Early-stage glottic cancer: importance of dose fractionation in radiation therapy

Hypofractionated radiotherapy versus conventional radiotherapy in early glottic cancer T1-2N0M0: A randomized study

Objective

Glottic cancer has an excellent probability of cure. The early glottic cancer is usually treated by radiotherapy with different fractionation schedules. The aim of this study was to compare conventional versus hypofractionated radiotherapy with respect to overall survival and disease-free survival.

Materials and Methods

A total of fifty patients with T1-2N0M0 glottic cancer with no previous treatment history were prospectively randomized into two arms. In Arm A (Study), patients received a total of 55 Gy in 20# at 2.75 Gy/#, 5 days a week. In Arm B (Control), patients received a total of 66 Gy in 33# at 2 Gy/#, 5 days a week. Disease response was evaluated by the WHO criteria at the end of treatment, then at 1, 2, and 3 months to complete their 6-month follow-up. Overall survival and disease-free survival were evaluated at 1, 2, and 3 years.

Results

Overall, 100% of patients in the study arm and 96% of patients in the control arm had complete response after 6 months. Overall survival rates at 1, 2, and 3 years were 96%, 96%, and 88%, respectively, in the study arm, while in the control arm, these values were 92%, 84%, and 80%, respectively, and the difference was not statistically significant (P > 0.05). Disease-free survival at 3 years was 88% in the study arm and 80% in the control arm.

Conclusion

The study suggests that hypofractionated regimen may be better in local control and symptomatic relief with the added advantage of shorter treatment time, which offers better patient compliance and advantageous in busy setups where there is heavy patient load.

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.

Salvage radiotherapy for recurrent hypopharyngeal and laryngeal squamous cell carcinoma (SCC) after first-line treatment with surgery alone: a 10-year single-centre experience

Purpose

Salvage surgery of recurrent hypopharyngeal and laryngeal squamous cell carcinoma (SCC) results in limited local control and survival rates. As a result of recent technological progress, radiotherapy (RT) has become a valuable, potentially curative therapeutic option. Thus, we aimed to determine prognostic factors for survival outcome in order to optimize patient selection for salvage radiotherapy after failure of first-line treatment with surgery alone in this special patient cohort.

Methods

Seventy-five patients (85% male, median age of 64 years) underwent salvage RT in a secondary setting for recurrent hypopharyngeal or laryngeal SCC after prior surgery alone between 2007 and 2017. On average, patients were treated with one prior surgery (range 1–4 surgeries). Median time between surgery and salvage RT was 7 months (range 1–47 months) for initially advanced tumors (T3/4, N+, extracapsular spread) and 18 months (range 5–333 months) for initially early stage tumors. The majority of patients received concomitant chemotherapy (n = 48; 64%) or other kind of systemic treatment concurrent to radiotherapy (n = 10; 13%).

Results

Median follow-up was 41 months (range 3–120 months). Overall, fifteen patients were diagnosed with local failure (all were in-field) at last follow-up (20%). Median time to recurrence was 35 months (range 3–120 months) and 3-year local progression-free survival (LPFS) was 75%, respectively. Dose-escalated RT with 70.4 Gy applied in 2.1 Gy or 2.2 Gy fractions corresponding an EQD2 > 70 Gy (p = 0.032) and the use of concomitant cisplatin weekly chemotherapy (p = 0.006) had a significant positive impact on LPFS. 3-year OS and DPFS were 76 and 85%, respectively. No toxicity-related deaths occurred. Reported grade > 3 side effects were rare (n = 4/70, 6%).

Conclusion

Salvage radiotherapy resulted in excellent local control rates while radiation dose and the use of cisplatin weekly chemotherapy were identified as prognostic factors for LPFS. Nevertheless, patient selection for curative salvage treatment remains challenging.

Radiotherapy for T1 Carcinoma of the Glottis

Aims and background

The management of patients with T1 carcinoma of the glottic larynx is controversial, because surgery and radiation therapy are reported to be effective treatments. Several studies have shown radiotherapy to be safe and effective, with a high percentage of voice preservation and minimal complications, but most Italian physicians prefer to surgically treat such patients.

Methods

From 1980 to 1990, 36 patients with stage I squamous cell glottic carcinoma were treated with radiotherapy alone at the Institute of Radiology of University of Rome “La Sapienza”. In all patients the irradiation fields were limited to the larynx, with field size ranging from 4 × 4 cm to 7 × 7 cm. Total tumor doses ranged between 51 and 70 Gy (median 60 Gy) with a mean number of 30 fractions of 2 to 3 Gy per fraction (3 or 5 fractions per week).

Results

After a median follow-up of 98 months, we observed an overall survival rate at 5 years of 91.4% and actuarial 10-year survival of 85.7%. Local control was achieved in 97.1% of cases, with an event-free survival of 94.2% at 5 and 10 years. No major complications like necrosis or persistent edema of the larynx were observed. Minor complications like dysphonia (8%) and dysphagia (5.5%) were temporary; laryngeal function was completely preserved at the end of therapy. Final voice quality ranged from good to excellent.

Conclusions

Our series confirms that radiation therapy has a major role in the management of early glottic cancer, with results comparable to surgical approaches and with better voice preservation.

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 .

Cisplatin-based chemotherapy versus cetuximab in concurrent chemoradiotherapy for locally advanced head and neck cancer treatment

BACKGROUND AND PURPOSE

This study aimed to analyze survival, clinical responses, compliance, and adverse effects in locally advanced head and neck cancer (LAHNC) patients treated with split-dose cisplatin-based concurrent chemoradiation therapy (SD-CCRT) or cetuximab with concurrent radiation therapy (BioRT).

MATERIALS AND METHODS

We retrospectively evaluated 170 LAHNC patients diagnosed between January 1, 2009, and July 31, 2012: 116 received CCRT and 54 received BioRT.

RESULTS

Complete response rates were similar in the SD-CCRT and BioRT groups (63.8% versus 59.3%; P = 0.807), and locoregional relapse rates were 18.1% and 13.0%, respectively (P = 0.400). The 3-year relapse-free survival rate was 65.8% in the SD-CCRT group and 65.5% in the BioRT group, respectively (P = 0.647). The 3-year overall survival rate was 78.5% in the SD-CCRT group and 70.9% in the BioRT group, respectively (P = 0.879). Hematologic side effects were significantly more frequent in the SD-CCRT than in the BioRT group. Mucositis frequency was similar.

CONCLUSIONS

Primary SD-CCRT and BioRT both showed good clinical response and survival. Hematologic toxicities were more frequent, but tolerable, in the SD-CCRT group. Both groups showed good compliance.

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.

Outcome of T1N0M0 squamous cell carcinoma of the larynx treated with short-course radiotherapy to a total dose of 50 Gy in 16 fractions: the Birmingham experience

AIMS

To review the results of hypofractionated radiotherapy in T1N0M0 squamous cell carcinoma of the larynx.

MATERIALS AND METHODS

A series of 100 patients treated with radiotherapy between 1993 and 2001 was reviewed. The median age was 67 years. The median follow-up was 7 years (range 3-14 years). Radiotherapy was delivered to a total dose of 50 Gy in 16 fractions treating daily, 5 days a week over 21 days.

RESULTS

Locoregional control rates with radiotherapy alone were 92% at 2 years and 88% at 5 years. After salvage surgery, the ultimate locoregional control rate was 96%. The relapse-free survival rates at 2 and 5 years were 85 and 70%, respectively. The cause-specific survival rates at 2 and 5 years were 99 and 97%, respectively. Overall survival rates at 2 and 5 years were 91 and 76%, respectively. Second primary cancers occurred in 21% of patients, primarily in the lung.

CONCLUSIONS

Radiotherapy to a total dose of 50 Gy in 16 fractions for T1N0M0 squamous cell carcinoma of the larynx offers high locoregional control rates with voice preservation. These results from a hypofractionated radiotherapy schedule are comparable with other longer fractionation schedules and offer potential for optimising resource usage.

[Results of radiotherapy in elderly patients with early laryngeal cancer]

Evaluation of the results of radiotherapy in elderly patients with early laryngeal cancer, the relation between comorbidities and the overall treatment time, and the influence of treatment interruptions on the outcome of treatment.

MATERIALS AND METHODS

A clinical retrospective analysis of a group of 117 patients (over the 70 years old) with early laryngeal cancer was carried out. Patients were irradiated between the years 1980 and 2000 in the Centre of Oncology in Cracow. The analysed group consisted of 105 men (90%) and 12 women (10%). Patients' age ranged from 70 to 87 years, median - 73 years. Most of them had various comorbidities. Three different irradiation techniques and fractionation schemes were used according to the site, stage and grade of cancer: two oblique beams including the larynx with total dose of 60 Gy in 24 fractions (46 patients), two parallel opposing beams including the larynx and cervical lymph nodes with total dose of 60 Gy in 30 fractions (38 patients), and mixed photon-electron unilateral beam including the larynx with total dose of 60 Gy in 30 fractions (33 patients).

RESULTS

The median follow-up was 48 months. During the follow-up period 78 patients (66.6%) died. Among them 29 patients (37.2%) died of laryngeal cancer, 6 (7%) patients of other malignancy, and 43 (55%) patients died of concomitant diseases without evidence of cancer. The actuarial 5/10-year overall survival (OS) and disease specific survival (DSS) were 51%/23% and 77%/68%, respectively. The overall tolerance of radiation therapy was good; only 3 patients had G3 early mucosal reaction, and 1 patient had G3 early skin reaction were observed. Comorbidities were not demonstrated to have statistically significant influence on DSS rate. In 6 (5.1%) from 117 patients complete tumor regression was not achieved after radiotherapy. During the follow-up period loco-regional relapse were observed in 27 patients (23.5%), and distant metastases in 2 patients (1.7%).

CONCLUSIONS

Radiotherapy of the elderly patients with laryngeal cancer is effective and well tolerated method. Comorbidities do not significantly influence the treatment results. T stage, localization in supraglottic area, age over 73 years old, fractionation dose under 2 Gy and overall treatment time over 43 days are statistically significant negative prognostic factor for DSS rate.

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.

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.

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.

Patterns of failure in patients receiving definitive and postoperative IMRT for head-and-neck cancer

PURPOSE

To analyze the patterns of locoregional failure in patients with head-and-neck cancer treated with inverse planning intensity-modulated radiotherapy (IMRT).

METHODS AND MATERIALS

Between February 1997 and December 2000, 165 patients with histologically confirmed head-and-neck cancer were treated using a parotid-sparing inverse planning IMRT protocol. Thirty-nine patients who received either palliative repeat irradiation or IMRT as a boost were excluded from this analysis, leaving 126 patients for this analysis. Of the 126 patients, 30 were women and 96 were men (median age 56 years, range 13-84). Fifty-two patients (41%) received definitive IMRT. Of the 52 patients, 17 were treated with RT alone and 35 with concurrent cisplatin-based chemotherapy regimens. Seventy-four patients (59%) received postoperative IMRT. The median follow-up was 26 months (range 12-55). IMRT was used only in the upper neck for salivary sparing. The lower neck was treated with a conventional AP low-neck port abutted to the inferior IMRT dose distribution border. The radiation dose was prescribed to the two clinical target volumes (CTVs) according to the assumed risk of containing disease. The mean dose for definitive IMRT patients was 72.64 +/- 4.83 Gy to CTV1 and 64.34 +/- 5.15 Gy to CTV2. The mean dose to CTV1 and CTV2 in postoperative cases was 68.53 +/- 4.71 Gy and 60.95 +/- 5.33 Gy, respectively. The locations of failure were analyzed.

RESULTS

Seventeen locoregional failures (persistent or recurrent disease) were found. Of these 17 failures, 9 (53%) were inside CTV1. One failure (6%) was marginal to CTV1 but inside CTV2. One failure (6%) occurred outside CTV1 but inside CTV2. Another failure was marginal to CTV2. Of the 17 failures, 5 (28%) were found outside of the IMRT field and in the lower neck. Dose-volume histogram analysis revealed that for all but 1 patient, the recurrent/persistent disease within the CTVs received comparable or superior dose coverage relative to the CTV. The 2-year actuarial locoregional control rate was 85%, and the ultimate locoregional control rate after surgical salvage was 89%. We observed no dermal failure and only one marginal failure in the region adjacent to the spared parotid glands.

CONCLUSION

We have shown that the target definition and coverage for patients treated with IMRT for parotid sparing is adequate. The predominant tumor failure within CTV1 may imply the need to identify patients with radioresistant tumor subvolumes (such as hypoxic regions) within the CTV. This information would assist in discriminating a subgroup of tumors for a more aggressive and target-specific therapeutic approach.

Organ preservation strategies in the treatment of laryngeal cancer

For most patients, a total laryngectomy should not be used as the initial treatment for any stage laryngeal tumor. The goal in treating a patient with laryngeal cancer must be not only to cure but also to provide the best functional outcome for the patient. In the United States, the treatment of laryngeal cancer has moved from radical surgery toward a more conservative approach involving definitive radiotherapy and chemotherapy, with extirpative surgery held in reserve for salvage. In Europe, there has been increasing reliance on limited endoscopic cordectomy procedures for early tumors and the use of function-preserving surgical approaches for more advanced lesions. Careful monitoring of the conservatively treated patient is mandatory to allow for early salvage of failures to the original therapy. Because of the high costs of hospitalization, the direct medical costs attributable to conservative approaches are equal to or less than the costs for more radical surgical resections. Even if survivals are only equivalent, organ preservation approaches should be the treatment of choice for most patients.

[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.

Definitive radiotherapy for squamous carcinoma of the larynx

Definitive radiotherapy for T1 or T2 laryngeal carcinoma offers good local control and quality of voice. Recent clinical trials with hyperfractionated radiotherapy and concurrent chemoradiotherapy demonstrated improved rates of local control for advanced laryngeal cancer treated with primary radiotherapy and provides the opportunity for organ preservation. The use of amifostine and pilocarpine may prevent or ameliorate radiation-induced xerostomia. Recent advances in 3-D conformal radiotherapy and IMRT lead to a better dose distribution for sparing normal organs while treating target volumes with full dose.

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.

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.

Clinical radiobiology of glottic T1 squamous cell carcinoma

PURPOSE

Radiation therapy is the treatment of choice for early glottic squamous cell cancer in many institutions over the world. Despite a relatively homogenous clinical model of T1 glottic tumors for the fractionation studies, the relationships between dose-time parameters remain unclear. To analyze the influence of fractionation parameters and hemoglobin level on tumor cure, this study has been performed.

MATERIALS AND METHODS

This is a retrospective review of 235 patients with T1N0M0 glottic cancer treated by radiation therapy alone given in a conventional schedule with 5 fractions each week. The individual total dose, dose per fraction, and overall treatment time (OTT) ranged from 51-70 Gy, 1.5-3.0 Gy, and 24-79 days, respectively. The median follow-up was 48 months. Patient data--total dose, dose per fraction, OTT, and hemoglobin level (Hb) measured before the radiation treatment--were fitted by the mixed LQ/log-logistic model.

RESULTS

The 5-year local relapse-free survival rate was 84%. All parameters included in the mixed LQ/log-logistic model improved the fit significantly. The dose-response curve for 235 patients with T1 glottic cancer was well defined and steep, and showed significant decrease in tumor control probability (TCP) when total doses were below 61 Gy. The 10-day prolongation of OTT, from 45 to 55 days, decreased the TCP by 13%. The dose of 0.35 Gy/day, compensated repopulation during the 1 day of prolongation, which indicates a potential doubling time (Tpot) for glottic T1 tumor clonogens of 5.5 days. The drop of Hb level of 1 g/dl (from 13.8 g/dl to 12.8 g/dl) gave a 6% decrease of TCP, provided that OTT was 45 days.

CONCLUSION

The significant correlation between the total dose, overall treatment time, hemoglobin concentration, and tumor control probability has been found for T1 glottic cancer.

The impact of treatment time and smoking on local control and complications in T1 glottic cancer

PURPOSE

To define the optimal treatment regimen, patients with T1N0M0 glottic larynx carcinoma were treated with six different radiotherapy (RT) schedules. To assess the influence of patient characteristics, complication rates, and to evaluate the overall larynx preservation.

METHODS AND MATERIALS

Out of a consecutive series of 383 patients treated for T1N0M0 glottic larynx carcinoma between 1965 and 1992, 352 evaluable patients were treated with six different "standard" fractionation schedules: 65 Gy (20 x 3.25 Gy), 62 Gy (20 x 3.1 Gy), 61.6 Gy (22 x 2.8 Gy), 60 Gy (25 x 2.4 Gy), 66 Gy (33 x 2 Gy) and 60 Gy (30 x 2 Gy). The median follow-up of all patients was 89 months. Patient factors analyzed included: age, sex, concurrent illness, smoking habits, tumor localization and extension, tumor differentiation, the effect of tumor biopsy or stripping of the vocal cord, and the presence of visible tumor at the start of radiotherapy. Treatment parameters evaluated were: year of treatment, beam energy, treatment planning, field size, fractionation schedule, fraction size, number of fractions, total dose, treatment time and treatment gap, the use of wedges, and neck diameter.

RESULTS

The overall 5-year actuarial locoregional control was 89%, varying between 83 and 93% for the different schedules. Univariately, local control decreased with increasing treatment time. This could not be explained by the confounding variables sex, tumor extension, and field length (p = 0.0065). Adjusted for these variables, 5-year local control percentage decreased from 95% (SE 2%) for 22-29 days to 79% (SE 6%) for treatment time > or = 40 days. The overall complication rate (grade I-IV) at 5 years was 15.3%, and varied between the different schedules, from 7 to 17%. No relation was found between complications and treatment factors. Patients who continued smoking had a higher complication rate than those who never smoked or stopped smoking, univariately as well as adjusted for tumor extension, macroscopic tumor, and neck diameter (p = 0.0038). Twenty-eight percent (SE 6%) of the patients who continued smoking had complications at 10 years, compared to about 13% (SE 4%) of those who stopped before or after RT. No evidence was found for any other relation between complications and patient or tumor factors. Severe edema and necrosis (grade III and IV) were not observed in the 2 Gy fraction schedules. A laryngectomy was performed in 36 patients: 30 for recurrence, 3 for complications (at 40, 161, and 272 months), and 3 for a second primary. The overall larynx preservation was 90% at 10 years, and for the different schedules it was 20 x 3.25 Gy: 97%; 20 x 3.1 Gy: 96%; 22 x 2.8 Gy: 92%; 25 x 2.4 Gy: 89%; 33 x 2 Gy: 78%; and 30 x 2 Gy: 80%.

CONCLUSION

Overall treatment time is the most significant factor for locoregional control of T1 glottic cancer. A schedule of 25 x 2.4 Gy appeared to be the optimal treatment schedule considering both tumor control and long term toxicity. The complication rate was increased in patients who continued smoking.

Effect of tumor bulk on local control and survival of patients with T1 glottic cancer

PURPOSE

To evaluate the effect of tumor bulk in relation to various tumor-related prognostic factors and treatment-related variables on local control and survival of patients with T1 N0 M0 squamous cell carcinoma of the glottis.

MATERIALS AND METHODS

In 114 patients with T1 squamous cell carcinoma of the glottic larynx who were irradiated with curative intent, we determined the effect of tumor bulk in relation to mucosal extent (stage and anterior commissure involvement), histologic differentiation and various radiation factors, especially overall treatment time on local control and survival. Tumors were classified retrospectively as small surface lesions or bulky tumors. Seventy-seven patients had small lesions and 37 had bulky tumors. The anterior commissure was involved with cancer in 43 patients. The overall duration of irradiation ranged from 39 to 64 days. The median follow-up time was 6 years (range 5-24 years).

RESULTS

The 5-year actuarial local control rate for all patients was 82% after radiotherapy and 92% after salvage laryngectomy. On univariate analysis, bulky tumors and tumors involving the anterior commissure showed an adverse effect on local control, whereas the overall duration of irradiation had a borderline significance. The actuarial local control rate was 91% for small tumors and 58% for bulky tumors (P = 0.0002), 88% when the anterior commissure was not involved and 67% when the anterior commissure was involved (P = 0.01) and 89% when radiation was given in less than 50 days and 73% when irradiation exceeded 50 days (P = 0.06). On multivariate analysis. tumor bulk was the only significant factor that affected local control (P = 0.02). The 5-year actuarial survival for all patients was 73% and the disease-free survival was 92%.

CONCLUSION

This study shows that tumor bulk has a highly significant effect on the radiation control of T1 glottic cancer. Patients who had bulky tumors had lower local control and disease-free survival rates than those patients who had small tumors.

Quality control in planning and technique of radiotherapy with cobalt-60 for T1 glottic cancer increase local control and organ preservation

BACKGROUND

In order to evaluate whether individualized technique and dosimetry of radiotherapy increase local control, organ preservation, and survival of patients with T1 glottic cancer, we reviewed 76 cases treated from 1979 to 1993.

METHODS

Group A included 32 patients treated from 1979 to 1989 with different techniques, based on clinical aspects. Group B included 44 patients treated from 1990 to 1993 with individualized technique according to tumor extension and patient's anatomy.

RESULTS

Five-year local control with radiotherapy alone was achieved in 53% of group A versus 91% of group B (P > 0.005). Survival was similar in both groups with rescue surgery (90% versus 96%). Five-year survival with larynx preservation was 65% in group A versus 88% in group B (P = 0.02). Most recurrences (78%) appeared within 24 months of follow-up.

CONCLUSION

Adequate staging, individualized technique, computing planning using simulation and use of immobilization devices during cobalt-60 radiotherapy significantly increase local control and organ preservation in T1 glottic cancer.

Radiation therapy for early glottic carcinoma (T1N0M0). The adverse effect of treatment interruption

PURPOSE

Clarification of the adverse effects of treatment interruption on the local control of early glottic carcinoma.

PATIENTS AND METHODS

From May 1982 through February 1992, 273 patients with early glottic carcinoma (T1N0M0) were treated at this department. Of 253 patients administered 60 Gy in 30 fractions 77 patients had no treatment interruption and treatment was completed within 6 weeks (group I), overall treatment time was prolonged for 176 patients: 141 patients 43 to 49 days (group II) and 35 patients 50 to 62 days (group III). Treatment was interrupted due to public holidays (156 cases), patients convenience (13 cases) and severe mucosal reactions (seven cases). The major reason was public holidays, 91% in group II and 80% in group III.

RESULTS

The 3-year recurrence-free survival rates were for group I 95%, group II 89% and group II 80%. Survivals for groups I and II, groups II and III and groups I and III were essentially the same. At 40 Gy tumor clearance was more than 50% in the 3-groups. For complete clearance cases at 40 Gy, recurrence-free survival was essentially the same for the 3 groups although for incomplete clearance cases, statistically significant difference for groups I and III (log-rank test p = 0.0004; Wilcoxon test p = 0.0004) and marginally significant difference for groups II and III (p = 0.0157, p = 0.0045) but no difference for groups I and II (p = 0.0669, p = 0.0853) were noted by adjusting the p-value.

CONCLUSION

Prolongation of overall treatment time and tumor clearance at 40 Gy appeared to be a factor of the local control.

Influence of fraction size, total dose, and overall time on local control of T1-T2 glottic carcinoma

PURPOSE

To evaluate the influence of fraction size, overall time, total dose, and other prognostic factors on local control of T1 and T2 glottic carcinomas.

METHODS AND MATERIALS

Between 1956 and 1995, 398 consecutive patients with early glottic carcinoma (315 T1 and 83 T2) were treated with once-a-day definitive radiotherapy at the University of California, San Francisco, and associated institutions. Treatment was delivered 5 days per week. Minimum tumor dose ranged from 46.6 to 77.6 Gy (median: 63 Gy). The fraction size was < 1.8 Gy in 146; 1.8-1.99 Gy in 128; 2.0-2.24 Gy in 62, and > or = 2.25 Gy in 62 patients. Overall time ranged from 34 to 75 days (median: 50 days). The majority of patients treated with a fraction size of 2.25 Gy completed therapy within 43 days. Median follow-up of all alive patients was 116 months (range 3-436 months).

RESULTS

Five-year local control was 85% for T1 and 70% for T2 glottic carcinomas (p = 0.0004). For T1 lesions, within the dose and time range evaluated, there was no apparent relationship between fraction size, overall time, total dose, and local control on multivariate analysis. Treatment era was the only significant prognostic factor (p = 0.02), and anterior commissure (AC) involvement was of borderline significance (p = 0.056). Five-year local control was 77% for patients treated between 1956-1970, 89% for between 1971-1980, and 91% for between 1981-1995; 80% for patients with AC involvement and 88% for those without. For T2 lesions, prognostic factors for local control on multivariate analysis were: overall time (p = 0.003), fraction size (p = 0.003), total dose (p = 0.01), impaired vocal cord mobility (p = 0.02), and subglottic extension (p = 0.04). Five-year local control was 100% for T2 lesions treated with overall time < or = 43 days vs. 84% for overall time > 43 days; 100% for fraction size > or = 2.25 Gy vs. 44% for fraction size < 1.8 Gy; 78% for total dose > 65 Gy vs. 60% for total dose < or = 65 Gy; 79% for normal cord mobility vs. 45% for impaired cord mobility, and 58% for lesions with subglottic extension vs. 77% for those without. The severe complication rate for the entire group was low: 1.8%.

CONCLUSIONS

Total dose, fraction size, and overall time were significant factors for local control of T2 but not T1 glottic carcinomas. Anterior commissure involvement was associated with decreased local control for T1 but not T2 lesions. For T1 lesions, local control improved over the treatment era. For T2 lesions, local control decreased with impaired cord mobility and subglottic extension.

Definitive radiotherapy for early glottic carcinoma: prognostic factors and implications for treatment

PURPOSE

Treatment and disease-related factors were analyzed for their influence on the outcome of patients treated definitively with irradiation (RT) for early glottic carcinoma.

METHODS AND MATERIALS

One hundred two patients with stage T1 or T2 glottic carcinomas were treated definitively with RT from December 1983 through September 1993. Median follow-up time was 63 months. Factors analyzed for each patient included age, sex, stage, anterior commissure involvement, surgical alternative, histologic differentiation, field size, total dose, fraction size, and total treatment time. Survival analysis methods were employed to assess the effects of these factors on local control and complication rates.

RESULTS

The 5-year local control rates by stage were as follows: T1a, 92%; T1b, 80%; T2a, 94%; and T2b, 23%. By univariate analysis, factors found to have a significant impact on local control were stage, surgical alternative, fraction size, anterior commissure involvement, and overall treatment time. By multivariate analysis, stage, field size, and fraction size were the only significant factors that independently influenced local control.

CONCLUSION

The inferior control rate for stage T2b lesions has implications for treatment. Our study supports the conclusion of reports in the literature showing that low fraction size negatively influences outcome in patients with early glottic cancer.

Definitive radiotherapy for early glottic carcinoma: prognostic factors and implications for treatment

PURPOSE

Treatment and disease-related factors were analyzed for their influence on the outcome of patients treated definitively with irradiation (RT) for early glottic carcinoma.

METHODS AND MATERIALS

One hundred two patients with stage T1 or T2 glottic carcinomas were treated definitively with RT from December 1983 through September 1993. Median follow-up time was 63 months. Factors analyzed for each patient included age, sex, stage, anterior commissure involvement, surgical alternative, histologic differentiation, field size, total dose, fraction size, and total treatment time. Survival analysis methods were employed to assess the effects of these factors on local control and complication rates.

RESULTS

The 5-year local control rates by stage were as follows: T1a, 92%; T1b, 80%; T2a, 94%; and T2b, 23%. By univariate analysis, factors found to have a significant impact on local control were stage, surgical alternative, fraction size, anterior commissure involvement, and overall treatment time. By multivariate analysis, stage, field size, and fraction size were the only significant factors that independently influenced local control.

CONCLUSIONS

The inferior control rate for stage T2b lesions has implications for treatment. Our study supports the conclusions of reports in the literature showing that low fraction size negatively influences outcome in patients with early glottic cancer.

Early glottic cancer: the influence of primary treatment on voice preservation

PURPOSE

Retrospective analysis was performed to assess the influence of primary surgical or irradiation treatment on local control, survival, and final preservation of larynx in comparable groups of patients with T1N0 and T2N0 glottic cancer.

METHODS AND MATERIALS

Two hundred sixty-three previously untreated patients with invasive squamous cell carcinoma of the glottis (187T1 and 76T2) were treated with primary radiotherapy (159T1 and 60T2) or primary surgery (28T1 and 16T2) between January 1976 and December 1990, at the University of Ljubljana, Slovenia. Conventional one daily fraction of 2 Gy to doses of 60-74 Gy (median: 65 Gy) were used in 98% of primarily irradiated patients through out the observed period. To enable better comparison between the two treatment groups, primarily irradiated patients were retrospectively stratified by the criteria of suitability for primary voice-sparing operation. Several host, tumor, and treatment parameters were analyzed.

RESULTS

Only the stage of the disease significantly influenced both 10-year recurrence-free and disease-specific survival regardless primary treatment modality (p = 0.0002). In all primary irradiated patients local control was significantly better for those with overall treatment time of less than 48 days (p = 0.007). In patients suitable for voice-sparing operation, local control of primarily operated patients was similar to that of patients primarily irradiated with shorter overall treatment time, which was 93 and 88% for T1 and 67 and 64% for T2 tumors, respectively. Ultimate local control in primary surgery and radiotherapy group was 96 and 96% for T1 and 89 and 88% for T2 tumors, respectively. Equal larynx preservation of 100% in T1 and 90% in T2 patients was achieved in finally cured primarily operated patients and those patients primarily irradiated with a shorter overall treatment time. If treatment time was longer than 48 days, significantly worse final larynx preservation of 84% in T1 and 75% in T2 patients was observed (p = 0.003). In patients unsuitable for voice sparing operation, 87% of T1 and 50% of T2 patients in primary radiotherapy group finally had their larynx preserved.

CONCLUSION

Stratification based on criteria of possibility for initial voice-sparing operation is important when comparing primary surgery with primary radiotherapy treatment in early glottic cancer. The detrimental effect of prolonged treatment time of irradiation resulted not only in inferior local control rate but also in worse final larynx preservation.

The effect of overall treatment time of radiation therapy on local control of T1-stage squamous cell carcinoma of the glottis

From 1975 to 1990, 72 patients with T1 glottic cancer, excluding a verrucous type of carcinoma, were treated with radiation therapy (RT). All treatments were given with a standard fractionation of 2 Gy per day. The total dose to the tumor ranged from 60 to 70 Gy. Six patients received a split-course RT. The overall local control rate was 87% at 5 years. Forty-one patients who completed RT in 45 days or less had a 5-year local control rate of 95%. Sixteen patients who completed a treatment course in 46 to 49 days had a local control rate of 81%. Fifteen patients with a treatment course of more than 50 days had a local control rate of 73%. There was a statistically significant difference in local control rates among the three groups (P<.05). The split-course RT group had a 5-year local control rate of 50%; that rate was statistically significantly inferior to that of the continuous course group (P<.001). Multivariate analysis also showed that an interruption of the treatment course was an important parameter in relation to the local control. The prolongation of standard RT schedules adversely affected local control of T1 glottic carcinoma and, therefore, should be avoided whenever possible.

Radiation therapy in early carcinoma of the glottic larynx T1N0M0

PURPOSE

The Purpose of this report is to present the local control rate and survival of patients treated by radiation therapy for T1N0M0 squamous cell carcinoma of the glottic larynx.

METHODS AND MATERIALS

A total of 41 patients with squamous cell carcinoma of the glottis were treated at the Veterans Administration Medical Center Minneapolis, MN, between 1976 and 1990. Of the 41 patients, 40 are available for retrospective analysis with a minimum of a 2-year follow-up and a median follow-up of 5.8 years. Treatment was given to all the patients by a 4 MeV linear accelerator. The vast majority of the patients were treated with bilateral laryngeal opposed wedged 6 x 6 cm fields with a dose of 1.75 Gy per fraction to a total of 70 Gy in 40 fractions over 56 elapsed treatment days.

RESULTS

The data indicated local control and survival of 92.3 % at 2 years and 91.8 % at 3 years, post irradiation, with ultimate disease-free survival after surgical salvage of 97.4 % and 97.2 % at 2 years and 3 years, respectively. These local control and survival rates are comparable to those published in the literature when a higher fractional dose was given. No patients developed notable complications with our technique.

CONCLUSIONS

A dose of 1.75 Gy to 1.8 Gy per fraction to a total of 70 Gy in 56 elapsed treatment days is well tolerated and yields ultimate disease free-survival of 97.2% at 3 years. This time-dose fractionation could be used safely for treating patients who demonstrate low tolerance to irradiation with a risk of laryngitis, laryngeal edema, or difficulty of swallowing, with a higher fractional dose.

Radiation therapy for T1,2 glottic carcinoma: impact of overall treatment time on local control

PURPOSE

Local control probabilities of T1,2 glottic laryngeal cancer were evaluated in relation to dose and fractionation of radiation therapy (RT).

MATERIALS AND METHODS

Between 1975 and 1993, 96 T1N0M0 glottic cancers and 32 T2N0M0 glottic cancers were treated with definitive RT. Total RT dose was 60-66 Gy/2 Gy for most of the T1 and T2 tumors, although 10 T2 tumors were treated with hyperfractionation (72-74.4 Gy/1.2 Gy bid). Of the 128 patients, 90 T1 glottic tumors and 30 T2 glottic tumors were followed for > 2 years after treatment. Multivariate analyses using the Cox proportional hazards model and a logistic regression analysis were performed to evaluate the significance of prognostic variables on local control.

RESULTS

The 5-year local control probability for T1 tumors was 85%, whereas that for T2 tumors was 71%. Multivariate analyses demonstrated that only overall treatment time (OTT) was a significant variable for local control. Total RT dose, normalized total doses at a fraction size of 2 Gy, and fraction size were not significant. Local control probability of T1 tumors with an OTT of 42-49 days was significantly higher than that of tumors with an OTT of > 49 days (P < 0.02). Only a 1-week interruption of RT, due to holidays, significantly reduced the 5-year local control probability of T1 glottic tumors from 89 to 74% (P < 0.05).

CONCLUSIONS

These results indicate that OTT is a significant prognostic factor for local control of T1 glottic tumors.

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

PURPOSE

To evaluate treatment and patient related prognostic factors that may influence local control in the treatment of T1-T2 squamous cell carcinoma of the glottic larynx.

METHODS AND MATERIALS

One hundred nine patients with invasive, previously untreated T1-T2 squamous cell carcinoma of the glottic larynx were treated with curative intent with radiotherapy at the Fox Chase Cancer Center between June 1980 and November 1991. Follow-up ranged from 26-165 months (mean 83 months).

RESULTS

The 2-year local control rates for patients with T1 and T2 lesions were 89% and 80%, respectively. The 2-year local control rate for patients whose overall treatment time was < 50 days was 92% vs. 82% for patients whose overall treatment time was > 50 days (p = 0.07). The 2-year local control rate for patients treated with an irradiated area < 36 cm(2) was 90% compared to 86% in patients who were treated to an area > or = 36 cm(2). The 2-year local control rate for patients treated with 60Co was 83% vs. 92% for patients treated with 6 MV x-ray. Cox proportional hazards regression analysis was performed using the following variables: treatment energy, irradiated area, gender, tobacco pack years, tumor differentiation, overall treatment time, total dose, dose per fraction, and T stage. Overall treatment time (p = 0.05) was the only variable that significantly influenced local control.

CONCLUSION

Extending the overall treatment time was found to adversely influence local control. Neither the irradiated area nor treatment energy was found to influence local control in early stage vocal cord carcinoma.

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.

Primary radiotherapy of T1 and T2 glottic carcinoma--analysis of treatment results and prognostic factors in 223 patients

Treatment results in 223 patients with T1 and T2 glottic carcinoma were analysed. A multivariate analysis was performed to evaluate the prognostic significance of factors related to tumour, patient and treatment. Locoregional control after radiotherapy was 90% for 129 patients with T1 tumours and 73% for 94 with T2 tumours. Disease-specific survival was 96% and 81% for patients with T1 and T2 tumours, respectively. In the multivariate analysis of locoregional control, subglottic extension contributed prognostic information to T-stage. In the univariate analysis, number of involved tumour sites, cord mobility and treatment interruption had a significant influence, which was lost in the multivariate analysis. Age gave additional prognostic information in the multivariate analysis of disease-specific survival. Significant adverse effects of radiotherapy were found in 9 patients (4%). Forty-nine patients (22%) had a second malignancy, 11 (5%) diagnosed before the glottic carcinoma.

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.

Radiation therapy in early glottic carcinoma: uni- and multivariate analysis of prognostic factors affecting local control

PURPOSE

The purpose of this report is to clarify prognostic factors affecting local control of T1 and T2 glottic tumors and to define an optimal regimen for radiation therapy.

METHODS AND MATERIALS

Two hundred and ten patients (199 males, 11 females, age range 30 to 86 years with an average of 62 years) with previously untreated invasive squamous cell carcinoma of the glottis were treated with radiation therapy at the University of Tokyo between January 1972 and December 1989. Endoscopic microsurgery was introduced as an integral part of treatment in 1974. From 1974 to 1979 the radiation dose was gradually reduced, reaching a mean of 20 Gy in 2 weeks in 1979. From 1980 to 1983, the total dose increased to 50.4 Gy, with a fraction size of 1.8 Gy, over a mean of 5.6 weeks. From 1984 onward, the mean total radiation dose increased to 60 Gy with a fraction of 2 Gy.

RESULTS

Recurrence-free 5 year survival rates for T1a, T1b, and T2 were 79%, 73%, and 67%, respectively. When the relationship between radiation dose and local control rates was analyzed for each year from 1974 to 1989, total doses were strongly associated with local control for patients with T1a disease. Age, sex, daily dose, total dose, radiation machine (Co-60 or 10 MV Lineac), treatment technique (anterior wedged pair or parallel opposed fields), treatment volume, use of endoscopic microsurgery, and involvement of the anterior commissure were examined for effects upon relapse-free survival in T1a disease by uni- and multivariate analysis. Total dose was the only significant factor for T1a disease (p < 0.02). The effect of these variables upon relapse-free survival in T2 disease as well as the effect of cord mobility, and number of involved sites was examined by multivariate analysis. Total dose (p < 0.03), cord mobility (p < 0.05), and number of involved sites (p < 0.04) significantly affected relapse-free survival in T2 disease.

CONCLUSION

At least 50 Gy is required for treatment of T1 disease when 2 Gy is used as a daily dose, even if endoscopic microsurgery is performed. Better local control of T2 disease in patients with impaired cord mobility or more than three involved sites leads to an improved prognosis; we recommend doses of at least 70 Gy or use of hyperfractionation in such patients with these factors. Although the daily dose did not significantly affect prognosis in multivariate analyses, 1.8 Gy is not recommended for treatment of T2 tumors instead of 2 Gy.

Does prolonged treatment course adversely affect local control of carcinoma of the larynx?

PURPOSE

The purpose of this paper is to present local control rates of carcinoma of the larynx in relation to the total treatment course after radical radiation therapy.

METHODS AND MATERIALS

A total of 1350 patients with laryngeal carcinoma treated at the Massachusetts General Hospital for the past three decades were available for analysis. Treatment courses were divided into two groups: 45 days and > 45 days. The local control rates were compared and evaluated for statistical differences.

RESULTS

The data indicated that prolonged treatment course adversely affects local tumor control of both advanced glottic and supraglottic lesions, but to a lesser degree for the early tumors.

CONCLUSION

The study indicated that for optimal local control, radiation treatment should be completed as soon as possible, preferably within 6.5 weeks, either by once- or twice-daily accelerated programs. The local control of early T1 glottic cancer has been exceedingly satisfactory by conventional once-daily radiation therapy. Further improvement by shortening of treatment time for such early lesions will be difficult to assess without a prospective randomized trial.

A critical review of radiotherapy in the management of T1 glottic carcinoma

INTRODUCTION

It is generally believed that patients presenting with T1 glottic cancer can be treated with either surgery or radiation therapy (RT) with similar expectations relative to tumor control. Accordingly, many institutions routinely treat patients with T1 glottic cancer with RT. This retrospective study was undertaken to ascertain the efficacy of RT in the treatment of these patients.

MATERIALS AND METHODS

The records of 40 patients initially treated with RT between 1974 and 1989 were retrospectively reviewed. Parameters assessed included incidence of tumor control, need for and type of subsequent salvage surgical procedures, quality of voice, and ultimate survival rate.

RESULTS

In a group of 38 evaluable patients, 10 (26%) developed recurrence in the larynx and 2 (5.6%) in the cervical lymphatics. Salvage surgery resulted in 6 (16%) total laryngectomies. Death from T1 glottic cancer occurred in 1 (2.6%) patient. Speech results were judged good in 24% of patients, whereas 66% were felt to have impaired speech with elements of glottic fry, harshness, low pitch, and inefficient breath support. The additional costs incurred by patients requiring subsequent intervention are substantial.

CONCLUSION

Cordectomy may be a superior option for management of T1 glottic cancer. Initial tumor control is probably superior and literature review suggests that surgery may be a more economical option and should be seriously considered for the management of T1 glottic cancer. This is a US government work. There are no restrictions on its use.

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

Between January 1975 and December 1985, 45 patients with carcinoma in situ or invasive squamous cell carcinoma of the glottic larynx received radiation therapy at the Mayo Clinic. Local control in the entire group of 45 patients was 84% (in 6 of 6 with carcinoma in situ and in 32 of 39 with invasive cancers). Three of seven patients (43%) with local recurrences underwent successful larynx-preserving surgical procedures; thus, the rate of laryngeal preservation was 91%. In our study of several treatment factors, including the duration of treatment, type of treatment (continuous course versus split course), photon energy (60Co versus 4-MV photons versus 6-MV photons), total dose, and dose per fraction, we found that only total dose of 6,300 cGy or more was associated with significantly improved local control (in 35 of 38 patients [92%]). Two patients (4%) died of uncontrolled delayed nodal metastases, one of which was preceded by a local recurrence. Severe laryngeal edema developed in two patients, associated with recurrent glottic carcinoma in one of them. No larynx was lost because of complications. In our current treatment recommendations, patients receive a total dose of 6,300 cGy in 28 fractions of 225 cGy each, administered in a continuous course with use of 6-MV photons.