Pathology-based staging for HPV-positive squamous carcinoma of the oropharynx.

OBJECTIVE: The rapid worldwide rise in incidence of human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) has generated studies confirming this disease as an entity distinct from traditional OPSCC. Based on pathology, surgical studies have revealed prognosticators specific to HPV-positive OPSCC. The current AJCC/UICC staging and pathologic nodal (pN)-classification do not differentiate for survival, demonstrating the need for new, HPV-specific OPSCC staging. The objective of this study was to define a pathologic staging system specific to HPV-positive OPSCC. METHODS: Data were assembled from a surgically-managed, p16-positive OPSCC cohort (any T, any N, M0) of 704 patients from five cancer centers. Analysis was performed for (a) the AJCC/UICC pathologic staging, (b) newly published clinical staging for non-surgically managed HPV-positive OPSCC, and (c) a novel, pathology-based, "HPVpath" staging system that combines features of the primary tumor and nodal metastases. RESULTS: A combination of AJCC/UICC pT-classification and pathology-confirmed metastatic node count (⩽4 versus ⩾5) yielded three groups: stages I (pT1-T2, ⩽4 nodes), II (pT1-T2, ⩾5 nodes; pT3-T4, ⩽4 nodes), and III (pT3-T4, ⩾5 nodes), with incrementally worse prognosis (Kaplan-Meier overall survival of 90%, 84% and 48% respectively). Existing AJCC/UICC pathologic staging lacked prognostic definition. Newly published HPV-specific clinical stagings from non-surgically managed patients, although prognostic, showed lower precision for this surgically managed cohort. CONCLUSIONS: Three loco-regional "HPVpath" stages are identifiable for HPV-positive OPSCC, based on a combination of AJCC/UICC primary tumor pT-classification and metastatic node count. A workable, pathologic staging system is feasible to establish prognosis and guide adjuvant therapy decisions in surgically-managed HPV-positive OPSCC.

Using FDG-PET to measure early treatment response in head and neck squamous cell carcinoma: quantifying intrinsic variability in order to understand treatment-induced change.

BACKGROUND AND PURPOSE: Quantification of both baseline variability and intratreatment change is necessary to optimally incorporate functional imaging into adaptive therapy strategies for HNSCC. Our aim was to define the baseline variability of SUV on FDG-PET scans in patients with head and neck squamous cell carcinoma and to compare it with early treatment-induced SUV change. MATERIALS AND METHODS: Patients with American Joint Committee on Cancer stages III-IV HNSCC were imaged with 2 baseline PET/CT scans and a third scan after 1-2 weeks of curative-intent chemoradiation. SUVmax and SUVmean were measured in the primary tumor and most metabolically active nodal metastasis. Repeatability was assessed with Bland-Altman plots. Mean percentage differences (%ΔSUV) in baseline SUVs were compared with intratreatment %ΔSUV. The repeatability coefficient for baseline %ΔSUV was compared with intratreatment %ΔSUV. RESULTS: Seventeen patients had double-baseline imaging, and 15 of these patients also had intratreatment scans. Bland-Altman plots showed excellent baseline agreement for nodal metastases SUVmax and SUVmean, but not primary tumor SUVs. The mean baseline %ΔSUV was lowest for SUVmax in nodes (7.6% ± 5.2%) and highest for SUVmax in primary tumor (12.6% ± 9.2%). Corresponding mean intratreatment %ΔSUVmax was 14.5% ± 21.6% for nodes and 15.2% ± 22.4% for primary tumor. The calculated RC for baseline nodal SUVmax and SUVmean were 10% and 16%, respectively. The only patient with intratreatment %ΔSUV above these RCs was 1 of 2 patients with residual disease after CRT. CONCLUSIONS: Baseline SUV variability for HNSCC is less than intratreatment change for SUV in nodal disease. Evaluation of early treatment response should be measured quantitatively in nodal disease rather than the primary tumor, and assessment of response should consider intrinsic baseline variability.

Stereotactic radiotherapy for malignancies involving the trigeminal and facial nerves.

Involvement of a cranial nerve caries a poor prognosis for many malignancies. Recurrent or residual disease in the trigeminal or facial nerve after primary therapy poses a challenge due to the location of the nerve in the skull base, the proximity to the brain, brainstem, cavernous sinus, and optic apparatus and the resulting complex geometry. Surgical resection caries a high risk of morbidity and is often not an option for these patients. Stereotactic radiosurgery and radiotherapy are potential treatment options for patients with cancer involving the trigeminal or facial nerve. These techniques can deliver high doses of radiation to complex volumes while sparing adjacent critical structures. In the current study, seven cases of cancer involving the trigeminal or facial nerve are presented. These patients had unresectable recurrent or residual disease after definitive local therapy. Each patient was treated with stereotactic radiation therapy using a linear accelerator based system. A multidisciplinary approach including neuroradiology and surgical oncology was used to delineate target volumes. Treatment was well tolerated with no acute grade 3 or higher toxicity. One patient who was reirradiated experienced cerebral radionecrosis with mild symptoms. Four of the seven patients treated had no evidence of disease after a median follow up of 12 months (range 2-24 months). A dosimetric analysis was performed to compare intensity modulated fractionated stereotactic radiation therapy (IM-FSRT) to a 3D conformal technique. The dose to 90% (D90) of the brainstem was lower with the IM-FSRT plan by a mean of 13.5 Gy. The D95 to the ipsilateral optic nerve was also reduced with IM-FSRT by 12.2 Gy and the D95 for the optic chiasm was lower with FSRT by 16.3 Gy. Treatment of malignancies involving a cranial nerve requires a multidisciplinary approach. Use of an IM-FSRT technique with a micro-multileaf collimator resulted in a lower dose to the brainstem, optic nerves and chiasm for each case examined.

Ultrasound guided pO2 measurement of breast cancer reoxygenation after neoadjuvant chemotherapy and hyperthermia treatment.

The objective of this study was to determine whether neoadjuvant chemotherapy in combination with hyperthermia (HT) would improve oxygenation in locally advanced breast tumours. The study describes a new optimized ultrasound guided technique of pO2 measurement using Eppendorf polarographic oxygen probes in 18 stage IIB-III breast cancer patients. Prior to treatment, tumour hypoxia (median pO2<10 mmHg) was present in 11/18 patients (average median pO2=3.2 mmHg). Seven patients had well oxygenated tumours (median pO2 of 48.3 mmHg). Eight patients with hypoxic tumours prior to treatment had a significant improvement (p=0.0008) in tumour pO2 after treatment (pO2 increased to 19.2 mmHg). In three patients, tumours remained hypoxic (average median pO2=4.5 mmHg). The advantages of the ultrasound guided pO2 probe are in the accuracy of the Eppendorf electrode placement in tumour tissue, the ability to monitor electrode movement through the tumour tissue during the measurement and the ability to avoid electrode placement near or in large blood vessels by using colour Doppler imaging. The results of this preliminary study suggest that the combination of neoadjuvant chemotherapy and hyperthermia improves oxygenation in locally advanced breast tumours that are initially hypoxic.

The role of amifostine as a radioprotector.

Effective radiotherapy for patients with cancer should include maximal tumor cell killing with minimal injury to normal tissue. Radiation doses that can be delivered, without causing severe damage to surrounding normal tissues, can be insufficient to eradicate a tumor. Agents have been developed to protect normal tissue from the toxicities of radiation. The aminothiol amifostine (Ethyol) is the subject of extensive research as a protector. Several studies have demonstrated that amifostine protects normal tissues from both acute and late radiation damage without protecting the tumor. This article reviews the physicochemical basis of radiation therapy on biologic tissues and the mechanisms responsible for the protective effects of amifostine. The increasing body of biochemical, preclinical, and clinical data can justify the use of protectors such as amifostine with radiotherapy to provide improved therapeutic efficacy and quality of life for the patient. This article will review the current understanding of the nature of toxicity resulting from radiation therapy and the benefits that can be derived from using protection to increase the tolerance of normal tissue to radiation damage.

Elevated tumor lactate concentrations predict for an increased risk of metastases in head-and-neck cancer.

PURPOSE: Hypoxia shifts the balance of cellular energy production toward glycolysis with lactate generation as a by-product. Quantitative bioluminescence imaging allows for the quantitation of lactate concentrations in individual tumors. We assessed the relationship between pretreatment tumor lactate concentrations and subsequent development of metastatic disease in patients with newly diagnosed head-and-neck cancer. METHODS AND MATERIALS: At the time of biopsy of the primary site, a separate specimen was taken and flash-frozen for subsequent quantitation of lactate concentration using a luciferase bioluminescence technique. The two-dimensional spatial distribution of the bioluminescence intensity within the tissue section was registered directly using a microscope and an imaging photon counting system. Photon intensity was converted to distributions of volume-related tissue concentrations (micromol per gram wet weight). Treatment consisted of either surgery and postoperative radiotherapy or primary radiotherapy, based on presenting disease stage and institutional treatment policies. The subsequent development of metastatic disease constituted the primary clinical endpoint. RESULTS: Biopsies obtained from 40 patients were evaluable in 34. The larynx was the most frequent primary site (n = 25). Other sites included oropharynx (n = 5), hypopharynx (n = 3), and oral cavity (n = 1). Most patients (74%) presented with an advanced stage T3 or T4 primary tumor. Nodal involvement was present in 19 (54%) patients. The median tumor lactate concentration was 7.1 micromol/g. Tumors were classified as having either low or high lactate concentrations according to whether these values were below or above the median. The median follow-up time for surviving patients is 27 months. Two-year actuarial survival was 90% for patients with low-lactate-concentration tumor vs. 35% for patients with high-lactate-concentration primaries (<0.0001). Two-year metastasis-free survival was adversely influenced by high tumor lactate concentrations (90% vs. 25%, p < 0.0001). The median lactate concentration for tumors that subsequently metastasized was 12.9 micromol/g vs. 4.8 micromol/g for patients who remained continuously free of disease (p < 0.005). Lactate concentration was not correlated with presenting T stage or N stage. DISCUSSION: Elevated tumor lactate concentrations are associated with the subsequent development of nodal or distant metastases in head-and-neck cancer patients. This more aggressive malignant phenotype is probably associated with hypoxia-mediated radioresistance and the upregulation of metastasis-associated genes.

Simultaneous administration of glucose and hyperoxic gas achieves greater improvement in tumor oxygenation than hyperoxic gas alone.

PURPOSE: To test the feasibility of hyperglycemic reduction of oxygen consumption combined with oxygen breathing (O(2)), to improve tumor oxygenation. METHODS AND MATERIALS: Fischer-344 rats bearing 1 cm R3230Ac flank tumors were anesthetized with Nembutal. Mean arterial pressure, heart rate, tumor blood flow ([TBF], laser Doppler flowmetry), pH, and pO(2) were measured before, during, and after glucose (1 or 4 g/kg) and/or O(2). RESULTS: Mean arterial pressure and heart rate were unaffected by treatment. Glucose at 1 g/kg yielded maximum blood glucose of 400 mg/dL, no change in TBF, reduced tumor pH (0.17 unit), and 3 mm Hg pO(2) rise. Glucose at 4 g/kg yielded maximum blood glucose of 900 mg/dL, pH drop of 0.6 unit, no pO(2) change, and reduced TBF (31%). Oxygen tension increased by 5 mm Hg with O(2). Glucose (1 g/Kg) + O(2) yielded the largest change in pO(2) (27 mm Hg); this is highly significant relative to baseline or either treatment alone. The effect was positively correlated with baseline pO(2), but 6 of 7 experiments with baseline pO(2) < 10 mm Hg rose above 10 mm Hg after combined treatment. CONCLUSION: We demonstrated the feasibility of combining hyperglycemia with O(2) to improve tumor oxygenation. However, some cell lines are not susceptible to the Crabtree effect, and the magnitude is dependent on baseline pO(2). Additional or alternative manipulations may be necessary to achieve more uniform improvement in pO(2).

A phase II trial testing the thermal dose parameter CEM43 degrees T90 as a predictor of response in soft tissue sarcomas treated with pre-operative thermoradiotherapy.

We prospectively evaluated whether delivering a thermal dose of > 10 cumulative equivalent minutes at 43 degrees C to >90% of the tumour sites monitored (CEM43 degrees T90) would produce a pathologic complete response (pCR) in > 75% of high-grade soft tissue sarcomas treated pre-operatively with thermoradiotherapy. The impact of thermal dose on local failure (LF), distant metastasis (DM), and toxicity was also assessed. Thirty-five patients > or = 18 years old with grade 2 or 3 soft tissue sarcomas accessible for invasive thermometry were enrolled on the protocol. All patients received megavoltage external beam radiotherapy (RT) in daily fractions of 1.8-2.0 Gy, five times a week, to a median total dose of 50 Gy and an initial hyperthermia treatment (HT) of I h duration utilizing the BSD 2000 with Sigma 60 or MAPA applicators at frequencies of 60-140 MHz. Further HT was given for patients with CEM43 degrees T90 > 0.5 after initial HT ('heatable' patients), twice a week to a maximum of 10 HT or CEM43 degrees T90 > 100. Of the 35 patients entered, 30 had heatable tumours, one of which was inevaluable for pCR or LF as the patient died of DM prior to surgery, leaving 29 evaluable patients. Of these 29 patients, 15 (52%) had a pCR (95% CI: 37-73%), significantly less than the projected rate of > or = 75% (p = 0.02). Of the 25 heatable tumours that achieved CEM43 degrees T90 > or = 10, 14 (56%) had a pCR (95% CI: 39-78%) significantly less than the projected rate (p = 0.06). Three of the 29 patients (10%) with heatable tumours had a LF, versus 1/5 unheatable tumours (p = 0.48). Fourteen of the 30 patients (47%) with heatable tumours developed DM, versus 2/5 unheatable tumours (p = 1.00). Ten of the 30 patients (33%) with heatable tumours developed treatment-induced toxicity. Thus, no correlation of thermal dose with histologic response was observed. Prospective control of CEM43 degrees T90 failed to achieve the projected pCR rate following pre-operative thermoradiotherapy for high-grade soft tissue sarcomas, despite excellent local control. Possible explanations for this outcome are discussed.

Effect of amifostine on patient assessed clinical benefit in irradiated head and neck cancer.

PURPOSE: To determine if head and neck (H/N) cancer patients receiving daily amifostine during radiation therapy (RT) experienced clinical benefit (improvement in their ability to carry out normal functions with reduced discomfort) compared to nonamifostine treated patients. METHODS AND MATERIALS: This was an open-label, multi-institutional randomized trial in 303 H/N cancer patients treated with RT +amifostine. Clinical benefit was measured using an 8-item validated Patient Benefit Questionnaire (PBQ) during and up to 11 months after RT. RESULTS: 301 patients completed one or more PBQ assessments. Amifostine patients had significantly better PBQ scores (p < 0.05) than controls. The improvement in PBQ scores was most significant during chronic xerostomia. CONCLUSIONS: Amifostine use results in improved Patient Benefit Questionnaire (PBQ) scores, which is indicative of improved oral toxicity related outcomes and improved clinical benefit. Less oral toxicity should lead to preservation of late dental and oral health, and improvements in activities such as diet, nutrition, and sleep.

Review of methods used to study oxygen transport at the microcirculatory level.

The existence of hypoxic regions in tumors has long been recognized as a key factor leading to radiation resistance. More recently, it has been found that low oxygen levels also affect drug resistance, angiogenesis, cytokine production, cell cycle control, apoptosis, and metastatic propensity of tumors. Until now, most approaches to eliminating hypoxia have been empirical. However, improved understanding of the underlying mechanisms may permit the development of more soundly based, effective approaches. As discussed in this review, critical evaluation of the factors governing oxygen transport in tumors requires a thorough understanding of the methods used to study this process. Many experimental methodologies can be used to address these issues. In this review, the emphasis is placed on techniques that measure parameters on the scale of the diffusion distance of oxygen. Studies at the microregional level provide the most detailed physiological information on such processes. Over the past few years, significant progress in technology has allowed us to measure tumor oxygenation, yet spatial and temporal heterogeneities continue to provide significant challenges to obtaining clear knowledge of oxygen transport.

Phase III randomized trial of amifostine as a radioprotector in head and neck cancer.

PURPOSE: Radiotherapy for head and neck cancer causes acute and chronic xerostomia and acute mucositis. Amifositine and its active metabolite, WR-1065, accumulate with high concentrations in the salivary glands. This randomized trial evaluated whether amifostine could ameliorate these side effects without compromising the effectiveness of radiotherapy in these patients. PATIENTS AND METHODS: Patients with previously untreated head and neck squamous cell carcinoma were eligible. Primary end points included the incidence of grade > or =2 acute xerostomia, grade > or =3 acute mucositis, and grade > or =2 late xerostomia and were based on the worst toxicity reported. Amifostine was administered (200 mg/m(2) intravenous) daily 15 to 30 minutes before irradiation. Radiotherapy was given once daily (1.8 to 2.0 Gy) to doses of 50 to 70 Gy. Whole saliva production was quantitated preradiotherapy and regularly during follow-up. Patients evaluated their symptoms through a questionnaire during and after treatment. Local-regional control was the primary antitumor efficacy end point. RESULTS: Nausea, vomiting, hypotension, and allergic reactions were the most common side effects. Fifty-three percent of the patients receiving amifostine had at least one episode of nausea and/or vomiting, but it only occurred with 233 (5%) of 4,314 doses. Amifostine reduced grade > or =2 acute xerostomia from 78% to 51% (P<.0001) and chronic xerostomia grade > or = 2 from 57% to 34% (P=.002). Median saliva production was greater with amifostine (0.26 g v 0.10 g, P=.04). Amifostine did not reduce mucositis. With and without amifostine, 2-year local-regional control, disease-free survival, and overall survival were 58% versus 63%, 53% versus 57%, and 71% versus 66%, respectively. CONCLUSION: Amifostine reduced acute and chronic xerostomia. Antitumor treatment efficacy was preserved.

Temperature-dependent changes in physiologic parameters of spontaneous canine soft tissue sarcomas after combined radiotherapy and hyperthermia treatment.

PURPOSE: The objectives of this study were to evaluate effects of hyperthermia on tumor oxygenation, extracellular pH (pHe), and blood flow in 13 dogs with spontaneous soft tissue sarcomas prior to and after local hyperthermia. METHODS AND MATERIALS: Tumor pO2 was measured using an Eppendorf polarographic device, pHe using interstitial electrodes, and blood flow using contrast-enhanced magnetic resonance imaging (MRI). RESULTS: There was an overall improvement in tumor oxygenation observed as an increase in median pO2 and decrease in hypoxic fraction (% of pO2 measurements <5 mm Hg) at 24-h post hyperthermia. These changes were most pronounced when the median temperature (T50) during hyperthermia treatment was less than 44 degrees C. Tumors with T50 > 44 degrees C were characterized by a decrease in median PO2 and an increase in hypoxic fraction. Similar thermal dose-related changes were observed in tumor perfusion. Perfusion was significantly higher after hyperthermia. Increases in perfusion were most evident in tumors with T50 < 44 degrees C. With T50 > 44 degrees C, there was no change in perfusion after hyperthermia. On average, pHe values declined in all animals after hyperthermia, with the greatest reduction seen for larger T50 values. CONCLUSION: This study suggests that hyperthermia has biphasic effects on tumor physiologic parameters. Lower temperatures tend to favor improved perfusion and oxygenation, whereas higher temperatures are more likely to cause vascular damage, thus leading to greater hypoxia. While it has long been recognized that such effects occur in rodent tumors, this is the first report to tie such changes to temperatures achieved during hyperthermia in the clinical setting. Furthermore, it suggests that the thermal threshold for vascular damage is higher in spontaneous tumors than in more rapidly growing rodent tumors.

Double blind randomized trial of sucralfate vs placebo during radical radiotherapy for head and neck cancers.

BACKGROUND: This study sought to determine whether sucralfate prophylaxis during a course of high dose radiation therapy (RT) for head and neck cancer decreases acute side effects. METHODS: Patients receiving curative intent RT for advanced head and neck cancers participated in a single institution double-blind randomized trial comparing sucralfate to placebo. Patients were stratified according to fractionation, use of concurrent chemotherapy, Karnofsky performance status (KPS), age, and pretreatment presence of a feeding gastrostomy. Patients were prospectively evaluated during weekly treatment checks, and analyzed with regard to time (measured in terms of dose) until development of the following: weight loss, mucositis, pain, nutritional intake, and need for a treatment break. After completion of RT, time until healing was similarly compared. RESULTS: Fifty-two patients received sucralfate and 50 received placebo. The mean (+/-SD) prescribed dose was 69 +/- 7 Gy. Sixty-nine patients received BID fractionation and 27 received concurrent chemotherapy. No difference was detected in any outcome measure in the direct comparison between the two groups. On multivariate analysis, weight loss >5% or >10% occurred more frequently in patients receiving chemotherapy (p < 0.01 and p = 0.05, respectively). Grade 3 mucositis was more common in patients receiving chemotherapy (p = 0.05) or BID fractionation (p = 0.04) or having a poor KPS (p = 0.02). Interval to healing was not associated with any of the pretreatment- or treatment-related factors. Sucralfate did not result in any additional toxicity. CONCLUSIONS: Prophylactic treatment with sucralfate during high-dose head and neck RT did not decrease acute treatment side effects. Other modalities should be investigated.

The treatment of high-grade soft tissue sarcomas with preoperative thermoradiotherapy.

PURPOSE: To explore the use of a novel program of preoperative radiation and hyperthermia in the management of high-grade soft tissue sarcomas (STS). METHODS AND MATERIALS: Eligible patients were adults over 18 with Grade 2 or 3 STS, surgically resectable without a local excision prior to referral to Duke University Medical Center and without distant metastases. Patients were staged generally with CT and/or MR imaging. The diagnosis was established with fine needle aspiration or incisional biopsy. Patients were then treated with 5000 to 5040 cGy, 180-200 cGy per fraction. Chemotherapy was usually not employed. Generally two hyperthermia treatments per week were given with a planned thermal dose of 10-100 CEM 43 degrees T90. Invasive thermometry and thermal mapping were done in all patients. Surgical resection was planned 4-6 weeks after the completion of radiation and hyperthermia. RESULTS: Ninety-seven patients were treated on study between 1984 and 1996. Follow-up ranged from 12 to 155 months (median 32). All tumors were high-grade in nature, 44 greater than 10 cm in size (maximum tumor diameter), 43 5-10 cm in size, 10 less than 5 cm. Seventy-eight of the 97 tumors were located in an extremity. Of the 97 patients, 48 remain alive and continually free of disease following initial therapy. Of the remaining 49 patients, 44 have relapsed (34 dead, 10 living with disease), 3 have died secondary to complications of therapy, and 2 have died of unrelated causes. Ten-year actuarial overall survival, cause-specific survival, and relapse-free survival are 50, 47, and 47% respectively. The predominant pattern of failure has been distant metastases with only 2 patients developing local failure alone. Ten-year actuarial local control for extremity tumors is 94%, 63% for the 19 patients with tumors at sites other than the extremity. Of the 78 patients with extremity lesions, 63 have had limb preservation and remain locally controlled. Overall 38 patients experienced 57 major complications. There were 3 deaths, one due to adriamycin cardiomyopathy and two secondary to wound infections. Four patients required amputation secondary to postoperative wound healing problems. Complications directly attributable to hyperthermia occurred in 15 patients with 11 instances of second- or third-degree burns and two instances of subcutaneous fat necrosis. The hyperthermia complications were generally not severe and either healed readily or were excised at the time of surgical resection of the primary tumor. CONCLUSIONS: For these aggressive high-grade soft tissue sarcomas, this treatment program of preoperative thermoradiotherapy provided excellent local regional control for extremity lesions (95%) and satisfactory local regional control (63%) of nonextremity sarcomas, but did not appear to influence the rate of distant metastases or survival. Complications were frequent but apart from the direct thermal burns, not too different from those reported for preoperative radiotherapy alone. More effective adjuvant systemic therapy is necessary to impact favorably on survival.

Conformal radiation therapy treatment planning reduces the dose to the optic structures for patients with tumors of the paranasal sinuses.

PURPOSE: Compare dose distributions of traditional versus conformal beam orientations in paranasal sinus malignancies. MATERIALS AND METHODS: Maximum normal tissue doses, dose volume histograms (DVH), normal tissue complication probabilities (NTCP), and the percentage of each normal tissue receiving >80% of the average target dose (V80) were calculated. RESULTS/CONCLUSIONS: Conformal planning reduced the V80 to the optic nerves and chiasm as well as the normal tissue maximum doses to the ipsilateral and contralateral optic nerves and chiasm, and mean NTCPs.

Oxygenation of head and neck cancer: changes during radiotherapy and impact on treatment outcome.

BACKGROUND AND PURPOSE: To evaluate the long term clinical significance of tumor oxygenation in a population of head and neck cancer patients receiving radiotherapy and to assess changes in tumor oxygenation during the course of treatment. METHODS AND MATERIALS: Patients with head and neck cancer receiving primary RT underwent pretreatment polarographic tumor oxygen measurement of the primary site or a metastatic neck lymph node. Treatment consisted of once daily (2 Gy/fraction to a total dose of 66-70 Gy) or twice daily irradiation (1.25 Gy/fraction to 70-75 Gy) to the primary site. Twenty-seven patients underwent a second series of measurements early in the course of irradiation. RESULTS: Sixty-three patients underwent pretreatment tumor oxygen assessment (primary site, n = 24; nodes, n = 39). The median pO2 for primary lesions was 4.8 mmHg, and it was 4.3 mmHg for cervical nodes. There was a weak association between anemia and more poorly oxygened tumors, but many non-anemic patients still had poorly oxygenated tumors. Repeat assessments of tumor oxygenation after 10-15 Gy were unchanged compared to pretreatment baselines. Poorly oxygenated nodes pretreatment were more likely to contain viable residual disease at post-radiation neck dissection. Median follow-up time for surviving patients was 20 months (range 3-50 months). Hypoxia (tumor median pO2 <10 mmHg) adversely affected 2 year local-regional control (30 vs. 73%, P = 0.01), disease-free survival (26 vs. 73%, P = 0.005), and survival (35 vs. 83%, P = 0.02). CONCLUSION: Tumor oxygenation affects the prognosis of head and neck cancer independently of other known prognostic variables. This parameter may be a useful tool for the selection of patients for investigational treatment strategies.

Future directions in toxicity prevention.

The modern practice of radiation therapy has developed over several decades, taking into consideration the anatomic location of the tumor, technical aspects of radiation delivery, combined treatment modalities, and patient comorbidity. Improved understanding of tumor biology and kinetics has resulted in a more intensive application of multimodality therapy for many forms of cancer in the endeavor to increase treatment efficacy. However, increased treatment intensity carries a risk of increased toxicity. Conversely, reduction of toxicity by lessening treatment intensity incurs the risk of reduced efficacy. Preventing or minimizing toxicity while maintaining or increasing efficacy is necessary for overall improvement in the therapeutic ratio. New methods for reducing toxicity are currently being explored and include identification of risk factors associated with increased toxicity, the development of radioprotectants, and the use of growth factors to accelerate the replacement of damaged cells.

Artificial neural network model of survival in patients treated with irradiation with and without concurrent chemotherapy for advanced carcinoma of the head and neck.

PURPOSE: This study was performed to investigate the feasibility of predicting survival in squamous cell carcinoma of the head and neck (SCCHN) with an artificial neural network (ANN), and to compare ANN performance with conventional models. METHODS AND MATERIALS: Data were analyzed from a Phase III trial in which patients with locally advanced SCCHN received hyperfractionated irradiation with or without concurrent cisplatin and 5-fluorouracil. Of the 116 randomized patients, 95 who had 2-year follow-up and all required data were evaluated. ANN and logistic regression (LR) models were constructed to predict 2-year total survival using round-robin cross-validation. A modified staging model was also examined. RESULTS: The best LR model used tumor size, nodal stage, and race to predict survival. The best ANN used nodal stage, tumor size, stage, and resectability, and hemoglobin. Treatment type did not predict 2-year survival and was not included in either model. Using the respective best feature sets, the area under the receiver operating characteristic curve (Az) for the ANN was 0.78 +/- 0.05, showing more accurate overall performance than LR (Az = 0.67 +/- 0.05, p = 0.07). At 70% sensitivity, the ANN was 72% specific, while LR was 54% specific (p = 0.08). At 70% specificity, the ANN was 72% sensitive, while LR was 54% sensitive (p = 0.07). When both models used the five predictive variables best for an ANN, Az for LR decreased [Az = 0.61 +/- 0.06, p < 0.01 (ANN)]. The models performed equivalently when using the three variables best for LR. The best ANN also compared favorably with staging [Az = 0.60 +/- 0.07, p = 0.02 (ANN)]. CONCLUSIONS: An ANN modeled 2-year survival in this data set more accurately than LR or staging models and employed predictive variables that could not be used by LR. Further work is planned to confirm these results on larger patient samples, examining longer follow-up to incorporate treatment type into the model.

Hyperfractionated irradiation with or without concurrent chemotherapy for locally advanced head and neck cancer.

BACKGROUND: Radiotherapy is often the primary treatment for advanced head and neck cancer, but the rates of locoregional recurrence are high and survival is poor. We investigated whether hyperfractionated irradiation plus concurrent chemotherapy (combined treatment) is superior to hyperfractionated irradiation alone. METHODS: Patients with advanced head and neck cancer who were treated only with hyperfractionated irradiation received 125 cGy twice daily, for a total of 7500 cGy. Patients in the combined-treatment group received 125 cGy twice daily, for a total of 7000 cGy, and five days of treatment with 12 mg of cisplatin per square meter of body-surface area per day and 600 mg of fluorouracil per square meter per day during weeks 1 and 6 of irradiation. Two cycles of cisplatin and fluorouracil were given to most patients after the completion of radiotherapy. RESULTS: Of 122 patients who underwent randomization, 116 were included in the analysis. Most patients in both treatment groups had unresectable disease. The median follow-up was 41 months (range, 19 to 86). At three years the rate of overall survival was 55 percent in the combined-therapy group and 34 percent in the hyperfractionation group (P=0.07). The relapse-free survival rate was higher in the combined-treatment group (61 percent vs. 41 percent, P=0.08). The rate of locoregional control of disease at three years was 70 percent in the combined-treatment group and 44 percent in the hyperfractionation group (P=0.01). Confluent mucositis developed in 77 percent and 75 percent of the two groups, respectively. Severe complications occurred in three patients in the hyperfractionation group and five patients in the combined-treatment group. CONCLUSIONS: Combined treatment for advanced head and neck cancer is more efficacious and not more toxic than hyperfractionated irradiation alone.