Radiation therapy for glottic cancer using 6-MV photons

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

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

Effective atomic number of soft tissue, water and air for interaction of various hadrons, leptons and isotopes of hydrogen

PURPOSE

Characterization of soft tissue, water and air in terms of effective atomic number (Z_eff) with respect to the interactions of hadrons, leptons and isotopes of hydrogen.

METHOD

Mass collision stopping powers (MCSPs) were calculated first using Bethe formula. Then, these values were used to estimate Z_eff using linear-logarithmic interpolation. A scale equation was also used to calculate MCSP.

RESULTS

Variation in Z_eff, over the 0.5-50 MeV energy range considered, is minimum for muon and pion (π meson) interactions (relative difference [RD] ≤ 7%), while maximum variation has been noticed in Z_efffor heavy charged particles, i.e. alpha particle (RD ≤ 26%). The highest values of Z_eff were obtained for muon particle, the lightest particle while the minimum values of Z_eff were obtained for alpha particle interaction. Except for very low kinetic energies, water equivalence of soft tissue is very satisfactory (RD ≤ 3%). The Z_eff of water relative to air was found to be almost constant at high energies. The present results should be valid for especially high energies where the Bethe formula can be applied. This applies to relatively higher energies (>2 MeV) for heavier particles such as alpha particles and applies to relatively lower energies (>0.5 MeV) for lighter particles such as protons.

CONCLUSIONS

In view of the importance of water equivalence in particle therapy, new data on Z_eff in soft tissue, water and air for fundamental particle interaction should be important. Results revealed that soft tissue could be considered as water equivalent for interaction of various fundamental particles.

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

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

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

OBJECTIVES/HYPOTHESIS

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

STUDY DESIGN

Retrospective case-control study.

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

4 Laryngoscope, 127:1061-1067, 2017.

Treatment results and prognostic factors of patients undergoing postoperative radiotherapy for laryngeal squamous cell carcinoma

Postoperative radiotherapy (PRT) is widely advocated for patients with squamous cell carcinomas of the head and neck that are considered to be at high risk of recurrence after surgical resection. The aims of this study were to evaluate the treatment outcomes of PRT for patients with laryngeal carcinoma and to identify the value of several prognostic factors. We reviewed the records of 256 patients treated for laryngeal squamous cell carcinoma between January 1993 and December 2005. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Log-rank test was employed to identify significant prognostic factors for DFS and OS. The Cox proportional hazards model was applied to identify covariates significantly associated with the aforementioned endpoints. Our results showed the 3-, 5-, and 10-year DFS for all patients were 69.9%, 59.5%, and 34.9%, respectively. The 3-, 5-, and 10-year OS rates were 80.8%, 68.6%, and 38.8%, respectively. Significant prognostic factors for both DFS and OS on univariate analysis were grade, primary site, T stage, N stage, overall stage, lymph node metastasis, overall treatment times of radiation, the interval between surgery and radiotherapy, and radiotherapy equipment. Favorable prognostic factors for both DFS and OS on multivariate analysis were lower overall stage, no cervical lymph node metastasis, and using 60Co as radiotherapy equipment. In conclusion, our data suggest that lower overall stage, no cervical lymph node metastasis, and using 60Co as radiotherapy equipment are favorable prognostic factors for DFS and OS and that reducing the overall treatment times of radiation to 6 weeks or less and the interval between surgery and radiotherapy to less than 3 weeks are simple measures to remarkably improve treatment outcome.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Role of radiotherapy in early glottic carcinoma

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Radiotherapy for patients with early-stage glottic carcinoma: univariate and multivariate analyses in a group of consecutive, unselected patients

BACKGROUND

Radiotherapy (RT) has a remarkable success rate in the treatment of patients with glottic carcinoma. The objectives of the current study were to assess the results in a group of consecutive patients with comparable characteristics who were treated with RT (6-megavolt photon linear accelerator) and to determine the prognostic factors that may influence local control in patients with early-stage glottic carcinoma. The impact on local control of tobacco smoking and second primary malignancies also was investigated.

METHODS

Four hundred ten patients with T1-T2 squamous cell carcinoma of the glottis who were treated between 1986 and 2001 were analyzed retrospectively with regard to local control and overall survival. Potential prognostic factors for local control were evaluated with univariate and multivariate models. The impact of technologic advances also was evaluated.

RESULTS

The 5-year and 10-year overall survival rates were 83% and 63.5%, respectively. The overall 10-year local control rate for patients with T1-T2 glottic carcinoma was 89%. The median time to recurrence was 7 months. Univariate analysis showed that tumor category, tumor size, macroscopic appearance of the lesion, RT fraction size, persistent edema, year of RT treatment, unchanged dysphonia, and surgical option all had a significant influence on local control; whereas multivariate analysis showed that only persistent dysphonia and year of RT treatment were significantly associated with increased local control. A 22.2% rate of second primary malignancies was reported: second primary tumors were the major cause of death in the patients studied. Only 2 patients died of laryngeal carcinoma; 304 patients were alive with their disease in complete remission, 1 patient was alive with recurrent laryngeal carcinoma after undergoing salvage surgery, and 103 patients died of either intercurrent disease or a second primary tumor.

CONCLUSIONS

The use of a 6-megavolt photon linear accelerator achieved a high rate of local control in patients with T1-T2 glottic carcinoma. Dysphonia and the year of RT treatment were the most important prognostically significant factors for patient outcome. The occurrence of a second primary tumor was the most frequent cause of death, especially among patients who did not stop smoking after a diagnosis of glottic carcinoma.

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.

Quality of life, functional outcome, and costs of early glottic cancer

OBJECTIVE

To analyze quality of life, functional outcome, and hidden costs by primary treatment with surgery or radiation therapy in patients with early glottic cancer.

STUDY DESIGN

Retrospective study in a tertiary care facility.

METHODS

A group of 101 patients with carcinoma in situ and T1 invasive squamous cell carcinoma treated primarily with either surgery or radiation, between January 1990 and December 2000, were identified from searching our tumor registry. Patients completed two previously validated questionnaires and one local questionnaire. Statistical significance was assessed with the rank sum test, chi2 test, or Fisher's Exact test.

RESULTS

Questionnaires were completed in 59% (44 of 74) of the surgical cohort and 41% (11 of 27) of the radiation therapy cohort. The primary surgical treatments were endoscopic excision (86%), hemilaryngectomy (12%), and total laryngectomy (1%). Patient-reported problems with swallowing, chewing, speech, taste, saliva, pain, activity, recreation, and appearance showed no difference between the endoscopic excision or radiation therapy cohorts. Comparing endoscopic excision versus radiation therapy, respectively, median number of treatments (2 vs. 35), total median travel distance (150 vs. 660 miles), total median travel time (180 vs. 1440 min), and total median number of hours of work missed (76 vs. 24) all differed significantly (P <.01).

CONCLUSIONS

Almost all patients with early glottic cancer, whether treated with surgery or radiation therapy, reported excellent quality of life outcomes and functional results. In addition to actual costs, the hidden costs for radiation therapy versus endoscopic excision were all greater in terms of total number of hours of work missed, total travel time, and total travel distance.

[Influence of thermoplastic masks on the absorbed skin dose for head and neck tumor radiotherapy]

The influence of thermoplastic masks used in clinical routine for patient immobilization in head and neck radiotherapy treatment on the absorbed skin dose has been investigated at Gustave-Roussy Institute. The measurements were performed in 60Co gamma-rays, 4 and 6MV X-rays and in 8 and 10MeV electron beams. Initially, the measurements were performed with thermoluminescent dosimeters (LiF) and a NACP chamber on a polystyrene phantom in order to study the influence of physical parameters (distance, field size, energy...) on first millimeters depth variation dose. The study was completed with in vivo measurements on 14 patients using various dosimeters (thermoluminescent detectors, diodes) in order to assess the increase of dose on first millimeters depth and to verify the delivered dose during treatment sessions (quality control). In treatment conditions, masks lead to an important increase of dose on the first millimeter in 60Co gamma-rays beams (dose value normalized to maximum of dose increase from 57.1% to 77.7% for 0.5 mm-water depth and from 78.5% to 88% for 1 mm-water depth); its contribution is less important in 4 and 6 MV X-rays beams (dose value normalized to maximum of dose increase from 49.5% to 63.2% for 0.5 mm-water depth and from 59% to 70.1% for 1 mm-water depth). Concerning 8 and 10 MeV electron beams, the normalized dose value increase respectively from 78.4% to 81.7% and from 82.2% to 86.1% for 0.5 mm-water depth. In vivo dosimetry enabled the quality control of delivered dose during treatment. Measured dose is in agreement within +/- 5% with the prescribed dose for 92.3% of cases. In routine, in vivo dosimetry allowed to quantify the increase of skin dose induced by thermoplastic masks for various energies of photon and electron beams as well as quality control.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE

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

METHODS AND MATERIALS

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

RESULTS

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

CONCLUSION

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

Radiation treatment of glottic squamous cell carcinoma, stage I and II: analysis of factors affecting prognosis

PURPOSE

At least in some European Countries, there is still considerable controversy regarding the choice between surgery and radiotherapy for the treatment of patients with early laryngeal-glottic carcinoma.

METHODS AND MATERIALS

Two hundred and forty-six patients with laryngeal-glottic neoplasms, Stage I-II, were treated with radical radiotherapy. Before radiotherapy the patients were evaluated to determine the surgical procedure of choice. Either 66-68.4 Gy (33-38 fractions) or 63-65 Gy (28-29 fractions) of radiation therapy (RT) were administered. The overall disease free survival was determined for each subgroup of patients. Univariate and multivariate analyses were performed to determine significant prognostic variables.

RESULTS

Five- and 10-year overall survival rates were 83 and 72%, respectively. At a median follow-up of 6 years 204 patients are alive and disease free. No patient developed distant metastases. One patient died of a large local recurrence, 38 patients died of causes unrelated to their tumor, and 3 patients were lost to follow-up. The multivariate analysis confirmed that performance status (PS), macroscopic presentation of the lesion, and persistence of dysphonia after radiotherapy are significant prognostic factors.

CONCLUSIONS

According to the multivariate analysis, the patients with PS > 80 and with exophytic lesions are eligible for radical RT. The surgical procedure proposed for each patient was not found to be an independent prognostic factor.

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.