Total body irradiation as a primary therapy in non-Hodgkin lymphoma.

Thirty-three patients with non-Hodgkin lymphoma have been treated with total body irradiation (TBI). A very high remission rate is obtained in lymphocytic lymphomas (83%), but response in histiocytic lymphoma is extremely poor. Bone marrow study suggests that marrow depression following TBI is transient and complete recovery occurs provided the bone marrow is not already compromised by previous chemotherapy and radiation therapy. Extreme caution is required when TBI is repeated as this may lead to progressive marrow hypoplasia.     

Total-body irradiation in advanced lymphosarcoma.

Thirty patients with stage III and IV non-Hodgkin's lymphoma were treated by total-body irradiation (TBI). Eleven patients had previously received local radiotherapy or chemotherapy. Toxicity was confined to haematological depression. Complete remission of disease was achieved in 14 patients. Non-leukaemic patients who had received no previous treatment reacted best to TBI (ten complete remissions in 13 patients). We consider TBI a helpful treatment in non-leukaemic patients with advanced lymphosarcoma.     

Total-Body Irradiation—Role and Indications

BACKGROUND AND PURPOSE: Total-body irradiation (TBI) is a key part of the conditioning regimen before hematopoietic stem cell transplantation (HSCT). The exact role of TBI as part of the conditioning regimen is largely unclear. In order to determine the relevance of TBI, the status of TBI utilization was analyzed on the basis of a nationwide registry. MATERIAL AND METHODS: 14,371 patients (1998-2002) documented in the German Stem Cell Transplantation Registry (DRST) were analyzed regarding TBI utilization prior to autologous or allogeneic transplantation, underlying disorder, type of donor, stem cell source, and size of the treatment center. RESULTS: For autologous HSCT approximately 10% of the patients (873/8,167) received TBI, with chronic lymphocytic leukemia (CLL, approximately 80%, 171/214) and low-grade non-Hodgkin's lymphoma (l-NHL, approximately 35%, 330/929) being the most important disorders. In the allogeneic setting 50% of the patients (2,399/4,904) received TBI, with acute lymphocytic leukemia (ALL, 85%, 794/930), acute myeloid leukemia (AML, 45%, 662/1,487) and chronic myeloid leukemia (CML, 49%, 561/1,156) being the key indications. The type of donor, stem cell source and center size did not strongly influence the use of TBI. CONCLUSION: TBI has only a limited role for the conditioning prior to autologous HCST. For allogeneic HSCT TBI is widely accepted with no major changes over the observation time. The use of TBI is generally accepted for ALL, whereas approximately half of the patients with CML or AML received TBI. Although a considerably large database was analyzed, no clear determinants for the use of TBI could be distinguished.     

Factors affecting 131I-Lym-1 pharmacokinetics and radiation dosimetry in patients with non-Hodgkin's lymphoma and chronic lymphocytic leukemia.

Lym-1, a monoclonal antibody that preferentially targets malignant lymphocytes, has induced therapeutic responses in patients with non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) when labeled with 131I. Responders had statistically significant prolongation of survival compared with nonresponders. The nonmyeloablative, maximum tolerated dose for each of two doses of 131I-Lym-1 was 3.7 GBq/m2 (total 7.4 GBq/m2 [100 mCi/m2, total 200 mCi/m2]) of body surface area. The purpose of this study was to determine the pharmacokinetics and radiation dosimetry for the initial 131I-Lym-1 therapy dose in patients with NHL and CLL and to compare tumor dosimetry with 131I-Lym-1 dosing and other patient parameters. METHODS: Fifty-one patients with stage 3 or 4 lymphoma were treated with 131I-Lym-1 (0.74-8.04 GBq [20-217 mCi]) in either a maximum tolerated dose (MTD) or low-dose (LD) trial. Total Lym-1 given to each patient was sufficient in all instances to exceed the threshold required for stable pharmacokinetics. Quantitative imaging and physical examination, including caliper and CT measurement of tumor size and analysis of blood, urine and feces, were performed for a period of 7 to 10 d after infusion to assess pharmacokinetics and radiation dosimetry. Clinical records were reviewed to obtain data required for comparative assessments. RESULTS: The concentration (%ID/g) and biologic half-time of 131-Lym-1 in tumor were about twice those in normal tissues, although tumor half-time was similar to that of the thyroid. Pharmacokinetics were similar for patients in the MTD and LD trials, and for NHL and CLL patients in the LD trial, except that the latter group had less tumor concentration of 131I. Mean tumor radiation dose per unit of administered 131I was 1.0 Gy/GBq (3.7 rad/mCi) for patients with NHL whether in MTD or LD trials, about nine times greater than that for body or marrow. Tumor radiation dose was less and liver radiation dose was more in patients with CLL. Otherwise, radiation dosimetry was, on average, remarkably similar among groups of patients and among individual patients. Pharmacokinetics and dosimetry did not appear to be influenced by the amount of 131I or Lym-1 within the ranges administered. Tumor concentration of 131I and radiation dose per gigabecquerel were inversely related to tumor size but did not seem to be related to histologic grade or type, tumor burden or therapeutic response. CONCLUSION: The therapeutic index of 131I-Lym-1 was favorable, although the index for patients with CLL was less than that for patients with NHL. Pharmacokinetics and radiation dosimetry were, on average, remarkably similar among patients and groups of patients in different trials.     

Detection of Richter's transformation of chronic lymphocytic leukemia by PET/CT.

Our objective was to evaluate the accuracy of PET/CT for the diagnosis of Richter's transformation of chronic lymphocytic leukemia (CLL) to diffuse large cell lymphoma. METHODS: A retrospective study was performed of 37 patients with CLL who underwent 18F-FDG PET/CT at our institution between March 2003 and July 2005. All PET/CT scans were reviewed in consensus by 2 diagnostic radiologists. Sites of abnormal 18F-FDG uptake with a maximum standardized uptake value (SUVmax) of greater than 5 were considered highly suggestive of Richter's transformation. The PET/CT findings were correlated with histologic findings from bone marrow or lymph node biopsy performed within 6 wk of PET/CT and with clinical follow-up. RESULTS: The 37 patients (26 men and 11 women; mean age, 61 y, range, 40-82 y) underwent 57 PET/CT scans. In 10 (91%) of 11 patients with Richter's transformation, PET/CT detected sites of abnormal 18F-FDG uptake having an SUVmax of greater than 5. Richter's transformation was missed in 1 patient who had only low-grade 18F-FDG uptake (SUVmax < 5). Nine patients had false-positive PET/CT findings; in 3 of these patients, alternative malignancies were diagnosed (Hodgkin's disease; metastatic neuroendocrine carcinoma; non-small cell lung cancer). In all remaining patients, PET/CT correctly excluded Richter's transformation. For the specific diagnosis of Richter's transformation of CLL to diffuse large B-cell lymphoma, PET/CT had overall sensitivity, specificity, and positive and negative predictive values of 91%, 80%, and 53% and 97%, respectively. CONCLUSION: PET/CT can detect Richter's transformation of CLL to diffuse large B-cell lymphoma with a high sensitivity and a high negative predictive value.     

Stage I-II low grade non-Hodgkin's lymphoma: prognostic factors and treatment results.

48 patients with stage I-II low-grade non-Hodgkin's lymphoma were treated by radiation and/or chemotherapy between 1970 and 1986. The histologic types were diffuse lymphocytic well differentiated, eleven patients; nodular lymphocytic poorly differentiated, 28 patients; nodular mixed, nine patients. Complete remission was obtained in 45 patients (94%). Overall survival was 83% and 68% at five and ten years, respectively. Five and ten-year relapse-free survival of complete responders was 71% and 57%, respectively. Univariate analysis of potential prognosticators showed the following to significantly increase the survival rate: one or two sites of disease (p less than 0.01), stage I (p less than 0.02), age less than 65 years (p less than 0.02), complete excision of tumor mass (p less than 0.03), and the use of radiotherapy (p less than 0.02). The extent of radiotherapy field did not affect survival. Multivariate analysis by the stepwise proportional hazards model of Cox showed that the use of radiotherapy was the factor which significantly produced better survival figures (p less than 0.03). It is concluded that two thirds of stage I-II low-grade lymphoma patients are potentially curable; radiotherapy plays a major role in the management.     

Differential diagnosis of lymphocytic interstitial pneumonia and malignant lymphoma on high-resolution CT.

OBJECTIVE: Lymphoproliferative disorders span a spectrum from inflammatory lesions to malignant neoplasms. The purpose of this study was to compare high-resolution CT findings of lymphocytic interstitial pneumonia with those of malignant lymphoma of the chest. MATERIALS AND METHODS: The study included 17 patients with lymphocytic interstitial pneumonia and 44 patients with malignant lymphoma (35 with non-Hodgkin's lymphoma and nine with Hodgkin's disease). Without knowledge of the pathologic diagnosis, two chest radiologists evaluated the frequency and distribution of high-resolution CT findings in both groups of patients. RESULTS: Cysts were more common in patients with lymphocytic interstitial pneumonia (14/17, 82%) than in patients with malignant lymphoma (1/44, 2%) (p < .0001). Air-space consolidation was more commonly seen in patients with malignant lymphoma (29/44, 66%) than in patients with lymphocytic interstitial pneumonia (3/17, 18%) (p < .001). Large nodules (11-30 mm in diameter) were more common in patients with malignant lymphoma (41%) than in patients with lymphocytic interstitial pneumonia (6%). Pleural effusions (25%) were seen only in patients with malignant lymphoma. We found no statistically significant difference in the distribution of lung lesions between patients with lymphocytic interstitial pneumonia and patients with malignant lymphoma. CONCLUSION: On high-resolution CT, cysts are characteristic in patients with lymphocytic interstitial pneumonia, whereas consolidation, large nodules, and pleural effusions are characteristic in patients with malignant lymphoma. These findings on high-resolution CT help differentiate lymphocytic interstitial pneumonia from malignant lymphoma.     

Richter transformation of chronic lymphocytic leukemia presenting as a dural-based non-hodgkin lymphoma mass

Richter transformation is defined as a diffuse large cell lymphoma, occurring by transformation of chronic lymphocytic leukemia (CLL). We present a 64-year-old man with a history of CLL and a left parieto-occipital transtentorial extra-axial mass. The patient underwent CT and MR imaging, demonstrating a large dural-based mass with extracranial extension, which occluded the left transverse sinus. Biopsy of the mass proved a pathologic diagnosis of diffuse large cell non-Hodgkin lymphoma, consistent with Richter transformation of CLL.     

左旋门冬酰胺酶联合方案治疗外周T细胞淋巴瘤疗效观察

目的：评价含左旋门冬酰胺酶（L-ASP）化疗方案治疗外周T细胞淋巴瘤（PTCL）的疗效。方法：初治T细胞淋巴瘤患者27例,L-ASP组15例接受联合化疗（LOD）,对照组12例接受不含L-ASP的LOD。比较两组的有效率和2年生存率。结果：有效率（完全缓解加部分缓解）L-ASP组为73.3%,对照组为25%（P〈0.05）。1年生存率L-ASP组57.4%,2年生存率43.1%,对照组1年生存率21.2%,2年生存率为0（P〈0.05）。L-ASP治疗的不良反应主要表现为白细胞减少和胃肠道反应。结论：L-ASP为主的化疗方案可能提高PTCL的疗效和1年、2年生存率,不良反应可耐受。     

介入微球栓塞治疗对化疗不敏感的中晚期非小细胞肺癌的临床效果研究

目的：观察单纯介入微球栓塞治疗化疗无效的非小细胞肺癌患者的近、远期疗效及生存情况。 方法：收集2011年8月至2015年9月鞍钢总医院介入治疗中心收治的经化疗后无效的Ⅲa~Ⅳa期非小细胞肺癌105例（介入栓塞组）,予以支气管动脉经微导管超选择微球栓塞,3个月后复查,必要时行再次栓塞。选取同期我院化疗科Ⅲa~Ⅳa期非小细胞肺癌患者76例（化疗对照组）,使用PE方案及MIC方案联合化疗。3~4周化疗1次,3、4个化疗周期为1个疗程,持续4~6个周期。两组均是每3个月进行1次复查、病情评估及疗效评价。 结果：介入栓塞组的有效率（RR）为74.3%,高于化疗对照组的45.5%,差异有统计学意义（P=0.025）,介入栓塞组的中位生存时间为14.5个月,长于化疗对照组的11个月,两组生存率差异有统计学意义（P=0.042）。 结论：对于化疗不敏感的非小细胞肺癌患者,行单纯介入微球栓塞是一种安全、有效的姑息性治疗方法。     

On long-term survivals in non-Hodgkin's lymphoma with 'gentle' treatment.

Eighty-seven cases of non-Hodgkin's lymphomas from the Southern California Permanente Medical Group have been reviewed. The patients were treated between 1953 and 1960, all in an era of 'minimal' radiotherapeutic and chemotherapeutic treatment. The favourable prognostic factors for long-term survival using gentle treatment are, firstly, nodular pattern, presenting in clinically localised Stages I and II and, secondly, diffuse well-differentiated lymphocytic lymphoma (DLWD) presenting either in a localised or generalised fashion. In this series moderate dose irradiation (2500 rad) to involved areas with or without modest chemotherapy has resulted in the survival of 26 out of 32 DLWD patients for more than five years and in most cases for over ten years.     

眼内淋巴瘤患者化学药物治疗后的眼底变化

目的 观察眼内淋巴瘤患者化学药物治疗(简称化疗)后的眼底变化。方法 回顾性分析2015-01至2021-12就诊于解放军总医院第一医学中心眼科的11例(15眼)眼内淋巴瘤患者，其中男7例，女4例，年龄47～67岁，平均55.9岁，观察化疗后眼底变化。结果 11例给予眼部局部化疗或联合全身治疗后眼部淋巴瘤消退效果良好，观察至今(随访截至2022-05)未出现中枢神经系统受累。2年内发生化疗相关性视网膜病变7例(7眼),视神经病变7例(9眼)给予眼部相关对症治疗后，1年内眼底未见进展性变化，病情稳定；3例(6眼)全身其他部位确诊淋巴瘤化疗后，1年内确诊化疗相关性视神经病变及化疗相关视网膜病变，给予眼科对症治疗，观察1年眼底肿瘤未见进展性病变，病情稳定；1例(1眼)全身其他部位确诊淋巴瘤，化疗后1年内单眼视网膜特发性出血，给予眼科对症治疗，观察1年，眼底未见进展性病变。结论 全身淋巴瘤合并眼内淋巴瘤患者无论眼内单纯化疗或者眼内局部化疗联合全身化疗后，容易合并化疗性视神经视网膜病变，给予眼部及全身对症治疗可稳定或减缓病变的发生和进展，减少中枢神经受累。     

Interstitial pneumonitis following allogeneic bone marrow transplantation in the treatment of leukemia based on BMT survey in Japan

Data from 208 patients with leukemia who were treated with allogeneic bone marrow transplantation between 1975 and 1985 were reported to the Japanese Bone Marrow Transplant Registry and were available for this analysis. These patients were classified into 82 of acute lymphocytic leukemia, 91 of acute non-lymphocytic leukemia, and 35 of chronic myelocytic leukemia. The incidence of interstitial pneumonitis (IP) was 39% (81/208) and fatality rate was 60% (49/81). Cytomegalovirus was the most frequent causative organism (54%). Using Cox's proportional hazard regression model, age of recipient (P = 0.0068), status of disease (P = 0.0191), and number of platelet transfusion (P = 0.0425) were found to be significant risk factors associated with IP. Probabilities of developing IP at three years were 65% and 42% in single dose and fractionated total body irradiation (TBI), respectively. In single dose TBI group, dose-rate affected the incidence of IP. On the contrary, in fractionated TBI group, number of fractions as well as dose-rate had no impact on the incidence of IP.     

Increased metabolic activity in the thymus gland studied with 18F-FDG PET: age dependency and frequency after chemotherapy.

This study was designed to evaluate the age dependency of 18F-FDG uptake in the thymus and the frequency of PET confirmation of thymus hyperplasia after chemotherapy in cancer patients. METHODS: Whole-body FDG PET recordings of 168 patients were retrospectively examined for a retrosternal lesion in the anterior mediastinum that was attributable to the thymus. The patients were assigned to the following four groups: children with malignant lesions before the first therapy (group Ia; n = 15; mean age +/- SD, 11.9 +/- 3.7 y), children with malignant disease after chemotherapy (group Ib; n = 12; mean age, 10.3 +/- 5.0 y), adults with histologically confirmed malignant lymphoma before the first therapy (group IIa; n = 37; mean age, 43.9 +/- 16.7 y), and adult lymphoma patients 3 wk to 4 mo after chemotherapy (group IIb; n = 104; mean age, 40.9 +/- 14.6 y). RESULTS: Increased FDG accumulation in the thymus was seen in 11 patients (73%) of group Ia and 9 patients (75%) of group Ib. Thymus hyperplasia was found in 5 patients (5%) of group IIb. The eldest of these 5 patients was 25 y old. No increased FDG accumulation in the thymus was observed in any of the group IIa patients. In cases of visible FDG uptake in the thymus, standardized uptake values did not exceed 4. CONCLUSION: FDG accumulation in the thymus is a common finding in children and can occasionally be observed in young adults after chemotherapy. Knowledge of the characteristics of a typical retrosternal lesion in conjunction with the clinical history allows avoidance of diagnostic uncertainty and unnecessary procedures.     

淋巴瘤化疗后并发间质性肺炎72例临床分析

目的通过总结分析淋巴瘤患者化疗后间质性肺炎发生的临床特点和治疗转归,以加强对该病的预防并提高治疗效果。方法回顾性地分析近5年来经治的72例淋巴瘤患者化疗后发生间质性肺炎的相关因素、临床特征和治疗转归规律,总结甲基强的松龙冲击治疗的疗效和副作用。结果 72例患者中,有55例同时接受了含蒽环类和环磷酰胺方案的化疗,其中含CD20单抗者31例,含有博莱霉素者19例。72例患者均给予糖皮质激素治疗,其中65例联用了抗生素治疗,7例仅给予激素治疗。有50例经激素等治疗后病情逐步好转,另有22例患者经激素治疗后好转,但在激素减量或停用后间质性肺炎再复发加重,其中16例再次给予激素治疗仍然有效,另6例后期合并严重的肺部混合性感染和呼吸衰竭而死亡。结论淋巴瘤患者化疗后并发质性肺炎可能与环磷酰胺、博莱霉素等细胞毒化疗药物所致肺损伤和化疗及利妥昔单抗导致机体免疫失调等相关,早期激素治疗能有效缓解患者的症状和病情。     

Radiotherapy and High-Dose Chemotherapy in Advanced Ewing's Tumors

BACKGROUND: Ewing's tumors are sensitive to radio- and chemotherapy. Patients with multifocal disease suffer a poor prognosis. Patients presenting primary bone marrow involvement or bone metastases at diagnosis herald a 3-year disease-free survival below 15%. The European Intergroup Cooperative Ewing's Sarcoma Study (EICESS) has established the following indications for high-dose therapy in advanced Ewing's tumors: Patients with primary multifocal bone disease, patients with early (< 2 years after diagnosis) or multifocal relapse. PATIENTS AND METHOD: As of 1987, 83 patients have been treated in the EICESS group, 39 of them at the transplant center in Düsseldorf, who have been analyzed here. All individuals received 4 courses of induction chemotherapy with EVAJA and stem cell collection after course 3 and 4. Consolidation radiotherapy of the involved bone compartments was administered in a hyperfractionated regimen 2 times 1.6 Gy per day, up to 22.4 Gy simultaneously to course 5 and 22.4 Gy to course 6 of chemotherapy. The myeloablative chemotherapy consisted of melphalan and etoposide (ME) in combination with 12 Gy TBI (Hyper-ME) or Double-ME with whole lung irradiation up to 18 Gy (without TBI). RESULTS: The survival probability at 40 months was 31% (44% DOD; 15% DOC). Pelvic infiltration did not reach prognostic relevance in this cohort. Radiotherapy encompassed 75% of the bone marrow at maximum (average 20%). Engraftment was not affected by radiotherapy. CONCLUSION: High-dose chemotherapy can improve outcome in poor prognostic advanced Ewing's tumors. The disease itself remains the main problem. The expected engraftment problems after intensive radiotherapy in large volumes of bone marrow can be overcome by stem cell reinfusion.     

Fractionated and hyperfractionated total body irradiation in the conditioning of allogenic bone marrow transplant in acute lymphatic leukemia. Results

Two different Total Body Irradiation (TBI) regimens were employed (1981 to July 1983) in Genoa in the conditioning program for the allogeneic Bone Marrow Transplantation (BMT) of 22 patients suffering from Acute Lymphoblastic Leukemia (ALL) in remission (7 patients in 1st remission, and 15 in 2nd remission). All patients were treated with Cyclophosphamide -60 mg/kg administered for two consecutive days (day -7 and -6)--and subsequently underwent fractionated TBI (days -3, -2, -1), that is, our conventional TBI regimen: 3.3 Gy/day per 3 days (total dose: 9.9 Gy). From August 1983 through 1988, 33 patients (14 in 1st remission and 19 in 2nd remission) were given 2 Gy twice a day, 6 hours apart, for 3 consecutive days (total dose: 12 Gy). Cyclosporine A was used for GvHD prophylaxis. At 58 months, out of the total figure of ALL patients in 2nd remission, 19% of those treated with 9.9 Gy/3 fr/3 days (fractionated TBI) is likely to be in remission, versus 65% of the cases treated with 12 Gy/6 fr/3 days (p less than 0.01) (hyperfractionated TBI); the actuarial overall survival is 23% after fractionated vs 60% after hyperfractionated TBI (p = 0.05). The incidence of idiopathic interstitial pneumonitis was very low (3.6%). Thus, we conclude that, in ALL patients in second remission, hyperfractionated TBI (12 Gy/6 fr/3 days) yields better results than fractionated TBI (9.9 Gy/3 fr/3 days), with lower relapse rate (33% vs 83%) and higher survival.     

Diagnosis and therapy of Hodgkin's disease in Freiburg in Breisgau 1964 to 1976. 2. Results during the treatment period 1972-1976 compared with the period 1964-1971

The total group of patients with Hodgkin's disease submitted to primary treatment from May 1964 till December 1976 is divided with respect to diagnostics and therapy into a preponderantly clinically assessed group (CS) treated during the years of 1964 to 1971 (n = 190) and a preponderantly surgically assessed group (PS) treated during the years of 1972 to 1976 (n = 180). The first subgroup was treated with differently large irradiation fields and, in case of combined therapy, mostly with cyclophosphamide. The second subgroup was treated with extended fields, even until total lymphoid irradiation and, in case of drug administration, with primary combined chemotherapy (MOPP). The overall five-year remission rates of both subgroups (stages I to IV) have improved from 35.4% to 54.8% (P less than or equal to 0.001) and the five-year survival rates from 67.2% to 78.2% (P less than or equal to 0.001). If a complete remission was achieved, this was obtained, as far as judgeable, already at an earlier moment in the individual groups: e.g., in stage I with 95.5% after one year as against 94.1% after five years and in stage II with 91.3% after four years as against 72.9% after seven years. The prognostic differences of stages I and II and the histologic manifestations: lymphocytic predominance, nodular sclerosis, and mixed cellularity were equalized under the therapeutic measures of the intensive treatment period.     

Total lymphoid irradiation preceding bone marrow transplantation for chronic myeloid leukaemia

Between August 1985 and October 1987 we treated 35 patients with chronic myeloid leukaemia (CML) by high dose chemotherapy, total body irradiation (TBI) (1000 or 1200 cGy, n = 31) and total lymphoid irradiation (TLI) (800 or 600 cGy, n = 35) preceding allogeneic bone marrow transplantation (BMT). Both TBI and TLI were given at 200 cGy/fraction. Twenty-three patients had HLA-identical sibling donors, nine patients had HLA-matched but unrelated donors, and three partially HLA-mismatched donors. Twenty-two patients received T-cell depleted marrow. The addition of TLI to the standard protocol did not add greatly to the toxicity. Four patients had recurrent leukaemia before engraftment was evaluable. The other 31 patients engrafted and no graft failed. Twenty-two patients survive at a median time from transplant of 305 days (range 81-586 days). Fourteen have no evidence of disease; eight have or had only cytogenetic evidence of leukaemia. We conclude that the addition of TLI to pretransplant immunosuppression increases the probability of reliable engraftment in patients receiving T-cell depleted marrow. This benefit is not associated with significantly increased toxicity.     

The in vitro radiosensitivity of lymphocytes from chronic lymphocytic leukaemia using the differential staining cytotoxicity (DiSC) assay. II--Results on 40 patients.

A tumour sensitivity assay, the differential staining cytotoxicity (DiSC) assay, which has been shown to have potential in predicting tumour response to cytotoxic drugs, has been used to investigate the radiosensitivity of peripheral blood lymphocytes isolated from patients with chronic lymphocytic leukaemia (CLL). The isolated lymphocytes were irradiated and incubated for 4 days. Radiation-induced cell kill was assessed by differential staining of dead and live cells with subsequent calculation of tumour cell viability. The results of 61 CLL specimens from 40 patients are reported, showing profound inter-patient differences in the sensitivity of cells to radiation. Five patient specimens, which were radioresistant in vitro, were from patients who were also resistant clinically to irradiation. Another patient who responded very well clinically was found to be extremely sensitive in the assay.