A Prospective Phase II Dose Escalation Study Using IMRT for High Risk N0M0 Prostate Cancer

PURPOSE/OBJECTIVE(S)

Published data supports the use of very high dose intensity modulated radiotherapy (IMRT) in achieving high efficacy and low toxicity for high-risk prostate cancer (HRPCa). This phase II multi-institutional non-randomized prospective dose escalation study using intensity modulated radiotherapy (IMRT) for high risk N0M0 prostate cancer was designed to investigate dose escalation using 1.8 Gy increments from baseline 75.6 Gy up to maximum 81 Gy, once dose volume constraints were adhered to.

MATERIALS/METHODS

Inclusion criteria were patients undergoing a radical course of RT for high and very high-risk disease, defined as one or more of the criteria ≥ T3*, ≥ Gleason 8, Prostate specific antigen (PSA) > 20ng/ml. All patients received Androgen Deprivation Therapy (ADT) and none had radiological evidence of distant metastatic disease. The primary objective was to determine if dose escalated IMRT for high risk localized prostate cancer could provide freedom from biochemical relapse (BR; PSA rising > nadir +2ng/mL or initiation of salvage hormone therapy) similar to that reported in the literature. The Kaplan-Meier method was used to estimate survival times. Secondary objectives included OS, Disease Free Survival (DFS), and the incidence and severity of Genito-urinary (GU), Gastro-intestinal (GI) and erectile dysfunction (ED) toxicities (CTCAE v.3). Toxicities and performance status were collected and graded weekly during RT, 2 months after completing RT, 8 months' post RT, and 6 monthly thereafter to year five and annually thereafter to year nine.

RESULTS

A total of 230 evaluable patients were enrolled between April 2009 and June 2016. The median follow-up was 7.3 years. The cumulative proportion of patients surviving without BR at 5 years was 91% (95% Confidence Interval (CI): 86% to 94%). Overall survival at 5 and 7 years was 92% (88% to 95%) and 89% (83% to 92%) respectively, while the cumulative proportion of patients free from disease was 89% (84% to 93%) at 5 years and 81% (75% to 86%) at 7 years. The incidence of acute G2 and G3 toxicities were; GU; 57.8% G2, 12.6% G3, GI; 15.2% G2, 0.4% G3, ED; 30.0% G2 and 61.7% G3. The incidence of late G2, G3 and G4 toxicities were; GU; 40.9% G2, 8.7% G3, GI; 36.5% G2, 2.2% G3, 0.4% G4, ED; 11.7% G2 and 86.1% G3. The percentage of patients receiving each dose level was; 3.5% received 75.6Gy in 42 fractions, 2.2% received 77.4Gy in 43 fractions, 93% received 81Gy in 45 fractions.

CONCLUSION

The findings indicate that high-dose IMRT is well tolerated and is associated with excellent long-term tumor-control outcomes in patients with localized high and very high-risk prostate cancer, with 91% of patients surviving at 5 years without biochemical relapse. The rates of long term G3 GU and GI toxicity were low at 8.7% and 0.4% respectively.

Enhancing Specialist Training in Radiation Oncology through the Implementation of Structured Radiotherapy Contouring Workshops

PURPOSE/OBJECTIVE(S)

Contouring tumor volumes and organs at risk is a key component of Radiation Oncology specialist training. As trainees rotate through different tumor sites, they are expected to develop proficiency in contouring skills relevant to their year of training. These skills have historically been acquired in an unstructured manner during supervised clinical work. However, trainees often struggle to learn these skills due to variability in practice and approach amongst senior colleagues. Research has shown that contouring workshops improve the standardization of contouring and can be an effective way of enhancing the learning experience through interaction, instant feedback and reflection. We present our experience of implementing structured contouring workshops and the feedback received from the trainees.

MATERIALS/METHODS

Eight contouring workshops were held in our institution over a period of 3 years between 2019 and 2022. These included Head & Neck (3), Prostate (1), SABR Lung (2), Breast (1), and Esophagus (1). Six were held in-person pre-COVID and two in a virtual format during the pandemic. Each workshop was 2 hours long and attended by trainees with varying levels of contouring experience. All the workshops were facilitated by a consultant radiation oncologist and a clinical tutor and followed a similar format consisting of a brief tutorial on the tumor site, followed by a contouring demonstration on an anonymized case on an Eclipse planning platform referencing published contouring atlases. Each of the trainees had access to a copy of the same case throughout the workshop and their contours were then reviewed both individually and collectively. A key component of the workshops was instant feedback, as trainees could compare their contours to that of the tutors and discuss any differences. Feedback on the contouring workshop was then collected through a post workshop questionnaire.

RESULTS

The workshops were attended by an average of 12 trainees (range 10 to 14). Regardless of their year of training, all trainees rated the content and format of the workshops highly and stated they were relevant to their daily practice. Their subjective level of confidence in contouring in that specific tumor site improved significantly, going from an average of 5.6 out of 10 (range of 4 to 7) before the workshop to 8.7 (range of 8 to 9) after the 8 workshops. All the workshops were conducted at no extra cost as they were held using our existing planning software.

CONCLUSION

The trainees indicated that the workshops were of definite educational benefit and strongly supported incorporating this approach to teaching contouring skills into the curriculum. Based on this feedback, these contouring workshops have been integrated into the recently revised higher specialist training curriculum on a more structured basis. This will ensure that trainees will continue to develop progressive expertise in contouring skills in keeping with best international practice as they advance through their training scheme.

Late Toxicity and Long-Term Local Control in Patients With Ultra-Central Lung Tumours Treated by Intensity-Modulated Radiotherapy-Based Stereotactic Ablative Body Radiotherapy With Homogenous Dose Prescription

AIMS

To report late toxicity and long-term outcomes of intensity-modulated radiotherapy (IMRT)-based stereotactic ablative body radiotherapy (SABR) in patients with ultra-central lung tumours.

MATERIALS AND METHODS

This is a single-institution retrospective analysis of patients treated with SABR for ultra-central tumours between May 2008 and April 2016. Ultra-central location was defined as tumour (GTV) abutting or involving trachea, main or lobar bronchi. Respiratory motion management and static-field dynamic-IMRT were used, with dose prescribed homogeneously (maximum <120%). Descriptive analysis, Kaplan-Meier method, log-rank test and Cox regression were used to assess outcomes.

RESULTS

Sixty-five per cent of patients had inoperable primary non-small cell lung cancer and 35% had lung oligometastases. The median age was 72 (range 34-85) years. The median gross tumour volume and planning target volume (PTV) were 19.6 (range 1.7-203.3) cm³ and 57.4 (range 7.7-426.6) cm³, respectively. The most commonly used dose fractionation was 60 Gy in eight fractions (n = 51, 87.8%). Median BED₁₀ for D98%PTV and D2%PTV were 102.6 Gy and 115.06 Gy, respectively. With a median follow-up of 26.5 (range 3.2-100.5) months, fatal haemoptysis occurred in five patients (8.7%), of which two were directly attributable to SABR. A statistically significant difference was identified between median BED₃ for 4 cm³ of airway, for patients who developed haemoptysis versus those who did not (147.4 versus 47.2 Gy, P = 0.005). At the last known follow-up, 50 patients (87.7%) were without local recurrence. Freedom from local progression at 2 and 4 years was 92 and 79.8%, respectively. The median overall survival was 34.3 (95% confidence interval 6.1-61.6) months. Overall survival at 2 and 4 years was 55.1 and 41.2%, respectively.

CONCLUSION

In patients with high-risk ultra-central lung tumours, IMRT-based SABR with homogenous dose prescription achieves high local control, similar to that reported for peripheral tumours. Although fatal haemoptysis occurred in 8.7% of patients, a direct causality with SABR was evident in only 3%. Larger studies are warranted to ascertain factors associated with outcomes, especially toxicity, and identify patients who would probably benefit from this treatment.

Stereotactic Ablative Radiation Therapy for Large (≥5 cm) Non-small Cell Lung Carcinoma

AIMS

Stereotactic ablative radiation therapy (SABR) is a standard of care for medically inoperable early stage non-small cell lung carcinoma. Tumours greater than 5 cm have been excluded from randomised trials using SABR and, hence, it is not used as a standard for larger lung tumours. However, improvements in radiation therapy techniques and the success of SABR in treatment of early stage disease may allow safe delivery of ablative doses to larger tumours. We analysed our experience with tumours ≥5 cm to determine the efficacy and toxicity profile of SABR in this setting.

MATERIALS AND METHODS

We evaluated survival, control rates, patterns of failure and toxicity in patients with a tumour diameter larger than 5 cm that had no nodal or distant metastases treated with SABR technology. Patients had been treated in two centres since 2009 and were retrospectively analysed. All patients had positron emission tomography staging, were discussed at a tumour board and were documented to have no nodal or distant metastatic disease. Treatment outcomes were analysed using Kaplan-Meier estimates and compared using the Log-rank test. Cox regression was used to investigate the association between the survival outcomes and predictor variables.

RESULTS

In total, 86 patients were identified. Six patients had no follow-up imaging. Therefore, 80 patients were available for analysis. All patients were reclassified according to the updated AJCC eighth edition. The median follow-up was 19.6 months. No patients received neoadjuvant or concurrent systemic therapy. One patient received adjuvant systemic therapy. The median age at treatment was 77 years (range 58-91). Eighty-four per cent were stage T3N0M0 and 16% were staged T4N0M0. The median tumour diameter was 5.8 cm (range 5.0-9.3 cm). The median gross tumour volume, measured on a single phase of the respiratory cycle, was 45.7 cm³ (range 12.1-203.3 cm³). The median overall survival was 20.9 months (95% confidence interval 12.6-29.1 months). One-, 2- and 3-year overall survival was 71%, 48% and 32%, respectively. The median local failure-free survival was 19.5 months (95% confidence interval 14.4-24.6). The median disease-free survival was 15.1 months (95% confidence interval 9.9-20.4 months). Local control at 1, 2 and 3 years was 85% (95% confidence interval 76-94%), 71% (95% confidence interval 58-84%) and 57% (95% confidence interval 40-74%), respectively. Forty-four patients (55%) had any treatment failure (local, mediastinal, intrapulmonary or distant metastases). Out-of-field intrapulmonary disease progression was the most common mode of failure, occurring in 21 patients (26%). Local failure occurred in 19 patients (24%) - alone or in combination with other progression. Distant metastases occurred in 20 patients (25%). Neither histological subtype, tumour size nor gross tumour volume had a statistically significant effect on local failure-free survival. Two patients experienced grade 3 late dyspnoea. There were no other reported grade 3 or higher acute or late toxicities.

CONCLUSION

SABR for larger lung tumours ≥5 cm results in high local control and acceptable survival in patients with medically inoperable large non-small cell lung carcinoma treated with radiation alone. Such patients should be considered for SABR owing to fewer treatment fractions and acceptable toxicity. Local control analysis reveals a sustained pattern of local failure emphasising the need for long-term follow-up. Improvements in technical strategies are required to further improve local control.

Multiplex profiling identifies clinically relevant signalling proteins in an isogenic prostate cancer model of radioresistance

The exact biological mechanism governing the radioresistant phenotype of prostate tumours at a high risk of recurrence despite the delivery of advanced radiotherapy protocols remains unclear. This study analysed the protein expression profiles of a previously generated isogenic 22Rv1 prostate cancer model of radioresistance using DigiWest multiplex protein profiling for a selection of 90 signalling proteins. Comparative analysis of the profiles identified a substantial change in the expression of 43 proteins. Differential PARP-1, AR, p53, Notch-3 and YB-1 protein levels were independently validated using Western Blotting. Pharmacological targeting of these proteins was associated with a mild but significant radiosensitisation effect at 4Gy. This study supports the clinical relevance of isogenic in vitro models of radioresistance and clarifies the molecular radiation response of prostate cancer cells.

(ICORG 05-03): prospective randomized non-inferiority phase III trial comparing two radiation schedules in malignant spinal cord compression (not proceeding with surgical decompression); the quality of life analysis

BACKGROUND

The optimal primary external beam radiation therapy (EBRT) radiation schedule for malignant epidural spinal cord compression (MSCC) remains to be determined. The ICORG 05-03 trial assessed if a 10 Gy single fraction radiation schedule was not inferior to one with 20 Gray (Gy) in five daily fractions, in terms of functional motor outcome, for the treatment of MSCC in patients not proceeding with surgical decompression. This article reports on two of the secondary endpoints, Quality of life (QoL), assessed according to the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) version 3.0 (EORTC Data Center, Brussels, Belgium) and pain control assessed using a visual analog scale.

METHODS

A randomized, parallel group, multicenter phase III trial was conducted by Cancer Trials Ireland (formerly All-Ireland Cooperative Oncology Research Group, ICORG), across five hospital sites in Ireland and Northern Ireland. Patients were randomized to 10 Gy single fraction of EBRT or 20 Gy in five fractions in a 1:1 ratio. Patients with baseline and 5-week follow up QoL data are included in this analysis.

FINDINGS

From 2006 to 2014, 112 eligible patients were enrolled for whom 57 were evaluated for this secondary analysis. After adjusting for pre-intervention scores, there was no statistically significant difference in post-treatment Summary scores (excl. FI and QL), or pain scores between the two RT schedules at 5 weeks and 3 months following EBRT. There was a statistically significant relationship between the pretreatment and post-treatment Summary scores (p =  .002) but not between the pre-treatment and post-treatment pain scores.

INTERPRETATION

Primary radiotherapy for the treatment of MSCC significantly improves QoL in patients not proceeding with surgical decompression. After adjusting for pre-intervention scores, there was no statistically significant difference between a 10 Gy single fraction radiation schedule and one with 20 Gy in five daily fractions on post-treatment QoL Summary scores. For most patients, an effective treatment with low burden would be desirable. A single fraction schedule should be considered for this group of patients.

Laparoscopic pelvic sling placement facilitates optimum therapeutic radiotherapy delivery in the management of pelvic malignancy

BACKGROUND

Radiotherapy has a significant role in the management of pelvic malignancies. However, the small intestine represents the main dose limiting organ. Invasive and non-invasive mechanical methods have been described to displace bowel out of the radiation field. We herein report a case series of laparoscopic placement of an absorbable pelvic sling in patients requiring pelvic radiotherapy.

METHODS

Six patients were referred to our minimally invasive unit. Four patients required radical radiotherapy for localised prostate cancer, one was scheduled for salvage localised radiotherapy for post-prostatectomy PSA progression and one patient required adjuvant radiotherapy post-cystoprostatectomy for bladder carcinoma. All patients had excessive small intestine within the radiation fields despite the use of non-invasive displacement methods.

RESULTS

All patients underwent laparoscopic mesh placement, allowing for an elevation of small bowel from the pelvis. The presence of an ileal conduit or previous surgery did not prevent mesh placement. Post-operative planning radiotherapy CT scans confirmed displacement of the small intestine allowing all patients to receive safely the planned radiotherapy in terms of both volume and radiation schedule.

CONCLUSION

Laparoscopic mesh placement represents a safe and efficient procedure in patients requiring high-dose pelvic radiation, presenting with unacceptable small intestine volume in the radiation field. This procedure is also feasible in those that have undergone previous major abdominal surgery.

Radiation enteropathy

Radiation enteritis is a functional disorder of the intestine that occurs during or after a course of radiotherapy to the abdomen, pelvis or rectum. It presents in both an acute and chronic form and has sequelae that can be life threatening. As radiotherapy is now being used more than ever before in the treatment of solid organ malignancies in the abdomen and pelvis, the incidence of radiation enteropathy is likely to increase in the future. We present two patients with severe forms of this condition in order to clarify the salient issues regarding its diagnosis and, in particular, its distinction from mechanical bowel obstruction. We also review its pathophysiology, management and current preventative strategies.

A randomised phase II trial assessing the impact of the addition of gefitinib to the combination of radiotherapy and short-term maximal androgen blockage in high-risk localised prostate cancer: Safety evaluation

14613

Background: Given the in-vitro evidence of potential increase in tumour radiosensitisation and hormonal deprivation-related tumour growth inhibiting effect by the addition of EGFR inhibitors, a randomised unblinded phase II trial was initiated to evaluate the impact of the addition of gefitinib to a combination of radiotherapy (RT) and maximal androgen blockage (MAB) in patients (pts) with high-risk localised prostate cancer. Methods: Eligible pts had biopsy proven localised prostate carcinoma Gleason score ≥7 and/or cT3 stage and/or initial PSA ≥ 20; without nodal and distant metastases. All pts were treated by 8 months MAB using LH-RH agonist (Zoladex 3.6 mg/month) and peripheral anti-androgen (Casodex 50 mg/day), and localised Conformal RT (Prostate + Seminal Vesicles, 75.6 Gy/42 daily fractions), initiated after 4 months of MAB. Pts were randomised to receive or not gefitinib 250 mg/day concomitantly for 8 months. The planned accrual was 98 pts. The end-points were ASTRO defined PSA-relapse-free survival at 18 months and toxicity. A safety evaluation was performed mid 2005. Results: 20 pts (10 per arm) were included from 10/2003 to 02/2005. No significant difference in RT or MAB-related toxicity was seen between the 2 arms. The addition of gefitinib significantly increased the frequency and intensity of reversible skin toxicity events (Rash-CTC grade 3–4: 4 pts Vs O pts, p = 0.04), with a trend for reversible transaminase enzymes elevation (TEE) (CTC grade 3–4: 2 pts Vs 0 pts). No treatment interruption was reported in the control arm. In the experimental arm, 3 pts completed treatment, 3 pts had a temporary (<10 days) gefitinib discontinuation (reversible asthenia and skin rash) and 4 pts had a permanent gefitinib discontinuation for reversible CTC grade 3 toxicity (skin rash: 2 pts, TEE: 2 pts). Conclusions: Gefitinib-related toxicity led to treatment discontinuation in 4 out of 10 patients. The trial is under review. This trial was supported by AstraZeneca.

No significant financial relationships to disclose.

Modulation of fluorouracil by leucovorin in patients with advanced colorectal cancer: an updated meta-analysis

PURPOSE

The modulation of fluorouracil (FU) by folinic acid (leucovorin [LV]) has been shown to be effective in terms of tumor response rate in patients with advanced colorectal cancer, but a meta-analysis of nine trials previously published by our group failed to demonstrate a statistically significant survival difference between FU and FU-LV. We present an update of the meta-analysis, with a longer follow-up and the inclusion of 10 newer trials.

PATIENTS AND METHODS

Analyses are based on individual data from 3,300 patients randomized in 19 trials on an intent-to-treat basis. Two trials had multiple comparisons, leading to a total of 21 pair-wise comparisons. FU doses were similar in both arms in 10 pair-wise comparisons, 15% to 33% higher in the FU-alone arm in six comparisons, and more than 66% higher in five comparisons.

RESULTS

Overall analysis showed a two-fold increase in tumor response rates (11% for FU-LV v 21% for FU-LV v 11% for FU [corrected] alone; odds ratio, 0.53; 95% CI, 0.44 to 0.63; P <.0001) and a small but statistically significant overall survival benefit for FU-LV over FU alone (median survival, 11.7 v 10.5 months, respectively; hazards ratio, 0.90; 95% CI, 0.87 to 0.94; P =.004), which were primarily seen in the first year. We observed a significant interaction between treatment benefit and dose of FU, with tumor response and overall survival advantages of FU-LV over FU-alone being restricted to trials in which a similar dose of FU was prescribed in both arms.

CONCLUSION

This updated analysis demonstrates, on a large data set, that FU-LV improves both response rate and overall survival compared with FU alone and that this benefit is consistent across various prognostic factors.

Adjuvant radiotherapy in Stage I endometrial cancer. Where do we stand?

This paper reviews the anatomical spread and failure patterns of surgical Stage I endometrial cancer. The controversial aspects of the optimal adjuvant treatment are presented. An attempt is made to identify the most effective management approach based on the pertinent literature data.

Alpha-interferon does not increase the efficacy of 5-fluorouracil in advanced colorectal cancer

Two meta-analyses were conducted to quantify the benefit of combining alpha-IFN to 5FU in advanced colorectal cancer in terms of tumour response and survival. Analyses were based on a total of 3254 individual patient data provided by principal investigators of each trial. The meta-analysis of 5FU +/- LV vs. 5FU +/- LV + alpha-IFN combined 12 trials and 1766 patients. The meta-analysis failed to show any statistically significant difference between the two treatment groups in terms of tumour response or survival. Overall tumour response rates were 25% for patients receiving no alpha-IFN vs. 24% for patients receiving alpha-IFN (relative risk, RR = 1.02), and median survivals were 11.4 months for patients receiving no alpha-IFN vs. 11.5 months for patients receiving alpha-IFN (hazard ratio, HR = 0.95). The meta-analysis of 5FU + LV vs. 5FU + alpha-IFN combined 7 trials, and 1488 patients. This meta-analysis showed an advantage for 5FU + LV over 5FU + alpha-IFN which was statistically significant in terms of tumour response (23% vs. 18%; RR = 1.26;P = 0.042), and of a borderline significance for overall survival (HR = 1.11;P = 0.066). Metastases confined to the liver and primary rectal tumours were independent favourable prognostic factors for tumour response, whereas good performance status, metastases confined to the liver or confined to the lung, and primary tumour in the rectum were independent favourable prognostic factors for survival. We conclude that alpha-IFN does not increase the efficacy of 5FU or of 5FU + LV, and that 5FU + alpha-IFN is significantly inferior to 5FU + LV, for patients with advanced colorectal cancer.

Relation between tumour response to first-line chemotherapy and survival in advanced colorectal cancer: a meta-analysis. Meta-Analysis Group in Cancer

BACKGROUND

Treatment of advanced colorectal cancer has progressed substantially. However, improvements in response rates have not always translated into significant survival benefits. Doubts have therefore been raised about the usefulness of tumour response as a clinical endpoint.

METHODS

This meta-analysis was done on individual data from 3791 patients enrolled in 25 randomised trials of first-line treatment with standard bolus intravenous fluoropyrimidines versus experimental treatments (fluorouracil plus leucovorin, fluorouracil plus methotrexate, fluorouracil continuous infusion, or hepatic-arterial infusion of floxuridine). Analyses were by intention to treat.

FINDINGS

Compared with bolus fluoropyrimidines, experimental fluoropyrimidines led to significantly higher tumour response rates (454 responses among 2031 patients vs 209 among 1760; odds ratio 0.48 [95% CI 0.40-0.57], p<0.0001) and better survival (1808 deaths among 2031 vs 1580 among 1760; hazard ratio 0.90 [0.84-0.97], p=0.003). The survival benefits could be explained by the higher tumour response rates. However, a treatment that lowered the odds of failure to respond by 50% would be expected to decrease the odds of death by only 6%. In addition, less than half of the variability of the survival benefits in the 25 trials could be explained by the variability of the response benefits in these trials.

INTERPRETATION

These analyses confirm that an increase in tumour response rate translates into an increase in overall survival for patients with advanced colorectal cancer. However, in the context of individual trials, knowledge that a treatment has benefits on tumour response does not allow accurate prediction of the ultimate benefit on survival.

Survival impact of chemotherapy in patients with colorectal metastases confined to the liver: a re-analysis of 1458 non-operable patients randomised in 22 trials and 4 meta-analyses. Meta-Analysis Group in Cancer

BACKGROUND

Metastases confined to the liver is a frequent situation in patients with advanced colorectal cancer. For non-operable patients, 5-FU-based chemotherapy is often proposed but the importance of the choice of first line 5-FU regimen remains debatable.

DESIGN

In four previously performed meta-analyses, our group had compared bolus intravenous fluoropyrimidines (bolus FU group) with experimental fluoropyrimidines (experimental FU group), consisting of 5-FU plus leucovorin, 5-FU plus methotrexate, continuous infusion 5-FU, or hepaticartery infusion FUDR. We re-analysed this data set to focus on 1458 patients with non-operable colorectal metastases confined to the liver, randomised in 22 trials. All analyses were stratified by trial and used individual patient data.

RESULTS

Median survival times were 11.3 months in the bolus FU group (95% CI: 10.5-12.0 months) compared to 12.7 months in the experimental FU group (95% CI: 120-13.1 months). This difference, although clinically small, was statistically significant, with an overall survival hazard ratio of 0.88 (95% CI: 0.79-0.99, P = 0.037). In a multivariate analysis, performance status was the only significant predictor of survival (P < 10(-4)), whereas the statistical significance of allocated treatment was borderline (P = 0.058).

CONCLUSIONS

The outcome of patient with non-operable colorectal metastases confined to the liver is poor, and mainly driven by their initial performance status. Experimental chemotherapy schedules yield a small improvement in their overall survival, indicating the importance of the choice of first-line chemotherapy.

Analysis by alkaline comet assay of cancer patients with severe reactions to radiotherapy: defective rejoining of radioinduced DNA strand breaks in lymphocytes of breast cancer patients

Therapeutic exposure to ionising radiation reveals inter-individual variations in normal tissue responses. To examine whether a defect in DNA repair capacity might be involved in such hypersensitive phenotypes, we analysed, using the alkaline comet assay, the response as a function of time to in vitro irradiation at 5 Gy of lymphocytes from 17 breast cancer and 9 Hodgkin's disease patients who developed severe reactions to radiotherapy in comparison with 22 patients with "average" reactions and 24 healthy donors. A difference between breast cancer over-reactors and both patients with normal reactions and healthy donors was observed 30 and 60 min after exposure. A subgroup of breast cancer over-reactors (7/17) reproducibly demonstrated increased levels of residual damage. When the kinetic analyses were prolonged to 120 min, results were in favour of delayed kinetics of rejoining in these patients. Among Hodgkin's disease over-reactors, only one patient showed defective repair. Interestingly, all patients with the most severe complications (grade 4 RTOG/EORTC), i.e., 5 breast cancer and 1 Hodgkin's disease, showed impaired rejoining. Our results suggest that impairment in DNA strand break processing may be associated, in specific subgroups of breast cancer patients, with an individual risk of major toxicity of radiation therapy. Thus, the alkaline comet assay appears to be useful for documenting the DNA repair phenotype in cancer patients.

[Role of radiotherapy in the treatment of adult nodal non-Hodgkin's lymphoma]

RADIOTHERAPY OF ADULT NODAL NON HODGKIN'S LYMPHOMA: The role of radiotherapy in the treatment of nodal non-Hodgkin's lymphoma has been modified by the introduction of efficient chemotherapy and the development of different pathological classifications. INTERMEDIATE GRADE OR HIGH GRADE LYMPHOMA: The recommended treatment of early-stage aggressive lymphomas is primarily a combination chemotherapy. The interest of adjuvant radiotherapy remains unclear and has to be established through large prospective trials. If radiation therapy has to be delivered, the historical results of exclusive radiation therapy showed that involved-fields and a dose of 35-40 Gy (daily fraction of 1.8 Gy, 5 days a week) are the optimal schedule. The interest of radiotherapy in the treatment of advanced-stage aggressive lymphoma is yet to be proven. Further studies had to stratify localized stages according to the factors of the International Prognostic Index. LOW-GRADE LYMPHOMA: For early-stage low-grade lymphoma, radiotherapy remains the standard treatment. However, the appropriate technique to use is controversial. Involved-field irradiation at a dose of 35 Gy seems to be the optimal schedule, providing a 10-year disease-free survival rate of 50% and no major toxicity. There is no standard indication of radiotherapy in the treatment advanced-stage low-grade lymphoma. RARE AND NEW ENTITY: For "new" nodal lymphoma's types, the indication of radiotherapy cannot be established (mantle-zone lymphoma, marginal zone B-cell lymphoma) or must take into account the natural history (Burkitt's lymphoma, peripheral T-cell lymphoma) and the sensibility to others therapeutic methods.