Radiotherapy with or without chemotherapy for patients with T1-T2 glottic carcinoma: retrospective analysis

Effects of Chemotherapy and Radiation Therapy on Early Laryngeal Cancers

Background/Aim

Treatments for early laryngeal squamous cell carcinoma (SCC) include radiotherapy (RT), chemoradiotherapy (CRT), and larynx-preserving surgery. In this study, early laryngeal SCC was treated with RT in patients with stage I (T1N0) tumors and with CRT and docetaxel (DOC) in patients with stage II (T2N0) tumors and the treatment results and effectiveness of the chemotherapy were compared.

Patients and Methods

A total of 78 patients with early-stage laryngeal SCC were enrolled in this study. The T1N0 patients received radiation for the primary lesions as outpatients at a total dose of 63-70 Gy. By contrast, the T2N0 patients were hospitalized and treated with CRT, receiving a total radiation dose of 66-70 Gy. Docetaxel (DOC, 10 mg/m2) was administered intravenously once a week for 6-8 consecutive weeks concurrently with radiotherapy. The adverse events and survival rates with local control rates were examined.

Results

The number of non-glottic T2N0 patients was significantly higher than that of T1N0 patients. Although all patients completed their treatment schedule, significantly more grade 3 adverse events were observed in the T2N0 patients, in particular mucositis and dermatitis, than in T1N0 patients. The 5-year overall survival rate, disease specific survival rate, local control rate, and laryngeal preserve rate of the T1N0 and T2N0 patients were 86.1, 93.3, 88.6, and 94.3% and 85.9, 88.0, 93.1, and 93.1%, respectively.

Conclusion

CRT with docetaxel showed the best therapeutic outcomes for the treatment of laryngeal SCC in patients with T2N0 tumours, with a higher local control rate, effective laryngeal preservation, and relatively few adverse events.

Daily fraction dose-adjusted radiotherapy policy to avoid prolonging the overall treatment time for early glottic squamous cell carcinoma: a single-institutional retrospective study

The objective of this study was to determine the outcomes of radical radiotherapy for early glottic squamous cell carcinoma (EGSCC) with the policy of increasing the fraction size during radiotherapy when the overall treatment time (OTT) was expected to be prolonged. Patients diagnosed with clinical T1-2N0M0 EGSCC, who were treated with radical radiotherapy between 2008 and 2019 at Hokkaido University Hospital, were included. Patients received 66 Gy in 33 fractions for T1 disease and 70 Gy in 35 fractions for T2 disease as our standard regimen (usual group [UG]). If the OTT was expected to extend for >1 week, the dose fraction size was increased from 2.0 to 2.5 Gy from the beginning or during radiotherapy (adjusted group [AG]). At this time, we performed a statistical analysis between UG and AG. In total, 116 patients were identified, and the treatment schedules of 29 patients were adjusted. The median follow-up was 60.9 months. In the T1 group, the cumulative 5-year local failure rate was 12.0% in the AG and 15.4% in the UG, and in the T2 group, the rate was 40.7% in the AG and 25.3% in the UG. There were no significant differences between the AG and UG. Similarly, no significant differences were observed for overall survival and progression-free survival rates. Our single-institutional retrospective analysis of EGSCC patients suggested that a method of adjusting the radiotherapy schedule to increase fraction size from the beginning or during the course may be effective in maintaining treatment outcomes.

Comparison of prognostic and treatment between T1a and T1b glottic cancer: a propensity score-matched SEER database analysis

PURPOSE

The prognoses of T1a and T1b glottic cancers are still controversial. This study aimed to compare the prognosis difference between the two groups based on the population-based Surveillance, Epidemiology, and End Results database (SEER).

METHODS

Data for patients with T1a or T1b glottic cancers were extracted from the SEER database. The bias between T1a and T1b glottic cancers was minimized with Propensity Score Matching (PSM), and disease-specific survival (DSS) was analyzed using the Kaplan-Meier method, log-rank test, and Cox proportional hazards models.

RESULTS

A total of 5,272 patients were extracted from the database, including 847 patients with T1b glottic cancer that were 1:1 propensity score-matched with patients with T1a glottic cancer. After propensity score-matching, there was no statistical difference in disease-specific survival between T1a and T1b patients, whilst survival was impaired by old age. However, on the multivariate analysis, the T1a stage was associated with improved DSS compared with the T1b stage.

CONCLUSION

Our analysis showed that T1a glottic cancers didn't have a significantly better prognosis compared with T1b after PSM. However, the DSS of T1a patients is superior to that of T1b patients in multivariate analysis.

Management of Subglottic Cancer

Primary subglottic carcinoma is a rare subgroup of laryngeal malignancy with exact incidence unknown due to the lack of a standard definition of its anatomic boundaries. Early-stage subglottic carcinoma can be treated with either primary radiation or surgery with similar overall survival rates. Most patients present at an advanced stage due to a paucity of symptoms, and these patients are treated in a multidisciplinary fashion. Particular attention should be paid to the prelaryngeal and pretracheal nodal basins, as well as the stoma region, when managing these patients.

Prognostic and Treatment Differences Between T1a and T1b Glottic Cancer

OBJECTIVES

This study was designed to evaluate significant differences in treatment and survival outcomes between patients with T1a and T1b glottic cancer.

METHODS

Patients within the SEER Research Plus, 18 Registries dataset who were diagnosed with Stage I T1a or T1b cancer of the glottis between 2004 and 2015 were included in this study. Data prior to 2004 could not be included, as the SEER database did not distinguish between T1a and T1b glottic cancer until that year.

RESULTS

The 5-year disease-specific survival for T1a patients was significantly better than that of patients diagnosed with T1b glottic cancer. Age and year of diagnosis were also independent factors that impacted mortality. More patients who were diagnosed with T1b glottic cancer underwent external beam radiation than those diagnosed with T1a glottic cancer.

CONCLUSION

Our data shows that there are several independent factors effecting mortality including T classification, age at time of diagnosis, and year of diagnosis. T1a glottic cancers also show a significantly better prognosis compared with T1b. T1b glottic cancers are much more likely to be treated with primary radiotherapy compared with surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

Poor local control of ulcerative T1 glottic cancer treated with 2.25-Gy per fraction radiotherapy

The Tokai Study Group for Therapeutic Radiology and Oncology (TOSTRO) started managing T1 glottic cancer using 2.25 Gy/fraction radiotherapy in 2011. The aim was to evaluate the local control (LC) rate and toxicity with 2.25-Gy radiotherapy in clinical practice and identify prognostic factors.The eligibility criteria were T1 glottic squamous cell carcinoma patients with age ≥20 years, treated with 2.25 Gy/fraction without chemotherapy between 2011 and 2017. LC rates were evaluated based on age, performance status, sex, T-category, tumor type (ulcerative or non-ulcerative), presence of anterior commissure invasion, tumor size, X-ray beam energy, and overall treatment time. Acute and late adverse events were evaluated using CTCAE version 4.0. A total of 202 patients were enrolled. The median follow-up period was 34.2 months. The 2- and 4-year LC rates were 93.8% and 93.1%, respectively. There was a significant difference in the LC rate between non-ulcerative type and ulcerative type (95.2% vs. 74.1% at 2 years, 94.4% vs. 74.1% at 4 years; p = 0.01). On univariate analysis, only tumor type was significantly correlated with a poor LC rate (hazard ratio 4.3; 95% confidence interval 1.2-15.4; p = 0.03). Acute grade 3 adverse events occurred in 17 patients. However, no late adverse events of grade 3 or higher have occurred to date. T1 glottic cancer treatment outcomes using hypofractionated radiotherapy with 2.25 Gy/fraction in clinical practice were comparable to previously reported results. However, ulcerative type tumor was associated with a poor LC rate.

Proposal for personalized treatment of early glottic cancer with radiation therapy

The preservation of both the organ and its function is important for the treatment of early stage glottic cancer, and radiation therapy is an important and useful option. However, treatment with radiation therapy alone is insufficient. Therefore, to improve the local control rate even for early stage glottic cancer, attempts have been made to individualize treatment with radiation therapy (±chemotherapy) based on T stage and morphological characteristics. This individualized treatment greatly improved the local control rate for early glottic cancer. In the future, more suitable individualization can be achieved by investigating the radiosensitivity of biomarkers using biopsy materials before radiation therapy, in addition to T stage and morphological characteristics. Currently, many biomarkers are being investigated; however, appropriate biomarkers for predicting local control remain unknown.

Outcomes after radiation therapy for T2N0/stage II glottic squamous cell carcinoma

BACKGROUND

We report outcomes for patients with T2N0M0 glottic squamous cell carcinoma (SCC) treated with radiation therapy (RT).

METHODS

Patients who received definitive RT for T2 glottic SCC from 2000 through 2013 were retrospectively reviewed.

RESULTS

One hundred and thirteen patients were analyzed (median follow-up time 91 months; 85 patients received three-dimensional conformal radiotherapy [3D-CRT] and 28 received intensity-modulated radiation therapy [IMRT]). Fractionation was conventional (58%) or altered (42%); 20 patients (18%) received concurrent chemotherapy. Five-year local control was 83% for the 3D-CRT vs 81% for the IMRT group (P = .76). The ultimate locoregional control at 5 years was 100% for IMRT vs 91% for 3D-CRT (P = .1). The 5-year overall survival (OS) was 78% for 3D-CRT vs 81% for IMRT (P = .83). On multivariate analysis, younger age was the only independent predictor of improved OS (P = .0002).

CONCLUSIONS

Oncologic and survival outcomes were excellent for patients with T2N0 glottic cancer. Patients treated with IMRT and 3D-CRT had no statistically significant differences in all investigated endpoints.

Comparison of long-term treatment outcomes of T2N0M0 laryngeal squamous cell carcinoma using different treatment methods

Early [stage I and II (T2N0M0)] laryngeal cancer types are currently recommended to be treated with a single modality, consisting of definitive radiation therapy or larynx-preserving surgery. Although the treatment outcomes of stage I are good, the frequency of successful outcomes decreases with T2N0M0. Therefore, the present study investigated the treatment outcomes of different treatment methods in T2N0M0 laryngeal cancer. In total, 83 patients with previously untreated T2N0M0 laryngeal squamous cell carcinoma were enrolled. Patients were grouped by treatment method: Radiation therapy (RT; 27 patients); chemoradiotherapy (CRT; 46 patients) with cisplatin base; and surgery-based therapy (SBT; ten patients). The recurrence rates of the RT, CRT and SBT groups were 44.4, 19.6 and 50%, respectively. Moreover, the local control rates of the RT, CRT and SBT groups were 55.6, 87.0 and 80%, respectively. The CRT group had a significantly lower recurrence rate and higher local control rate compared with the RT group (P<0.05). In the survival analysis, overall and disease-specific survival rate did not differ significantly among the treatment groups. However, 3- and 5-year disease-free survival rates (DFS) of the RT group were both 55%, those of the SBT group were both 50% and those of the CRT group were both 80%. Furthermore, the DFS was significantly higher in CRT group compared with the other groups (P=0.02). Using multivariate analysis with Cox regression, it was found that the treatment method was the most important factor for DFS and had a significant impact in the CRT group. In addition, in patients with glottic cancer with anterior commissure and subglottic invasion, the CRT group had significantly improved DFS compared with the RT group, whereas there was no significant difference between the two groups in patients without subglottic invasion. According to National Cancer Institution Common Toxicity Criteria (version 5.0), more patients had toxicity in the CRT group compared with the RT group. However, in the RT and CRT groups, no patients demonstrated mortality due to toxicity, and treatment-related toxicities were manageable. Collectively, although definitive conclusions could not be established, due to the limitations of this retrospective study, the results suggest that CRT had a positive impact on the local control and DFS rates with manageable toxicity in patients with T2N0M0 laryngeal cancer.

T1 Glottic Cancer: Does Anterior Commissure Involvement Worsen Prognosis?

Radiotherapy (RT) and transoral laser microsurgery (TLM) represent the main treatment modalities for early glottic carcinoma. Local failure is notoriously more frequent in T1b glottic cancer in comparison to T1a and T2 tumors. In this scenario, the role of anterior commissure (AC) involvement is still controversial. The aim of the present study was therefore to determine its potential prognostic power in worsening patients’ survival and outcomes. We categorized different tumor glottic fold locations with respect to the involvement of one (T1a) or both vocal cords, with or without AC involvement. We analyzed a retrospective cohort of 74 patients affected by Stage I glottic cancer, treated between 2011 and 2018 by TLM or RT at a single academic institution. There were 22 T1a (30%) and 52 T1b (70%) cases. The median follow-up period was 30 months (mean, 32.09 ± 18.738 months; range, 12–79). Three-year overall survival (OS), disease-specific survival (DSS), recurrence-free survival (RFS), and laryngectomy-free survival (LFS) were compared according to tumor location, extension, and cT category. According to both uni- and multivariate analyses, an increased risk for recurrence in T1b with AC involvement and T1a tumors was 7.31 and 9.45 times, respectively (p-values of 0.054 and 0.030, respectively). Among the 17 recurrences, T1b with AC involvement experienced 15 tumor relapses (88.2%), thus significantly affecting both the RFS and LFS in comparison to the other two tumor subcategories (T1a, p = 0.028 and T1b without AC involvement, p = 0.043). The deteriorating prognosis in the presence of AC involvement likely reflects the need to power the hazard consistency and discrimination of the T1b category when associated with such a risk factor, thus deserving an independent T category.

Multifactorial analysis of local control and survival in patients with early glottic cancer

OBJECTIVES

The purpose of this study is to determine the effects of various prognostic factors for early glottic cancer patients who underwent radiotherapy.

METHODS

We retrospectively reviewed the all patients who were treated at our hospital for early glottic squamous cell carcinoma from 2004 to 2016. Data included patient's age, sex, T classification, tumor size, pathological grade, anterior commissure involvement, subglottic extension, laryngeal ventricle involvement, and restriction of vocal cord movement.

RESULTS

There were 74 patients with T1 tumors and 31 with T2 tumors. Recurrence was found in four patients with T1 and eight patients with T2. There were 99 males and six females enrolled, and the mean age was 67.5 ± 9.2 years for T1a, 67.3 ± 11.2 years for T1b, and 67.4 ± 7.9 years for T2. One patient with recurrence after 1 month was thought to have a residual tumor. The 5-year overall survival (OS) rate and the 5-year disease-specific survival (DSS) rate for T1-T2 patients were both 100%. The rate of larynx preservation was 94.6% for T1 and 74.2% for T2. A univariate analysis showed that the effective factors were age, T, size, SE. A multivariate logistic regression analysis showed that age influenced the recurrence status. Size is also suspected to be a prognostic factor.

CONCLUSIONS

This study revealed that the effective factors were age, T, size, and SE.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1701-1706, 2020.

Optimized treatment strategy of radiotherapy for early glottic squamous cell carcinomas: An initial analysis

The purpose of this study was to evaluate the clinical outcomes of radiotherapy for patients with T1/T2 glottic carcinoma. Patients with T1/T2 glottic carcinoma histopathologically diagnosed with squamous cell carcinoma and treated at our hospital between 2007 and 2015 were analyzed retrospectively. Our strategy for T1/T2 glottic carcinoma was as follows: radiotherapy alone with 2.25 Gy per fraction to a total of 25–28 fractions for patients with non-bulky T1 glottic carcinoma; concurrent chemoradiotherapy with oral S-1 and radiotherapy with 2 Gy per fraction to a total of 30 fractions for patients with T1 bulky/T2 favorable glottic carcinoma; or chemoradiotherapy with high-dose cisplatin and radiotherapy with 2 Gy per fraction to a total of 35 fractions for T2 unfavorable glottic carcinoma. Forty-eight patients were eligible. The median follow-up period among surviving patients was 38 months (range, 11–107). The disease was T1a in 23%, T1b in 13%, and T2 in 65% of patients. The 3-year local control rate in all patients, T1a, T1b, and T2 was 96.7%, 100%, 100%, and 96.0%, respectively. Of the 46 patients, one with T2 glottic carcinoma developed recurrent disease at the primary site, and one with T2 glottic carcinoma had lymph node recurrences in the neck. Acute Grade 3 dermatitis occurred in 8 (17%) patients and late Grade 2 hypothyroidism occurred in 2 (4%) patients. This retrospective study shows that our optimized treatment strategy of radiotherapy depending on the stage of early glottic carcinoma is not only effective but also well-tolerated.

Study Protocol: Prospective Study of Concurrent Chemoradiotherapy with S-1 and Hypofractionated Radiotherapy for Outpatients with Early Glottic Squamous Cell Carcinomas

Background:

The recommended treatment strategies for early glottic carcinoma with intent of larynx preservation are primarily radiotherapy. However, the outcomes of radiotherapy for bulky T1 or T2 glottic carcinoma are unsatisfactory. We designed a protocol consisting of concurrent chemoradiotherapy using S-1 as the radiosensitizer. We have performed this protocol in patients with favorable T2 lesions and demonstrated its efficacy and safety. In contrast, we have treated non-bulky T1 glottic carcinomas with 2.25 Gy per fraction, for a total of 25-28 fractions, starting in 2011 to improve efficacy and shorten the treatment period. Since this treatment strategy was implemented for T1 disease, no local failure has occurred to date, and it appears to be almost as safe as radiotherapy using 2.0 Gy per fraction. With the aim of improving the local control rate and shortening the treatment period primarily for favorable T2 disease, we changed the dose of radiation in our protocol from 2.0 Gy to 2.25 Gy per fraction, for a total of 25 fractions (from 30 fractions). The present study aims to evaluate the efficacy and safety of this new protocol.

Methods:

This study will be conducted as a clinical, prospective, single-armed, non-randomized trial. Patients are to receive S-1 (55.3 mg /m² /day, once daily) and radiotherapy (2.25 Gy per fraction, for a total of 25 fractions). S-1 and radiotherapy are started on the same day that radiotherapy is performed, 3-6 hours after oral administration of S-1. The primary study aim is the 3-year local control rate. The secondary study aims are overall survival, voice-preservation survival, disease-free survival, complete response rate, completion rate, and toxicity.

Result and conclusion:

This is the first single-center, non-randomized, prospective study of concurrent chemoradiotherapy with S-1 and hypofractionated radiotherapy to be conducted. The trial will evaluate the efficacy and safety of our protocol.

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

Purpose To update the guideline recommendations on the use of larynx-preservation strategies in the treatment of laryngeal cancer. Methods An Expert Panel updated the systematic review of the literature for the period from January 2005 to May 2017. Results The panel confirmed that the use of a larynx-preservation approach for appropriately selected patients does not compromise survival. No larynx-preservation approach offered a survival advantage compared with total laryngectomy and adjuvant therapy as indicated. Changes were supported for the use of endoscopic surgical resection in patients with limited disease (T1, T2) and for initial total laryngectomy in patients with T4a disease or with severe pretreatment laryngeal dysfunction. New recommendations for positron emission tomography imaging for the evaluation of regional nodes after treatment and best measures for evaluating voice and swallowing function were added. Recommendations Patients with T1, T2 laryngeal cancer should be treated initially with intent to preserve the larynx by using endoscopic resection or radiation therapy, with either leading to similar outcomes. For patients with locally advanced (T3, T4) disease, organ-preservation surgery, combined chemotherapy and radiation, or radiation alone offer the potential for larynx preservation without compromising overall survival. For selected patients with extensive T3 or large T4a lesions and/or poor pretreatment laryngeal function, better survival rates and quality of life may be achieved with total laryngectomy. Patients with clinically involved regional cervical nodes (N+) who have a complete clinical and radiologic imaging response after chemoradiation do not require elective neck dissection. All patients should undergo a pretreatment baseline assessment of voice and swallowing function and receive counseling with regard to the potential impact of treatment options on voice, swallowing, and quality of life. Additional information is available at www.asco.org/head-neck-cancer-guidelines and www.asco.org/guidelineswiki .

A multicenter survey of stage T1 glottic cancer treated with radiotherapy delivered in 2.25-Gy fractions in clinical practice: An initial 5-year analysis

The purpose of this study was to evaluate the acute and late toxicity as well as local control (LC) in T1 glottic cancer (GC) patients treated with hypofractionated radiotherapy (RT) in clinical practice. The Tokai Study Group for Therapeutic Radiology and Oncology started RT treatment with a dose of 2.25 Gy for T1 GC in 2011. Ten institutions combined data from 104 patients with T1 squamous cell carcinoma between 2011 and 2015. In total, 104 patients with T1 GC were irradiated with a standard radiation dose of 63 Gy in 28 fractions.The median follow-up duration was 18 (3.7-49.5) months. Acute grade 3 adverse events were observed in 7 patients, with 4 patients (5%) having dermatitis and 3 patients (4%) having mucositis. Late adverse events above grade 3 were not observed. Two patients developed local recurrence. The rates of acute adverse events in the present study were comparable to those in previous studies that have used 2 Gy fractions of RT.

Comparison of survival between radiation therapy and trans-oral laser microsurgery for early glottic cancer patients; a retrospective cohort study

BACKGROUND

The literature reports various treatment methodologies, such as trans-oral laser microsurgery, radiation therapy, total/partial laryngectomies, and concurrent radiation chemotherapy for patients with early larynx cancer. However, at the forefront of early glottis treatment is trans-oral laser microsurgery and radiation therapy, likely due to better functional and survival outcomes. Here we conduct the largest Canadian head-to-head comparison of consecutive patients treated with either radiation therapy or trans-oral laser microsurgery. Additionally, we compare these two treatments and their 5-year survival rates post treatment to add to the existing literature.

METHODS

Charts of patients who were diagnosed with early glottic cancer between 2006 and 2013 were reviewed. Seventy-five patients were identified, and split into 2 groups based on their primary treatment, trans-oral laser microsurgery and radiation therapy. Kaplan-Meier survival curves, life-tables, and the log-rank statistic were reported to determine if there was a difference between the two treatment groups and their disease-specific survival, disease-free survival, and total laryngectomy-free survival. Additionally, each different survival analysis was stratified by potential confounding variables, to help conclude which treatment is more efficacious in this population.

RESULTS

The 5-year disease-specific survival rate is 93.3 % σ = 0.063 and 90.8 % σ = 0.056 for patients treated with trans-oral laser microsurgery and radiation therapy, respectively (χ (2) < 0.001, p = 0.983). The disease free survival rate is 60.0 % (σ =0.121) for patients treated with trans-oral laser microsurgery, and 67.2 % (σ = 0.074) for those who received RT (χ (2) = 0.19, p = 0.663). Additionally, the total laryngectomy-free survival rate is 84.1 % (σ = 0.1) and 79.1 % (σ = 0.072) for patients' early glottic cancer treated by trans-oral laser microsurgery and radiation therapy, respectively (χ (2) = 0.235, p = 0.628). Chi-square analysis of age-group versus treatment group (χ (2) = 6.455, p = 0.04) and T-stage versus treatment group (χ (2) = 11.3, p = 0.001) revealed a statistically significant relationship, suggesting survival analysis should be stratified by these variables. However, after stratification, there was no statistically significant difference between the trans-oral laser microsurgery and radiation therapy groups in any of the survival analyses.

CONCLUSION

No difference was demonstrated in the 5-year disease-specific survival, disease-free survival, and total laryngectomy-free survival, between the RT and TLM treatment groups. Additionally, both groups showed similar 5-year survival after stratifying by confounding variables.

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.

Somatic evolution of head and neck cancer - biological robustness and latent vulnerability

Despite recent advancements in multidisciplinary treatments, the overall survival and quality of life of patients with advanced head and neck squamous cell carcinoma (HNSCC) have not improved significantly over the past decade. Molecular targeted therapies, which have been addressed and advanced by the concept of “oncogene addiction”, have demonstrated only limited successes so far. To explore a novel clue for clinically effective targeted therapies, we analyzed the molecular circuitry of HNSCC through the lens that HNSCC is an evolving system. In the trajectory of this somatic evolution, HNSCC acquires biological robustness under a variety of selective pressures including genetic, epigenetic, micro‐environmental and metabolic stressors, which well explains the major mechanism of “escaping from oncogene addiction”. On the other hand, this systemic view appears to instruct us approaches to target latent vulnerability of HNSCC that is masked behind the plasticity and evolvability of this complex adaptive system.

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There is an urgent need to develop a novel conceptual framework for the treatment of HNSCC.

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The biological robustness of HNSCC was analyzed through a somatic evolution model.

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This model well explains the mechanism of “escaping from oncogene addiction”.

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We discuss about the possible approaches to target vulnerability of evolving HNSCC.

Multi-institutional analysis of early glottic cancer from 2000 to 2005

BACKGROUND

The purpose of this study is to analyze the outcome of patients with early glottic cancer (GC) treated with radiotherapy (RT) with or without chemotherapy at 10 institutions in the Tokai District, Japan.

METHODS

Ten institutions combined data from 279 patients with T1-T2 GC treated with RT with or without chemotherapy between 2000 and 2005. The overall survival rate, disease-specific survival rate, and local control rate were evaluated in 270 patients, except for incomplete cases due to issues such as discontinuation, using the method of Kaplan-Meier and compared using the log-rank test. Results were considered statistically significant at the level of p < 0.05.

RESULTS

For 122 patients, the tumors were classified as T1a, while 64 patients had T1b tumors, and 84 patients had T2 tumors. In three cases of T1 tumors, the subtype was unknown. Combined chemoradiotherapy (CRT) was administered during each stage, and various chemotherapy drugs and regimens were used. The median follow-up period was 55.4 months. The 5-year LC rates for T1a, Tb, and T2 tumors in all patients were 87.9%, 82.7%, and 74.1%, respectively. The difference between T1a and T2 was statistically significant (p = 0.016). The 5-year LC rates for T1a, Tb, and T2 with CRT were 92.7%, 78.6%, and 80.7%, respectively, while the rates with radiation alone were 86.5%, 83.8%, and 64.4%, respectively. The difference between CRT and RT alone was not statistically significant in each stage.

CONCLUSIONS

In this survey, CRT was performed for early GC at most institutions in clinical practice. Our data showed no statistical difference in the LC rates between CRT and RT alone in each stage. However, there was a tendency for the LCRs of the CRT group to be more favorable than those of the RT group in the T2-stage.

Definitive radiotherapy for early stage glottic cancer by 6 MV photons

Purpose

To evaluate the clinical outcome of early glottic cancer (GC) treated by primary radiotherapy (RT) with 6 MV photons.

Methods and materials

We retrospectively reviewed the medical records of 695 consecutive patients with T1N0 and T2N0 GC treated between 1983 and 2005 by RT in our institution. Clinical outcome in terms of local control (LC), overall survival (OS) and cause- specific survival (CSS) rate were evaluated.

Results

The median follow-up time was 10.5 years. The 10-year actuarial LC rates were as follows: T1A, 91%; T1B, 87%; T2, 77%. The 10-year OS were as follows: T1, 74.2%; T2, 70.7%. The 10-year CSS were as follows: T1, 97.7%; T2, 97.1%.

Poorly differentiated histology and tumor biologically effective dose < 65 Gy₁₅ were adverse factors in both LC of T1 and T2 disease. Involvement of anterior commissure was an adverse factor in both LC and CSS of T1 disease. Subglottic extension was associated with poor LC in T2 disease whereas hemoglobin <13.0 was associated with poor LC and CSS of T2 disease.

Conclusion

Primary RT remains an option among the various standard treatments for early GC. Clinical treatment outcome by 6MV photons is similar and comparable to historic data of Cobalt-60 and 2 MV photons.