Acute Pulmonary Edema After Hyperbaric Oxygen Treatment: A Case Report Written With ChatGPT Assistance

Acute pulmonary edema is a rare but severe complication of hyperbaric oxygen therapy. While patients with known cardiovascular problems may be able to withstand this therapy, rapid decompensation can still occur. Here, we present a case of a patient with known low ejection fraction and severe mitral regurgitation who developed acute pulmonary edema during the first hyperbaric treatment for a foot ulcer. This case highlights the importance of identifying patients that are high risk, such as those with moderate-to-severe cardiac disease, and pursuing other treatment options to avoid this complication.

Hyperbaric oxygen therapy does not alleviate tourniquet-induced acute ischemia-reperfusion injury in mouse skeletal muscles

During tourniquet application, blood flow is restricted to a limb to stop excessive limb hemorrhage in a trauma setting and to create a bloodless operating field in the surgical setting. During tourniquet-related ischemia, aerobic respiration stops, and ATP is depleted, and during subsequent reperfusion, there is an increase in reactive oxygen species (ROS) production and other endogenous substances, which leads to acute ischemia-reperfusion (IR) injuries, including tissue necrosis and skeletal muscle contractile dysfunction. Hyperbaric oxygen (HBO) therapy can increase the arterial oxygen tension in the tissues of patients with general hypoxia/anoxia, including carbon monoxide poisoning, circulatory arrest, and cerebral and myocardial ischemia. Here, we studied the protective effects of HBO pretreatment with 100% oxygen at 2.5 ATA against tourniquet/IR injury in mice. After one hour of HBO therapy with 100% oxygen at 2.5 ATA was administered to C57/BL6 mice, a rubber band was placed at the hip joint of the unilateral hindlimb to induce 3 h of ischemia and then released for 48 h of reperfusion. We analyzed gastrocnemius muscle morphology and contractile function and measured the levels of ATP and ROS accumulation in the muscles. HBO pretreatment did not improve tourniquet/IR-injured gastrocnemius muscle morphology and muscle contraction. Tourniquet/IR mice with HBO pretreatment showed no increase in ATP levels in IR tissues, but they did have a decreased amount of ROS accumulation in the muscles, compared to IR mice with no HBO pretreatment. These data suggest that one hour of HBO pretreatment with 100% oxygen at 2.5 ATA increases the antioxidant response to lower ROS accumulation but does not increase ATP levels in IR muscles and improve tourniquet/IR-injured muscle morphology and contractile function.

Carbon monoxide poisoning can act as a stress test to reveal underlying coronary artery disease: case report

Carbon monoxide (CO) poisoning presents with many different cardiac effects, but one important presentation is its effect as a CO stress test to reveal underlying coronary artery disease (CAD). There are a limited number of publications detailing this phenomenon, but after CO intoxication it is important to suspect CAD in association with mild troponin leak or non-ST segment elevation myocardial infarction (NSTEMI) shown on electrocardiogram (EKG). We recently treated three patients with CO poisoning who had underlying CAD. In the first case a man presented to the emergency department with CO toxicity and an ST segment elevation myocardial infarction (STEMI), resulting in emergent angioplasty and the discovery of severe CAD. The second case involved an individual who presented with CO poisoning with rising troponin levels. An angioplasty discovered a stable 90% occlusion. The third case was a patient with CO poisoning and transient inferior T wave inversion EKG with borderline troponin elevation. Angioplasty showed only 30% occlusion, so the patient's presentation was likely due to direct CO cardiac toxicity. These cases demonstrate the varied presentations that CO poisoning can have on patients with underlying heart disease.

Retinal Artery and Vein Occlusions Successfully Treated with Hyperbaric Oxygen

We present six cases of central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO) that we recently treated with hyperbaric oxygen (HBO₂). Patients in three of the six cases, including the CRVO case, experienced near to complete restoration of their vision. Another case had marked improvement. Our findings are similar to other case studies with approximately 65-70% improvement in patients treated for CRAO. Physicians should be aware that rapid referral of CRAO and CRVO patients to HBO₂ is efficacious. Such patients should be placed on 100% oxygen by non-rebreather mask as soon as the diagnosis is suspected, pending transportation to HBO₂.

Risk of continuous bladder irrigation in the monoplace hyperbaric chamber: a cautionary tale

We previously published our method of performing continuous bladder irrigation (CBI) in a monoplace hyperbaric chamber [1]. This method entailed the use of an IV pump to infuse saline into the monoplace chamber. The specter of causing iatrogenic rupture of the bladder was raised following such a case, reported herein, of a woman with hemorrhagic radiation cystitis leading to cystectomy. Due to the danger of bladder rupture while providing CBI with a pump, we retract ourpreviously reported method and encourage the use of either a gravity-fed system or delay in hyperbaric oxygen therapy treatment until CBI is no longer necessary.

Hyperbaric oxygen for late sequelae of carbon monoxide poisoning enhances neurological recovery: case report

Neuropsychiatric sequelae have been reported in 15%-45% of survivors of carbon monoxide (CO) poisoning. Hyperbaric oxygen (HBO₂) therapy reduces the incidence of cognitive and neurological a dysfunction. The efficacy of providing HBO₂ beyond the first one to two days after initial insult is unknown. However, some evidence exists for the benefit of this treatment. We report on treating a patient 14 months after CO injury, who responded with markedly improved neurologic status. A 27-year-old scholar was found comatose due to CO poisoning (carboxyhemoglobin = 31.7%). He received five acute HBO₂ treatments. After discharge, he developed chorea, Parkinsonism, dystonia, memory loss, slowed processing speed and verbal fluency, leaving him disabled. After the patient reached a clinical plateau, HBO₂ was tried again at 90 minutes at 2.4 ATA plus air breaks. Neuropsychological testing was performed at baseline and after each 20 HBO₂ cycles, five of which were performed during the period from 14-22 months after CO exposure. After the first 20 treatments, Parkinsonism and dystonia improved. After 40 sessions, further improvements were seen on mental speed, verbal fluency, and fine motor movements. The outcome following 100 treatments was that the patient regained independence, including the ability to drive and to become gainfully employed. Our case calls into question the concept that HBO₂ therapy has no role during the chronic phase of CO brain injury. Randomized clinical trials should be considered to evaluate the therapeutic efficacy of HBO₂ in patients with neurological sequelae following CO injury.

Hyperbaric oxygen-associated seizure leading to stroke

Oxygen toxicity seizures are a well-known complication of hyperbaric oxygen treatment (HBOT). Until now, there have not been any reported cases of an acute ischaemic event (stroke) as the result of a HBOT-associated oxygen toxicity seizure. We report an event in which a seizure and stroke occurred together and consider that the stroke may have been caused by seizure-induced demand ischaemia. This challenges the generally held view that oxygen toxicity seizures in the clinical hyperbaric setting are benign. A discussion of the literature on the subject of seizure-induced brain injury is included. Risk factors for cerebrovascular disease should be taken into consideration in determining treatment pressures for HBOT, as reducing pressure reduces seizure risk.

Endoscopic Bubble Trouble: Hyperbaric Oxygen Therapy for Cerebral Gas Embolism During Upper Endoscopy

Gas embolism is a rare but potentially devastating complication of endoscopic procedures. We describe 3 cases of gas embolism which were associated with endoscopic procedures (esophagogastroduodenoscopy and endoscopic retrograde cholangiopancreatography). We treated these at our hyperbaric medicine center with 3 different outcomes: complete resolution, death, and disability. We review the literature regarding this unusual complication of endoscopy and discuss the need for prompt identification and referral for hyperbaric oxygen therapy. Additional adjunctive therapies are also discussed.

Bitten by a Dragon

Komodo dragons (Varanus komodoensis) are large lizards known to take down prey even larger than themselves. They rarely attack humans. A 38-year-old woman was bitten by a Komodo dragon on her hand while cleaning its enclosure. She was transiently hypotensive. The wounds were extensively cleaned, and she was started on prophylactic antibiotics. Her wounds healed without any infectious sequelae. Komodo dragon bites are historically thought to be highly infectious and venomous. Based on a literature review, neither of these are likely true. As in any bite, initial stabilization followed by wound management are the main components to therapy.

Continuous bladder irrigation in the monoplace hyperbaric chamber: Two case reports

INTRODUCTION

Radiation-induced hemorrhagic cystitis is a serious side effect of radiation therapy. Anemia requiring transfusion can ensue. Treatment methods include bladder irrigation, fulguration, and hyperbaric oxygen (HBO2) therapy. Failure of treatment leads to cystectomy associated with a high risk of severe complications (42%) and mortality (16%). Continuous bladder irrigation (CBI) is often required to prevent further clot formation. HBO2 supports the healing process of radiation cystitis. In patients requiring CBI, the time in HBO2 can help cause clot accumulation and obstruction. We describe a method of providing CBI in a monoplace hyperbaric chamber.

MATERIALS AND METHODS

An IV to catheter adapter is used, allowing an IV pump to control CBI flow into the chamber. Drainage is collected in an extra-large (2- to 5-liter) bag. The rate is set so the volume does not exceed the bag's capacity. The bag is placed in a manner that precludes spilling and allows monitoring of outflow.

RESULTS

CBI was successfully maintained. Brief cases are presented and issues discussed.

SUMMARY/CONCLUSIONS

CBI is easily maintained in a monoplace hyperbaric chamber, with readily available equipment allowing for uninterrupted CBI of hemorrhagic cystitis. HBO2 helps mitigate the potential side effects of other interventions in a previously irradiated area.

Hyperbaric oxygen: a useful adjunct for purpura fulminans: case report and review of the literature

INTRODUCTION

We report a case of a previously healthy adult with flulike symptoms who precipitously declined due to pneumococcal sepsis complicated by disseminated intravascular coagulation (DIC) and purpura fulminans (PF). After one week of care, including ventilation support and hemodialysis, the patient was stable enough for hyperbaric oxygen (HBO2) in an attempt to salvage his threatened extremities. HBO2 resulted in reduction of ischemic tissue and demarcation of blackened tissue to the distal digits. We feel that much at-risk tissue has been spared by HBO2 as an adjunctive therapy.

METHODS

Literature on the use of hyperbaric oxygen for purpura fulminans was reviewed for precipitating issues, time to treatment, protocol, other adjuncts and outcomes.

RESULTS

Fifteen papers were identified representing 19 cases of PF treated with HBO2. No controlled studies exist. HBO2 was believed to be of value in most cases; the improvement was associated with timeliness and aggressiveness of initiating HBO2.

CONCLUSIONS

PF is a fulminant disorder with high mortality and morbidity. Hyperbaric oxygen appears to be useful for the management of PF complications, imposing minimal side effects or complications. Aggressive therapy should be started as soon as it is safe to transfer the patient to a facility for HBO2 treatments.

Preliminary results of Radiation Therapy Oncology Group 97-03: a randomized phase ii trial of concurrent radiation and chemotherapy for advanced squamous cell carcinomas of the head and neck

PURPOSE

To define further the role of concurrent chemoradiotherapy for patients with advanced squamous carcinoma of the head and neck.

PATIENTS AND METHODS

The Radiation Therapy Oncology Group developed this three-arm randomized phase II trial. Patients with stage III or IV squamous carcinoma of the oral cavity, oropharynx, or hypopharynx were eligible. Each of three arms proposed a radiation schedule of 70 Gy in 35 fractions. Patients on arm 1 were to receive cisplatin 10 mg/m(2) daily and fluorouracil (FU) 400 mg/m(2) continuous infusion (CI) daily for the final 10 days of treatment. Treatment on arm 2 consisted of hydroxyurea 1 g every 12 hours and FU 800 mg/m(2)/d CI delivered with each fraction of radiation. Arm 3 patients were to receive weekly paclitaxel 30 mg/m(2) and cisplatin 20 mg/m(2). Patients randomly assigned to arms 1 and 3 were to receive their treatments every week; patients on arm 2 were to receive their therapy every other week.

RESULTS

Between 1997 and 1999, 241 patients were entered onto study; 231 were analyzable. Ninety-two percent, 79%, and 83% of patients on arms 1, 2, and 3, respectively, were able to complete their radiation as planned or with an acceptable variation. Fewer than 10% of patients had unacceptable deviations or incomplete chemotherapy in the three arms. Estimated 2-year disease-free and overall survival rates were 38.2% and 57.4% for arm 1, 48.6% and 69.4% for arm 2, and 51.3% and 66.6% for arm 3.

CONCLUSION

We have demonstrated that three different approaches of concurrent multiagent chemotherapy and radiation were feasible and could be delivered to patients in a multi-institutional setting with high compliance rates.

Association of revascularisation with low mortality in non-ST elevation acute coronary syndrome, a report from GUSTO IV-ACS

BACKGROUND

Immediate, as well as early, revascularisation is of benefit in patients with acute coronary syndromes (ACS) presenting with ST elevation. However, trials comparing invasive versus medical treatment in patients with an acute coronary syndrome without ST elevation do not consistently show improvement in survival after revascularisation. Accordingly, additional data are warranted.

METHODS

The effect of revascularisation within 30 days on one-year survival in the GUSTO IV ACS trial was investigated. A total of 7800 patients were included with an acute coronary syndrome without ST elevation, documented by either elevated cardiac troponin or transient or persistent ST-segment depression. In this trial, comparing abciximab versus placebo as initial medical therapy, coronary angiography within 60 h after randomisation was discouraged. In 30-day survivors, those who underwent revascularisation were compared with 30-day survivors without revascularisation. Adjustments were made for patient characteristics, and for a propensity score that was adjusted for covariates associated with the likelihood of early revascularisation.

FINDINGS

Of the 7496 patients who survived at least 30 days, 2265 (30%) underwent coronary revascularisation within 30 days: 789 patients CABG, 1450 PCI and 26 both CABG and PCI. Procedure-related mortality was low at 1.8%. Patients with revascularisation had a lower one-year mortality compared to medically treated patients (2.3% vs. 5.6%, p < 0.001). After multivariable analyses, patients with revascularisation had a relative risk of subsequent mortality within 1 year of 0.53 (95% CI 0.37-0.77) compared to patients without revascularisation.

CONCLUSIONS

Revascularisation within 30 days is associated with an improved prognosis in ACS without ST-segment elevation. The relative high mortality in medically treated patients may be related in part to patient selection, but warrants further studies to improve outcome of these patients.

Long-term results after the glycoprotein IIb/IIIa inhibitor abciximab in unstable angina: one-year survival in the GUSTO IV-ACS (Global Use of Strategies To Open Occluded Coronary Arteries IV--Acute Coronary Syndrome) Trial

BACKGROUND

This study was designed to investigate long-term effects of the glycoprotein IIb/IIIa inhibitor abciximab in patients with acute coronary syndrome without ST elevation who were not scheduled for coronary intervention.

METHODS AND RESULTS

A total of 7800 patients were included with an acute coronary syndrome without ST elevation, documented by either elevated cardiac troponin or transient or persistent ST-segment depression. They were randomized to abciximab bolus and 24-hour infusion, abciximab bolus and 48-hour infusion, or matching placebo. The overall 1-year mortality rate was 8.3% (649 patients). One-year mortality was 7.8% in the placebo group and 8.2% in the 24-hour and 9.0% in the 48-hour abciximab infusion group. Compared with placebo, the hazard ratio for the 24-hour infusion of abciximab was 1.1 (95% CI 0.86 to 1.29), and for the 48-hour infusion, it was 1.2 (95% CI 0.95 to 1.41). The lack of benefit of abciximab was observed in every subgroup studied. Patients with negative troponin or elevated C-reactive protein had a higher mortality rate after treatment with abciximab for 48 hours than with placebo: 8.5% versus 5.8% in those with negative troponin (P=0.02), 16.3% versus 12.1% in those with elevated C-reactive protein (P=0.04).

CONCLUSIONS

Compared with placebo, abciximab did not provide any survival benefit at 1 year in patients admitted with an acute coronary syndrome with ST depression and/or elevated troponin who were not scheduled to undergo early coronary revascularization. In subgroups of patients, in particular those with low cardiac troponin or elevated C-reactive protein, abciximab was associated with excess mortality.

Elective radiation therapy for high-risk malignant melanomas

PURPOSE

Local-regional recurrence rates of 30%-50% have been reported after resection of high-risk malignant melanomas (multiple node involvement, extracapsular spread, deep invasion, recurrent disease, and/or microscopically involved margins). Recently, we have been offering elective radiation therapy, after definitive surgery, to selected patients who have high-risk malignant melanomas. We herein report our initial results.

PATIENTS AND METHODS

From 1993 to 1999, 40 patients who underwent surgery for high-risk malignant melanomas (multiple involved lymph nodes [21 patients]; close or microscopically involved surgical margins [nine patients]; extracapsular extension [six patients]; previously resected, recurrent disease [three patients]; and/or primary tumors more than 4 mm thick [four patients]) received elective radiation therapy. Thirty-six patients received 3000 cGy in five fractions (600 cGy per fraction given twice weekly), and four patients received 3600 cGy in six fractions.

RESULTS

At a median follow-up of 18.4 months (range, 3.8-74.1 months), the actuarial 5-year local-regional control rate was 84%. Systemic recurrence rates in these patients were similar to those reported for this subset of patients, and the actuarial overall survival rate at 5 years was 39%. Acute toxicity was limited to erythema of the skin and, in one instance, probable cellulitis, with no late sequelae.

DISCUSSION

Elective radiation therapy (600 cGy per fraction for five or six fractions) effectively controlled residual subclinical disease after surgery; however, better adjuvant systemic therapies need to be designed to eliminate distant metastases and to alter survival rates.

Validation of the RTOG recursive partitioning classification for head and neck tumors

BACKGROUND

We previously demonstrated that a mathematical technique called recursive partitioning analysis (RPA), when applied to the Radiation Therapy Oncology Group Head and Neck Cancer database, created rules that formed subgroups ("classes") having unique outcomes. We sought to learn if the application of RPA-derived rules to a new head and neck database would create classes that were similarly associated with outcome and thereby validate this technique.

METHODS

The rules derived from recursive partitioning analysis of the previous database were used to subgroup an independent, new head and neck cancer database (RTOG 85-27), created as part of a phase III trial of the hypoxic-cell radiosensitizer, Etanidazole. The resulting classes were compared with each other and with the classes formed from the previous database.

RESULTS

The rules derived by RPA from our previous database correctly grouped the tumors in the new database into unique classes of similar outcome. RPA could successfully use either survival or local-regional control of disease as the measure of outcome. As judged by comparison of the 95% confidence intervals, the outcome of the classes in the new database is essentially indistinguishable from the outcome of the classes in the previous database.

CONCLUSION

RPA-derived rules provide a reliable method to assort head and neck tumors into unique classes that are predictive of outcome. These rules can be successfully applied to new databases that were not used in the creation of the rules and thereby validate the methodology.

The impact of smoking status, disease stage, and index tumor site on second primary tumor incidence and tumor recurrence in the head and neck retinoid chemoprevention trial

Second primary tumors (SPTs) develop at an annual rate of 3-7% in patients with head and neck squamous cell cancer (HNSCC). In a previous Phase III study, we observed that high doses of 13-cis-retinoic acid reduced the SPT rate in this disease. In 1991, we launched an intergroup, placebo-controlled, double-blind study to evaluate the efficacy of low-dose 13-cis-retinoic acid in the prevention of SPTs in patients with stage I or II squamous cell carcinoma of the larynx, oral cavity, or pharynx who had been previously successfully treated with surgery, radiotherapy, or both, and whose diagnoses had been established within 36 months of study entry. As of September 16, 1999, the Retinoid Head and Neck Second Primary (HNSP) Trial had completed accrual with 1384 registered patients and 1191 patients randomized and eligible. All of the patients were followed for survival, SPT development, and index cancer recurrence. Smoking status was assessed at study entry and during study. Smoking cessation was confirmed biochemically by measurement of serum cotinine levels. The annual rate of SPT development was analyzed in terms of smoking status and tumor stage. As of May 1, 2000, SPTs have developed in 172 patients. Of these, 121 (70.3%) were tobacco-related SPTs, including 113 in the aerodigestive tract (57 lung SPTs, 50 HNSCC SPTs, and 6 esophageal SPTs) and 8 bladder SPTs. The remaining 51 cases included 23 prostate adenocarcinomas, 8 gastrointestinal malignancies, 6 breast cancers, 3 melanomas, and 11 other cancers. The annual rate of SPT development observed in our study has been 5.1%. SPT development related to smoking status was marginally significant (active versus never, 5.7% versus 3.5%; P = 0.053). Significantly different smoking-related SPT development rates were observed in current, former, and never smokers (annual rate = 4.2%, 3.2%, and 1.9%, respectively, overall P = 0.034; current versus never smokers, P = 0.018). Stage II HNSCC had a higher overall annual rate of SPT development (6.4%) than did stage I disease (4.3%; P = 0.004). When evaluating the development of smoking-related SPTs, stage was also highly significant (4.8% for stage II versus 2.7% for stage I; P = 0.001). Smoking-related SPT incidence was significant for site as well (larynx versus oral cavity, P = 0.015; larynx versus pharynx, P = 0.011). Primary tumors recurred at an annual rate of 2.8% in a total of 97 patients. The rate of recurrence was higher in patients with stage II disease (4.1% versus 2.2%, P = 0.004) as well as oral cavity site when compared with larynx (P = 0.002). This is the first large-scale prospective chemoprevention study evaluating smoking status and its impact on SPT development and recurrence rate in HNSCC. The results indicate significantly higher SPT rates in active smokers versus never smokers and significantly higher smoking-related SPT rates in active smokers versus never smokers, with intermediate rates for former smokers.

Radiation palliation of cervical cancer

Radiation is a useful modality for palliation of local-regional disease in patients with cervical cancer who require palliation because of distant metastases, extensive local-regional disease, medical consideration, or patient concerns. Two radiation schedules have been reported on for the treatment of advanced pelvic disease including cervical cancer. The large single-dose schedule consisted of 10-Gy fractions repeated at monthly intervals to a maximum of 30 Gy. This schedule has produced good palliative results with symptomatic improvement in approximately 50% of patients and objective response in 35%-80%. However, severe late toxicity was shown to be as high as 42% (actuarial). The second schedule tested by the Radiation Therapy Oncology Group consisted of 3.7-Gy fractions given twice a day for 2 days (14.8 Gy) repeated after 2-4 weeks for a maximum of 44.4 Gy. There were 284 patients accrued, and the subgroup of 61 cervical cancer patients is analyzed in this article. The subjective response (50%-100% complete response) and objective response (53%) were similar to those observed with the large single-fraction schedule. The late toxicity was significantly lower (7%-actuarial). For patients who may survive 6 months or longer, this second schedule is preferable.

A Radiation Therapy Oncology Group (RTOG) phase III randomized study to compare hyperfractionation and two variants of accelerated fractionation to standard fractionation radiotherapy for head and neck squamous cell carcinomas: first report of RTOG 9003

PURPOSE

The optimal fractionation schedule for radiotherapy of head and neck cancer has been controversial. The objective of this randomized trial was to test the efficacy of hyperfractionation and two types of accelerated fractionation individually against standard fractionation.

METHODS AND MATERIALS

Patients with locally advanced head and neck cancer were randomly assigned to receive radiotherapy delivered with: 1) standard fractionation at 2 Gy/fraction/day, 5 days/week, to 70 Gy/35 fractions/7 weeks; 2) hyperfractionation at 1. 2 Gy/fraction, twice daily, 5 days/week to 81.6 Gy/68 fractions/7 weeks; 3) accelerated fractionation with split at 1.6 Gy/fraction, twice daily, 5 days/week, to 67.2 Gy/42 fractions/6 weeks including a 2-week rest after 38.4 Gy; or 4) accelerated fractionation with concomitant boost at 1.8 Gy/fraction/day, 5 days/week and 1.5 Gy/fraction/day to a boost field as a second daily treatment for the last 12 treatment days to 72 Gy/42 fractions/6 weeks. Of the 1113 patients entered, 1073 patients were analyzable for outcome. The median follow-up was 23 months for all analyzable patients and 41.2 months for patients alive.

RESULTS

Patients treated with hyperfractionation and accelerated fractionation with concomitant boost had significantly better local-regional control (p = 0.045 and p = 0.050 respectively) than those treated with standard fractionation. There was also a trend toward improved disease-free survival (p = 0.067 and p = 0.054 respectively) although the difference in overall survival was not significant. Patients treated with accelerated fractionation with split had similar outcome to those treated with standard fractionation. All three altered fractionation groups had significantly greater acute side effects compared to standard fractionation. However, there was no significant increase of late effects.

CONCLUSIONS

Hyperfractionation and accelerated fractionation with concomitant boost are more efficacious than standard fractionation for locally advanced head and neck cancer. Acute but not late effects are also increased.

Radiation Therapy Oncology Group (RTOG) trials for head and neck cancer

Clinical investigations for cancer of the head and neck, primarily tumors of the upper respiratory and digestive tracts, have been one of the most important components of the Radiation Therapy Oncology Group (RTOG) since its inception 30 years ago. Emphasis from the very beginning to the present time has been on altered fractionation. Studies of hypoxic cell sensitizers were also explored for many years. More recently, combinations of radiation therapy with cytotoxic chemotherapeutic agents, either sequentially or concurrently, have been a major focus. Although the majority of the trials have been for unresectable tumors, surgical adjuvant radiation therapy alone or combined with chemotherapy has also been an important activity. Combined modality trials emphasizing organ conservation have been carried out within the last decade. The RTOG represents a national and international resource for studies of cancer of the head and neck. Its results influence the care of patients and the clinical research environment.

Improved outcome secondary to concurrent chemoradiotherapy for advanced carcinoma of the nasopharynx: preliminary corroboration of the intergroup experience

PURPOSE

The recent Intergroup 0099 trial of concurrent chemoradiotherapy for advanced nasopharyngeal carcinomas, demonstrated improved survival for chemoradiotherapy as compared to radiation therapy alone. Following closure of this study, we adopted the chemoradiotherapy regimen used in 0099 as our standard of practice. We herein report our recent institutional results, representing a relatively large uniformly treated cohort.

METHODS AND MATERIALS

Between 1995 and 1997, 35 consecutive patients, who had clinically nondisseminated Stage III or IV nasopharyngeal cancer, were treated by chemoradiotherapy. The prescribed radiation regimen was 7000 cGy delivered in 35 fractions over 7 weeks to all macroscopic disease and 5000 cGy to areas considered at risk of harboring microscopic disease. Chemotherapy was designed to deliver cisplatin (100 mg/m(2) i.v.) on Days 1, 22, and 43 of radiation therapy and cisplatin (80 mg/m(2) i.v.) on Days 71, 99, and 127 plus flurouracil (5-FU; 1 g/m(2)/day by 96-h infusion) on Days 71-74, 99-102, and 127-130.

RESULTS

All patients had at least a partial response (PR) to treatment, including an 85% complete response (CR) rate. The actuarial 3-year overall survival rate was 93% and the disease-free survival rate was 65%. Both represent substantial improvements over our institutional historical controls treated by radiation therapy alone and both are similar to the rates observed in the Intergroup trial.

CONCLUSION

Our data support the conclusion that concurrent chemoradiotherapy followed by adjuvant chemotherapy (as was used in Intergroup 0099) should be considered the current standard of care for patients who have advanced cancers of the nasopharynx.

Chemoradiotherapy of locally advanced esophageal cancer: long-term follow-up of a prospective randomized trial (RTOG 85-01). Radiation Therapy Oncology Group

CONTEXT

Carcinoma of the esophagus traditionally has been treated by surgery or radiation therapy (RT), but 5-year overall survival rates have been only 5% to 10%. We previously reported results of a study conducted from January 1986 to April 1990 of combined chemotherapy and RT vs RT alone when an interim analysis revealed significant benefit for combined therapy.

OBJECTIVE

To report the long-term outcomes of a previously reported trial designed to determine if adding chemotherapy during RT improves the survival rate of patients with esophageal carcinoma.

DESIGN

Randomized controlled trial conducted 1985 to 1990 with follow-up of at least 5 years, followed by a prospective cohort study conducted between May 1990 and April 1991.

SETTING

Multi-institution participation, ranging from tertiary academic referral centers to general community practices.

PATIENTS

Patients had squamous cell or adenocarcinoma of the esophagus, T1-3 N0-1 M0, adequate renal and bone marrow reserve, and a Karnofsky score of at least 50. Interventions Combined modality therapy (n = 134): 50 Gy in 25 fractions over 5 weeks, plus cisplatin intravenously on the first day of weeks 1, 5, 8, and 11, and fluorouracil, 1 g/m2 per day by continuous infusion on the first 4 days of weeks 1, 5, 8, and 11. In the randomized study, combined therapy was compared with RT only (n = 62): 64 Gy in 32 fractions over 6.4 weeks.

MAIN OUTCOME MEASURES

Overall survival, patterns of failure, and toxic effects.

RESULTS

Combined therapy significantly increased overall survival compared with RT alone. In the randomized part of the trial, at 5 years of follow-up the overall survival for combined therapy was 26% (95% confidence interval [CI], 15%-37%) compared with 0% following RT. In the succeeding nonrandomized part, combined therapy produced a 5-year overall survival of 14% (95% CI, 6%-23%). Persistence of disease (despite therapy) was the most common mode of treatment failure; however, it was less common in the groups receiving combined therapy (34/130 [26%]) than in the group treated with RT only (23/62 [37%]). Severe acute toxic effects also were greater in the combined therapy groups. There were no significant differences in severe late toxic effects between the groups. However, chemotherapy could be administered as planned in only 89 (68%) of 130 patients (10% had life-threatening toxic effects with combined therapy vs 2% in the RT only group).

CONCLUSION

Combined therapy increases the survival of patients who have squamous cell or adenocarcinoma of the esophagus, T1-3 N0-1 M0, compared with RT alone.

Effect of combined adoptive immunotherapy and radiotherapy on tumor growth

Advanced squamous cell carcinomas of the head and neck are difficult to control despite optimal surgery, radiotherapy and/or chemotherapy, and the tumors are usually not immunogenic. Because of the anatomic accessibility of the tumors, local adoptive immunotherapy of these tumors is feasible and may interact with radiotherapy to retard tumor growth. It is hypothesized that antigens released from tumor cells injured by radiation may stimulate, in the presence of interleukin-2, an enhanced immunocytodestruction of live tumor cells by adoptively transferred lymphokine activated killer cells and recruited tumor cytotoxic cells. DBA/2 mice were injected subcutaneously with 5 x 10(5) syngeneic squamous cell carcinoma cells in the thigh and the resulting tumors were treated for two weeks with daily peritumoral injections of interleukin-2 (1,000 International Units) or saline, four radiation treatments of 625 cGy each, and four peritumoral injections of 10(7) lymphokine activated killer cells. The results suggested that radiotherapy combined with peritumoral injection of lymphokine activated killer cells and interleukin-2 resulted in a significant reduction (P < 0.01) of tumor size whereas radiation alone, at the same dose, failed to produce a significant effect. Such results may have direct clinical application in enhancing the response of tumors to radiotherapy and in reducing the incidence of tumor recurrence.

Anemia is associated with decreased survival and increased locoregional failure in patients with locally advanced head and neck carcinoma: a secondary analysis of RTOG 85-27

PURPOSE

The purpose of the present study is to investigate the strength of association between anemia and overall survival, locoregional failure, and late radiation therapy (RT) complications in a large prospective study of patients with advanced head and neck cancer treated with conventional radiotherapy with or without a hypoxic cell sensitizer.

METHODS AND MATERIALS

Between March 1988 and September 1991, 521 patients with Stage III or IV squamous cell carcinoma of the head and neck were entered into a randomized trial examining the addition of etanidazole (SR 2508) to conventional radiation therapy (RT) (66-74 Gy in 33-37 fractions, 5 days a week). Patients with hemoglobin (Hgb) levels measured and recorded prior to the second week of RT were included in this secondary analysis. Hemoglobin levels were stratified as normal (> or = 14.5 gm% for men, > or = 13 gm% for women) or anemic (< 14.5 gm% for men, < 13 gm% for women). Locoregional failure rates were calculated using the cumulative incidence approach. Overall survival was estimated according to the Kaplan-Meier method. Late RT toxicity was scored according to the RTOG morbidity scale. Differences in rates of overall survival, locoregional failure, and late complications were tested by the Cox proportional hazard model.

RESULTS

Of 504 eligible patients, 451 had a Hgb level measured and recorded prior to the second week of RT. One hundred sixty-two patients (35.9%) were considered to have a normal Hgb level and 289 patients (64.1%) were considered to be anemic. The estimated survival rate is 35.7% at 5 years in patients with a normal Hgb, versus 21.7% in anemic patients (p = 0.0016). The estimated locoregional failure rate is 51.6% at 5 years in patients with a normal Hgb, versus 67.8% in anemic patients (p = 0.00028). The estimated rate of grade 3 or greater toxicity is 19.8% at 5 years in patients with a normal Hgb, versus 12.7% in anemic patients (p = 0.063). On multivariate analysis, several variables were found to be independent predictors of survival including: T stage, Karnofsky performance status, N stage, age, total radiation dose to the primary, and Hgb level. Independent predictors of locoregional control included T stage, Karnofsky performance status, N stage, radiation dose, and Hgb level. The only variables which predicted for the development of late RT complications were gender (p = 0.0109) and age (p = 0.0167). These findings were consistent regardless of whether Hgb level was considered a dichotomous or continuous variable.

CONCLUSION

Low Hgb levels are associated with a statistically significant reduction in survival and an increase in locoregional failure in this large prospective study of patients with advanced head and neck cancer. Hgb level should be considered as a stratification variable in subsequent studies of head and neck cancer. Strategies to increase Hgb prior to RT in patients with head and neck cancer may lead to improved survival and loco-regional control.

Precisely defining high-risk operable head and neck tumors based on RTOG #85-03 and #88-24: targets for postoperative radiochemotherapy?

BACKGROUND

Local-regional recurrence of disease remains the major obstacle to cure of advanced head and neck cancers.

METHODS

This investigation reviewed data derived from Radiation Therapy Oncology Group (RTOG) protocols #85-03 and #88-24 to identify characteristics of tumors that predicted local-regional recurrence of disease following surgery and postoperative radiotherapy (RT).

RESULTS

The presence of tumor in two or more lymph nodes, and/or extracapsular spread of nodal disease, and/or microscopic-size tumor involvement of the surgical margins of resection imparts a high risk of local-regional (L-R) relapse. Our data also support the hypothesis that, following surgery, the concurrent addition of chemotherapy (CT) to RT may increase the likelihood of L-R control of disease for patients who have these high-risk characteristics.

CONCLUSION

A prospective trial of surgery followed by concurrent RT and CT is warranted for patients who have high-risk characteristics found at surgery.

The evolution of the role of radiation therapy in the management of mucocutaneous malignant melanoma

The role of radiation therapy in the treatment of malignant melanoma has evolved substantially over time. Years ago, malignant melanomas were generally considered radioresistant. Over time, the palliative value of radiation therapy was established. Most recently it also has become clear that judiciously applied therapy may be curative in either an adjuvant setting or for small-volume disease.

A comparison of staging systems for nasopharyngeal carcinoma

BACKGROUND

The fifth edition of the American Joint Committee on Cancer staging manual defines new rules for classifying nasopharyngeal carcinoma. The authors tested the value of this new system by applying these rules retrospectively to their previously treated patients and comparing the results with those obtained using the fourth edition of the AJCC staging manual or the Ho staging system.

METHODS

Information from 107 patients who had biopsy-proven squamous cell carcinoma of the nasopharynx that was treated in a constant fashion with definitive-intent radiation therapy alone at one institution provided the data base for this analysis. The extent of disease of each patient was staged according to the rules of 1) the fourth edition of the AJCC staging manual, 2) the Ho staging system, and 3) the fifth edition of the AJCC staging manual.

RESULTS

The new system appears to be better than the two previous systems. It separated patients into cohorts of more equal size than did either of the other systems. It also correlated with outcome for the study population more appropriately than did the fourth edition of the AJCC staging manual or the Ho staging system.

CONCLUSIONS

The fifth edition of the AJCC staging manual appears to be an improvement over the previous AJCC or Ho staging systems for the staging of nasopharyngeal carcinoma.

Palliation of AIDS-related primary lymphoma of the brain: observations from a multi-institutional database

PURPOSE

To catalogue the presenting symptoms of patients with AIDS who are presumed to have primary central nervous system lymphoma (PCNSL). To document the palliative efficacy of cranial irradiation (RT) relative to the endpoints of complete and overall response for the respective symptoms.

METHODS

An analysis of 163 patients with AIDS-related PCNSL who were evaluated at nine urban hospitals was performed. These patients were treated for PCNSL after the establishment of a tissue diagnosis or on a presumptive basis after failing empiric treatment for toxoplasmosis. All patients were treated between 1983 and 1995 with radiotherapy (median dose-fractionation scheme = 3 Gy x 10) and steroids (>90% dexamethasone). Because multiple fractionation schemes were used, prescriptions were converted to biologically effective doses according to the formula, Gy10 = Total Dose x (1 + fractional dose/alpha-beta); using an alpha-beta value of 10.

RESULTS

The overall palliative response rate for the entire group was 53%. In univariate analysis, trends were present associating complete response rates with higher performance status (KPS > or = 70 vs. KPS < or = 60 = 17% vs. 5%), female gender (women vs. men = 29% vs. 8%), and the delivery of higher biologically effective doses (BED) of RT (Gy10 > 39 vs. < or = 39 = 20% vs. 5%). In multivariate analysis of factors predicting complete response, both higher KPS and higher BED retained independent significance. A separate univariate analysis identified high performance status (KPS > or = 70 vs. KPS < or = 60 = 71% vs. 47%), and young age (< or = 35 vs. > 35 = 61% vs. 40%) as factors significantly correlating with the endpoint of the overall response. In multivariate analysis, high performance status and the delivery of higher biologically effective doses of irradiation correlated significantly with higher overall response rates.

CONCLUSION

Most AIDS patients who develop symptoms from primary lymphoma of the brain can achieve some palliation from a management program that includes cranial irradiation. Young patients with excellent performance status are most likely to respond to treatment. The delivery of higher biologically effective doses of irradiation also may increase the probability of achieving a palliative response.

Postoperative radiotherapy with concurrent cisplatin appears to improve locoregional control of advanced, resectable head and neck cancers: RTOG 88-24

PURPOSE

Despite aggressive surgery and postoperative radiation therapy, only 30% of patients who have advanced, potentially resectable carcinomas of the head and neck survive for 5 years. In the hope of improving this situation we studied the effect of postoperative radiotherapy delivered concurrently with cisplatin.

METHODS AND MATERIALS

Patients who had Stage IV tumors and/or involved surgical margins received 60 Gy in 30 fractions over 6 weeks plus 100 mg/m2 of cisplatin on radiotherapy days 1, 23 and 43. Fifty-two patients participated in this trial and 51 were evaluated. Forty-three (84%) patients had pathologic T3 or T4 disease, 43 (84%) had Stage IV disease, and 27 (53%) had histologically involved surgical margins.

RESULTS

Severe and life-threatening toxicities occurred in 20% and 12% of patients, respectively; the most common drug-related toxicities were leukopenia, anemia, nausea, and vomiting. Seventeen patients (43%) remain alive with no evidence of disease. Four patients (8%) died with no evidence of neoplastic disease, and one patient has died of a second independent malignancy. By actuarial analysis at 3 years, 48% of patients are alive, 81% have locoregional control of disease, and 57% are free of distant metastases.

CONCLUSIONS

Based on comparison with similar patients treated in a prior Radiation Therapy Oncology Group/Intergroup trial (RTOG), we conclude that postoperative radiotherapy with concurrent cisplatin may improve locoregional control rates and should be prospectively tested.

Performance status and age as independent predictors of survival among AIDS patients with primary CNS lymphoma: a multivariate analysis of a multi-institutional experience

PURPOSE

There is limited information about the outcome of AIDS patients with primary central nervous system lymphoma treated with definitive irradiation. The purpose of this study was to determine factors associated with increased survival in such patients.

METHODS

An analysis was performed of 163 patients with AIDS who were evaluated at nine urban hospitals. These patients were treated for primary central nervous system lymphoma after the establishment of a tissue diagnosis or on a presumptive basis after failing empiric treatment for toxoplasmosis. All patients were treated between 1983 and 1995 with radiotherapy (median dose-fractionation scheme = 3 Gy x 10) and steroids (> 90% dexamethasone). Because multiple fractionation schemes were used, prescriptions were converted to biologically effective dose according to the formula Gy10 = Total Dose x (1 + fractional dose/alpha-beta), using an alpha-beta of 10.

RESULTS

Longer median survival times were associated with high Karnofsky performance status (KPS > or = 70 vs < or = 60: 181 vs 77 days), young age (< 35 vs > 35: 162 vs 61 days), and high total definitive irradiation doses (> 39 Gy10 vs < 39 Gy10: 162 vs 40 days). Tissue diagnosis, gender, race, number of lesions (solitary vs multiple), and the presence of other cancers did not influence outcome. In multivariate analysis, young age, high Karnofsky performance status, and the delivery of higher biologically effective doses of irradiation retained independent significance relative to the endpoint of survival.

CONCLUSIONS

Even at urban tertiary medical centers, few AIDS patients with intracranial lesions undergo biopsies to establish a precise tissue diagnosis. Survival following definitive irradiation is strongly related to two pretreatment factors (young age, high performance status) and one treatment factor (total biologically effective dose of cranial radiotherapy). These variables should be considered in selecting patients for definitive irradiation and in designing future studies.

Evolution of the Radiation Therapy Oncology Group clinical trials for head and neck cancer

During the past 25 years, the Radiation Therapy Oncology Group (RTOG) has played a major role in head and neck cancer clinical research. The major research themes for recent and currently active trials have been: (a) combined modality therapy, (b) altered fractionation radiotherapy, (c) hypoxic cell sensitizers, (d) organ preservation, (e) chemoprevention, and (f) clinical/laboratory correlations. For advanced operable disease, the RTOG showed improved local-regional control with postoperative radiotherapy as compared to preoperative radiotherapy for carcinoma of the supraglottic larynx and hypopharynx. This established the use of surgery followed by postoperative radiotherapy as the standard treatment in subsequent RTOG and Intergroup trials for operable disease. For advanced inoperable disease, the RTOG demonstrated the feasibility of testing altered fractionation radiotherapy in a multiinstitutional clinical trials setting. A Phase III trial comparing hyperfractionation and accelerated fractionation to conventional fractionation is now in progress. Phase I/II combined modality studies established the efficacy of concurrent high-dose cisplatin and radiotherapy in the treatment of advanced disease and provided the basis for further testing in Phase III trials for nasopharyngeal carcinoma, larynx preservation, and high-risk advanced operable disease. Analysis of the extensive RTOG Head and Neck Cancer database established the incidence of second malignancies and their adverse impact on patients whose initial tumors were cured by radiotherapy, and provided the basis for chemoprevention trials. Recursive partitioning analysis identified 6 distinct prognostically homogeneous patient groups based on pretreatment tumor or patient characteristics and/or treatment variables. Retrospective analysis identified tumor p105 antigen density as an independent prognostic indicator in patients irradiated for head and neck cancer. Future trials will continue to focus on the reduction of morbidity and mortality, and improvement of the quality of life of head and neck cancer patients through innovative radiotherapy delivery, multimodality approaches, use of chemical and biological modifiers, and other novel therapies, identification of clinical and biological prognostic indicators, and prevention or diminution of acute morbidity and late complications of the disease and its treatment.

Recursive partitioning analysis of 2105 patients treated in Radiation Therapy Oncology Group studies of head and neck cancer

BACKGROUND

The Radiation Therapy Oncology Group conducts large-scale prospective, randomized trials to test new concepts in cancer patient care and provide information about pretreatment and treatment factors that may influence outcome.

METHODS

Recursive partitioning analysis (RPA) was used to examine the data derived from 2105 patients. RPA grouped patients according to the influence of tumor, of host, and of treatment variables on outcome.

RESULTS

For survival, the most important factor was T classification. For lesions less than T3, the primary tumor was the next most important factor, whereas for T3 and T4 lesions the Karnofsky score was the next most predictive factor. Six distinct groups were formed by RPA, with median survivals ranging from 6.8 to 151.8 months. For local-regional control, the N classification was the most important factor. For patients with no adenopathy, T classification was the next most important factor, whereas for patients with adenopathy, the number of treatment fractions was the next most important factor. Such analysis created 5 distinct groups. In the most favorable, the median time to local-regional relapse has not yet been reached. In the least favorable group, fewer than 50% of the patients experienced complete response at any time following treatment.

CONCLUSIONS

RPA clarifies the relative importance and potential interactions of pretreatment and treatment variables and should permit more accurate stratification of patients in future trials.

Additional experience with empiric radiotherapy for presumed human immunodeficiency virus-associated primary central nervous system lymphoma

BACKGROUND

In light of the steadily improving capability to treat opportunistic infections, the authors reviewed their recent experience with short course empiric radiotherapy for the treatment of human immunodeficiency virus (HIV)-associated presumed central nervous system (CNS) lymphoma.

METHODS

Medical records were reviewed of 32 previously unreported HIV-infected patients who had computed tomography and/or magnetic resonance imaging findings consistent with lymphoma, whose lesions had failed to respond to antitoxoplasmosis therapy and therefore subsequently treated with empiric radiotherapy to the cranium and meninges, nearly always 3000 cGy in 10 fractions.

RESULTS

The majority of patients were in poor general condition (median Karnofsky score = 50) when radiotherapy was initiated. Fifty percent improved during or after radiation. Median survival was 2.1 months.

CONCLUSIONS

Despite progress made in the past several years in the treatment of opportunistic infections and brief clinical response to radiotherapy, patients with acquired immunodeficiency syndrome who have a presumed diagnosis of CNS lymphoma continue to have extremely poor survival. Early biopsy in patients with lesions that fail to respond to empiric antitoxoplasmosis treatment or with lesions radiographically most consistent with lymphoma may improve outcome.

Results of an RTOG phase III trial (RTOG 85-27) comparing radiotherapy plus etanidazole with radiotherapy alone for locally advanced head and neck carcinomas

PURPOSE

The objectives of this study were to determine the efficacy and toxicity of Etanidazole (ETA), a hypoxic cell sensitizer, when combined with conventional radiotherapy (RT) in the management of advanced head and neck carcinomas.

METHODS AND MATERIALS

From March 1988 to September 1991, 521 patients who had Stage III or IV head and neck carcinomas were randomized to receive conventional RT alone (66 Gy in 33 fractions to 74 Gy in 37 fractions, 5 fractions per week) or RT+ETA (2.0 g/m2 thrice weekly for 17 doses), of whom 504 were eligible and analyzable. Treatment assignments were stratified before randomization according to the primary site (oral cavity + hypopharynx vs. supraglottic larynx + oropharynx + nasopharynx), T-stage (T1-3 vs. T4), and N-stage (N0-2 vs. N3). Pretreatment characteristics were balanced. In the RT-alone arm, 39% of patients had T3 and 34% had T4 disease, whereas in the RT+ETA arm, 42% of patients had T3 and 33% had T4 disease. Thirty-eight percent of the RT-alone patients and 37% of the RT+ETA patients had N3 disease. The median follow-up of surviving patients was 3.38 years, with a range between 0.96 and 5.63 years.

RESULTS

One hundred and ninety-four of the 252 (77%) RT+ETA patients received at least 14 doses of the drug. Overall RT protocol compliance rate was 82% in the RT-alone arm and 86% in the RT+ETA arm. No Grade 3 or 4 central nervous system or peripheral neuropathy was observed in the RT+ETA arm. Eighteen percent of the patients developed Grade 1 and 5% developed Grade 2 peripheral neuropathy. Other drug related toxicities included nausea/vomiting (27%), low blood counts (15%), and allergy (9%). Most of these toxicities were Grade 1 and 2. The incidence of severe acute and late radiation effects were similar between the two arms. The 2-year actuarial local-regional control rate (LCR) was 40% for the RT-alone arm and 40% for the RT+ETA arm. Two-year actuarial survival was 41% for the RT-alone arm and 43% for the RT+ETA arm (p = 0.65). Multivariate analyses were performed to investigate the influence of covariates on treatment effects. A strong treatment interaction with N-stage was revealed: LCR (50% vs. 40% at 2 years), RT+ETA improved for patients with N0-2 disease but not for N3 patients (22% for RT+ETA and 40% for RT). Further analyses showed that RT+ETA was more advantageous in N0-1 patients, with a 2-year LCR of 55% for RT+ETA vs. 37% for RT only (p = 0.03). A similar phenomenon was observed when using survival as the end point.

CONCLUSION

The results showed that adding Etanidazole to conventional RT produced no global benefit for patients who had advanced head and neck carcinomas. There was a suggested benefit for patients who had N0-1 disease, and that needs to be confirmed by another study.

Late effects of radiation therapy in the head and neck region

The head and neck region is composed of numerous structures, each with an inherent response to radiation that is largely governed by the presence or absence of mucosa, salivary glands, or specialized organs within that site. Irradiated mucocutaneous tissues demonstrate increased vascular permeability that leads to fibrin deposition, subsequent collagen formation, and eventual fibrosis. Irradiated salivary tissue degenerates after relatively small doses, leading to markedly diminished salivary output. This, in turn, effects the teeth by promoting dental decay which, in turn, effects the integrity of the mandible. Details of these changes are presented, including their pathophysiology, clinical syndromes, and potential treatment.

The use of digitally reconstructed radiographs for three-dimensional treatment planning and CT-simulation

PURPOSE

Recent interest in computed tomography-simulation (CT-simulation) suggests the possibility of a shift to digital images for field verification. This article examines the quality of Digitally Reconstructed Radiographs (DRRs) to determine if they can reasonably be substituted for conventional simulator films, and suggests techniques to improve these images.

METHODS AND MATERIALS

Special developmental software and computer hardware allowed extremely rapid reformatting of CT data to produce images geometrically equivalent to treatment unit portal films. The technique uses a trilinear interpolation algorithm and gives a 512 x 512 DRR for any arbitrary beam direction. Resolution in line pairs/cm (lp/cm) for both simulator radiographs and DRRs was measured with a special test phantom. Patient data was reformatted to illustrate methods for improving the quality of the DRR.

RESULTS

The equipment used for this study reformats 50 512 x 512 CT scans in 8 s. The resolution for a DRR is limited by the voxel size of the CT scans. For typical voxel dimensions, the resolution was found to be 7 lp/cm transverse and 1.0 lp/cm longitudinal compared to 21.0 lp/cm for a simulator radiograph. Patient movement during the scan procedure further degrades the DRR. The reduced quality of this image makes it more difficult to discern structures, and it may not always be possible to perform essential tasks such as counting vertebral bodies. However, viewing the treatment field superimposed on a DRR displayed with a step function to include only bone aided in the identification of relevant landmarks. Switching between soft tissue, bone, or air windows takes less than 10 s on the equipment used for this study, and the use of different display techniques improved the viewer's ability to evaluate field positioning.

CONCLUSIONS

A DRR cannot match the spatial resolution of a radiograph taken with a short exposure and small focal spot, but the ability to change the display mode for the DRR increases the usefulness of these images. Fast reformatting is particularly important when evaluation of field position requires the comparison of each portal image to a series of DRRs.

Predicting risk-reducing occupational AIDS behaviors in a sample of emergency medical personnel

Increase of AIDS precautionary occupational behaviors of 46 emergency medical personnel was significantly predicted by subjects' concern about becoming HIV-infected but not by their HIV/AIDS knowledge.

Flow cytometric quantification of the proliferation-associated nuclear antigen p105 and DNA content in advanced head & neck cancers: results of RTOG 91-08

PURPOSE

p105 is a proliferation-associated nuclear antigen which identifies proliferating but not resting cells. The objectives of this Radiation Therapy Oncology Group (RTOG) protocol (91-08) were: (1) to correlate tumor proliferative potential estimated using the p105 assay and deoxyribonucleic acid (DNA) analysis with treatment outcome in patients irradiated for advanced squamous cell carcinoma of the head and neck; and (2) to evaluate the potential of p105 labeling indices as a predictive assay.

METHODS AND MATERIALS

Paraffin blocks of pretreatment biopsies of the primary tumor or metastatic neck nodes of patients with Stage III or IV squamous cell carcinoma of the head and neck treated with radiotherapy alone in three previous RTOG protocols (79-13, 79-15, and 83-13) were retrospectively obtained. From these paraffin blocks, areas of tumor were selected based on histological examinations and sectioned. Nuclei suspensions were then prepared and processed for p105 antibody and DNA staining and subsequent flow cytometric quantification of p105 labeling indices and DNA content and correlation with local-regional control and survival.

RESULTS

Paraffin blocks of tumor biopsies from 148 out of a total of 598 eligible patients were available. Of these, 143 were analyzable. The median and (range) of p105 labeling index (LI-C), p105 labeling index of cells in S phase (LI-S), and p105 antigen density (AD) were: 66.6 (3.85-99.5), 9 (1.55-36), and 93.2 (7.4-628.5), respectively. Deoxyribonucleic acid was diploid in 67 (47%), aneuploid in 22 (15%) and mixed aneuploid/diploid in 54 (38%) patients. There was a strong correlation between AD and DNA ploidy. Antigen density was above median in 91.5% of the aneuploid or mixed aneuploid/diploid tumors, but only in 8.5% of the diploid tumors. Patients with aneuploid or mixed aneuploid/diploid tumors had significantly greater local-regional failures than patients with diploid tumors (p = .0180). Those with p105 LI-C below the median or p105 AD above the median also had significantly greater local-regional failures (p = .0500 and p = .0167, respectively). Patients with p105 AD below the median had significantly better survival than those above the median (p = .0444), although there was no significant difference in survival with respect to DNA ploidy or p105 LI-C. Multivariate analyses showed that T-stage (p = .0001) and p105 AD (p = .0044) were significant prognostic factors for local-regional control, and T-stage (p = .0080), N-stage (p = .0021), primary site (p = .0110), and p105 AD (p = .0326) were significant prognostic factors for survival.

CONCLUSION

These results suggest that flow cytometric quantitation of the proliferation-associated nuclear antigen p105 and DNA content of pretreatment tumor biopsies may be a potentially useful predictive assay in patients irradiated for advanced squamous cell carcinomas of the head and neck.

Penetration of the pulp chamber by carbamide peroxide bleaching agents

Hydrogen peroxide readily penetrates the pulp chamber of freshly extracted teeth. This study was undertaken to determine whether carbamide peroxide also penetrates the pulp chamber. Freshly extracted teeth were sectioned 2 to 3 mm apical to the cementoenamel junction and the coronal pulpal tissue was removed. Acetate buffer was placed in the pulp chamber to absorb and stabilize any peroxide that might penetrate. The coronal portion of each tooth was immersed in either carbamide peroxide gel or gelled hydrogen peroxide at various concentrations for 15 min at 37 degrees C. The buffer was removed, leukocrystal violet was added, and the optical density of the resulting blue solution was determined spectrophotometrically. Amounts of peroxide found in the pulp chamber after 15 min ranged from 3.3 +/- 0.38 micrograms for the 10% sample to 40.4 +/- 3.51 micrograms for the 30% sample.

Phase II trial of combination chemotherapy and irradiation in non-small-cell lung cancer, Radiation Therapy Oncology Group 88-04

Encouraging results of several clinical trials utilizing combination chemotherapy and irradiation in unresectable non-small-cell lung cancer have been reported. A recent report from a cooperative group study suggested that preirradiation vinblastine and cisplatin improved survival over irradiation alone. In an attempt to enhance the possible effectiveness of combination chemotherapy and irradiation, the Radiation Therapy Oncology Group embarked on a Phase II trial utilizing preirradiation vinblastine (5 mg/m2 weekly x 5) and cisplatin (100 mg/m2) on days 1 and 29 prior to irradiation and on days 50, 71, and 92 during irradiation. The irradiation began on day 50 and consisted of 6300 cGy in 7 weeks. Between May 20, 1988 and May 1, 1989, 30 patients were entered on study. Seventy-two percent of patients had Karnofsky status greater than 90, and 76% had weight loss less than 5%. Forty-eight percent of the patients were younger than 60 years of age. Forty-five percent of the patients had Stage IIIA disease. Eighty-three percent of the patients received at least four courses of vinblastine, and 59% received at least four courses of cisplatin. Seventy-eight percent of the patients received at least 95% of the prescribed irradiation. The major toxicity was hematologic, and there were two fatal complications in the study group. The preliminary survival figures are encouraging. This combination of chemotherapy and irradiation appears to be tolerable and may merit further investigation.