Early-stage squamous cell carcinoma of the glottic larynx managed with radiation therapy

Radiotherapy after Partial Laryngectomy: An Analysis of 36 Cases and a Proposal to Optimize Radiotherapy

Aims and background

Laryngeal cancer treatment options include radical surgery, “organ preservation surgery”, radiotherapy and chemotherapy. There is no proven evidence of a significant increase in late toxicity with adjuvant radiotherapy after conservative surgery. The aim of this retrospective study was to evaluate the toxicity, local-regional control and overall survival of adjuvant radiotherapy after conservative surgery.

Methods

A total of 36 patients was treated with radiotherapy after partial laryngectomy at the Radiotherapy Department of the Institute for Cancer Treatment and Research (IRCC) of Candiolo and of the Mauriziano Hospital in Turin, between 1994 and 2007. The postoperative treatment doses ranged from 45 to 70.2 Gy with conventional fractionation. The Kaplan-Meier method was applied for statistical analysis. The RTOG-EORTC scale was used to evaluate late and acute toxicity.

Results

Overall 5- and 10-year survival was 93% and 47%, respectively. Local control was 93.5% at 5 and was unchanged at 10 years. Grade 2 acute cutaneous and mucous toxicity was 41% and 62%, and grade 3, 6.9% and 3.5%, respectively. Only one patient required percutaneous endoscopic gastrostomy due to severe dysphagia and one patient required temporary tracheostomy for severe acute laryngeal edema (grade 3). Two patients experienced late toxicity greater than grade 3. The median dose to the residual larynx was 59.5 Gy (range, 45–70.2), and the median dose to the neck was 50.4 Gy (range, 39.6 −55.8).

Conclusions

The results of our study showed a dose-dependent increase in the late toxicity trend at doses over and above 60 Gy, which is higher than the cutoff dose reported in the literature. There was no indication from our data that adjuvant postoperative radiotherapy means additional toxicity. The use of highly conformal techniques can further reduce toxicity of the radiotherapy.

Structures constituting the sound source after the treatment of early glottic cancer

INTRODUCTION

We indicate the exclusive radiation therapy as initial approach for T1a glottic tumors, and the frontolateral laryngectomy for the tumors staged as T1b and selected T2 glottic tumors. The videolaryngostroboscopy is a useful tool to analyze the laryngeal structural changes and compensatory motion after the therapeutic approach.

OBJECTIVES

To evaluate the endolaryngeal structures of patients who participate in the vibratory sound source after the early glottic cancer treatment through the videolaryngostroboscopy.

METHODS

It was a retrospective transversal study in which 20 patients who underwent exclusive radiation therapy and 25 patients who underwent frontolateral laryngectomy were analyzed by means of videolaryngostroboscopy. The radiation doses ranged from 5000 to 7020 cGy in the radiation therapy group. The mucosal wave and the vibratory source components were evaluated.

RESULTS

All of the irradiated patients presented vibratory behavior, and hyperfunction was occasionally observed in four cases. The mucosal wave source was glottic in 18 cases and mixed in two cases. In the laryngectomy group, 10 supraglottic sources, 10 glottic sources, and five mixed sources were identified. Among the 10 cases of supraglottic source, eight patients presented global constriction and two patients presented medial constriction. Among the five cases of mixed source, two patients presented global constriction, one patient presented medial constriction, and one patient presented anteroposterior constriction. Regarding the number of anatomical structures presenting vibratory pattern, five patients had two structures, four patients had three structures, and one patient had four structures.

CONCLUSION

Patients who underwent radiation therapy recruit less supraglottic structures as vibratory source than the patients undergoing vertical laryngectomy.

Laryngeal carcinoma in nonsmoking patients

OBJECTIVES

Smoking is a known risk factor for laryngeal carcinoma. We sought to describe the clinicopathologic characteristics and outcomes of nonsmoking patients with laryngeal carcinoma.

METHODS

Of 1,443 patients treated for laryngeal carcinoma between 1960 and 2006, 55 (3.8%) were nonsmokers: 40 (73%) had never smoked and 15 (27%) had stopped smoking 12 years or more before diagnosis. Patient characteristics and outcomes were reviewed.

RESULTS

The study group consisted of 87% men; the mean age at diagnosis was 67 years. All lesions but one were located in the glottis. The 5-year survival rate for the whole group was 85%. Most tumors were detected early. Of 38 patients (69%) with stage T1 disease, there was no significant difference in prognostic features between those who had never smoked and those who had smoked in the past.

CONCLUSIONS

Fewer than 5% of patients with laryngeal carcinoma were nonsmokers. Like smokers, this subgroup was characterized by a male predominance and an approximate age at diagnosis in the seventh decade. Unlike smokers, nonsmokers show a greater predilection for glottic rather than supraglottic disease. There was no difference in prognosis between smokers and nonsmokers, regardless of whether they had smoked in the past.

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.

Evaluation of underdosage in the external photon beam radiotherapy of glottic carcinoma: Monte Carlo study

PURPOSE

Underdosage in the human larynx may be the true factor behind the decrease in local control rates.

PATIENTS AND METHODS

To evaluate underdosage with Monte Carlo a CT-based geometrical model of the patient's neck (mathematical neck) was created. Dose was calculated for a pair of 6 Me V parallel-opposed photon beams modulated with 15 degree steel wedges.

RESULTS

At least 5% of volume of 3.5 cm(3) hypothetical tumor near the air wall of the larynx receives less than 86% of the maximum tumor dose. The same volume received less than 91% of the maximum tumor dose when the mathematical neck had no air cavities.

CONCLUSIONS

We conclude the significant underdosage at the air-tissue interface in the larynx occurs in traditional radiotherapy treatments, especially in the glottic part of the larynx.

[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.

Radiotherapy with 6-megavolt photons for early glottic carcinoma: potential impact of extension to the posterior vocal cord

PURPOSE

Radiation therapy has a high success rate in the treatment of early glottic carcinoma. Excellent outcomes have been reported from centers using cobalt-60 or relatively low-energy (< or = 4 MV) radiation therapy to achieve these results. Whether similar outcomes can be achieved with a 6 MV linear accelerator has been less rigorously evaluated. This study assesses the efficacy of 6 MV radiation therapy for early stage glottic cancer and identifies prognostic factors for local control and overall survival in this common disease.

MATERIALS AND METHODS

One hundred twenty-eight consecutive cases of Tis, T1, and T2 squamous cell carcinomas of the glottis from 1982 to 1996 were retrospectively analyzed with regard to local control and survival. All patients were treated with definitive radiation therapy with a 6-MV linear accelerator. Potential prognostic factors for local control and survival were evaluated with univariate and multivariate models. Median follow-up of locally controlled patients was 65 months.

RESULTS

The overall 3-year actuarial local control rates for T1 and T2 carcinomas were 86% and 68%, respectively. Patients with lesions involving the posterior third of the vocal cord had significantly worse 3-year local control (76% vs. 86%, P =.038). Radiation therapy technique and overall treatment time did not significantly affect local control. For patients with Tis and T1 lesions, factors associated with significantly worse local control included cordectomy-ineligible disease (P =.024), dose less than 6,600 cGy (P =.024), and lesions limited to the posterior third of the vocal cord (P =.004). Three-year local control was 76%, with doses less than 6,600 cGy and 90% with higher doses. High rates of second primary malignancies were observed and represented the major cause of death. Five-year overall survival was 84%.

CONCLUSIONS

The use of 6-MV photons for treatment of early glottic cancer seems to achieve local control similar to that reported with lower-energy photons. However, patients with posterior third involvement had a poorer local control rate with standard radiation therapy, thereby suggesting that alternative approaches be considered.

Salvage surgery for patients with recurrent squamous cell carcinoma of the upper aerodigestive tract: when do the ends justify the means?

OBJECTIVES/HYPOTHESES

Salvage surgery is widely viewed as a "double-edged sword." It is the best option for many patients with recurrent cancer of the upper aerodigestive tract, especially when original therapy included irradiation, yet it may provide only modest benefit at high personal cost to the patient. The stakes are high because alternatives are of limited value. The primary objective of this study was to fully assess the value of salvage surgical procedures in the treatment of local and regional recurrence. The following hypotheses were developed to focus the study design and data analysis. 1) The efficacy of salvage surgery correlates recurrent stage, recurrent site, and time to presalvage recurrence. 2) The economic and noneconomic costs of salvage surgery increase with higher recurrent stage. 3) Information relating the value of salvage surgery to recurrent stage and recurrent site will be useful to these patients and the physicians who treat them.

STUDY DESIGN

Two complimentary methods of investigation were used: a meta-analysis of the published literature and a prospective observational study of patients undergoing salvage surgery for recurrent cancer of the upper aerodigestive tract.

METHODS

The meta-analysis combined 32 published reports to obtain an estimate of average treatment effect for salvage surgery with regard to survival, disease-free survival, surgical complications, and operative mortality. The prospective observational study included detailed data in 109 patients who underwent salvage surgery. In addition to parameters studied in the meta-analysis, we obtained baseline and interval quality of life data (Functional Living Index for Cancer [FLIC] scores), baseline and interval performance status evaluations (Performance Status Scale for Head and Neck Cancer Patients [PSS head and neck scores]), length of hospital stay, and hospital and physician charges, and related this data primarily to recurrent stage, recurrent site, and time to presalvage recurrence.

RESULTS

The weighted average of 5-year survival in the meta-analysis was 39% in 1,080 patients from 28 different institutions. In the prospective study, median disease-free survival was 17.9 months in 109 patients, and this correlated strongly with recurrent stage, weakly with recurrent site, and not at all with time to presalvage recurrence. Noneconomic costs for patients and economic costs correlated with recurrent stage, but not with site. Baseline FLIC and PSS head and neck scores correlated with recurrent stage, but not with site. After salvage surgery the percentage of patients reaching or exceeding baseline was 51% for FLIC scores, and this differed significantly with recurrent stage. Postoperative interval "success" in PSS head and neck subscale scores for diet and eating in public also correlated with recurrent stage.

CONCLUSIONS

Overall, the expected efficacy for salvage surgery in patients with recurrent head and neck cancer was surprisingly good, but success was limited and costs were great in stage III and, especially, in stage IV recurrences. A strong correlation of efficacy and noneconomic costs with recurrent stage allowed the creation of expectation profiles that may be useful to patients. Additional systematic clinical research is needed to improve results. In the end, the decision to undergo salvage surgery should be a personal choice made by the patient after honest and compassionate discussion with his or her surgeon.

Has radiotherapy become too expensive to be considered a treatment option for early glottic cancer?

BACKGROUND

External beam radiotherapy and surgery produce equivalent long-term survival and tumor control in early glottic cancer. The expense and cost of radiotherapy have been challenged.

METHODS

A retrospective review was performed for 57 patients undergoing radiotherapy for glottic cancer. End points included local tumor control, relapse-free survival, cause-specific survival, medical charges, and costs. The results were compared with those of 265 patients who underwent transoral endoscopic removal or an open laryngeal procedure at the same institution.

RESULTS

The local control, larynx preservation, re-treatment, voice quality, relapse-free survival, and cancer death results and medical charges and costs are reported by treatment.

CONCLUSIONS

Radiotherapy provides at least equivalent, if not superior, local tumor control, larynx preservation, voice quality, and survival, compared with the surgical options. Overall medical charges and costs for radiotherapy are similar to transoral endoscopic resection and less than partial vertical laryngectomy.

Radiotherapy for early vocal cord cancer: a dosimetric analysis of 60CO versus 6 MV photons

BACKGROUND

Currently, many patients with early vocal cord cancers are treated with 6 MV photons, but almost all the published radiotherapy data are based on patients treated with 60Co, 2-MV, or 4-MV X-rays. A theoretical risk of underdosage exists with higher energy beams due to lack of dose build-up. This dosimetric study compares 6-MV photons with 60Co.

METHODS

A tissue-equivalent phantom was constructed of a stack of 0.5-cm-thick acrylic plates. With a male subject in treatment position as the model, the external surfaces of the phantom were machined to match the contour of the neck. To precisely represent the internal contour of the airway, computed tomography (CT) was performed on the subject in treatment position, with images at 0.5-cm intervals, and the airway shown on the CT was cut out of each corresponding acrylic plate. Thermoluminescent dosimetry (TLD) rods were inserted into the phantom. For each measurement, a calculated tumor dose of 10 Gy was delivered to the volume specified as the entire right true vocal cord in the phantom, with either 60Co or 6-MV photons (15 measurements were made with each). In a second series of eight experiments with each modality, TLD minichips were used to measure the dose received by the immediate surface of the vocal cords with delivery of a calculated tumor dose of 0.5 Gy.

RESULTS

The doses received at the vocal cords, as well as a point 6 mm beneath the anterior skin surface, did not differ significantly for the two energies compared. The dose delivered to the skin and a point 3 mm beneath the anterior skin surface was significantly lower with the use of 6-MV photons.

CONCLUSION

Although there is no difference in the dose received by the vocal cords, underdosage of the anterior tissues may occur with the use of 6-MV photons.

Radiation therapy for glottic cancer using 6-MV photons

BACKGROUND

It has been recommended that cobalt-60 or 4-MV photons be used when treating glottic cancer with radiation therapy. Underdosing may occur when using higher energy photons, particularly when the anterior commissure is involved. The authors report their experience using higher energy photons (6 MV) for the treatment of glottic cancer.

METHODS

Between January 1975 and July 1991, 73 patients with Tis, T1, T2, or T3 glottic tumors underwent radiation therapy with curative intent. Cobalt-60 or 4-MV photons were used to treat the cancers of 30 patients, and 6-MV photons were used to treat 43 patients. Clinical records were reviewed retrospectively to determine patterns of treatment failure, cancer deaths, and local tumor control in the 43 patients receiving treatment with 6-MV photons. Patients were followed until death or for a minimum of two years.

RESULTS

Treatment failures were: local recurrence, one patient; local recurrence and distant metastasis, one patient; delayed neck metastasis, two patients; and delayed neck metastasis with distant metastasis, one patient. Three patients who had treatment failure are alive and free of cancer after salvage treatment. Two patients died of neck and distant metastases. The 2-year initial local tumor control rate was 94.8%.

CONCLUSIONS

Glottic cancer can be treated successfully with 6-MV photons. Local tumor control is similar to that reported using cobalt-60 or 4-MV photons.

Head and neck cancer

This synthesis of the literature on radiotherapy for head and neck cancer is based on 424 scientific articles, including 3 meta-analyses, 38 randomized studies, 45 prospective studies, and 246 retrospective studies. These studies involve 79174 patients. The literature review shows that radiotherapy, either alone or in combination with surgery, plays an essential role in treating head and neck cancers. When tumors are localized, many tumor patients can be cured by radiotherapy alone and thereby maintain full organ function (1, 2). Current technical advancements in radiotherapy offer the potential for better local tumor control with lower morbidity (3). This, however, will require more sophisticated dose planning resources. To further improve treatment results for advanced tumors, other fractionation schedules, mainly hyperfractionation, should be introduced (5). This mainly increases the demands on staff resources for radiotherapy. The combination of radiotherapy and chemotherapy should be subjected to further controlled studies involving a sufficiently large number of patients (4, 5). Interstitial treatment (in the hands of experienced radiotherapists) yields good results for selected cancers. The method should be more generally accessible in Sweden. Intraoperative radiotherapy should be targeted for further study and development.