Acute and late toxicity, tumour control and intrinsic radiosensitivity of primary fibroblasts in vitro of patients with advanced head and neck cancer after concomitant boost radiochemotherapy

Tumour volume and radiotherapy prolongation in locally advanced head and neck cancer patients treated with radical IMRT

AIMS

The relationship of tumour volume, radiotherapy treatment time and other prognostic factors affecting prognosis was evaluated.

METHODS

184 patients with locally advanced head and neck cancer were treated with radical intensity modulated radiotherapy (IMRT) and compared retrospectively.

RESULTS

In the multivariate analysis the overall survival was dependent on gross tumour volume (GTV), clinical stage (CS), radiotherapy treatment time (RTT) and p16 status. Local control was influenced by GTV, overall RTT and age. DFS was significantly affected by GTV, CS, RTT, p16 status and concomitant chemotherapy (CHT).

CONCLUSIONS

The tumour volume and the radiotherapy treatment time were the most significant prognostic factors with the best outcomes in patients with GTV ≤ 55 cc and RTT ≤ 48 days (mean LC 8.1, DFS 7.1 and OS 6.4 years) and worst outcomes with GTV > 55 cc and RTT >48 days (mean LC 4.4, mean DFS 3.2 and mean OS 2.6 years).

A data review of airway management in patients with oral cavity or oropharyngeal cancer: a single-institution experience

Background

Oral cavity and oropharyngeal cancer impose significant threat to airway management. Head and neck radiotherapy (HNRT) may further increase the difficulty of tracheal intubation. We hypothesized that a history of HNRT would be associated with a high rate of difficult tracheal intubation.

Methods

Adult patients with a history of HNRT were identified. Non-HNRT controls were case-matched by age, sex and body mass index. The tracheal intubation status between the two patient groups (treated vs. untreated with HNRT) was compared. The t test was used to evaluate differences in continuous variables between the 2 groups. Fisher’s exact test or a chi-square test was used to test for associations between radiation status and patient characteristics that may be associated with difficult tracheal intubation. Odds ratio and its confidence interval were used to assess the effect of radiation status on intubation status.

Results

The final cohort of 472 matched patients in age, sex and body mass index consisted of 236 patients who had HNRT before surgery and 236 who had upfront surgery without HNRT. The percentage of patients who had restricted neck range of motion in the HNRT group was significantly higher than in the control group (22.3% vs. 11.0%; p = 0.001). The proportion of patients with trismus (p = 0.11) or difficult tracheal intubation (p = 0.73) did not differ significantly between the 2 groups. 12.7% patients in the study had difficult tracheal intubation. Patients who had mallampati scores of 3 or 4 had significantly higher rate of difficult tracheal intubation than did patients with mallampati scores of 1 or 2 (17.8% vs. 8.7%; p = 0.004). Multivariate logistic regression model showed no difference between HNRT and intubation status after adjusting neck range of motion and mallampati score (OR = 0.91, 95% CI: 0.510 to1.612).

Conclusions

Previous treatment with HNRT was not associated with additional risk of difficult tracheal intubation. Mallampati score may be a sensitive measurement for difficult tracheal intubation in this patient population.

Hyperfractionated Radiotherapy for T2N0 Glottic Carcinoma: A Retrospective Analysis at 10 Years Follow-up in a Series of 60 Consecutive Patients

Aims and background

To report results of hyperfractionated radiotherapy for T2N0 glottic carcinoma at a single institution after extended follow-up.

Methods

Between 1980 and 1988 at Varese University Hospital, 60 consecutive patients with T2N0 glottic carcinoma received exclusive radiotherapy consisting of 1.5 Gy/fraction twice a day. Treatment gaps during the radiotherapy course were allowed according to individual tolerance. This policy resulted in a wide range of elapsed treatment time: median, 5.7 weeks; range, 3.7-8.9. Median follow-up is 9.8 years.

Results

As a result of dose/time distribution, 16, 20 and 24 patients received an average weekly dose rate of <10 Gy/week, equal to 10 Gy/week or >10 Gy/week, respectively. Mean total dose for each group was 62.8 Gy, 63.7 Gy and 63.8 Gy, respectively. Five-year local-regional control was 69 ± 6% (95% Cl); ultimate local-regional control, including salvage surgery, was 78 ± 5%. All failures were at the primary site, and no patient developed neck recurrence as first site of failure. The actuarial incidence of grade 2-3 late reactions at 5 years was 42 ± 6%. Most late toxicity events were grade 2: only 2 patients developed grade 3 reactions and none grade 4. None of the several clinical and treatment-related variables showed any statistically significant impact on local-regional control or late toxicity at univariate and multivariate analysis. In particular, 3-year local-regional control rates were 73 ± 11%, 84 ± 8% and 69 ± 10% for an average weekly dose rate of <10 Gy/week, equal to 10 Gy/week and >10 Gy/week, respectively (not significantly different).

Conclusions

At a very long follow-up, the hyperfractionated regimen tested in the study was shown to be effective and devoid of major complications, provided individual patient acute tolerance is carefully taken into account. Also, time factor did not affect outcome in this series.

Predicting feeding tube and tracheotomy dependence in laryngeal cancer patients

CONCLUSIONS

The two scales reliably measure laryngeal edema and dysfunction in laryngeal cancer patients. The eight categories from these scales, and abnormal pharyngeal squeeze, can be used to form a new rating scale intended to help clinicians identify and circumvent swallowing complications after chemo-irradiation.

OBJECTIVES

The objectives were to compare two laryngeal edema rating scales in laryngeal cancer patients and determine if post-radiation +/- chemotherapy edema predicts dependence on a feeding tube and/or tracheostomy.

METHODS

A retrospective chart review between 2005-2008 revealed 28 laryngeal cancer patients status post-radiation +/- chemotherapy, with video laryngoscopies performed within 6 months after treatment. Four raters evaluated videos based on the Laryngopharyngeal Edema Scale (LES) and the Reflux Finding Score (RFS). Tracheostomy and feeding tube outcomes were then correlated with the two scales.

RESULTS

Feeding tube and tracheostomy dependence were associated with pre-treatment vocal cord paralysis, advanced T stage, and chemoradiation. Eight categories from the LES and RFS scales were significantly associated with the need for a feeding tube.

Radiogenomics: A systems biology approach to understanding genetic risk factors for radiotherapy toxicity?

Adverse reactions in normal tissue after radiotherapy (RT) limit the dose that can be given to tumour cells. Since 80% of individual variation in clinical response is estimated to be caused by patient-related factors, identifying these factors might allow prediction of patients with increased risk of developing severe reactions. While inactivation of cell renewal is considered a major cause of toxicity in early-reacting normal tissues, complex interactions involving multiple cell types, cytokines, and hypoxia seem important for late reactions. Here, we review 'omics' approaches such as screening of genetic polymorphisms or gene expression analysis, and assess the potential of epigenetic factors, posttranslational modification, signal transduction, and metabolism. Furthermore, functional assays have suggested possible associations with clinical risk of adverse reaction. Pathway analysis incorporating different 'omics' approaches may be more efficient in identifying critical pathways than pathway analysis based on single 'omics' data sets. Integrating these pathways with functional assays may be powerful in identifying multiple subgroups of RT patients characterised by different mechanisms. Thus 'omics' and functional approaches may synergise if they are integrated into radiogenomics 'systems biology' to facilitate the goal of individualised radiotherapy.

Measuring Edema in Irradiated Head and Neck Cancer Patients

Objectives:

Edema is a common side effect of radiotherapy for head and neck cancer. Systems have been developed to record and monitor changes that occur after radiotherapy. These lack the sensitivity to record edema in specific laryngopharyngeal structures. The aim of this study was to develop a rating scale to measure edema in the larynx and pharynx.

Methods:

This was an exploratory study to develop a new measure, with the help of an expert panel, assessing interrater and intrarater reliability. A consensus group developed the rating scale. Eleven structures and 2 spaces were identified as areas sensitive to the development of edema. The terms no, mild, moderate, and severe were used to describe the degrees of edema. The scale was piloted and then tested for interrater and intrarater reliability on 5 speech and language therapists. They viewed 25 nasendolaryngoscopic images (23 patients who had had radiotherapy and 2 healthy volunteers). The images were rated with the scale. This process was repeated 1 week later.

Results:

Images were taken from patients with oral, oropharyngeal, nasopharyngeal, or laryngeal cancer. All had had radiotherapy or chemoradiotherapy. All raters were experienced in viewing larynges via nasendolaryngoscopy. The interrater reliability for scoring the edema rating scale was moderate (weighted kappa, 0.54). Lower levels of agreement were found for the tongue base, valleculae, pharyngeal walls, and anterior commissure. The intrarater reliability was very good (weighted kappa, 0.84).

Conclusions:

The edema rating scale can be scored with very good test-retest reproducibility and moderate levels of agreement between clinicians. Modifications to the method are suggested to increase interrater reliability.

Correlation between the radiation responses of fibroblasts cultured from individual patients and the risk of late reaction after breast radiotherapy

Late normal tissue toxicity varies widely between patients and limits breast radiotherapy dose. Here we aimed to determine its relationship to DNA damage responses of fibroblast cultures from individual patients. Thirty-five breast cancer patients, with minimal or marked breast changes after breast-conserving therapy consented to receive a 4 Gy test irradiation to a small skin field of the left buttock and have punch biopsies taken from irradiated and unirradiated skin. Early-passage fibroblast cultures were established by outgrowth and irradiated in vitro with 0 or 4 Gy. 53BP1 foci, p53 and p21/CDKN1A were detected by immunofluorescence microscopy. Residual 53BP1 foci counts 24 h after in vitro irradiation were significantly higher in fibroblasts from RT-sensitive versus RT-resistant patients. Furthermore, significantly larger fractions of p53- but not p21/CDKN1A-positive fibroblasts were found in cultures from RT-sensitive patients without in vitro irradiation, and 2 h and 6 d post-irradiation. Exploratory analysis showed a stronger p53 response 2 h after irradiation of fibroblasts established from patients with severe reaction. These results associate the radiation response of fibroblasts with late reaction of the breast after RT and suggest a correlation with severity.

Survival Fraction at 2 Gy and γH2AX Expression Kinetics in Peripheral Blood Lymphocytes From Cancer Patients: Relationship With Acute Radiation-Induced Toxicities

PURPOSE

Predictive assays for acute radiation toxicities would be clinically relevant in radiation oncology. We prospectively examined the predictive role of the survival fraction at 2 Gy (SF2) and of γH2AX (double-strand break [DSB] DNA marker) expression kinetics in peripheral blood mononuclear cells (PBMCs) from cancer patients before radiation therapy.

METHODS AND MATERIALS

SF2 was measured with Trypan Blue assay in the PBMCs from 89 cancer patients undergoing radiation therapy at 4 hours (SF2[4h]) and 24 hours (SF2[24h]) after ex vivo irradiation. Using Western blot analysis and band densitometry, we further assessed the expression of γH2AX in PBMC DNA at 0 hours, 30 minutes, and 4 hours (33 patients) and 0 hour, 4 hours, and 24 hours (56 patients), following ex vivo irradiation with 2 Gy. Appropriate ratios were used to characterize each patient, and these were retrospectively correlated with early radiation therapy toxicity grade.

RESULTS

The SF2(4h) was inversely correlated with the toxicity grade (P=.006). The γH2AX-ratio(30min) (band density of irradiated/non-irradiated cells at 30 minutes) revealed, similarly, a significant inverse association (P=.0001). The DSB DNA repair rate from 30 minutes to 4 hours, calculated as the relative RγH2AX-ratio (γH2AX-ratio(4h)/γH2AX-ratio(30min)) showed a significant direct association with high toxicity grade (P=.01).

CONCLUSIONS

Our results suggest that SF2 is a significant radiation sensitivity index for patients undergoing radiation therapy. γH2AX Western blot densitometry analysis provided 2 important markers of normal tissue radiation sensitivity. Low γH2AX expression at 30 minutes was linked with high toxicity grade, suggesting that poor γH2AX repair activity within a time frame of 30 minutes after irradiation predicts for poor radiation tolerance. On the other hand, rapid γH2AX content restoration at 4 hours after irradiation, compatible with efficient DSB repair ability, predicts for increased radiation tolerance.

The clinical application of the 100mL water swallow test in head and neck cancer

Water swallow tests have been used as to screen patients with neurological dysphagia who are at risk of aspiration. This study examines the clinical utility of the 100mL water swallow test (WST) in head and neck cancer, by measuring its sensitivity and specificity for identifying aspiration and for monitoring swallow performance up to one year following (chemo)radiotherapy. Patients referred for (chemo)radiotherapy were assessed on the WST (n=173) pre-treatment and 3, 6 and 12months post-treatment. Patients failed the test if they coughed or had a wet voice quality post swallow or were unable to finish the task. A Flexible Endoscopic Evaluation of Swallowing was conducted at the same time points, to test for the presence of aspiration. The WST was timed and the number of swallows required was recorded. Sensitivity of the WST for predicting aspiration was >67%, specificity >46%. There was marked deterioration from pre- to 3months post-treatment for the time taken to drink 100mL (p=0.005), but this improved over the first year (p=0.001). Disease characteristics, patient demographics, radiotherapy dose, or treatment volume were not predictors of this improvement. The 100mL WST is a quick and simple assessment for identifying patients with aspiration, post (chemo)radiotherapy. This test is a useful adjunct to a clinical examination, helping to highlight patients who require an instrumental assessment such as videofluoroscopy. Furthermore, quantitative measures can be derived from this test, which can be used as a measure of swallow performance over time.

High-speed digital imaging of the neoglottis after supracricoid laryngectomy with cricohyoidoepiglottopexy

OBJECTIVE

To determine the utility of high-speed digital imaging (HSDI) in evaluating vocal kinetics of the neoglottis after supracricoid laryngectomy with cricohyoidoepiglottopexy (SCL-CHEP).

STUDY DESIGN

Case series.

SETTING

The University of Tokyo Hospital.

SUBJECTS AND METHODS

High-speed digital recordings of laryngeal images were obtained from six patients after SCL-CHEP to clarify the vocal kinetics of the postoperative neoglottis. Simultaneous recording of electroglottograms (EGGs) were obtained and multiline kymograms were generated on the basis of the recorded images. The distribution of frequency, amplitude, and phase in the neoglottis were visualized by using gradients of colors superimposed onto the glottal and supraglottal areas of laryngeal images to produce laryngeal topograms. Furthermore, waveforms of estimated laryngeal sound source (ELSS) were obtained on the basis of glottal inverse filtering of the vocal signal to reflect vibratory motions in the neoglottis. The vibratory part of the neoglottis was determined as a possible sound source when the frequencies of the ELSS, EGG, and laryngeal topograms, as well as the waveforms of ELSS, EGG, and kymograms, were consistent with each other.

RESULTS

Spaces between the arytenoid(s) and epiglottis (5 patients) or pyriform sinus mucosa (1 patient) were estimated as the major source of sound during postoperative vocalization. The possible sound source could be determined by HSDI, even in the neoglottis, with more than one vibratory position.

CONCLUSION

HSDI could be useful for evaluating the vocal kinetics of the neoglottis after SCL-CHEP.

Constitutive mRNA expression of DNA repair-related genes as a biomarker for clinical radio-resistance: A pilot study in prostate cancer patients receiving radiotherapy

PURPOSE

Repair of radiation-induced DNA damage is believed to play a critical role in the development of adverse reactions in radiotherapy patients. Constitutive mRNA expression of repair genes was investigated in such patients to analyze whether expression patterns are predictive for therapy-related acute side effects.

MATERIALS AND METHODS

Prostate cancer patients (n = 406) receiving intensity-modulated radiotherapy were recruited in a prospective epidemiological study. Adverse effects were monitored during therapy using common toxicity criteria. For expression analyses, samples from 58 patients were selected according to their observed grade of clinical side effects to radiotherapy. Expression profiles were generated from peripheral blood lymphocytes using customized cDNA-arrays which carried probes for 143 DNA repair or repair-related genes. In addition, expression of selected genes was confirmed by quantitative real-time reverse transcription PCR (RT-PCR). Constitutive mRNA expression profiles were analyzed for predicting acute clinical radiosensitivity or radio-resistance.

RESULTS

Cluster analysis identified 19 differentially expressed genes. Many of these genes are involved in DNA double strand break repair. Expression levels of these genes differed up to 7-fold from the mean of all patients whereas expression levels of housekeeping genes varied only up to 2-fold. High expression of the identified genes was associated with a lack of clinical radiation sensitivity thus indicating radio-resistance.

CONCLUSIONS

Constitutive expression of DNA repair-related genes may affect the development of acute side effects in radiotherapy patients, and high expression levels of these genes seem to support protection from adverse reactions.

Long-term results of a prospective multicenter phase II study to preserve the larynx function using concomitant boost radiochemotherapy with Carboplatin

PURPOSE

This prospective phase II study was undertaken to assess the feasibility of a larynx preservation protocol with simultaneous radiochemotherapy.

PATIENTS AND METHODS

Between 3/1998 and 10/2000, 42 patients with moderately advanced cancer of the larynx (n=25) and hypopharynx (n=17) eligible for total laryngectomy (LE) were treated in a prospective larynx preservation study. The study protocol scheduled 66Gy in 5 weeks using a concomitant boost technique and 70mg/m(2) Carboplatin on days 1-5 in weeks 1 and 5.

RESULTS

The median follow-up time of the censored study patients was 41 months (9-95 months). The 5-year overall survival was 0.66 (95% CI 0.48-0.84), the 5-year laryngectomy-free survival 0.60 (95% CI 0.42-0.78), and the laryngeal preservation rate at 5 years 0.67 (95% CI 0.49-0.85). Cox multivariate regression analysis showed the total tumor volume to be the only statistically significant factor on locoregional failure-free survival. Six of 23 tumor-free long-term survivors received a tracheotomy because of late laryngeal toxicity associated with dysphagia 30-79 months after radiochemotherapy.

CONCLUSIONS

Due to the late laryngeal toxicity observed the value of this regimen for larynx preservation is limited.

Individual radiosensitivity measured with lymphocytes may predict the risk of acute reaction after radiotherapy

PURPOSE

We tested whether the chromosomal radiosensitivity of in vitro irradiated lymphocytes could be used to predict the risk of acute reactions after radiotherapy.

METHODS AND MATERIALS

Two prospective studies were performed: study A with 51 patients included different tumor sites and study B included 87 breast cancer patients. Acute reaction was assessed using the Radiation Therapy Oncology Group score. In both studies, patients were treated with curative radiotherapy, and the mean tumor dose applied was 55 Gy (40-65) +/- boost with 11 Gy (6-31) in study A and 50.4 Gy +/- boost with 10 Gy in study B. Individual radiosensitivity was determined with lymphocytes irradiated in vitro with X-ray doses of either 3 or 6 Gy and scoring the number of chromosomal deletions.

RESULTS

Acute reactions displayed a typical spectrum with 57% in study A and 53% in study B showing an acute reaction of Grade 2-3. Individual radiosensitivity in both studies was characterized by a substantial variation and the fraction of patients with Grade 2-3 reaction was found to increase with increasing individual radiosensitivity measured at 6 Gy (study A, p = 0.238; study B, p = 0.023). For study B, this fraction increased with breast volume, and the impact of individual radiosensitivity on acute reaction was especially pronounced (p = 0.00025) for lower breast volume. No such clear association with acute reaction was observed when individual radiosensitivity was assessed at 3 Gy.

CONCLUSION

Individual radiosensitivity determined at 6 Gy seems to be a good predictor for risk of acute effects after curative radiotherapy.

Residual γH2AX after irradiation of human lymphocytes and monocytes in vitro and its relation to late effects after prostate brachytherapy

BACKGROUND AND PURPOSE

Retention of gammaH2AX foci in irradiated cells can signify a deficiency in DNA double-strand break repair that may be useful as an indicator of individual radiosensitivity.

MATERIALS AND METHODS

To examine this possibility, the retention of gammaH2AX after irradiation was compared using white blood cells from 20 prostate brachytherapy patients who developed late normal tissue toxicity and 20 patients with minimal toxicity. Peripheral blood lymphocytes and monocytes were coded for analysis, exposed in vitro to 4 doses of 0.7 Gy X-rays at 3 hourly intervals, and retention of gammaH2AX was measured by flow cytometry 18 hours after the final irradiation.

RESULTS

Excellent reproducibility in duplicate samples and a range in residual gammaH2AX from 7% above background to 244% above background were observed. Residual gammaH2AX in lymphocytes showed a positive correlation with patient age. However, no relation was observed between the level of residual gammaH2AX in peripheral blood mononuclear cells and late normal tissue damage.

CONCLUSIONS

We conclude that the method of detection of residual gammaH2AX after in vitro irradiation of lymphocytes and monocytes was simple, reproducible, and sensitive. However, it failed to predict for late normal tissue toxicity after brachytherapy. Possible reasons are discussed.

In vitro radiation-induced expression ofXPC mRNA as a possible biomarker for developing adverse reactions during radiotherapy

Repair of radiation-induced DNA damage is believed to play a critical role in developing adverse reactions during radiotherapy. Ionizing radiation induces transcription of several DNA repair genes including XPC as a part of the p53-transmitted stress response. XPC gene induction was measured to analyze whether it predicts occurrence of therapy-related acute side effects. Prostate cancer patients (n = 406) receiving radiotherapy were monitored for development of acute adverse effects using common toxicity criteria. For gene induction analysis, lymphocytes from 99 patients were selected according to their observed grade of clinical side effects. Cells were irradiated in vitro with 5 Gy and analyzed after 4 hr for XPC gene induction using reverse transcription and quantitative real-time PCR. Analysis of modulation of XPC induction by personal, clinical or lifestyle factors was included. Inter-individual induction of XPC expression by ionizing radiation varied up to 20-fold (0.29-5.77) and was significantly higher in current or exsmokers than in never-smokers (p value: 0.008). Patients with XPC induction above the 90th percentile compared to those with lower induction levels were at increased risk of suffering from adverse reactions during radiotherapy (odds ratio 5.3, 95% confidence interval 1.2-24.5; adjusted for smoking). In summary, XPC mRNA levels induced by ionizing radiation were shown for the first time to be strongly affected by smoking and to be associated with an approximately 5-fold increased risk for developing acute side effects of radiotherapy. The predictive value of DNA damage-induced XPC levels as a possible biomarker for radiosensitivity has to be further investigated.

Correlation between DNA Repair Capacity in Lymphocytes and Acute Side Effects to Skin during Radiotherapy in Nasopharyngeal Cancer Patients

PURPOSE

Repair of radiation-induced DNA damage plays a critical role for both the susceptibility of patients to side effects after radiotherapy and their subsequent cancer risk. The study objective was to evaluate whether DNA repair data determined in vitro are correlated with the occurrence of acute side effects during radiotherapy.

EXPERIMENTAL DESIGN

Nasopharyngeal cancer patients receiving radiation therapy were recruited in a prospective epidemiologic study. As an indicator for clinical radiosensitivity, adverse reactions of the skin were recorded. Cryopreserved lymphocytes from 100 study participants were gamma-irradiated with 5 Gy in vitro and analyzed using the alkaline comet assay. Reproducibility of the assay was determined by repeated analysis (n = 22) of cells from a healthy donor. A coefficient of variation of 0.24 was calculated.

RESULTS

The various parameters determined to characterize the individual DNA repair capacity showed large differences between patients. Twenty-one patients were identified with considerably enhanced DNA damage induction, and 19 patients exhibited severely reduced DNA repair capacity after 15 and 30 minutes. Eight patients were considered as clinically radiosensitive, indicated by moist desquamation of the skin after a total radiation dose of 70 Gy.

CONCLUSIONS

Using the alkaline comet assay as described here, nasopharyngeal cancer patients were identified showing abnormal cellular radiation effects, but this repair deficiency corresponded only at a very limited extent to the acute radiation sensitivity of the skin.

Limitations of a TCP model incorporating population heterogeneity

The variation between individuals in their dose-response characteristics complicates attempts to extract estimates of radiobiological parameters (e.g. alpha, beta, etc) from fits to clinical dose-response data. The use of 'population' dose-response models that explicitly account for this variability is necessary to avoid obtaining skewed parameter estimates. In this work, we evaluated an example of a 'population' tumour control probability (TCP) model in terms of its ability to provide reliable parameter estimates. This was accomplished by performing fits of this population model to 'pseudo' data sets, which were generated with Monte Carlo techniques and based on preset values for the various radiobiological parameters. The fitting exercises illustrated considerable correlations between the model parameters. Especially significant was the large correlation observed between the parameter mu=alpha/sigmaalpha used to characterize the level of population heterogeneity in radiosensitivity and the alpha/beta parameter typically used to describe the response to fractionation. The results imply that fits to clinical data may not be able to distinguish between tumours exhibiting a high degree of heterogeneity and a strong beta-mechanism and those containing little heterogeneity and having a weak beta-mechanism. One implication is that basing the design of optimal fractionation regimes on such fitting results may be error-prone. If in vitro assays are to be used to independently determine biologically reasonable ranges for parameter values, an accurate knowledge of the relationship between in vitro and in vivo dose-response characteristics is required.

Carcinomes basocellulaires du cuir chevelu secondaires à une radiothérapie pour teigne : une série de 33 malades

Occurrence of basal cell carcinoma (BCC) following radiotherapy for tinea capitis is well known. The aim of this study was to specify the clinical and histological features of these BCC seen in 33 patients (1995-2000). Twenty seven men and six women were diagnosed with BCC. The age of onset varied between 32 an 62 years. Radiotherapy was received between 5 and 17 years of age. The interval between irradiation and the onset of carcinoma varied between 21 and 51 years. Total number of lesions was 55. Forty percent of BCC occurred on the occipital area, the number varied from 1 to 5 and the size from 2 to 45 mm. Clinically, the nodular type was found in 51% of cases. Pigment was present in 64% of cases. Histological study showed a nodular aspect in 76% and pigmentation in 63% of cases. Nodular and pigmented type were the predominant BCC occurring after radiotherapy for tinea capitis in our series. In the literature, BCC are the most frequent carcinomas occurring after radiotherapy (70-100%). Pigmentation was not described in other series. The nodular histological form was the most frequent.

Individual radiosensitivity measured with lymphocytes may be used to predict the risk of fibrosis after radiotherapy for breast cancer

BACKGROUND AND PURPOSE

To analyse the relationship of individual cellular radiosensitivity and fibrosis after breast conserving therapy. A new model was used describing the percentage of patients developing fibrosis per year and per patient at risk.

PATIENTS AND METHODS

In a retrospective study, 86 patients were included, who had undergone breast conserving surgery and irradiation of the breast with a median dose of 55 Gy (54-55 Gy) given at 2.5 Gy/fraction (n=57) or 2 Gy/fraction (n=29). Median age was 62 years (range 44-86) and median follow-up was 7.5 years (range 5-17). Patients were examined for fibrosis according to the LENT/SOMA score. For analysis, fibrosis was classified as grade 0 and grade 1 (G0-1) or present grade 2 and grade 3 (G2-3). The time to complete development of fibrosis was determined by analysis of yearly mammograms. Individual cellular radiosensitivity was determined by scoring lethal chromosomal aberrations in in vitro irradiated (6 Gy) lymphocytes using metaphase technique. Patients with low/intermediate cellular radiosensitivity were compared with patients with high cellular radiosensitivity using actuarial methods.

RESULTS

Ten patients developed fibrosis at 1-8 years after radiotherapy. Individual cellular radiosensitivity was described by normal distribution of lethal chromosomal aberrations, the average was 5.47 lethal aberrations per cell (standard deviation (SD) 0.71). Cellular radiosensitivity was defined as low/intermediate (< or =6.18 lethal aberrations) in 73 patients and high (>6.18 lethal aberrations; mean+SD) in 13 patients. In both groups, the actuarial rate of fibrosis-free patients decreased exponentially with time after radiotherapy. Patients with high cellular radiosensitivity showed a 2.3-fold higher annual rate for fibrosis than patients with intermediate and low radiosensitivity (3.6 versus 1.6% per year).

CONCLUSIONS

In breast cancer patients, high individual cellular radiosensitivity as determined by the number of lethal chromosome aberrations in in vitro irradiated lymphocytes might be associated with an enhanced annual rate of fibrosis.

Molecular mechanisms of individual radiosensitivity studied in normal diploid human fibroblasts

The molecular mechanisms of individual radiosensitivity were studied in normal diploid human fibroblasts. For fibroblasts irradiated with X-rays in G1-phase the individual radiosensitivity was shown to be correlated with the extent of double-strand break (dsb) repair. The number of residual dsbs (including both non- and mis-rejoined dsbs) varied between 2 and 5% of the initial number induced and was low for resistant and high for sensitive strains. In the G1-phase dsbs are considered to be mostly repaired via the non-homologous end-joining pathway (NHEJ). However, so far none of the parameters tested for this pathway was found to be correlated with the number of residual dsbs. The parameters tested were mRNA expression, protein level and localisation and activity of the DNA-PK, which is the central complex of NHEJ. The dsb-repair capacity is also not regulated by the differentiation status, which varies substantially among fibroblast strains, whereas there is some indication that dsb repair might depend on the chromatin structure, with more efficient repair in cells with condensed DNA. Residual dsbs are converted into lethal chromosome aberrations finally leading to the loss of clonogenic activity, when cells pass through mitosis. Beside this so-called mitotic death, X-irradiated human fibroblasts are also inactivated via the TP53-dependent permanent G1-arrest, while apoptosis appears to be not important. On average, mitotic death and G1-arrest are equally effective, but there is a broad variation from one strain to the other, with a negative correlation between these two pathways. Fibroblast strains exhibiting only a moderate G1-arrest showed a high number of lethal aberrations and vice versa. This result points to a common regulator of both G1-arrest and dsb repair, which is presently under investigation.

Why recent studies relating normal tissue response to individual radiosensitivity might have failed and how new studies should be performed

PURPOSE

New insights into the kinetics of late complications occurring after radiation therapy indicated that all patients have a constant risk of developing late tissue complications. These observations might have a great impact on studies relating normal tissue complications to individual radiosensitivity.

METHODS AND MATERIALS

Data previously published by Peacock et al. were used for analysis. In this study, 39 breast cancer patients with severe reactions (responders) were compared with 65 matched patients showing no reactions (nonresponders). Cellular radiosensitivity as measured in vitro in terms of D(0.01) did not show significant differences between the two groups, both for high-dose-rate (5.84 +/- 0.06 vs. 5.85 +/- 0.07 Gy) and low-dose-rate (7.44 +/- 0.10 vs. 7.56 +/- 0.09 Gy) irradiation.

RESULTS

A theoretical distribution was calculated for the individual radiosensitivity of patients with Grade <or= 1, Grade 2, or Grade 3 reactions under the following assumptions: (1). The variation of the individual radiosensitivity is described by a normal distribution. (2). All patients and not only a subgroup have a risk of developing late complications. Based on the normal distribution of low-dose-rate data (mean value [MV] = 7.56 Gy, standard deviation [SD] = 0.5 Gy), a total of 200 hypothetical patients were divided into three groups: a resistant group with a sensitivity >or=(MV + SD), a normal group with a sensitivity between MV - SD and MV + SD, and a sensitive group <or=(MV - SD), the relative fractions being 16%, 68%, and 16%, respectively. It was assumed that these groups differed in the risk of developing late complication; for Grade 3 the annual incidence rate was set at 1%, 2%, and 4% and for Grade 2 at 5%, 10%, and 20% per year, respectively. It was shown that the mean cellular sensitivity calculated for Grade 3 (7.39 +/- 0.10 Gy) or Grade 2 patients (7.46 +/- 0.06 Gy) was slightly but not significantly lower than that of Grade <or= 1 patients (7.65 +/- 0.04 Gy). This result demonstrated that even if the risk was assumed to depend clearly on the individual radiosensitivity, significant differences in the mean cellular sensitivity between responders and nonresponders were not expected, just as found by Peacock et al. It was shown that a significant correlation between these two parameters could be detected only when the risk was analyzed separately for each group of patients.

CONCLUSION

Most data published so far aiming at establishing a relationship between cellular radiosensitivity and the risk of late complications might need to be reevaluated, because the questions asked up to now were inadequate to arrive at a meaningful answer.

Indicators of late normal tissue response after radiotherapy for head and neck cancer: fibroblasts, lymphocytes, genetics, DNA repair, and chromosome aberrations

PURPOSE

To investigate the relationship between late tissue response after radiotherapy, cellular sensitivity and DNA repair capacity measured in dermal fibroblasts and chromosomal aberrations measured in lymphocytes. The study was in particular designed to compare cellular parameters of patients with maximum differences in late tissue reactions.

MATERIALS AND METHODS

The study was performed with 16 pair-wise matched head and neck cancer patients 2-7 years after curative therapy exhibiting maximum differences (grade 1 vs. grade 3) in late normal tissue reactions. Clinical endpoints were fibrosis, telangiectasia, mucositis and xerostomia using the radiation therapy oncology group score. Patients with grade 3 reactions were tested for mutations in ataxia telangiectasia (AT), Nijmegen Breakage Syndrome (NBS), MRE11, RAD50 and DNA ligase IV genes by means of polymerase chain reaction-single-strand conformation polymorphism and sequencing analysis. Skin fibroblasts obtained from biopsies were used to determine the cellular sensitivity by colony formation and the induction and repair of DNA double-strand breaks (dsb) using constant-field gel electrophoresis. Lymphocytes were taken to measure chromosomal damage either in metaphase using conventional chromosome analysis or in G(0) using premature chromosome condensation (PCC)-technique.

RESULTS

Patients with extreme late reactions (grade 3) showed no evidence for an AT, NBS, MRE11 or RAD50 mutation. Studies with fibroblasts revealed that extreme late reactions were associated neither with a pronounced cellular radiosensitivity nor with a difference in dsb repair capacity. In contrast, there was a significant difference in chromosomal damage measured in lymphocytes. After in vitro irradiation with 6Gy, lymphocytes taken from overreacting patients showed on average a significantly higher number of lethal aberrations than lymphocytes isolated from patients with mild reactions (7.2+/-0.8 vs. 5.0+/-0.3). Similar differences were found for PCC fragments.

CONCLUSION

This study suggests that lymphocytes are more promising than fibroblasts to predict patient's normal tissue response after radiotherapy.

Subcutaneous fibrosis after whole neck irradiation

PURPOSE

To identify the risk factors for moderate to severe subcutaneous fibrosis after whole neck irradiation.

MATERIALS AND METHODS

We analyzed 233 cases of patients who had undergone whole neck irradiation with 4-MV X-ray or 8-10-MeV electrons, or both, and had been followed with regard to their skin condition for at least 1 year. The prescribed dose to the whole neck ranged from 19.2 to 72.4 Gy (median 50). The skin-absorbed dose was specified as that at a depth of 4.1 mm (d4.1-mm(depth)), and a biologically equivalent dose (BED) of d4.1-mm(depth) was also estimated (BED(1.8) 4.1-mm(depth)).

RESULTS

Univariate analysis revealed that previous neck dissection, concurrent chemotherapy, corticosteroid administration as a part of chemotherapy, fractionation, and BED(1.8) 4.1-mm(depth) were significant prognostic variables. Multivariate analysis showed that BED(1.8) 4.1-mm(depth) and previous neck dissection were the only prognostic variables for moderate to severe subcutaneous fibrosis.

CONCLUSION

A high dose to a 4.1-mm depth of the skin and a history of neck dissection were identified as the predominant risk factors for moderate to severe subcutaneous fibrosis after whole neck irradiation. A subcutaneous dose should be considered in radiotherapy treatment planning involving the whole neck, especially in cases in which patients have undergone previous neck dissection.

Role of multimodal treatment in oropharynx, larynx, and hypopharynx cancer

Due to recent advances in radiation fractionation, radiochemotherapy, and conservative surgical techniques, the concept of multimodal therapy in head and neck cancer is currently changing. The recently published RTOG Phase III trial 9003, with 1,113 patients accrued, showed that hyperfractionation and accelerated fractionation with concomitant boost are more efficacious than standard fractionation for locally-advanced head and neck cancer. Acute, but not late, toxicity was also increased. Three meta-analyses have suggested that the impact of chemotherapy in head and neck cancer is small but is highly associated with the timing of therapy. Concomitant administration of radiation therapy and chemotherapy led to an absolute benefit in 5-year survival of about 10%. This finding has been further supported by recently published randomized prospective trials comparing concomitant radiochemotherapy with radiotherapy alone in advanced head and neck cancer. There is now clear evidence that radiochemotherapy provides a substantial and statistically significant improvement in survival and local-regional control, as compared to radiotherapy alone. Radiochemotherapy should be considered an accepted standard of care in cancers of the oropharynx, particularly for patients with locally-advanced disease who have a good performance status. Two randomized studies conducted by the Department of Veterans' Affairs and the EORTC, with a total of 534 patients accrued, showed that induction chemotherapy followed by radiotherapy of responders yields survival rates equal to those of total laryngectomy with postoperative radiotherapy. After 4 years, one-half to two-thirds of survivors of the chemotherapy arm retained a functional larynx. Larynx preservation using induction chemotherapy can now be regarded as feasible but still investigational. Current phase II studies show excellent larynx preservation rates using a primary concomitant radiochemotherapy with an altered fractionation regimen. More clinical and laboratory research is required to further evaluate the different treatment options of the multimodality concept, and to develop prognostic models that will allow individualization of the therapy.

Protective effect of amifostine on dental health after radiotherapy of the head and neck

PURPOSE

The cytoprotective agent amifostine has been shown to reduce the radiation-induced acute and chronic xerostomia in head and neck cancer patients. The purpose of this study was to evaluate whether or not amifostine also reduces the incidence of dental caries associated with the radiation-induced xerostomia.

METHODS AND MATERIALS

The dental status before and 1 year after radiotherapy was retrospectively compared in 35 unselected patients treated as part of the prospective randomized and multicenter open-label Phase III study (WR-38) at the University Hospitals of Heidelberg, Freiburg, and Erlangen. The WR-38 study compared radiotherapy in head and neck cancer with and without concomitant administration of amifostine.

RESULTS

Patient and treatment characteristics (particularly the radiation dose and percentage of parotids included in the treatment volume) were equally distributed between the patients who received (n = 17) or did not receive (n = 18) amifostine. Fifteen patients of the amifostine group showed no deterioration of the dental status 1 year after radiotherapy as compared to 7 patients who did not receive the cytoprotector (p = 0. 015, two-tailed Fisher exact test).

CONCLUSION

Our data suggest a protective effect of amifostine on the dental health after radiotherapy of the head and neck. The dental status should be used as a primary endpoint in future studies on amifostine.

[Radiation-induced superficial fibrosis and TGF-alpha 1]

Radiation-induced fibrosis is a late sequela of both therapeutic and accidental irradiations, which has been described in various tissues, including the lung, liver, kidney and skin. This review presents different aspects of superficial radiation-induced fibrosis, such as clinical observations, histological changes, cellular and molecular regulations, and medical management. Recent evidence on the critical role played by TGF-beta 1 in the initiation, development and persistence of fibrosis are discussed, as well as the possibility that this cytokine may constitute a specific target for antifibrotic agents.