The balance between oncological and voice and swallowing functions represents the fundamental principle underlying rEGC management. Future studies should focus on molecular profiling of rEGC, and on the results of the emerging radiation delivery techniques and mini-invasive procedures.

Comparison of Three Fractionation Schedules in Radiotherapy for Early Glottic Squamous Cell Carcinoma

BACKGROUND/AIM

Radiotherapy is widely accepted as the treatment of choice for early glottic squamous cell carcinoma (EGSCC), although it varies greatly with respect to dose, dose per fraction, and treatment techniques. The study aim was to evaluate the use of accelerated fractionation strategy (AFS) for EGSCC in standard clinical practice.

PATIENTS AND METHODS

Patients treated with definitive radiotherapy for EGSCC between 2008 and 2019 were retrospectively identified and received either conventional fractionation, hypofractionation, or hyperfractionation.

RESULTS

One hundred six patients were analyzed, and 19, 71, and 16 patients underwent conventional fractionation, hypofractionation, and hyperfractionation, respectively. The median follow-up was 56 months. The 5-year local control and overall survival rates were 79% and 83%; 78% and 79%; and 87% and 77%, respectively, and no significant difference was observed between the fractionation schedules.

CONCLUSION

Our findings confirmed the utility of AFS in standard clinical practice and support its use for patients with EGSCC.

Predictive factors for local control of early glottic squamous cell carcinomas after definitive radiotherapy

The aim of the present study was to retrospectively investigate the risk factors of local failure for T1 glottic carcinoma irradiated with a prescription dose of 66 Gy. Between July 2006 and December 2017, 64 patients with T1 glottic squamous cell carcinoma treated with 66 Gy/33 fractions were analyzed for risk factors of local failure. The sex, age, performance status, T stage, overall treatment time, anterior commissure involvement, smoking status during/after treatment, histological tumor grade and pretreatment hemoglobin level were investigated. The maximum, mean and minimum doses, and the homogeneity index for the glottic larynx were calculated for dosimetric risk factors of local failure. The median follow-up duration was 51 months. Local failure was observed in 6 patients (9.5%). Among all risk factors, only the minimum dose to the glottic larynx was found to be significantly associated with local failure (P=0.025). The 5-year local control rates for a minimum dose to the glottic larynx of <65 and ≥65 Gy were 79 and 95%, respectively, with a statistically significant difference (P=0.015). No patients exhibited grade ≥3 late adverse effects. The minimum dose to the glottic larynx was the only factor significantly associated with local failure. Thus, local control of T1 glottic carcinoma may improve with a minimum dose of ≥65 Gy to the glottic larynx. In conclusion, radiotherapy with a minimum prescription dose of ≥65 Gy to the glottic larynx appears to be safe and achieves a high local control rate for T1 glottic carcinoma.

Outcome of Early-Stage Glottic Laryngeal Carcinoma Patients Treated with Radical Radiotherapy Using Different Techniques

Purpose

The aim was to evaluate the treatment outcomes and prognostic characteristics of patients with early-stage glottic laryngeal carcinoma who underwent radical radiotherapy (RT) with different techniques.

Patients and Methods

Radiotherapy was applied using the 2D conventional technique between 1991 and 2004 (130 patients), 3DCRT until 2014 (125 patients), and by VMAT until January 2017 (44 patients). Clinical T stages were 38 (12.7%) for Tis, 209 (69.9%) for T1, and 52 (17.4%) for T2. Radiotherapy technique and energy, anterior commissure involvement, and stage were analyzed as prognostic factors.

Results

The median total dose was 66 (50–70) Gy, and median follow-up time was 72 (3–288) months; 5-year disease-specific survival (DSS) rates were 95.8%, 95.5%, and 88.6%, respectively, in Tis, T1, and T2 stages. In multivariate analyses, anterior commissure involvement was found significant for all survival and local control rates. The patients treated with VMAT technique had better local control and DSS rates. However, these results were not statistically significant.

Conclusion

In early-stage laryngeal carcinomas, radical RT is a function sparing and effective treatment modality, regardless of treatment techniques.

Prognostic Factors in Early Glottic Carcinoma Implications for Treatment

Aim

In this study we aimed to determine the prognostic factors affecting local control (LC) in limited glottic carcinoma treated with definitive radiotherapy (RT).

Material and methods

Between June 1991 and December 2001, 114 patients with early squamous-cell carcinoma of the glottis were treated with definitive RT at our institution. Only four (3.5%) patients were women. The median age was 60 (27-79). Fifteen percent, 72% and 13% of the patients had Tis, T1 and T2 tumors, respectively. Forty-three (37.7%) patients had anterior commissure invasion. Prior to RT 35 (31%) patients had undergone vocal cord stripping and two (2%) cordectomy. A median dose of 66 Gy (50-70.2) was given over a median period of 46 days (20-60). Univariate and multivariate analyses were performed for LC. The prognostic parameters analyzed for LC were T classification, anterior commissure involvement, total RT dose, and overall treatment time.

Results

Five-year local and regional control rates were 84.2% and 97.7%. RTOG grade 3-4 late side effects were observed only in one (0.9%) patient. In 15 patients with local failure, salvage treatment consisted of partial laryngectomy in eight patients and total laryngectomy in five. One of the remaining two patients was medically inoperable, and the other refused salvage surgery. In one of the three patients with regional failure, salvage surgery was applied and the other two were given palliative chemotherapy because of unresectable disease. Following salvage treatments, the ultimate five-year LC rate was 96.9% and the five-year larynx preservation rate was 91.1%. Second primary cancer was diagnosed in 17 (14.9%) patients. Only one patient developed distant metastases and two patients died of laryngeal cancer. While T2 disease and anterior commissure involvement were found to be unfavorable prognostic factors significantly influencing LC in univariate analyses, only T2 disease remained independent in multivariate analysis.

Conclusion

In patients with early glottic carcinoma, T classification proved to be the only independent prognostic factor affecting LC after primary radiotherapy according to the results of this study.

Hypofractionated radiotherapy for early glottic cancer: a retrospective interim analysis of a single institution

PURPOSE

To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer.

MATERIALS AND METHODS

Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3-2.5 Gy per tumor fraction.

RESULTS

The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrencefree survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V35, p < 0.001; V50, p < 0.001).

Conclusions

Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.

Hyperfractionated Radiotherapy for T2N0 Glottic Carcinoma: A Retrospective Analysis at 10 Years Follow-up in a Series of 60 Consecutive Patients

Aims and background

To report results of hyperfractionated radiotherapy for T2N0 glottic carcinoma at a single institution after extended follow-up.

Methods

Between 1980 and 1988 at Varese University Hospital, 60 consecutive patients with T2N0 glottic carcinoma received exclusive radiotherapy consisting of 1.5 Gy/fraction twice a day. Treatment gaps during the radiotherapy course were allowed according to individual tolerance. This policy resulted in a wide range of elapsed treatment time: median, 5.7 weeks; range, 3.7-8.9. Median follow-up is 9.8 years.

Results

As a result of dose/time distribution, 16, 20 and 24 patients received an average weekly dose rate of <10 Gy/week, equal to 10 Gy/week or >10 Gy/week, respectively. Mean total dose for each group was 62.8 Gy, 63.7 Gy and 63.8 Gy, respectively. Five-year local-regional control was 69 ± 6% (95% Cl); ultimate local-regional control, including salvage surgery, was 78 ± 5%. All failures were at the primary site, and no patient developed neck recurrence as first site of failure. The actuarial incidence of grade 2-3 late reactions at 5 years was 42 ± 6%. Most late toxicity events were grade 2: only 2 patients developed grade 3 reactions and none grade 4. None of the several clinical and treatment-related variables showed any statistically significant impact on local-regional control or late toxicity at univariate and multivariate analysis. In particular, 3-year local-regional control rates were 73 ± 11%, 84 ± 8% and 69 ± 10% for an average weekly dose rate of <10 Gy/week, equal to 10 Gy/week and >10 Gy/week, respectively (not significantly different).

Conclusions

At a very long follow-up, the hyperfractionated regimen tested in the study was shown to be effective and devoid of major complications, provided individual patient acute tolerance is carefully taken into account. Also, time factor did not affect outcome in this series.

Hypofractionated accelerated radiotherapy in T1-3 N0 cancer of the larynx: A prospective cohort study with historical controls

AIM

The goal of this prospective study was to assess the effectiveness of a hypofractionated accelerated regime in treatment of the larynx cancer.

BACKGROUND

Multiple radiotherapy delivery regimes are used for treatment of the larynx cancer. Hypofractionated regimes could provide similar results with reduced use of radiotherapy facilities.

MATERIAL AND METHODS

223 patients with squamous cell carcinoma of the upper or middle larynx have been treated with 63 Gy delivered in 28 fractions of 2.25 Gy during 38 days, 5 fractions per week. The study endpoints were overall survival, progression-free survival, early and late treatment toxicity. Standard and accelerated radiotherapy groups from the study published by Hliniak et al.²⁰ served as controls.

RESULTS

Five-year actuarial overall survival was 87.5% in the study group, 84.5% in the control group receiving accelerated radiotherapy (33 fractions of 2.0 Gy, 6 fractions per week) and 86.2% in the control group (33 fractions of 2.0 Gy, 5 fractions per week). Five-year progression-free survival was 73.6%, 77.2% and 66.2%, respectively. Overall, treatment toxicity and complication rates did not differ between the study group and the control groups.

CONCLUSIONS

The hypofractionated accelerated radiotherapy protocol using 5 fractions per week reduced the use of radiotherapy facilities. There was no significant difference in overall survival and progression-free survival between the study and control groups treated with accelerated or standard radiotherapy.

Advantage of Accelerated Fractionation Regimens in Definitive Radiotherapy for Stage II Glottic Carcinoma

Objectives:

We evaluated the prognostic factors for local control of T2 glottic cancer and verified the efficacy of accelerated fractionation regimens such as hyperfractionation and accelerated hyperfractionation.

Methods:

A total of 86 patients with T2 NO MO glottic squamous cell carcinoma, who were treated with definitive radiotherapy, were analyzed retrospectively by multivariate analysis.

Results:

Overall treatment time of radiotherapy (p = .0003) and total dose (p = .0036) were the significant prognostic factors for local control on multivariate analysis. The group with a higher total dose (>67 Gy versus <67 Gy) showed a favorable prognosis (5-year local control rate of 91% versus 60%, respectively; p = .0013, log-rank test). Likewise, the group with a shorter overall treatment time of radiotherapy (<54 days versus >54 days) showed a favorable prognosis (5- year local control rate of 87% versus 71%, respectively; p = .023).

Conclusions:

A radiotherapy total dose of >67 Gy delivered for a shorter period is required for T2 glottic cancer. The fractionation regimens of hyperfractionation and accelerated hyperfractionation are more effective than conventional fractionation in terms of shortening overall treatment time and delivering a high total dose with acceptable toxicity.

Radiotherapy of Early-Stage Glottic Cancer: Analysis of Factors Affecting Prognosis

This study is a retrospective analysis of 134 patients treated with radiotherapy at our hospital. The sample included 88 stage T1 and 46 stage T2 patients. Sixty-two patients had anterior commissure involvement, 37 patients had impaired vocal cord mobility, and 24 patients had supraglottic or subglottic extension. Irradiation was given, with the dose ranging from 60 to 72 Gy. Laryngectomy was the main salvage treatment for local recurrence. The 5-year initial and final local control rates were 71% and 83%, and the 10-year initial and final local control rates were 69% and 80%, comparable to the results of other series. The 5-year rate of overall survival with final larynx preservation was 77%. Multivariate analysis revealed that anterior commissure involvement is prognostic of a poor outcome in patients with T1 glottic cancer. Further subgroup analysis revealed that a fraction size of >200 cGy could overcome the negative impact of anterior commissure involvement and significantly improve the 5-year local control rate in T1 patients (100% at >200 cGy versus 45% at ≤200 cGy; p = .04). Subglottic extension of the glottic cancer predicted poor outcome in T2 patients. The 5-year local control rates of patients with and without subglottic extension were 9% and 77%, respectively (p < .001). According to our results, radiotherapy with a fraction size of >200 cGy is recommended for T1 disease with anterior commissure involvement. For patients with T2 disease and subglottic extension, radiotherapy alone produces poor results. Further improvement of outcomes by other treatment strategies needs to be investigated.

Comparison between 4-MV and 6-MV radiotherapy in T1N0 glottic cancer

OBJECTIVES/HYPOTHESIS

The purpose of this study was to report the outcomes of a retrospective consecutive cohort study of patients with T1N0M0 glottic carcinoma treated with 4-MV or 6-MV radiotherapy.

STUDY DESIGN

Retrospective case-control study.

METHODS

This was a retrospective review of all patients with T1N0M0 glottic carcinoma treated with radiotherapy between January 2000 and December 2012 in the Department of Radiation Oncology at National Cancer Center Singapore. A total of 124 patients were included. Clinical endpoints of interest were: local control (LC), overall survival (OS), and disease-specific survival (DSS). Other prognostic factors for LC were also analyzed: age, gender, smoking status, T substage, dose fraction, field size, anterior commissure involvement, total dose, and overall treatment time.

RESULTS

Six-megavolt photon radiotherapy was used in 73 patients and 4-MV photon radiotherapy in 51 patients. Median follow-up was 4.9 years. The 5-year LC and OS were as follows: 4 MV, 91.6% and 83.4%; 6 MV, 88.8% and 82.8%; and the 5-year LC, OS, and DSS for all patients were 90.4%, 83.3%, and 98.3%. There was no significant difference in LR and OS between 4-MV and 6-MV radiotherapy (P = .92, P = .16, respectively). In the univariate analysis of LC, none of the prognostic factors was statistically significant. Twenty patients (23%) developed second primary cancers, the majority in the lungs.

CONCLUSIONS

Six-megavolt photon radiotherapy yields comparable results to 4-MV photons. Bolus and computed tomographic simulation are useful to ensure adequate dose coverage of target volume. Follow-up postradiotherapy should incorporate chest imaging, smoking cessation advice, and thyroid function test.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:1061-1067, 2017.

Effect of Prolonged Radiotherapy Treatment Time on Survival Outcomes after Intensity-Modulated Radiation Therapy in Nasopharyngeal Carcinoma

PURPOSE

To estimate the influence of prolonged radiation treatment time (RTT) on survival outcomes in nasopharyngeal carcinoma after continuous intensity-modulated radiation therapy.

METHODS AND MATERIALS

Retrospectively review 321 patients with NPC treated between October 2009 and December 2010 and all of them underwent simultaneous accelerated intensity-modulated radiation therapy. The fractionated dose was 2-2.47 Gy/F (median 2.27 Gy), and the total dose for nasopharyngeal region was 64-74 Gy/ 28-33 fractions. The association of prolonged RTT and treatment interruption with PFS, LRFS and DFFS were assessed by univariate analysis and multivariate analysis. Survival analyses were carried out using Kaplan-Meier methodology and the log-rank test was used to assess the difference. The Cox regression proportional hazard model was used for multivariate analyses and evaluating the prognostic parameters for PFS, LRFS and DFFS.

RESULTS

Univariate analysis revealed no significant associations between prolonged RTT and PFS, LRFS, DFFS when dichotomized using various cut-off values (all P>0.05). In multivariate analysis, RTT (range, 36-63 days) as a continuous variable, had no influence on any survival outcome as well (P>0.05). T and N classification were independent prognostic factors for PFS, LRFS and DFFS (all P<0.05, except T classification for LRFS, P = 0.057). Age was an independent prognostic factor for PFS (hazard ratio [HR], 1.033; P = 0.008) and DFFS (HR, 1.032; P = 0.043).

CONCLUSION

We conclude that no such association between survival outcomes and radiation treatment duration (range: 36-63 days) can be found in the present retrospective study, however, we have to remind that prolongation in treatment should be limited in clinical application and interruptions caused by any reason should be minimized as much as possible.

Effect of radiotherapy delay in overall treatment time on local control and survival in head and neck cancer: Review of the literature

Treatment delays in completing radiotherapy (RT) for many neoplasms are a major problem affecting treatment outcome, as increasingly shown in the literature. Overall treatment time (OTT) could be a critical predictor of local tumor control and/or survival. In an attempt to establish a protocol for managing delays during RT, especially for heavily overloaded units, we have extensively reviewed the available literature on head and neck cancer. We confirmed a large deleterious effect of prolonged OTT on both local control and survival of these patients.

A prospective randomized trial comparing hypofractionation with conventional fractionation radiotherapy for T1-2 glottic squamous cell carcinomas: results of a Korean Radiation Oncology Group (KROG-0201) study

BACKGROUND AND PURPOSE

To prospectively investigate the effect of radiotherapy fraction size on clinical outcomes in early glottic carcinoma

METHODS AND MATERIALS

Patients with T1-2 glottic carcinoma were eligible for the protocol. Although 282 patients were required, the study was closed prematurely due to poor accrual with only 156 patients. Of these, 82 patients were allocated to conventional fractionation (CONV) arm (66 Gy/33 fractions for T1 and 70 Gy/35 fractions for T2), with 74 patients to hypofractionation (HYPO) arm (63 Gy/28 fractions for T1 and 67.5 Gy/30 fractions for T2). The primary objective was local progression-free survival (LPFS).

RESULTS

With a median follow-up of 67 months (range, 2-122 months), the 5-year LPFS was 77.8% for CONV arm and 88.5% for HYPO arm (HR 1.55, p=0.213). No significant difference was observed in the toxicity profile between the two arms. In a subgroup exploratory analysis for T1a disease, the 5-year LPFS trended positively in HYPO arm (76.7% vs. 93.0%, HR 3.65, p=0.056).

CONCLUSIONS

Given that HYPO is at least not inferior to CONV with a similar toxicity profile, the hypofractionation scheme used in this study can be offered to patients with T1-2 glottic carcinoma with potential advantages in terms of local control and a shortened overall treatment time.

Radiotherapy with fraction size of 2.25 Gy in T1-2 laryngeal and hypopharyngeal cancer

This study was carried out to evaluate the influence of fraction size 2.25 Gy on local control of T1 and T2 laryngeal and hypopharyngeal cancers. Between August 2002 and December 2010, 80 patients with T1 and T2 laryngeal or hypopharyngeal cancers were treated with definitive radiotherapy with a fraction size of 2.25 Gy. Primary sites were the larynx in 69 and the hypopharynx in 11. Fifty-three patients were T1 and 27 were T2. All patients' pathology was squamous cell carcinoma except one carcinosarcoma. Radiotherapy was delivered 5 days/week with a 4-MV photon beam up to a total dose of 63.0 Gy. Median treatment time was 41 days. Statistical analysis of survival was calculated using the Kaplan-Meier method. No acute toxicity greater than grade 2 (CTCAE ver. 3.0.) including mucositis and dermatitis was observed. All but one patient had a complete response. The partial response patient received salvage surgery. The median follow-up period was 47 months (ranging from 4 to 108 months). No late toxicity greater than 1 was observed. Nine patients developed recurrence, seven local and two neck lymph nodes. Three patients died, one from laryngeal cancer and two from intercurrent diseases. The 5-year local control rates (LCRs) in the entire group, larynx T1, larynx T2 and hypopharynx T1 were 85.8%, 97.6%, 70.1% and 85.7%, respectively. The LCRs of T1 improved compared with our historical control, but not those of T2. The 2.25-Gy fraction size is safe and may have the potential to achieve good LCR in T1 lesions.

3D conformal hypofractionated radical radiotherapy in early glottic cancer

AIM

The purpose of this study was to evaluate acute and late toxicity and the locoregional control in patients treated with hypofractionated radical radiotherapy 2.25 Gy/fraction/day for early glottic carcinoma.

MATERIALS AND METHODS

A retrospective analysis was performed of 27 patients, stage T1-T2 N0 glottic squamous cell carcinoma, that underwent radical RT from April 2008 to October 2011. The mean age was 64.6 years (range 36-81). Seventeen patients were staged T1a, 3 patients T1b and 7 patients T2. All patients were 3D planned and treated in a 6 MV LINAC, 2.25 Gy/fraction/5 days per week, to a total dose between 63 Gy and 67.5 Gy. Biological Effective Dose (BED (α/β = 10)) ranged from 77.18 Gy to 82.69 Gy and EQD2 from 64.31 Gy to 68.91 Gy. Patients were evaluated in periodic follow-up. Toxicity was evaluated according to RTOG Toxicities Scales.

RESULTS

With a median follow-time of 24.7 months (range 3.6-44.2 months), no evidence of locoregional recurrence was observed. The treatment was well tolerated and no unscheduled interruptions in treatments for toxicity were documented, with the median overall treatment time of 41 days (range 38-48). Only grades 1 and 2 acute toxicity were observed and no evidence of severe late toxicity.

CONCLUSION

The authors believe that this moderately hypofractionated scheme can provide a good locoregional control for T1-T2 glottic carcinomas with no increase of toxicity. As the limitation of this work is the reduced number of patients and the lack of long term follow-up, the authors hope to update this retrospective study in the future in order to improve the power of the results.

Definitive radiotherapy for T1 glottic squamous cell carcinoma: a 15-year Cruces University Hospital experience

PURPOSE

To evaluate the treatment outcomes for T1 N0 glottic carcinoma after definitive radiotherapy.

METHODS

One hundred and seventeen patients treated with radical radiotherapy from 1990 to 2006 were retrospectively reviewed. The median follow-up duration for the entire group was 92 months (range 4-227). A median dose of 70 Gy (range 63-70 Gy) was administered. We determined the rates of local control (LC), regional control, overall survival (OS) and cause-specific survival (CSS) at 5, 10 and 15 years by Kaplan-Meier product-limit method. The Cox regression analysis was performed to identify significant prognostic factors for LC and survival. The incidence of secondary malignancies is also reported.

RESULTS

The 5-, 10- and 15-year LC rates for the whole group were 84, 80.2 and 80.2 %, respectively. There were 20 local recurrences, of which 19 were salvaged with laryngectomy, giving an ultimate control rate of 90.6 %. The 5-/10-/15-year OS and CSS rates were 81.2 %/66.1 %/48.3 % and 90.6 %/90.6 %/90.6 %, respectively. None of the parameters analyzed exhibited a statistically significant relationship with LC. The age ≥65 years had a statistically significant effect on OS (but not in CSS), with a hazard ratio of 2.45 (95 % confidence interval 1.29-4.66; p = 0.006). During follow-up, 26 patients (22 %) developed a secondary malignancy. Only two patients (1.7 %) presented with severe toxicity (edema and mucositis).

CONCLUSIONS

Radiotherapy alone offers a high likelihood of LC and an excellent CSS rate. In addition, the surgical approach for the salvage is a successful option.

Definitive radiation therapy for early glottic cancer: experience of two fractionation schedules

OBJECTIVES

The authors would report the results of definitive radiation therapy (RT) for early glottic cancer by two different radiation dose schedules.

METHODS

From February of 1995 till June of 2008, 157 patients with T1-2N0 glottic cancer were treated with curative RT at Samsung Medical Center. All patients had squamous cell carcinoma, and there were 89 patients (56.7%) with T1a, 36 (22.9%) with T1b, and 32 (20.4%) with T2. Two different radiation dose schedules were used: 70 Gy in 35 fractions to 64 patients (40.8%, group A); and 67.5 Gy in 30 fractions to 93 patients (59.2%, group B). The median treatment durations were 50 days (range, 44 to 59 days) and 44 days (range, 40 to 67 days) in the groups A and B, respectively.

RESULTS

The median follow-up durations were 85 and 45 months for the groups A and B. No severe late complication of RTOG grade 3 or higher was observed, and there was no difference in acute or chronic complication between the groups. Twenty-four patients experienced treatment failure: local recurrence only in 19 patients; regional recurrence only in one; combined local and regional recurrence in four; and systemic metastasis in none. The overall 5-year disease-free survival and disease-specific survival rates were 84.7% and 94.8%. The disease-free survival rate in the group B was better (78.3% vs. 90.8%, P=0.031). This difference was significant only in T1 stage (83.4% vs. 94.6%, P=0.025), but not in T2 (62.7% vs. 60.6%, P=0.965). Univariate analysis showed that the tumor extent, cord mobility, T-stage, and the dose schedule had significant influence on the disease-free survival, and multivariate analysis showed that only the tumor extent and the dose schedule were associated with the disease-free survival.

CONCLUSION

Superior disease-free survival could be achieved by 2.25 Gy per fraction without increased toxicity over shorter RT duration, when compared with 2.0 Gy per fraction.

Impact and relationship of anterior commissure and time-dose factor on the local control of T1N0 glottic cancer treated by 6 MV photons

BACKGROUND

To evaluate prognostic factors that may influence local control (LC) of T1N0 glottic cancer treated by primary radiotherapy (RT) with 6 MV photons.

METHODS

We retrospectively reviewed the medical records of 433 consecutive patients with T1N0 glottic cancer treated between 1983 and 2005 by RT in our institution. All patients were treated with 6 MV photons. One hundred and seventy seven (41%) patients received 52.5 Gy in 23 fractions with 2.5 Gy/fraction, and 256 (59%) patients received 66 Gy in 33 fractions with 2 Gy/fraction.

RESULTS

The median follow-up time was 10.5 years. The 10-year LC rates were 91% and 87% for T1a and T1b respectively. Multivariate analysis showed LC rate was adversely affected by poorly differentiated histology (Hazard Ratio [HR]: 7.5, p = 0.035); involvement of anterior commissure (HR: 2.34, p = 0.011); fraction size of 2.0 Gy (HR: 2.17, p = 0.035) and tumor biologically effective dose (BED) < 65 Gy15 (HR: 3.38, p = 0.017).

CONCLUSIONS

The negative impact of anterior commissure involvement could be overcome by delivering a higher tumor BED through using fraction size of > 2.0 Gy. We recommend that fraction size > 2.0 Gy should be utilized, for radiation schedules with five daily fractions each week.

Role of radiotherapy in early glottic carcinoma

BACKGROUND

Early glottic carcinoma has a high local control prospect with radiotherapy. This review evaluates a single center's experience.

METHODS

All patients from 1967 to 2006 diagnosed with Tis/T1/T2/N0 early glottic carcinoma treated definitively with radiotherapy at Prince of Wales Hospital were reviewed. Local control and cancer-specific survival (CSS) rates were primary endpoints, and the impact of various factors on these outcomes was statistically analyzed.

RESULTS

This review of 522 patients includes 24 with Tis, 356 with T1, and 142 with T2. Ultimate local control rates were as follows: Tis 87.5%, T1 94.7%, and T2 84.5%. Multivariate analysis found fitness for surgery, no involvement of anterior commissure, normal cord movement, and radiotherapy dose >60 Gy significant for local control. Fitness for surgery, no involvement of the anterior commissure, normal cord movement, and no ventricular involvement were significant prognostic factors for CSS.

CONCLUSION

Definitive radiotherapy for early glottic carcinoma provides high local control rates, with the option of surgical salvage to achieve ultimate local control.

Radiotherapy for glottic T1N0 carcinoma with slight hypofractionation and standard overall treatment time: importance of overall treatment time

OBJECTIVE

We retrospectively investigated treatment outcomes in patients with glottic T1 carcinoma treated with 65 Gy in 26 fractions four times a week and discuss the importance of the overall treatment time.

METHODS

Two hundred one patients with glottic T1 carcinoma were evaluated. Sixty-five Gray in 26 fractions were delivered for 200 patients, whereas 1 patient received 62.5 Gy in 25 fractions. We delivered radiotherapy once daily four times a week in this period, for a weekly dose of 10 Gy. Weekdays except Wednesday were treatment days.

RESULTS

The overall survival rate was 96.8 ± 1.3% (standard error) at 3 years and 90.8 ± 2.2% at 5 years. The local control rate was 91.9 ± 2.0% at 3 years and 89.8 ± 2.3% at 5 years. In patients with an overall treatment time equal to or longer than 47 days, the local control rate was 82.6 ± 6.0% at both 3 and 5 years. In the patients with overall treatment time equal to or less than 46 days, the local control rate was 94.6 ± 1.9% at 3 years and 91.8 ± 2.4% at 5 years. There was a significant difference between these two groups (P = 0.0349). A severe late radiation reaction occurred in one patient. He experienced severe laryngeal edema that required tracheotomy at 6 months after the completion of radiotherapy. The tracheotomy was closed at 14 months after completion of radiotherapy.

CONCLUSIONS

Overall treatment time seems to be an important factor for a good local control rate for glottic T1N0 carcinoma even when treated with slight hypofractionation.

Definitive radiation therapy for moderately advanced laryngeal cancer: effects of accelerated hyperfractionation

OBJECTIVE

The purpose of this retrospective study was to analyze the results of accelerated hyperfractionation for patients with moderately advanced (T2 and T3) laryngeal cancer.

METHODS

Between 1998 and 2007, 9 supraglottic carcinomas (6 T2N0M0, 2 T2N2M0, 1 T3N0M0), 30 glottic carcinomas (25 T2N0M0, 5 T3N0M0), and 1 T2N0M0 subglottic carcinoma were treated with definitive radiotherapy using accelerated hyperfractionation without concurrent chemotherapy. The dose-fractionation for 35 patients was 72.8 Gy/56 fractions/5.6 weeks, and that for four patients treated between 1998 and 2001 was 72 Gy/60 fractions/6 weeks. One patient who had been treated with steroid therapy for systemic lupus erythematosus was treated by 67.8 Gy/44 fractions/4.4 weeks.

RESULTS

The local control and overall survival probabilities at 5 years for supraglottic carcinomas were 75% and 86%, respectively. Those for glottic carcinomas were 80% and 92%, respectively. The 5-year local control probabilities for T2 and T3 tumors were 85% and 56%, respectively. This excellent local control rate especially for T2 laryngeal carcinomas may be attributable to the effect of accelerated hyperfractionation. No late toxicities of grade 2 or more was noted among the 39 patients treated with 72.8 Gy/56 fractions or 72 Gy/60 fractions.

CONCLUSION

Accelerated hyperfractionation of 72.8 Gy/56 fractions/5.6 weeks using 1.3 Gy/fraction seems a safe and effective dose-fractionation for patients with moderately advanced laryngeal carcinomas.

Effect of tumor bulk on local control and survival of patients with T1 glottic cancer: a 30-year experience

PURPOSE

To evaluate the effect of tumor bulk on local control and survival of patients with T1 glottic cancer.

METHODS AND MATERIALS

Effects of tumor bulk, T-stage, anterior-commissure involvement, treatment duration, and fraction size were analyzed in 208 patients; 136 had small tumors and 72 had bulky tumors. Anterior-commissure was involved in 54 patients. Treatment duration ranged from 39 to 64 days and fraction size ranged from 1.8 to 2.0 Gy. Median follow-up was 5.1 years.

RESULTS

Five-year actuarial local control rates were 86.1% and 91.4% after radiotherapy and salvage laryngectomy. On univariate analysis, local control rates were 92.6% and 73.6% for small and bulky tumors (p = 0.03), 89.6% and 75.9% for patients without and with anterior-commissure involvement (p = 0.01), 92.6% and 75.6% when treatment duration was <or=50 days and >50 days (p = 0.04), and 90.2% and 76.4% with 2 Gy and 1.8 Gy (p = 0.02) per fraction. On multivariate analysis, tumor bulk was the only significant factor that affected local control (p = 0.007). Ultimate local control rates after salvage were 97.1% and 80.5% for patients with small and bulky tumors. Disease-free survival rates at 5 years for small and bulky tumors were 96.3% and 84.7% (p = 0.001). Median duration to recurrence for small tumors was 30 months as compared with 11 months for bulky tumors.

CONCLUSION

Tumor bulk is a highly significant prognostic factor for radiation control of T1 glottic cancer. Patients with bulky tumors had lower local control and disease-free survival rates and shorter duration to recurrence than those with small tumors.

American Society of Clinical Oncology Clinical Practice Guideline for the Use of Larynx-Preservation Strategies in the Treatment of Laryngeal Cancer

Purpose

To develop a clinical practice guideline for treatment of laryngeal cancer with the intent of preserving the larynx (either the organ itself or its function). This guideline is intended for use by oncologists in the care of patients outside of clinical trials.

Methods

A multidisciplinary Expert Panel determined the clinical management questions to be addressed and reviewed the literature available through November 2005, with emphasis given to randomized controlled trials of site-specific disease. Survival, rate of larynx preservation, and toxicities were the principal outcomes assessed. The guideline underwent internal review and approval by the Panel, as well as external review by additional experts, members of the American Society of Clinical Oncology (ASCO) Health Services Committee, and the ASCO Board of Directors.

Results

Evidence supports the use of larynx-preservation approaches for appropriately selected patients without a compromise in survival; however, no larynx-preservation approach offers a survival advantage compared with total laryngectomy and adjuvant therapy with rehabilitation as indicated.

Recommendations

All patients with T1 or T2 laryngeal cancer, with rare exception, should be treated initially with intent to preserve the larynx. For most patients with T3 or T4 disease without tumor invasion through cartilage into soft tissues, a larynx-preservation approach is an appropriate, standard treatment option, and concurrent chemoradiotherapy therapy is the most widely applicable approach. To ensure an optimum outcome, special expertise and a multidisciplinary team are necessary, and the team should fully discuss with the patient the advantages and disadvantages of larynx-preservation options compared with treatments that include total laryngectomy.

Does 4MV perform better compared to 6MV in the presence of air cavities in the head and neck region?

BACKGROUND AND PURPOSE

The underdose near air cavities in the head and neck region at photon energies of 4 MV and 6 MV was studied in search for clinical advantages of the 4 MV over 6 MV treatments.

MATERIALS AND METHODS

The on-axis and off-axis dose distributions were measured with a parallel-plate ionization chamber and films in polystyrene phantoms containing an air cavity of appropriate size based on the results of computed tomography scans.

RESULTS

Although most results are similar for both energies, the 4 MV photon beams give a somewhat smaller underdose effect and a faster re-build up than the 6 MV. For both energies a significant underdose effect was observed at the edge of the field in the larynx phantom. This proved to be true for small and large fields, for smaller and larger cavities, for one-beam as well as parallel-opposed beams.

CONCLUSION

For most clinically relevant situations there is no remarkable benefit in the use of either of the two energies.

T1N0/T2N0 glottic carcinoma: A comparison of two fractionation schedules

The aim of this paper is the retrospective comparison of accelerated/hypofractionated radiotherapy regimen (AHFX) with standard fractionation regimen (SFX) for patients with early glottic carcinoma. One hundred and forty-five patients with T(1)-T(2) glottic cancer between 1986 and 1998 were eligible. Before 1992, patients received 60-66 Gy in 30-33 fractions over 6-6.5 weeks (SFX) with (60)Co and 6-MV beams. After 1992, patients received 52.5-55 Gy in 20 fractions over 4 weeks (AHFX) using 6-MV beams. The end-points were overall survival, laryngectomy-free survival (LFS), loco-regional control and toxicity. One hundred and two were stage T(1)N(0); 43 were stage T(2)N(0). Median follow up was 4.9 years. The 5-year overall survival was 78%. Five-year loco-regional control in T(1)N(0) patients was higher in AHFX than in SFX group (95 vs 75%, P = 0.002). Loco-regional control in T(2)N(0) patients was similar for AHFX and SFX (81 vs 80%, P = 0.813). Overall LFS was 88%. T(1)N(0) AHFX patients had 5-year LFS of 95% compared with 75% for SFX (P = 0.003). For T(2)N(0) AHFX patients, overall LFS was 92% compared with 80% for the SFX group (P = 0.291). No grade 4 or 5 late toxicity occurred. One AHFX patient developed grade 3 toxicity; two of 51 SFX patients developed grade 2 toxicity versus five of 94 AHFX patients. AHFX using 6-MV beams for treatment of early glottic cancer resulted in equivalent LFS and toxicity when compared with SFX.

Compromised local control due to treatment interruptions and late treatment breaks in early glottic cancer: Population-based outcomes study supporting need for intensified treatment schedules

PURPOSE

This population-based study describes the treatment of early glottic cancer in Ontario, Canada and assesses whether treatment variations were associated with treatment effectiveness.

METHODS AND MATERIALS

We studied 491 T1N0 and 213 T2N0 patients. Data abstracted from charts included age, sex, stage, treatment details, disease control, and survival.

RESULTS

The total dose ranged from 50 to 70 Gy, and the daily dose ranged from 1.9 to 2.8 Gy. In 90%, treatment duration was between 25 and 50 days. Field sizes, field reductions, beam arrangement, and beam energy varied. Late treatment breaks occurred in 13.6% of T1N0 and 27.1% of T2N0 cases. Local control was comparable to other reports for T1N0 (82% at 5 years), but was only 63.2% in T2N0. Variables associated with local failure in T1N0 were age less than 49 years (relative risk [RR], 3.21; 95% confidence interval [CI], 1.49-6.90) and >3 treatment interruption days (RR, 2.43; 95% CI, 1.00-5.91). In T2N0, these were field reduction (RR, 2.33; 95% CI, 1.23-4.42) and late treatment breaks (RR, 2.19; 95% CI, 1.09-4.41).

CONCLUSION

Some aspects of treatment for early glottic cancer were associated with worse local control. Problems with protracted treatment are of particular concern, underscoring the need for randomized studies to intensify radiotherapy.

Radiotherapy for early glottic carcinoma (T1N0M0): results of prospective randomized study of radiation fraction size and overall treatment time

PURPOSE

To investigate in a prospective randomized study the effect of radiation fraction size and overall treatment time on the local control of early glottic carcinoma.

METHODS AND MATERIALS

Between December 1993 and December 2001, 180 patients with early glottic carcinoma (T1N0M0) were treated at our department. The patients were randomly allocated to either treatment arm A (radiation fraction size 2 Gy, n = 89) or B (2.25 Gy, n = 91). The total radiation dose administered was 60 Gy in 30 fraction within 6 weeks for minimal tumors (two-thirds of the vocal cord or less) or 66 Gy in 33 fractions in 6.6 weeks for larger than minimal tumors (more than two-thirds of the vocal cord) in Arm A and 56.25 Gy in 25 fractions within 5 weeks for minimal tumor or 63 Gy in 28 fractions within 5.6 weeks for larger than minimal tumors in Arm B.

RESULTS

The 5-year local control rate was 77% for Arm A and 92% for Arm B (p = 0.004). The corresponding 5-year cause-specific survival rates were 97% and 100% (no significant difference). No significant differences were found between these two arms in terms of rates of acute mucosal reaction, skin reactions, or chronic adverse reactions.

CONCLUSION

Use of 2.25-Gy fractions with a shorter overall treatment time for Arm B showed superior local control compared with conventional use of 2-Gy fractions for Arm A without adverse reactions from the greater fraction.

Radical radiotherapy for early glottic cancer: Results in a series of 1087 patients from two Italian radiation oncology centers. II. The case of T2N0 disease

PURPOSE

To retrospectively evaluate local control rates, late damage incidence, functional results, and second-tumor occurrence according to the different patient, tumor, and treatment features in a large bi-institutional series of T2 glottic cancer.

METHODS AND MATERIALS

A total of 256 T2 glottic cancer cases treated consecutively with radical intent at the Florence University Radiation Oncology Department (FLO) and at the Radiation Oncology Department of the University of Brescia, Istituto del Radio "O. Alberti" (BS) were studied. Cumulative probability of local control (LC), disease-specific survival (DSS), and overall survival (OS) rates were calculated and compared in the different clinical and therapeutic subgroups by both univariate and multivariate analysis. Types of relapse and their surgical salvage were evaluated, along with the functional results of treatment. Late-damage incidence and second-tumor cumulative probability (STP) were also calculated.

RESULTS

In the entire series, 3-year, 5-year, and 10-year OS rates were, respectively, 73%, 59%, and 37%. Corresponding values for cumulative LC probability were 73%, 73%, and 70% and for DSS, 89%, 86%, and 85%, taking into account surgical salvage of relapsed cases. Seventy-three percent of the patients were cured with function preserved. Main determinants of a worse LC at univariate analysis were larger tumor extent and impaired cord mobility. At multivariate analysis, the same factors retained statistical significance. Twenty-year STP was 23%, with second-tumor deaths less frequent than larynx cancer deaths (20 of 256 vs. 30 of 256). Incidence of late damage was higher in the first decade of accrual (22%) than in the last decade (10%, p = 0.03); the same was true for severe late damage (9% vs. 1.8%).

CONCLUSION

Present-day radical radiotherapy can be considered a standard treatment for T2 glottic cancer. Better results are obtained in patients with less extended disease. Late damage is relatively infrequent, but a careful follow-up is warranted for early detection not only of relapses (because salvage surgery is feasible) but also of second malignant tumors, which constitute a relevant but not the leading cause of death in these patients and are potentially curable.

Radical radiotherapy for early glottic cancer: Results in a series of 1087 patients from two Italian radiation oncology centers. I. The case of T1N0 disease

PURPOSE

To retrospectively evaluate local control rates, late damage incidence, functional results, and second tumor occurrence according to the different patient, tumor, and treatment features in a large bi-institutional series of T1 glottic cancer.

METHODS AND MATERIALS

A total of 831 T1 glottic cancer cases treated consecutively with radical intent at the Florence University Radiation Oncology Department (FLO) and at the Radiation Oncology Department of the University of Brescia-Istituto del Radio "O. Alberti" (BS) were studied. Actuarial cumulative local control probability (LC), disease-specific (DSS), and overall survival (OS) rates have been calculated and compared in the different clinical and therapeutic subgroups with both univariate and multivariate analysis. Types of relapse and their surgical salvage have been evaluated, along with the functional results of treatment. Late damage incidence and second tumor cumulative probability (STP) have been also calculated.

RESULTS

In the entire series, 3-, 5-, and 10-year OS was equal to 86%, 77%, and 57%, respectively. Corresponding values for LC were 86%, 84%, and 83% and for DSS 96%, 95%, and 93%, taking into account surgical salvage of relapsed cases. Eighty-seven percent of the patients were cured with function preserved. Main determinants of a worse LC at univariate analysis were: male gender, earlier treatment period, larger tumor extent, anterior commissure involvement, and the use of Cobalt 60. At multivariate analysis, only gender, tumor extent, anterior commissure involvement, and beam type retained statistical significance. Higher total doses and larger field sizes are significantly related (logistic regression) with a higher late damage incidence. Scatterplot analysis of various combinations of field dimensions and total dose showed that field dimensions >35 and <49 cm2, together with doses of >65 Gy, offer the best local control results together with an acceptably low late damage incidence. Twenty-year STP was equal to 23%, with second tumor deaths being more frequent than larynx cancer deaths (67 of 831 vs. 46/831).

CONCLUSION

The results of this study support the opinion, suggested by some international guidelines, that radiotherapy is standard treatment for T1 glottic cancer. Better results are obtained in patients with less extended disease and with 4-6 MV photon beams. The use of doses in excess of 65 Gy and of field sizes of 36-49 cm2 is probably the best technical choice available. Late damage is infrequent, but careful follow-up is warranted to detect early not only relapses (because conservative salvage surgery is feasible), but also second malignant tumors, which constitute the main cause of death in these patients and are potentially curable.

Prognostic significance of G1 cell-cycle inhibitors in early laryngeal cancer

BACKGROUND

Radiation therapy yields a 2-year local control rate of 80% to 90% in early laryngeal squamous cell carcinoma. However, a subset of early laryngeal cancers has a significantly higher rate of local recurrence and lower rate of overall survival.

OBJECTIVE

The objective of this study was determine the prognostic significance of p53, p27, and p21 expression in patients with early laryngeal cancer.

METHODS

Expression of p53, p27, and p21 proteins in pretreatment biopsies from sixty-eight patients was analyzed by using immunohistochemistry. Low (</=10% cells) and high (>10% cells) levels of expression were measured. All patients were newly diagnosed and treated with external beam radiation. Other contributing factors were also studied, such as age, sex, race, tumor site, and stage.

RESULTS

Forty (58.8%) and 28 (41.2%) lesions were staged as T1 and T2, respectively, whereas 16 (23.5%) and 52 (76.5%) were located in the supraglottis and glottis, respectively. Overexpression of p27, p53, and p21 was found in 36.7%, 60.6%, and 60% of cases, respectively. Overexpression of p27 was found to be a significant predictor of recurrence by multivariate analysis (RR 3.3, P = .017). Overexpression of p21 and/or p53 was not predictive of recurrence. No factor predicted disease specific or nonspecific overall survival.

CONCLUSION

Our results indicate the significance of p27 overexpression as an indicator of recurrence in patients with early laryngeal squamous cell carcinoma.

Evaluation of Local Recurrence and Second Malignancy in Patients with T1 and T2 Squamous Cell Carcinoma of the Larynx

PURPOSE

Evaluate outcome in patients with T1 and T2 laryngeal cancer treated with radiation therapy.

PATIENTS AND METHODS

Retrospective review of 190 patients with SCC of the larynx, stage T1(63%) orT2 (37%), treated with primary radiation therapy from 1/75 through 12/93. Median age was 61 years and median follow-up was 16.6 years. Median field size was 6.0 cm x 6.0 cm with a median fraction size of 2 Gy delivered in 33 daily fractions over 48 days. Energy used was 2 MV (19%), 4 MV (46%), 6 MV (26%), or other (9%). Univariate Cox proportional hazards regression analysis was performed using the following variables: gender, age, T stage, anterior commissure involvement, treatment energy, treatment interruption, alcohol use, smoking history, and tobacco use during treatment.

RESULTS

Overall actuarial 5-year survival was 76%, and 10-year survival was 56%. Actuarial local recurrence free survival (LRFS) at 5 years was 81%, and 10 years LRFS was 79%. Local relapse correlated with T stage (9% T1 versus 28% T2, P = 0.0009) and smoking history (14% for less than 100 pack-year versus 29% for greater than 100 pack-year, P = 0.02). Gender, age, anterior commissure involvement, treatment energy, treatment interruption, alcohol history, alcohol use during treatment, and tobacco use during treatment had no influence on outcomes. Actuarial second malignancies rate at 5 years was 18%.

CONCLUSION

Heavy tobacco use and T stage appears to correlate with an increase in local relapse rates. Gender, age, anteriorcommissure involvement, treatment energy, treatment interruption, and alcohol use did not significantly correlate with local relapse rates. The risk of second malignancies is comparable to that of local relapse.

Cumulative interfraction interval analysis of time and fraction size in radiotherapy

AIMS

Overall treatment time (OTT) and fraction size influence treatment results with radiotherapy; yet, being inversely related, it is difficult to distinguish their effect independently of each other. This paper proposes a new approach for analysing the interrelationship of time and fraction size in terms of cumulative interfraction intervals (CIFI) (i.e. intervals between non-successive fractions of radiotherapy).

MATERIALS AND METHODS

We analysed the influence of CIFI1-6, CIFI1-11 and OTTon tumour control by Kaplan-Meier calculation of the primary relapse-free survival (PRFS) and Mann Whitney 'U' test in 242 patients with epidermoid cancer of the buccal mucosa-gingiva-palate region treated by either 2.4 Gy/fraction (60 Gy/5 weeks) or 3.5 Gy/fraction (52.5 Gy/3 weeks).

RESULTS

The results showed that (1) prolongation of CIFI1-11 significantly decreased tumour control in the 2.4 Gy but not 3.5 Gy schedule: (2) 3.5 Gy schedule was superior to 2.4 Gy schedule, particularly when CIFI1-11 was prolonged (5-year PRFS 80.3% vs 30.9%); and (3) OTT did not influence either schedule.

CONCLUSIONS

Prolonging interfraction intervals (by treatment interruptions, weekend gaps, etc.) in the first 2 weeks (when accelerated repopulation attempts are maximal) affects treatment results with low fraction sizes but not high fraction sizes; OTT probably vicariously reflects the effect of prolonging the intervening CIFI.

Radiotherapy patterns of practice: T1N0 glottic cancer in Ontario, Canada

AIMS

To describe the variation in the delivery of radiation therapy to patients with T1N0 glottic cancer who were diagnosed in Ontario, Canada, between 1982 and 1995.

MATERIALS AND METHODS

The patient population consisted of a random sample of 461 patients treated with curative intent from the nine cancer centres that administer radiation therapy in the province. Abstracted variables included prescribed dose (Gy) and fractionation (f), beam energy and arrangement, set-up, field size, beam modifiers, positioning and treatment interruptions.

RESULTS

Thirteen prescribed dose-fractionation schemes (> or = four cases each) were identified, including 50.0-53.0 Gy/20 f (54.5%), 55.0-61.0 Gy/25 f (30.3%), and 60.0-66.0 Gy/30-33 f (7.7%). All regimens used one fraction per day, 5 days per week. An isocentric set-up was used (94.3%), with megavoltage (MV) beam energies of Cobalt-60 (87.9%), 6 MV (6.1%) and 4 MV (6.1%). A lateral parallel-opposed pair of beams was the predominant technique (76.4%) versus an anterior oblique pair (17.2%) or angle-down pair (caudally directed fields to achieve shoulder clearance, 5.7%). Wedging (96.3%) and bolus (11.8%) were used as beam-modifying devices. Predominant field-width dimensions were 5.0-6.0 cm (43.4%) and 6.5-7.0 cm (43.1%), and field length dimensions were 5.0-6.0 cm (49.5%) and 6.5-7.0 cm (35.0%). Head, neck or chin immobilisation was used in 86.9% of the cases, with 94.6% of these being custom-made. We found that radiotherapy practice was stable over time, except for a trend of increasing field size and increasing use of immobilisation. In contrast, we found practice variations among the province's cancer centres. On the basis of our findings, we defined a predominant technical practice consisting of Cobalt-60 (reflecting machine availability during the period of the study), an isocentric set-up, a lateral parallel-opposed pair technique with wedging, and supine-head neutral positioning with custom immobilisation. Forty-two per cent of the cases had one or more components of treatment that differed from this definition.

CONCLUSIONS

Description of practice variation can provoke discussion about unrecognised differences in practice policies, perhaps identifying the need for better evidence, treatment guidelines, or both.

Three weeks radiotherapy for T1 glottic cancer: the Christie and Royal Marsden Hospital Experience

BACKGROUND AND PURPOSE

Radiotherapy for laryngeal carcinoma is conventionally given over a 6-7-week period. However, in a number of UK centres early lesions are treated over 3 weeks. We review recent results of this policy and discuss the reasons why short treatment times may be advantageous.

MATERIALS AND METHODS

Two hundred patients (100 from each centre) with T1 glottic invasive squamous cell carcinoma treated with definitive radiotherapy between 1989 and 1997 were analysed. The median age was 68 years. All patients received once daily fractionation, 5 days a week to a total tumour dose of 50.0-52.5 Gy in 16 fractions over 21 days; the fraction size ranged from 3.12 to 3.28 Gy. The median follow-up period was 5 years and 10 months.

RESULTS

The 5-year local control rates with radiotherapy for the whole group was 93%; there were 14 recurrences of which seven were salvaged by laryngectomy giving an ultimate local control of 96%. The 5-year overall survival was 80% and cause specific survival at 5 years was 97%. Univariate analysis revealed that T1 substaging (P=0.82) and anterior commissure involvement (P=0.47) did not significantly influence local control. A severe late radiation complication was seen in only one patient who continued to smoke heavily after treatment. There were no severe acute complications.

CONCLUSIONS

Once daily radiotherapy over 3 weeks gives excellent local control in patients with T1 glottic squamous-cell carcinoma and has a low rate of severe complications. The short overall treatment time and large fraction size may be advantageous in radiotherapy of these well-differentiated tumours.

[Treatment of T1N0 glottis carcinoma with radiotherapy. Results at our center and review of the literature]

OBJECTIVE

To evaluate the results of radiotherapy in the treatment of patients with T1N0 glottic squamous cell carcinoma.

MATERIAL AND METHODS

Retrospective study of a cohort of 338 patients with T1N0 glottic carcinoma treated with radiotherapy at our institution between 1985-1997. A review of the literature published during the last ten years was carried out.

RESULTS

Local control with radiotherapy in our patients was 82%, reaching 97% when salvage surgery was included. The local control with radiotherapy in most of the published series ranges between 81.90%.

CONCLUSIONS

Treatment with radiotherapy achieves local control in early glottic carcinomas (T1N0) in 80-90% of cases. In our centre such treatment achieved local control in 82% of cases.

Analysis of prognostic factors for T(1)N(0)M(0) glottic cancer treated with definitive radiotherapy alone: experience of the cancer hospital of Peking Union Medical College and the Chinese Academy Of Medical Sciences

PURPOSE

To analyze the prognostic factors for early-stage glottic cancer (T(1)N(0)M(0)) treated with radiotherapy alone.

METHODS AND MATERIALS

Between 1958 and 1994, 238 patients (220 male) with T(1)N(0)M(0) (UICC 1997) squamous cell carcinoma of the glottis were treated with 6- or 8 MV X-ray or 60Co radiation in parallel-opposed fields (median size: 22.5 cm(2)) over a median of 52 days to a median dose of 68 Gy. Locoregional control (LC) and overall survival (OS) were estimated by the Kaplan-Meier method. Log-rank and Cox regression analyses were used to identify prognostic factors.

RESULTS

The median follow-up time was 127 months (range: 4-410 months). Five- and 10-year OS rates were 84.0% and 74.9%. The 5-year LC rate was 82.2%. Forty-four patients had recurrent disease (41 locally, 2 in cervical lymph nodes, 1 lost to follow-up); 23 had second malignancies. On multivariate analysis, unfavorable prognostic factors for OS were age >65 years (p < 0.001) and second malignancy (p < 0.001). Unfavorable prognostic factors for LC were bulky tumor (p = 0.023), anterior commissure involvement (p = 0.024), and decrease in hemoglobin during treatment (p = 0.025).

CONCLUSIONS

Radiotherapy alone provides good control of early-stage glottic cancer. Bulky tumor, anterior commissure involvement, and decreasing hemoglobin are negative prognostic factors for LC.

Cumulative interfraction interval analysis of influence of time and interruptions on radiotherapy results in oral cancers

PURPOSE

To present a new approach to analyze the influence of time and interruptions in fractionated radiotherapy, in terms of cumulative interfraction intervals (CIFIs), that is, the interval between nonsuccessive fractions of radiotherapy.

METHODS AND MATERIALS

The subjects were 142 patients with epidermoid cancer of the buccal mucosa-gingiva-palate region treated by 60 Gy in 25 fractions during 5 weeks. The influence of CIFI between the first and sixth, eleventh, sixteenth, and twenty-first fractions (CIFI(1-6), CIFI(1-11), CIFI(1-16), and CIFI(1-21), respectively), as well as overall treatment time on local control, was analyzed by Kaplan-Meier calculation of the primary relapse-free survival and Mann-Whitney U testing of the difference in various CIFIs between the tumors that recurred (recurred group) and those that did not (controlled group).

RESULTS

Only CIFI(1-11) influenced local control significantly, with the 5-year primary relapse-free survival rate being 67.9%, 48.4%, and 32.6% in those with CIFI(1-11) of <14, 14, and >14 days (p = 0.0181). The median CIFI(1-11) in the controlled group was significantly lower than that in the recurred group (14 days vs. 15 days; p = 0.0037).

CONCLUSION

Interruptions during the first 11 fractions, including planned weekend gaps, decrease the effect of radiotherapy, possibly because of successful tumor cell repopulation during the protracted interfraction intervals. The analysis of time in terms of CIFI rather than overall treatment time appears to be a promising area for research.

Hyperfractionated-accelerated or conventionally fractionated radiotherapy for early glottic cancer

PURPOSE

To evaluate the effect of shortening overall treatment time by hyperfractionated-accelerated radiotherapy for T2N(0)M(0) glottic carcinomas. Results for local control and survival were calculated and compared to those for T1N(0)M(0) tumors treated with a once-a-day fractionated schedule.

METHODS AND MATERIALS

Between 1990 and 1998, 92 patients with T1N(0)M(0) and 45 patients with T2N(0)M(0) glottic cancers were treated with radical radiotherapy. The T1N(0)M(0) tumors were treated with a once-a-day fractionated schedule lasting 6.5 weeks to a total dose of 62.4 Gy. The T2N(0)M(0) tumors received a split-course hyperfractionated-accelerated treatment over a total of 4.5 weeks to a total dose of 64.6 Gy.

RESULTS

The 5-year local control was 85% for T1N(0)M(0) and 88% for T2N(0)M(0), whereas the 5-year locoregional control was 85% for both groups. The 5-year overall survival was 70% and 53% for T1N(0)M(0) and T2N(0)M(0), respectively. No significant statistical difference was found between the two groups for the parameters analyzed. The number of serious late complications was few and comparable for the two groups.

CONCLUSIONS

Hyperfractionated-accelerated radiotherapy proved beneficial for T2N(0)M(0) glottic cancer, giving local control rates comparable to those for T1N(0)M(0) tumors.

T1-T2N0 squamous cell carcinoma of the glottic larynx treated with radiation therapy

PURPOSE

The end results after radiation therapy for T1-T2N0 glottic carcinoma vary considerably. We analyze patient-related and treatment-related parameters that may influence the likelihood of cure.

PATIENTS AND METHODS

Five hundred nineteen patients were treated with radiation therapy and had follow-up for >or= 2 years. Three patients who were disease-free were lost to follow-up at 7 months, 21 months, and 10.5 years. No other patients were lost to follow-up.

RESULTS

Local control rates at 5 years after radiation therapy were as follows: T1A, 94%; T1B, 93%; T2A, 80%; and T2B, 72%. Multivariate analysis of local control revealed that the following parameters significantly influenced this end point: overall treatment time (P < .0001), T stage (P = .0003), and histologic differentiation (P = .013). Patients with poorly differentiated cancers fared less well than those with better differentiated lesions. Rates of local control with laryngeal preservation at 5 years were as follows: T1A and T1B, 95%; T2A, 82%; and T2B, 76%. Cause-specific survival rates at 5 years were as follows: T1A and T1B, 98%; T2A, 95%; and T2B, 90%. One patient with a T1N0 cancer and three patients with T2N0 lesions experienced severe late radiation complications.

CONCLUSION

Radiation therapy cures a high percentage of patients with T1-T2N0 glottic carcinomas and has a low rate of severe complications. The major treatment-related parameter that influences the likelihood of cure is overall treatment time.

Treatment of early and moderately advanced vocal cord carcinoma with 6-MV X-rays

PURPOSE

Whereas there are many reports regarding treatment of early vocal cord cancer with cobalt 60 or 2-4-MV X-rays, there are still few reports on the results of treatment with 6-MV X-rays. Theoretically, 6-MV X-rays result in greater underdosage of tumor at the air-tissue interface and at the anterior commissure. This paper analyzes the results of irradiation of early and moderately advanced squamous cell carcinoma of the true vocal cord treated exclusively with 6-MV X-rays in a community hospital. The literature pertinent to the issue is reviewed.

METHODS AND MATERIALS

Eighty-three patients with Tis, T1, T2, or T3 squamous cell carcinoma of the true vocal cord were treated with curative intent at Bethesda Memorial Hospital in Boynton Beach, Florida between April 1986 and April 1998. The dose schedules most commonly used were 63 Gy in 28 fractions (2.25 Gy per fraction once a day) for T1 tumors or 74.40 Gy in 62 fractions (1.2 Gy per fraction twice a day) for T2 and T3 tumors. All patients have minimum 2-year follow-up; 63 (76%) have 5-year minimum follow-up.

RESULTS

Local control was achieved in 6 of 6 Tis, 53 of 54 (98%) T1, 8 of 8 T2, and 6 of 6 T3 lesions. No complications were encountered.

CONCLUSIONS

A recent literature review indicates that the treatment of early vocal cord cancer with 6-MV X-rays remains controversial. The dose schedules used in the present paper produced a high rate of local control, a finding that is consistent with reports of other investigators who used dose schedules similar to those used in the present series. However, several other investigators have reported significantly lower rates of local control for T1 or T2 glottic cancer treated with 6-MV X-rays when compared to results obtained with cobalt 60 or 4 MV at their own institution. The latter institutions used lower total doses and/or lower dose per fraction than those institutions reporting high rates of local control with 6 MV. Data from the literature, as well as our own data, are consistent with the following hypotheses: (1) the lower rates of local control reported by several institutions when using 6 MV compared with cobalt or 2-4 MV, using the same radiation dose schedules for each beam energy, indicate that underdosage of mucosal surfaces in the laryngeal air cavity may be a clinically important phenomenon, and (2) time-dose factors, although certainly important for lower energy beams, may be even more important when using 6 MV.

Radiation therapy in T1-T2 glottic carcinoma: influence of various treatment parameters on local control/complications

PURPOSE

To evaluate the influence of various treatment parameters on local control as well as complications in T1 and T2 glottic carcinomas.

METHODS AND MATERIALS

Between 1975 and 1989, 676 patients with early glottic carcinoma (460 T1 and 216 T2) received curative radiation with three different treatment regimens, as follows: Regimen 1-50 Gy/15 Fr/3 weeks (3.33 Gy/daily) for 192 patients; Regimen 2-60-62.5 Gy/24-25 Fr/5 weeks (2.5 Gy/daily) for 352 patients; and Regimen 3-55-60 Gy/25-30 Fr/5-6 weeks (2-2.25 Gy/daily) for 132 patients.

RESULTS

The local control at 10 years was 82% and 57% for T1 and T2 lesions respectively (p = 0.0). For the T1N0M0 group, field size had significant impact on local control with both univariate (p = 0.05) and multivariate (p = 0.03) analysis. For T2N0M0, group field size (p = 0.03) as well as registration year (p = 0.016) were significant in univariate analysis whereas only field size remained significant on multivariate analysis. Persistent radiation edema was noted in 146 (22%) patients and was significantly worse with larger field size (p = 0.000) but not related to different treatment regimens.

CONCLUSION

The shorter fractionation schedule had comparable local control, without increased complications in comparison to the protracted schedule and is best suited for a busy department.