The role of altered fractionation in head and neck cancers

DAHANCA 28: A phase I/II feasibility study of hyperfractionated, accelerated radiotherapy with concomitant cisplatin and nimorazole (HART-CN) for patients with locally advanced, HPV/p16-negative squamous cell carcinoma of the oropharynx, hypopharynx, larynx and oral cavity

BACKGROUND

A phase I-II study to evaluate the feasibility and efficacy of intensified, primary radiotherapy (RT) for Locally Advanced Head and Neck Squamous Cell Carcinoma (LAHNSCC) employing dose escalation by hyperfractionation, acceleration of treatment time, concomitant chemotherapy and hypoxic modification.

METHODS

Patients with HPV/p16- LAHNSCC receiving primary hyperfractionated, accelerated RT, 76 Gy/56 fx, 10 fx/week for 5½ weeks, concomitant weekly cisplatin (40 mg/m²) and nimorazole (HART-CN) were included. Primary endpoint was locoregional failure (LRF). Secondary endpoints were overall survival (OS) and toxicity.

RESULTS

50 patients received HART-CN from 2013 to 2017. Median age was 60 years. Most patients had stage IV hypo- or oropharynx cancer with a heavy smoking history. All oropharyngeal cancers were HPV/p16-negative. Ninety-eight percent of patients completed RT, but compliance to cisplatin and nimorazole was lower. Median observation time was 44 months. LRF was diagnosed in 10 patients. All LRFs were in the high-dose CTV. The 3-year actuarial LRF was 21%, and OS was 74%. The peak incidence of acute toxicity showed that 67% of patients experienced severe dysphagia, 61% severe mucositis, and 78% were equipped with feeding tubes. Late severe morbidity was seen in 7 of 29 recurrence-free patients with at least 3 years of followup, who presented with either severe dysphagia (n = 2), severe xerostomia (n = 1), severe fibrosis of the neck (n = 3) or osteoradionecrosis (n = 1). Three were still tube dependent.

CONCLUSION

HART-CN is feasible in patients with HPV/p16- LAHNSCC in good health. Although acute toxicity was pronounced, the proportion of patients with late toxicity was acceptable and outcome at 3 years encouraging.

Time abides long enough for those who make use of it

Increased treatment package time is an independent poor prognostic factor for outcomes in head and neck squamous cell carcinoma (HNSCC). Similarly the timeliness of treatment initiation is a risk factor for disease recurrence. Despite these well-known issues, the timeliness of treatment initiation is actually worsening in the United States and the expeditious completion of radiation treatments continues to be difficult secondary to a number of patients and treatment related issues. This analysis evaluates the current data on treatment intervals in the management of head and neck cancer. Rapid staging/diagnosis of head and neck cancer, appropriate referrals to providers qualified to treat said cancer, and expeditious treatment completion remains the most cost-effective, widely applicable method to improve outcomes in head and neck cancer.

Hyperfractionated or accelerated radiotherapy in lung cancer: an individual patient data meta-analysis

PURPOSE

In lung cancer, randomized trials assessing hyperfractionated or accelerated radiotherapy seem to yield conflicting results regarding the effects on overall (OS) or progression-free survival (PFS). The Meta-Analysis of Radiotherapy in Lung Cancer Collaborative Group decided to address the role of modified radiotherapy fractionation.

MATERIAL AND METHODS

We performed an individual patient data meta-analysis in patients with nonmetastatic lung cancer, which included trials comparing modified radiotherapy with conventional radiotherapy.

RESULTS

In non-small-cell lung cancer (NSCLC; 10 trials, 2,000 patients), modified fractionation improved OS as compared with conventional schedules (hazard ratio [HR] = 0.88, 95% CI, 0.80 to 0.97; P = .009), resulting in an absolute benefit of 2.5% (8.3% to 10.8%) at 5 years. No evidence of heterogeneity between trials was found. There was no evidence of a benefit on PFS (HR = 0.94; 95% CI, 0.86 to 1.03; P = .19). Modified radiotherapy reduced deaths resulting from lung cancer (HR = 0.89; 95% CI, 0.81 to 0.98; P = .02), and there was a nonsignificant reduction of non-lung cancer deaths (HR = 0.87; 95% CI, 0.66 to 1.15; P = .33). In small-cell lung cancer (SCLC; two trials, 685 patients), similar results were found: OS, HR = 0.87, 95% CI, 0.74 to 1.02, P = .08; PFS, HR = 0.88, 95% CI, 0.75 to 1.03, P = .11. In both NSCLC and SCLC, the use of modified radiotherapy increased the risk of acute esophageal toxicity (odds ratio [OR] = 2.44 in NSCLC and OR = 2.41 in SCLC; P < .001) but did not have an impact on the risk of other acute toxicities.

CONCLUSION

Patients with nonmetastatic NSCLC derived a significant OS benefit from accelerated or hyperfractionated radiotherapy; a similar but nonsignificant trend was observed for SCLC. As expected, there was increased acute esophageal toxicity.

Hyperfractionated or accelerated radiotherapy for head and neck cancer

BACKGROUND

Several trials have studied the role of altered fractionation radiotherapy in head and neck squamous cell carcinoma, but the effect of such treatment on survival is not clear.

OBJECTIVES

The aim of this individual patient data (IPD) meta-analysis was to assess whether this type of radiotherapy could improve survival.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; CENTRAL (2010, Issue 3); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ISRCTN and additional sources for published and unpublished trials. The date of the most recent search was 8 August 2010.

SELECTION CRITERIA

We identified randomised trials comparing conventional radiotherapy with hyperfractionated or accelerated radiotherapy, or both, in patients with non-metastatic head and neck squamous cell carcinomas and grouped trials into three pre-specified treatment categories: hyperfractionated, accelerated and accelerated with total dose reduction. Trials were eligible if they began recruitment after 1969 and ended before 1998.

DATA COLLECTION AND ANALYSIS

We obtained updated individual patient data. Overall survival was the main outcome measure. The secondary outcome measures were local or regional control rates (or both), distant control rates and cause-specific mortality.

MAIN RESULTS

We included 15 trials with 6515 patients. The median follow up was six years. Tumour sites were mostly oropharynx and larynx; 5221 (74%) patients had stage III-IV disease (UICC 2002). There was a significant survival benefit with altered fractionation radiotherapy, corresponding to an absolute benefit of 3.4% at five years (hazard ratio (HR) 0.92, 95% CI 0.86 to 0.97; P = 0.003). The benefit was significantly higher with hyperfractionated radiotherapy (8% at five years) than with accelerated radiotherapy (2% with accelerated fractionation without total dose reduction and 1.7% with total dose reduction at five years, P = 0.02). There was a benefit in locoregional control in favour of altered fractionation versus conventional radiotherapy (6.4% at five years; P < 0.0001), which was particularly efficient in reducing local failure, whereas the benefit on nodal control was less pronounced. The benefit was significantly higher in the youngest patients (under 50 year old) (HR 0.78, 95% CI 0.65 to 0.94), 0.95 (95% CI 0.83 to 1.09) for 51 to 60 year olds, 0.92 (95% CI 0.81 to 1.06) for 61 to 70 year olds, and 1.08 (95% CI 0.89 to 1.30) for those over 70 years old; test for trends P = 0.007).

AUTHORS' CONCLUSIONS

Altered fractionation radiotherapy improves survival in patients with head and neck squamous cell carcinoma. Comparison of the different types of altered radiotherapy suggests that hyperfractionation provides the greatest benefit. An update of this IPD meta-analysis (MARCH 2), which will increase the power of this analysis and allow for other comparisons, is currently in progress.

Cancer stem cells and tumor response to therapy: current problems and future prospects

The presence of a subpopulation of cells within tumors, so-called cancer stemlike cells, that is uniquely capable of reestablishing the tumor during and after definitive radio(chemo)therapy and must be effectively controlled for a long-term cure is being increasingly appreciated. The existence and physiology of a rare cancer cell population, termed cancer cell clonogens, with similar properties has been extensively described in the radiobiology literature for several decades based on studies using tumor cells transplanted into syngeneic or immunodeficient animals. The earlier studies have identified important features that govern tumor establishment; tumor growth and homeostasis; and therapeutic resistance, including clonogen number, tumor type, vascular status, hypoxia, repopulation dynamics during treatment, and immunologic and microenvironmental status. These discoveries led to therapeutic strategies, some of which have shown efficacy and have become current standard clinical practice (eg, concomitant boost and concurrent radio chemotherapy). Although the identity of cancer stemlike cells and cancer cell clonogens has not been definitively shown, recent characterization of molecular signaling pathways controlling stem cells and their microenvironmental niche combined with the earlier findings on clonogen physiology may now lead to the development of molecularly targeted strategies to overcome therapeutic resistance of this rare subpopulation of tumor cells. Along these lines, we describe 3 unique treatment settings (ie, before, during, and after definitive radio[chemo]therapy) in which molecularly targeted approaches might specifically counteract cancer stemlike cell resistance mechanisms and enhance the curative efficiency of radio(chemo)therapy.

Five year results of a randomized trial comparing hyperfractionated to conventional radiotherapy over four weeks in locally advanced head and neck cancer

BACKGROUND AND PURPOSE

Fractionation strategies delivered over 4 weeks are of clinical and radiobiological interest because treatment is completed before radiotherapy (RT) induced clonogen proliferation commences in earnest approximately 3 to 4 weeks into a course of RT. We wished to test the clinical hypothesis that an increased total dose delivered over 4 weeks with smaller than standard doses per fraction in locally advanced squamous cell carcinoma (SCC) may result in relative protection of late responding tissues and an increased tumor control compared to a conventional daily course in the same overall time.

MATERIALS AND METHODS

Between 1988 and 1995 a randomized controlled trial employing RT alone was undertaken at the Princess Margaret Hospital that included 331 eligible patients with T3 or T4 N0 or any N-positive oropharynx, hypopharynx, or larynx primary SCC. RT was randomly assigned to one of two 4 week schedules, either 51 Gy in 20 equal daily fractions, termed conventional fractionation (CF), or 58 Gy in 40 equal fractions given twice per day as a hyperfractionated (HF) experimental arm.

RESULTS

The 5-year local relapse rate was reduced in the HF (41%) compared to the CF arm (49%). This difference was marginally not significant (p=0.082) when the effect was not adjusted. When the effect of the treatment was adjusted by Cox model for clinical factors that included N-category, ECOG performance status, site of disease, T-category, age, hemoglobin, and gender the HF achieved a significant effect (p=0.02). Survival (40% vs. 30%) was also improved with HF compared to CF arm. This difference was only marginally not significant (p=0.069) but again achieved statistical significance when the model was adjusted for clinical factors (p=0.01). Similar results were observed for disease free survival. Although reversible acute toxicity was increased with HF, the overall 5-year rate of grade 3 and 4 late toxicity for the CF was 10.5% compared to 7.7% in the higher dose HF arm.

CONCLUSIONS

HF delivered in 4 weeks permits enhanced RT doses achieving improved tumor control, without increased late toxicity, compared to daily fractionated radiotherapy in the same overall time.

HIV impact on acute morbidity and pelvic tumor control following radiotherapy for cervical cancer

OBJECTIVE

To determine the impact of HIV infection on acute morbidity and pelvic tumor control following external beam radiotherapy (EBRT) for cervical cancer.

METHOD

218 patients receiving EBRT who also had HIV testing after informed consent was obtained were evaluated. Acute treatment toxicity was documented weekly during treatment and 1 month post-EBRT. Pelvic tumor control was documented at 4 and 7 months post-EBRT. Clinicians were blinded for HIV results.

RESULTS

About 20% of the patients were HIV-positive. Overall, 53.4% of the patients had radiation-related acute toxicity (grade 3-4). HIV infection was associated with a 7-fold higher risk of multisystem toxicity: skin, gastrointestinal tract (GIT) and genitourinary tract (GUT) systems. It was also an independent risk factor for treatment interruptions (adjusted relative risk 2.2). About 19% of the patients had residual tumor at 4 and 7 months post-EBRT. HIV infection was independently and significantly associated with 6-fold higher risk of residual tumor post-EBRT. The hazard ratio of having residual tumor after initial EBRT was 3.1-times larger for HIV-positive than for HIV-negative patients (P = 0.014).

CONCLUSION

HIV is associated with increased risk of multisystem radiation-related toxicity; treatment interruptions and pelvic failure (residual tumor) following EBRT. HIV infection is an adverse prognostic factor for outcome of cervical cancer treatment.

Carboplatin and tegafur-uracil concomitant with standard radiotherapy in the management of locally advanced head and neck cancer

INTRODUCTION

We undertook a prospective study to determine the feasibility, toxicity, response and survival rate of simultaneous chemotherapy (CT) and radiotherapy (RT) for locally-advanced head and neck cancer.

MATERIAL AND METHODS

Fifty eight patients were treated with carboplatin (i.e. 100 mg/m(2)) weekly, tegafur-uracil (UFT) (oral 400 mg/m(2)) daily and simultaneous treatment with a cobalt-60 source of radiation (total dose 65-70 Gy).

RESULTS

Forty six patients (79%) received the total dose of RT while CT was delayed or reduced in 31 patients (53%). Grade 3-4 toxicity observed was mucositis in 27 (47%), leukopenia in 10 (17%), anaemia in 5 (9%), and diarrhoea in 4 (7%) patients. The objective response rate was 74%; 24 complete response (41%) and 19 partial response (33%). Overall, there are 11 patients (19%) disease-free, 7 (12%) alive with disease, 35 have died of progressive disease (60%) and 3 (5%) from other causes. There were 2 toxic deaths (3%). Median time to progression was 10 months and median survival was 18.4 months.

CONCLUSIONS

The use of carboplatin and UFT concomitant with radiotherapy has, in our study, a slightly lower activity than other chemo-radiotherapy protocols, especially with respect to complete responses, but with no significant differences in overall survival or disease-free survival rates.

Biweekly Escalated, Accelerated Hyperfractionated Radiotherapy With Concomitant Single-Dose Mitomycin C Results in a High Rate of Local Control in Advanced Laryngeal and Hypopharyngeal Cancer

The purpose of this study is to evaluate the efficacy of a dose-escalated, accelerated, and hyperfractionated radiotherapy schedule with a concomitant single dose of mitomycin C in the treatment of patients with advanced laryngeal or hypopharyngeal cancer. Twenty-one previously untreated patients with advanced squamous cell carcinoma (stage III, n = 6; stage IV, n = 15) were treated with a biweekly dose-escalated, accelerated, and hyperfractionated schedule up to a total dose of 74.4 Gy in 54 fractions over 5 weeks. A single dose of intravenous mitomycin C 10 mg/m2 was given on day 30. The median follow-up after treatment of surviving patients is 48 months (range, 28 to 61 months). All patients showed complete tumor control at the primary site when evaluated 2 months after chemoirradiation by laryngomicroscopy or hypopharyngoscopy and radiologic imaging (CT, MRI). Two laryngectomies were carried out after given therapy: 1 for residual cancer and 1 for suspected residual cancer. After a median follow-up of 43 months (range, 28 to 61 months), a local control rate of 70% and disease-free survival (DFS) rate of 60% were achieved in the laryngeal cancer patients; in patients with hypopharyngeal cancer, the corresponding figures were 64% (82% after salvage surgery) and 36%. The results are promising and warrant comparison with other chemoradiotherapy regimens.

Five compared with six fractions per week of conventional radiotherapy of squamous-cell carcinoma of head and neck: DAHANCA 6 and 7 randomised controlled trial

BACKGROUND

Although head and neck cancer can be cured by radiotherapy, the optimum treatment time for locoregional control is unclear. We aimed to find out whether shortening of treatment time by use of six instead of five radiotherapy fractions per week improves the tumour response in squamous-cell carcinoma.

METHODS

We did a multicentre, controlled, randomised trial. Between January, 1992, and December, 1999, of 1485 patients treated with primary radiotherapy alone, 1476 eligible patients were randomly assigned five (n=726) or six (n=750) fractions per week at the same total dose and fraction number (66-68 Gy in 33-34 fractions to all tumour sites except well-differentiated T1 glottic tumours, which were treated with 62 Gy). All patients, except those with glottic cancers, also received the hypoxic radiosensitiser nimorazole. Analysis was by intention to treat.

FINDINGS

More than 97% of the patients received the planned total dose. Median overall treatment times were 39 days (six-fraction group) and 46 days (five-fraction group). Overall 5-year locoregional control rates were 70% and 60% for the six-fraction and five-fraction groups, respectively (p=0.0005). The whole benefit of shortening of treatment time was seen for primary tumour control (76 vs 64% for six and five fractions, p=0.0001), but was non-significant for neck-node control. Six compared with five fractions per week improved preservation of the voice among patients with laryngeal cancer (80 vs 68%, p=0.007). Disease-specific survival improved (73 vs 66% for six and five fractions, p=0.01) but not overall survival. Acute morbidity was significantly more frequent with six than with five fractions, but was transient.

INTERPRETATION

The shortening of overall treatment time by increase of the weekly number of fractions is beneficial in patients with head and neck cancer. The six-fractions-weekly regimen has become the standard treatment in Denmark.

Relationship between acute and late normal tissue injury after postoperative radiotherapy in endometrial cancer

PURPOSE

To evaluate the relationship between acute and late normal tissue reactions in 317 consecutive endometrial cancer patients treated with surgery and adjuvant radiotherapy (RT).

METHODS

The data of 317 patients (staging according to the International Federation of Gynecology and Obstetrics) treated with postoperative RT were analyzed. Both low-dose-rate brachytherapy and external beam RT were applied in 247 patients (78%); brachytherapy only in 49 (15%) and external beam irradiation only in 21 (7%). The median follow-up was 7.3 years (range 4-21). The European Organization for Research and Treatment of Cancer, Radiation Therapy Oncology Group system with elements of the late effects of normal tissue, subjective, objective, management, analytic (LENT/SOMA) scale was used to score the RT reactions. The correlation between the occurrence and severity of acute and late bowel and bladder toxicity, as well as the relationship between the severity of acute effects and time to occurrence of late reactions, were assessed using linear and logistic regression analyses.

RESULTS

Of the 317 patients, 268 (85%) experienced acute RT reactions of any grade. Severe acute bowel reactions were observed in 15 patients (5%), urinary bladder complications in 1 patient (0.5%), cutaneous in 1 patient (0.5%), and vaginal in 1 patient (0.5%). Severe acute hematologic toxicity was seen in 3 patients (1%). A total of 158 patients (51%) experienced late RT reactions of any grade. Severe late bowel reactions were observed in 19 patients (6%), urinary bladder in 5 (2%), vaginal in 3 (1%), and bone in 10 (4%). When all toxic events were considered, there was a highly significant correlation between the acute and late bowel reactions (p <0.001), but the acute and late urinary bladder reactions did not correlate (p = 0.64). The grade of acute toxicity was found to predict the grade of late toxicity for the bowel but not for the bladder (p <0.001 and p = 0.47, respectively). The severity of acute bowel and bladder toxicity did not correlate with the time to occurrence of late toxicity in these locations (p = 0.34 and p = 0.47, respectively).

CONCLUSION

Patients with increased acute bowel toxicity during postoperative RT for endometrial cancer have an increased risk of late bowel injury. A higher grade of acute bowel complications correlated with more severe late events, but was not predictive for its latency time. These findings suggest the possibility of an early indication of patients with an increased risk of late toxicity in whom preventive measures might be attempted.

Recent Advances in Radiotherapy for Head and Neck Cancers

Advancements in surgery have made it possible to resect cancers that had previously been regarded as incurable. Similarly, new developments in radiation oncology have helped improve the outlook for patients with locally advanced or recurrent head and neck cancers. Among these advancements are refinements in altered fractionation, three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, stereotactic radiosurgery and fractionated stereotactic radiotherapy, neutron-beam radiotherapy, charged-particle radiotherapy, and intraoperative radiotherapy. These recent developments have allowed radiation oncologists to escalate the dose of radiation delivered to tumors while minimizing the dose delivered to surrounding normal tissue. Additionally, more continues to be learned about the optimum delivery of chemotherapy. This article provides an update on the status of these new developments in the treatment of head and neck cancers.

Uninterrupted moderately accelerated radiotherapy in the treatment of unresectable/advanced head and neck cancer: one institution's experience and a comparative review

Conventional radiotherapy alone in treatment of unresectable or locally advanced head and neck cancer has poor results. To improve outcome without significant increase in acute and late morbidity, we began a moderately accelerated hyperfractionation radiation therapy protocol without breaks for treatment of unresectable/advanced head and neck malignancies. From August 1984 to June 1995, 48 patients with unresectable or advanced carcinoma of the head and neck were treated using a protocol of accelerated hyperfractionation radiation therapy at Kaiser Permanente Medical Center, Los Angeles. Patients were treated twice a day using 150 cGy per fraction, 4 days per week, to a final dose of 60 Gy. Two patients were excluded from this analysis because they did not complete treatment. With a median follow-up of 33 months, 31 (67%) patients have had disease recurrence, 30 (65%) of whom had a locoregional component to their failures. At the last follow-up, 12 patients (26%) were alive with no evidence of disease, 30 patients had died of disease, and 4 had died of intercurrent disease without recurrence. Nine (19%) patients required treatment interruptions averaging 8 days in duration. This accelerated regimen resulted in outcomes similar to those with conventional radiotherapy, most likely because of a conservative total dose. Further refinement of fractionation schedules with potential incorporation of chemotherapy must be investigated.

Phase III comparison of twice-daily split-course irradiation versus once-daily irradiation for patients with limited stage small-cell lung carcinoma

PURPOSE

Because small-cell lung cancer is a rapidly proliferating tumor, it was hypothesized that it may be more responsive to thoracic irradiation (TI) given twice-daily than once-daily. This hypothesis was tested in a phase III trial.

PATIENTS AND METHODS

Patients with limited-stage small-cell lung cancer were entered onto a phase III trial, and all patients initially received three cycles of etoposide (130 mg/m(2) x 3) and cisplatin (30 mg/m(2) x 3). Subsequently, patients who did not have progression to a distant site (other than brain) were randomized to twice-daily thoracic irradiation (TDTI) versus once-daily thoracic irradiation (ODTI) given concomitantly with two additional cycles of etoposide (100 mg/m(2) x 3) and cisplatin (30 mg/m(2) x 3). The irradiation doses were TDTI, 48 Gy in 32 fractions, with a 2.5-week break after the initial 24 Gy, and ODTI, 50.4 Gy in 28 fractions. After thoracic irradiation, the patients received a sixth cycle of etoposide/cisplatin, followed by prophylactic cranial irradiation (30 Gy/15 fractions) if they had a complete response.

RESULTS

Of 311 assessable patients enrolled in the trial, 262 underwent randomization to TDTI or ODTI. There were no differences between the two treatments with respect to local-only progression rates, overall progression rates, or overall survival. The patients who received TDTI had greater esophagitis (> or = grade 3) than those who received ODTI (12.3% v 5.3%; P =.05). Although patients received thoracic irradiation encompassing the postchemotherapy volumes, only seven of 90 local failures were out of the portal of irradiation.

CONCLUSION

When TI is delayed until the fourth cycle of chemotherapy, TDTI does not result in improvement in local control or survival compared with ODTI.

A prospective phase II trial of concomitant chemotherapy and radiotherapy with delayed accelerated fractionation in unresectable tumors of the head and neck

BACKGROUND

Our study is a prospective evaluation of unresectable malignant cancers of the head and neck treated with concomitant chemotherapy and radiotherapy (RT) using delayed accelerated fractionation (concomitant boost).

METHODS

Between January 1988 and March 1995, 82 patients with unresectable cancers of the head and neck were enrolled in this phase II study. Of these, 52 patients were treated and followed for a minimum of 3 years and are the subject of this analysis. All patients had T4 lesions and were stage IV according to the American Joint Committee on Staging Criteria (AJCC). Patients received RT with accelerated fractionation to a total of 70 Gy in 6 weeks using a concomitant-boost technique. Concomitant cis platin (100 mg/M2) was given on days 1 and 22 of RT. Twenty-seven patients received mitomycin-C (7.5 mg/M2) on days 1 and 22, and 1 patient received mitomycin-C on day 1. In addition, 27 patients received adjuvant chemotherapy with cis platin and vinblastine. The mean follow-up was 45 months (range, 36-72 months). The minimum follow-up for surviving patients in 3 years.

RESULTS

At 3 years, the local control rate was 58%. Three-year local control rates for paranasal sinus, nasopharynx, oropharynx, and larynx/hypopharynx were 78%, 78%, 64%, and 100%, respectively. For all patients, the distant-metastasis-free survival was 56%, and the overall survival rate was 36%. Patients with oral cavity cancers experienced worse overall survival versus other sites, 0% versus 47% (p = .03). Salivary cancers also showed worse survival versus other sites, 0% versus 47%, but was not statistically significant. Severe acute complications occurred in 34% of patients. Treatment-related toxicity also resulted in the death of 2 patients. Severe late complications occurred in 7% of patients.

CONCLUSIONS

Treatment of this poor prognostic group of patients with aggressive chemotherapy and RT produced surprisingly good local control and survival.

Biweekly dose escalation in curative accelerated hyperfractionation for advanced head and neck cancer: a feasibility study

PURPOSE

To study the feasibility of a dose-escalated accelerated hyperfractionation schedule for patients with advanced head and neck cancer.

MATERIALS AND METHODS

Twenty-nine previously untreated patients with advanced squamous cell carcinoma were treated with the following biweekly dose-escalated accelerated hyperfraction schedule: during the first 2 weeks 1.2 Gy twice a daily (bid) up to 24 Gy, thereafter during the next following 2 weeks 1.4 Gy bid to 28 Gy in 20 fractions, and thereafter 22.4 Gy in 1.6 Gy bid fractions during 1 1/2 weeks. Thus, the the total dose was 74.4 Gy in 54 fractions given in 5 1/2 weeks.

RESULTS

The planned total dose was given within the planned time to 19 (66%) patients. For seven patients the treatment time was prolonged with 1 to 6 days because of department closure for holidays or machine-down days, and in three cases the treatment time was prolonged more than 8 weeks. When the tumor responses were evaluated at 3 months after given radiotherapy, 27 (93%) patients showed complete tumor clearance, 1 patient had a recidual focus, and 1 patient showed progressive disease. The ultimate 1-, 2-, and 3-year local control rates were: 87, 71, and 60%. Four patients had a salvage laryngectomy. The 1-, 2-, and 3-year survival rates for all patients were as follows: 96, 81, and 73%. All patients developed confluent mucositis, 15 patients were hospitalized for nutritional support, and 11 patients had moist desquamation. However, all acute reactions healed completely, and no serious late complications were observed.

CONCLUSIONS

This is a safe and effective treatment schedule for patients with advanced head and neck cancer.

Concomitant boost radiotherapy for squamous carcinoma of the tonsillar fossa

PURPOSE

To assess the efficacy of a concomitant boost fractionation schedule of radiotherapy for treating patients with squamous carcinoma of the tonsillar fossa.

PATIENTS AND METHODS

Between December 1983 and November 1992, 83 patients with squamous carcinoma of the tonsil were treated with concomitant boost fractionation. The distribution of American Joint Committee on Cancer T stages was TX-4, T1-5, T2-29, T3-41, T4-4; N stages were NX-1, N0-26, N1-13, N2-31, N3-12. Patients were treated with standard large fields to 54 Gy in 6 weeks. The boost treatment consisted of a second daily 1.5 Gy fraction for 10-12 fractions, usually delivered during the final phase of treatment. The tumor dose was 69-72 Gy, given over 6 weeks. Twenty-one patients, who all had N2 or N3 regional disease, underwent neck dissections, either before (13 patients) or 6 weeks after radiotherapy (8 patients); the other patients were treated with radiotherapy alone.

RESULTS

The 5-year actuarial disease-specific survival and overall survival rates were 71 and 60%, respectively. Patients with T2 and T3 primary tumors had 5-year actuarial local control rates of 96 and 78%, respectively. Patients with T3 disease who received the final-phase boost had a 5-year actuarial local control rate of 82%. Actuarial 5-year regional disease control rates were N0, 92%; N1, 76%; N2, 89%; and N3, 89%. The 21 patients who had neck dissections all had their disease regionally controlled. Patients presenting with nodal disease or after a node excision who were treated with radiation alone had a 5-year actuarial regional disease control rate of 79%. All but five patients had confluent Grade 4 mucositis during treatment. Severe late complications attributable to radiation included mandibular necrosis [1], in-field osteosarcoma [1], and chronic dysphagia for solid foods [5].

CONCLUSIONS

High rates of local and regional disease control were achieved with the concomitant boost fractionation schedule, with few cases of severe late morbidity. Patients with N2 and N3 neck disease were effectively treated with radiation and the selective use of neck dissections. The concomitant boost schedule is our preferred fractionation approach for treating patients with intermediate stage tonsil cancer who are not participating in our current research protocols.

Prognostic value of hemoglobin concentration in radiotherapy for cancer of supraglottic larynx

PURPOSE

The aim of this work is the estimation of correlations between hemoglobin concentration either before or after radiotherapy and local tumor control probability for laryngeal cancer.

METHODS AND MATERIALS

Retrospective analysis of 847 cases of laryngeal supraglottic squamous cell carcinoma treated with radiation alone was performed using maximum likelihood estimations, and step-wise logistic regression. All patients were in good initial performance status (Karnofsky index >70). The minimum follow-up time was 3 years.

RESULTS

Logistic regression showed that the hemoglobin concentration after radiotherapy is an important prognostic factor. There was a very strong correlation between hemoglobin concentration and tumor local control probability. Hemoglobin concentration at the beginning of radiotherapy does not correlate with treatment outcome, but any decrease of hemoglobin during therapy is a strong prognostic factor for treatment failure.

CONCLUSIONS

Although regression models with many variables may be instable, the present results suggest that hemoglobin concentration after treatment is at least as important as overall treatment time. It was not possible to find out whether the low concentration of hemoglobin is an independent cause of low TCP or whether it reflects other mechanisms that may influence both hemoglobin level and the TCP.

Induction thermochemotherapy increases therapeutic gain factor for the fractionated radiotherapy given to a mouse fibrosarcoma

PURPOSE

It has been shown that thermochemotherapy (TC) given prior to radiation reduces the number of clonogens, with a resultant decrease in the tumor control radiation dose. The purpose of this article was to investigate using an animal tumor model how this clonogen reduction affects subsequent fractionated radiotherapy, including repopulation of surviving clonogens, and whether the induction TC can increase the therapeutic gain factor (TGF).

METHODS AND MATERIALS

The single-cell suspensions prepared from the fourth-generation isotransplants of a spontaneous fibrosarcoma, FSa-II, were transplanted into the C3Hf/Sed mouse foot. TC was given by heating tumors at 41.5 degrees C for 30 min immediately after an intraperitoneal injection of cyclophosphamide (200 mg/kg) when tumors reached an average diameter of 4 mm. Fractionated radiotherapy (R) with equally graded daily doses was initiated 24 h after TC either in air (A) or under hypoxic conditions (H). The 50% tumor control dose (TCD50) and the radiation dose to induce a score 2.0 reaction (complete epilation with fibrosis) in one-half of irradiated animals, RD50(2.0), were obtained, and the TGF was calculated. Our previous results on the fractionated radiotherapy using the same tumor system served as controls.

RESULTS

The TCD50(A, single dose) and TCD50(H, single dose) following TC+R were 52.2 and 57.3 Gy, respectively, which were 14.0 and 20.4 Gy lower than those following radiation alone. The TCD50(A, TC+R) increased only slightly when the number of fractions was increased from one to 10 doses, and all TCD50s were significantly lower than the TCD50(A, R alone). Both TCD50(H, TC+R) and TCD50(H, R alone) increased consistently from a single dose to 20 doses, but all TCD50(H, TC+R) were significantly lower than the TCD50(H, R alone). Regarding the normal tissue reaction, the RD50 values both following TC+R and R alone increased consistently from a single dose to 20 daily doses. However, the RD50(TC+R) and RD50(R alone) for each corresponding number of fractions was not significantly different, resulting in the TGFs significantly > 1.0 for combined TC+R treatments, with the exception of 20 daily doses given in air.

CONCLUSION

The induction TC decreased the TCD50 values substantially without altering the RD50 for a late reaction, resulting in an significant increase in the TGF. These results encourage the use of TC as an induction treatment prior to fractionated radiotherapy.

Postoperative radiotherapy for head and neck squamous cell carcinomas: feasibility of a biphasic accelerated treatment schedule

PURPOSE

It has been suggested that postoperative tumor cell proliferation may influence the outcome of advanced head and neck squamous cell carcinomas treated by surgery and postoperative radiotherapy. This Phase I pilot study was undertaken to determine the feasibility of a biphasic accelerated radiotherapy regimen with early and late concomitant boost delivery for postoperative treatment of patients with advanced head and neck cancers.

METHODS AND MATERIALS

From April 1993 to April 1994, 29 patients with advanced head and neck cancers were enrolled in this study after they underwent complete surgical resection. The basic radiation course delivered a median dose of 49 Gy in 25 fractions over 5 weeks at 1.8-2 Gy/fraction. The concomitant boost was delivered to the high-risk areas as a second daily fraction during the first (1.4 Gy/fraction) and fifth weeks (1.6 Gy/fraction). The total dose to the high-risk areas was 64 Gy in 35 fractions over 5 weeks.

RESULTS

Twenty-seven patients (93%) completed the treatment without interruptions. Only two patients experienced severe acute toxicity requiring treatment breaks of 6 and 8 days, respectively. All patients developed confluent mucositis; in 69% of the cases it covered >50% of the treated surface. No patient developed Grade 5 (ulceration/bleeding) mucosal reaction. Mucositis required a median time of 7 weeks for complete healing (range 3-43). Two patients developed transient bone exposure. The median weight loss was 5.5% of pretreatment body weight (range 1.2-17.1%), and four patients required nutritional assistance with nasogastric feeding tube.

CONCLUSION

The results of this study show that this biphasic acceleration regimen is feasible with acceptable acute toxicity.

Base-of-tongue carcinoma: treatment results using concomitant boost radiotherapy

PURPOSE

To evaluate the efficacy of accelerated fractionated radiotherapy using the concomitant boost schedule for patients with squamous cell carcinoma of the base of tongue.

METHODS AND MATERIALS

Between September 1984 and July 1992, 54 patients with squamous carcinoma of the base of tongue were treated at The University of Texas M. D. Anderson Cancer Center using the concomitant boost schedule. The distribution of T and N stages was T1-4, T2-27, T3-22, and T4-1; N0-9, N1-11, N2-24, N3-7, and NX-3. American Joint Committee on Cancer (AJCC) stage groupings were II-6, III-14, and IV-34. Before radiation, nodal excision and neck dissection were done in 5 and 10 patients, respectively; 5 patients had neck dissections after radiotherapy. Standard on and off spinal cord fields were irradiated with 1.8 Gy fractions to 54 Gy given over 6 weeks. The boost was given concomitantly during the large field treatment as a second daily (1.5 Gy) fraction, with an interfraction interval of 4-6 h. The median dose to the primary tumor was 72 Gy (range, 66-74 Gy). The median treatment duration was 42 days (range, 39-48 days). Only three patients had treatment interrupted for more than one scheduled treatment day.

RESULTS

The 5-year actuarial overall survival and disease-specific survival rates were 59 and 65%, respectively, with a median follow-up of 41 months. The 5-year actuarial locoregional control rate was 76%. The actuarial local control rates achieved with radiotherapy at 5 years for T1, T2, and T3 primary tumors were 100%, 96%, and 67%, respectively; including surgical salvage, the local control rate of T3 primary tumors was 70%. Six patients had regional failures, which in three patients occurred in conjunction with primary tumor recurrence. Twenty-six patients with regional adenopathy were treated with radiation alone to full dose and had a complete clinical response in the neck; no planned neck dissections were performed in these patients. Only 2 of these 26 patients had subsequent regional failures. The 5-year actuarial risk of distant metastases in patients whose disease was controlled locoregionally was 21%. Grade 3 or 4 confluent acute mucositis occurred in 94% of patients. However, late complications were limited to two cases of transient mandibular exposure and three cases of self-limited mucosal ulcerations.

CONCLUSION

The concomitant boost fractionation schedule is a very effective regimen for this disease when appropriately selected patients are treated with meticulous technique. The therapeutic ratio is favorable, with a high rate of disease control and no persistent severe late complications. Patients whose neck disease responds completely to treatment with this schedule do not appear to need a planned neck dissection.

Derivation of the optimum dose per fraction from the linear quadratic model

The linear quadratic equation for fractionated radiotherapy has already been adapted to include a time factor for tumour repopulation: loge cell kill (E) is given as a function of dose per fraction (d), number of fractions (n), overall treatment time (T) and the clonogen doubling time (Tp). By incorporating a normal tissue isoeffect and replacing the relationship between T and n by a function f, the equation for E can be rewritten as a more complex function of d. In this form, E and d are continuous variables so that the dose per fraction (d') required to produce maximum values of E for isoeffective late normal tissue effects can be found by differential calculus. The derived equation takes the form (beta kTp-alpha Tp)d2 + 1.386fd + 0.693fk = 0 and when solved for d provides a direct estimation of the optimum dose per fraction. Where normal tissue sparing is possible and the tumour dose z is related to the normal tissue dose d, the optimum dose per fraction z' can be found by solving the equation (beta kTp-alpha gTp)z2 + 1.386fgz + 0.693fk = 0 The results show that a critical minimum dose per fraction is required to counteract rapid tumour clonogen repopulation in both conventional and accelerated radiotherapy. The calculus method is reasonably accurate for larger fraction numbers, when clonogen doubling times are 3.5 days or longer and for conventional radiotherapy given 5 days per week. The model is even more accurate for accelerated hyperfractionated radiotherapy providing that there is complete repair between successive fractions. Where greater normal tissue sparing is possible, as with focal teletherapy methods and brachytherapy, higher tumour doses per fraction can be used to increase further the tumour cell kill without exceeding normal tissue tolerance. These predicted doses per fraction are consistent with clinical experience when the given constraints in terms of frequency of treatment are considered. The model described can be used for tumours in which repopulation occurs at a constant rate throughout treatment. For tumours in which accelerated repopulation occurs, the optimum dose per fraction can be separately calculated for the initial phase of slow repopulation (for which very small doses per fraction are optimal) and also for the second phase of rapid repopulation (for which either accelerated hyperfractionated treatments or hypofractionated focal methods of treatment would be appropriate). The limitations of the model are fully discussed including the need for accurate radiobiological predictive assays. In the future such assays of pre-treatment doubling times and tumour cell radiosensitivities could be used to determine reasonable ranges for the optimum dose per fraction in experimental tumours and subsequently in clinical trails. This approach could produce major improvements in the therapeutic potential of radiotherapy.

Very accelerated radiation therapy: preliminary results in locally unresectable head and neck carcinomas

PURPOSE

To report preliminary results of a very accelerated radiation therapy Phase I/II trial in locally advanced head and squamous cell carcinomas (HNSCC).

METHODS AND MATERIALS

Between 01/92 and 06/93, 35 patients with an unresectable HNSCC were entered in this study. Thirty-two (91%) had Stage IV, and 3 had Stage III disease. The mean nodal diameter, in patients with clinically involved nodes (83%), was 6.3 cm. The median Karnovsky performance status was 70. The treatment consisted of a twice daily schedule (BID) giving 62 Gy in 20 days.

RESULTS

In all cases, confluent mucositis was observed, which started about day 15 and resolved within 6 to 10 weeks. Eighty percent of patients had enteral nutritional support. The nasogastric tube or gastrostomy was maintained in these patients for a mean duration of 51.8 days. Eighteen patients (53%) were hospitalized during the course of treatment due to a poor medical status or because they lived far from the center (mean 25 days). Nineteen patients (56%) (some of whom were initially in-patients) were hospitalized posttreatment for toxicity (mean 13 days). Five patients (15%) were never hospitalized. During the follow-up period, 12 local and/or regional failures were observed. The actuarial 18-month loco-regional control rate was 59% (95% confidence interval, 45-73%).

CONCLUSIONS

The dramatic shortening of radiation therapy compared to conventional schedules in our series of very advanced HNSCC resulted in: (a) severe acute mucosal toxicity, which was manageable but required intensive nutritional support in all cases; and (b) high loco-regional response rates, strongly suggesting that the time factor is likely to be critical for tumor control in this type of cancer.

Advances in radiotherapy for head and neck cancer

Selected advances in radiotherapy for treatment of head and neck cancer are reviewed. These include the role of postoperative radiotherapy, planned postirradiation neck dissection, altered fractionation, neoadjuvant chemotherapy and radiotherapy for laryngeal preservation, three-dimensional conformal treatment planning, charged particle irradiation for skull base tumors, and stereotactic radiosurgery.

Double-blind randomized study of lonidamine and radiotherapy in head and neck cancer

PURPOSE

Preclinical studies showed lonidamine to potentiate the effects of x-irradiation by inhibiting the repair of potentially lethal damage. This Phase III double blind, placebo-controlled study was performed to evaluate whether lonidamine can increase the tumor control of radiotherapy in the treatment of advanced head and neck cancer without any synergistic toxic effects on the exposed normal tissues.

METHODS AND MATERIALS

Ninety-seven patients with Stages II-IV squamous cell carcinoma of the head and neck were enrolled. Separate analyses were done on the 96 eligible patients and the 90 patients who completed the prescribed treatment regimen. Patients received radiotherapy up to a planned total of 60-66 Gy, in 2 daily fractions of 1.5 Gy each and either lonidamine (450 mg p.o. in three divided daily doses) or placebo, given continuously for 3 months or up to 1 month after the end of radiotherapy.

RESULTS

The rate of tumor clearance was 66% (32/48) in the lonidamine group and 65% (31/48) in the placebo group, while the subsequent failure rate was 50% and 77%, respectively (p < 0.05). The 3 and 5 year locoregional control rates in the adequately treated patients achieving complete tumor clearance were 66% and 63% for lonidamine vs. 41% and 37% for placebo. The disease-free survival in adequately treated patients was significantly better in the lonidamine group (p < 0.03), with 3 and 5 year rates of 44% and 40%, respectively, vs. 23% and 19% in the placebo group. The overall survival rate for all eligible patients at both 3 and 5 years was 44% in the lonidamine group and 44% and 31%, respectively, in the placebo group. Both acute and late radiation reactions were similar in the two groups. Myalgia and testicular pain were the most frequent side effects of lonidamine with an incidence of 8.5% and 4.2%, respectively.

CONCLUSION

The addition of lonidamine to hyperfractionated radiotherapy was correlated with a statistically and clinically significant proportion of long-term disease-free patients. The toxicity of radiotherapy was not aggravated by the drug and the overall tolerance of the combined regimen was acceptable.

Dynamics of tumor cell clonogen repopulation in a murine sarcoma treated with cyclophosphamide

Experiments were performed to establish the extent and kinetics of tumor cell repopulation in a murine sarcoma, designated SA-NH, treated with cyclophosphamide (CY). Mice bearing 8-mm leg tumors were treated with 200 mg/kg CY which caused a transient tumor regression. Changes in the absolute clonogen content of tumors was determined by the change in TCD50 values (50% tumor control) obtained under hypoxic conditions of local tumor irradiation at different times after CY treatment until tumors regrew to the pretreatment size. For comparison, hypoxic TCD50 values were determined during the growth of tumors not treated with CY. CY greatly depleted tumors of clonogenic cells as manifested by the reduction in the control TCD50 value of 64.5 Gy to 32.8 Gy 1 day after CY treatment. The reduced TCD50 value remained unchanged for 2 weeks after treatment with CY, at which time the TCD50 began to rapidly increase, continuing until the end of the observation period of 21 days when tumors reached the pretreatment size. In contrast, there was a constant but slower increase in TCD50 values during the growth of tumors not treated with CY. The daily increase in TCD50 was more than twice as high in CY-treated than in CY-untreated tumors: 4.5 Gy/day versus 2.1 Gy/day. This implies that the rate of clonogen production in CY-treated tumors was twice as high as that of unperturbed tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Potential doubling time in head and neck tumors treated by primary radiotherapy: preliminary evidence for a prognostic significance in local control

PURPOSE

The aim of the study was to determine preliminarily whether cell kinetic parameters evaluated using in vivo infusion of bromodeoxyuridine (BrdUrd) and flow cytometry, play a role as prognostic factors of loco-regional control in squamous cell head and neck carcinoma treated with radiotherapy.

METHODS AND MATERIALS

Between April 1989 and December 1991, 42 patients with unresectable Stage II-IV squamous cell carcinoma of the oral cavity, pharynx or larynx were given an infusion of BrdUrd solution prior to primary tumor biopsy sampling at 4-6 hr later. The simultaneous labeling S-phase fraction (LI) and duration (Ts) as well as the estimated potential doubling time (Tpot) were measured using flow cytometric analysis of BrdUrd and DNA content. Twenty-six patients received standard radiotherapy (70 Gy/35 fractions/7 weeks) whereas 15 patients were treated with the concomitant boost technique (75 Gy/40 fractions/6 weeks).

RESULTS

A complete set of flow cytometric data was available for 31 patients. The median value of LI, Ts, and Tpot were 9%, 9 hr and 5 days, respectively. Univariate analysis among the patients treated homogeneously by standard radiotherapy, indicated that local control was affected by Tpot value (p = 0.02). When the same analysis was performed for the patients treated with either standard radiotherapy or concomitant boost regimen, we found a p = 0.04. Thus, patients with a tumor Tpot value < or = 5 days had a significantly lower three-year local control than patients with Tpot > 5 days. Log-rank test univariate analysis showed, in addition, that nodal status was the strongest prognostic factor of local control (p = 0.005). Age, tumor stage, tumor site, performance status, grading, radiotherapy regimen, DNA ploidy and LI value were, instead, not significantly related to loco-regional control. Finally, when comparing the type of radiotherapy for tumors with Tpot < or = 5 days, we found a trend toward a better local control after concomitant boost regimen, with respect to standard regimen (p = 0.06).

CONCLUSION

The present preliminary results suggest that Tpot could play a role as additional prognostic factor influencing the disease outcome in head and neck carcinoma treated by radiotherapy.

Radiotherapy alone or combined with neck dissection for T1-T2 carcinoma of the pyriform sinus: an alternative to conservation surgery

PURPOSE

We present our experience with irradiation alone or combined with neck dissection for AJCC T1-T2 pyriform sinus carcinoma and compare our results to those obtained with conservation surgery.

METHODS AND MATERIALS

Seventy-three patients were treated between 1964 and 1990. All patients had a minimum of 2 years of follow-up; no patient was lost to follow-up.

RESULTS

The 5-year rates of local control and ultimate local control were, for Stage T1 (17 patients), 88% and 94%; and for Stage T2 (56 patients), 79% and 91%. Patients with T2 lesions had a significantly higher rate of local control after twice-daily, compared with once-daily, irradiation (p = .04). However, a multivariate analysis of various parameters revealed that none of the variables tested significantly influenced this end point: vocal cord mobility (p = .15), once- vs. twice-daily fractionation (p = .33), T1 vs. T2 (p = .32), apex invasion (p = .58), and pretreatment CT scan (p = .67). Local control with laryngeal voice preservation was obtained in 88% of patients with T1 cancers and 80% of those with T2 cancers. Ultimate control above the clavicles at 5 years according to AJCC stage was as follows: I and II, 100%; III, 78%; IVA, 75%; and IVB, 60%. The probability of cause-specific survival at 5 years was as follows: I and II, 100%; III, 83%; and IVA and IVB, 51%. Overall, nine patients (12%) developed severe complications, one of which was fatal.

CONCLUSION

Compared with available data from series using conservation surgery, radiotherapy alone or followed by neck dissection results in similar rates of local control and survival with a significantly lower risk of fatal complications.

Dose intensification in curative head and neck cancer radiotherapy--linear quadratic analysis and preliminary assessment of clinical results

PURPOSE

The feasibility of reducing overall treatment time by 2 weeks in the curative radiotherapeutic management of head and neck cancer patients is reported in a pilot trial of Hyperfractionated, Accelerated Radiotherapy with Dose Escalation (HARDE). This regimen prescribes 76 Gy in 5 weeks to definitive head and neck cancer patients, and 65 Gy in 5 weeks to high-risk postoperative patients. The linear quadratic model is used to compare predicted tumor cell kill with HARDE versus that expected with conventional fractionation (CF).

MATERIALS AND METHODS

Between January 1991 and March 1992, 40 head and neck cancer patients were treated with HARDE at the University of Wisconsin Comprehensive Cancer Center. Case-matched controls treated with CF were identified from patients treated at the same institution between 1980-1990, based on tumor site, stage, and extent of prior surgery. Individual patient treatment data (total dose, fraction size, overall time) rather than idealized schedule data from each group were analyzed using the linear quadratic model.

RESULTS

Seventy-nine case-matched controls were identified for comparison with HARDE patients. The predicted increase in log cell kill for HARDE patients over case-matched controls was 1.5 and 1.3 logs, respectively, in the definitive and postoperative settings. This difference in log cell kill projects an improvement in locoregional tumor control for HARDE patients of between 10-25%. HARDE patients experience very brisk acute mucosal reactions and moderately prolonged mucosal healing, however, 91% have completed therapy without a treatment break.

CONCLUSION

A 2-week reduction in overall treatment time for curative head and neck cancer patients is feasible while maintaining doses > 70 Gy. Based on radiobiologic predictions, such treatment intensification may significantly improve rates of locoregional tumor control. However, intensified acute mucosal reactions accompany such accelerated therapy.