Aggressive treatment of intrathoracic recurrences of thymoma.

Between 1974 and 1988, 21 patients with intrathoracic recurrences of thymoma received radiotherapy with radical intent; surgery was always attempted when considered feasible: 11 patients were partially (6 cases) or totally (5 cases) resected before irradiation, while in the other 10 radiotherapy was the only treatment. In 7 cases the recurrence was confined to the anterior mediastinum, 9 had pleural nodules without mediastinal lesions and 5 had both mediastinal and pleural lesions. Mediastinal recurrences were treated by opposed parallel mediastinal fields with 2/3 of the dose delivered through the anterior port: doses ranged between 38 and 44 Gy; a boost of 10-16 Gy was given in patients not radically resected. Pleural nodules were treated with a variety of techniques according to the extent of the lesions. The 7-year survival of the whole group was 70%; 5 patients died: 4 with intrathoracic progression and one with distant metastases. The survival was 74% in the 11 patients having received surgery, either radical or subtotal, and 65% in the 10 patients treated with radiotherapy alone: the difference is not significant. Patients with Karnofsky index greater than 70 had a significantly better survival (100%, versus 28%, p = 0.0015). This is a selected series of patients presenting recurrences still amenable to a radical treatment either by surgery and radiotherapy or by radiotherapy alone: the results confirm that an aggressive approach is warranted in patients in good general conditions with recurrences confined to the mediastinum and/or 1 hemithorax.

Role of radiation therapy in locally advanced thymoma.

The records of all patients treated for thymoma in the Department of Radiotherapy of the University of Torino between 1970 and 1988 were reviewed. There were 77 patients in stage III or IVa (59 in stage III and 18 in stage IVa); 74 patients were operated upon before radiotherapy and 3 had a pre-operative irradiation followed by surgery and post-operative boost. Complete resection was possible in 55.9% of cases with stage III and in none with stage IVa. Subtotal resection was done in 35.6% of patients in stage III and 83.3% in stage IVa. 8 patients had only a biopsy: 5 in stage III (8.5%) and 3 in stage IVa (16.6%). Post-operative radiation doses ranged between 39.6 and 46 Gy to the whole mediastinum followed by a 10-16 Gy boost on smaller fields in cases presenting residual disease after surgery. The pre-operative dose was 30 Gy followed by a post-operative boost of 16-24 Gy. Conventional fraction sizes of 1.8-2 Gy were always used. The 10 years survival rate was 58.3%. There was a significant difference between stage III (70.9%) and stage IVa (26.3%) (p less than 0.0004). Survival of patients in stage III was not significantly affected by the type of surgery. No significant difference in survival or recurrence rate was observed in patients with different histologies and in patients with or without myasthenia. Thoracic relapses occurred in 15.2% of patients in stage III and in 50% of patients in stage IVa (p less than 0.01). Only 7 relapses (9.1%) were within the limits of the radiation field.(ABSTRACT TRUNCATED AT 250 WORDS)

[Total skin therapy with electron beams. I. Physical and geometric factors]. / Terapia cutanea totale con fasci di elettroni. Parte I. Fattori fisici e geometrici.

The study pf physical and geometrical factors influencing dose distribution is necessary in performing the Total Skin Electron Therapy. The authors examined some aspects. Photographic emulsions in humanoid phantom were used for dosimetry. The techniques uses 6 dual fields at 320 cm treatment distance, with a degrading lucite filter 100 x 200 x 0.6 cm3 at 20 cm from the patient. Absorbed dose and energy were determined according TG 30 and 21 AAPM. The position of degrading filter was recognized to be the main factor influencing dose rate, penetration depth and dose homogeneity.

[Total skin therapy with electron beams. II. Clinical results in mycosis fungoides]. / Terapia cutanea totale con fasci di elettroni. Parte II. Risultati clinici nella micosi fungoide.

Between 1985 and 1989, 19 patients with mycosis fungoides were treated by Total Skin Electron Therapy (TSET). Overall and disease-free survival at 3 years were 72% and 40%. The complete remission (CR) rate was 100% in patients with plaque and 33.3% in those with tumor masses; patients with negative nodes had a 90% CR rate whereas in those with adenopathy the rate was 55%. Overall and disease free survivals were also correlated with these factors.

Technique, dosimetry and results of total body irradiation in preparation to ABMT in Torino.

Twenty-five patients with haematologic malignancies received total body irradiation (TBI) as part of their conditioning regimen prior to autologous bone marrow transplantation (ABMT). TBI was delivered with an 18 MeV photon beam through AP-PA ports; the total dose was 13.2 Gy/8 fractions over 4 days; shields were used to limit the total dose to the lung to 8-10 Gy. Five relapses were observed; among 14 patients with ALL or advanced lymphoblastic lymphoma, 10 patients are currently alive and free of disease. Acute and late morbidity of TBI were low.

Predictive value of the early response to chemotherapy in high-risk stages II and III Hodgkin's disease.

A series of 60 patients with "high risk" Stage II and III Hodgkin's disease (B symptoms, or large mediastinal mass, or E lung disease) were staged without laparotomy and treated with combined modality treatment: mechlorethamine, vincristine, procarbazine, and prednisone (6 MOPP) plus radiotherapy. Patients were restaged after the first three courses of MOPP and the status of response to therapy at that time was called early response to chemotherapy (ERC). The rate of nitrogen mustard and procarbazine delivery (MRD) during the first three cycles of chemotherapy also was assessed. At the completion of the therapy patients were restaged and the final response was assessed. Fifty-two (86.7%) patients entered complete remission (CR). Forty-eight percent of the complete responders achieved CR in the first three courses of MOPP. Eight-year survival and disease-free survival (DFS) rates of the patients achieving CR were 71% and 73%, respectively. Survival and DFS were significantly better for the patients who achieved CR in the first three cycles of chemotherapy than for patients who entered CR at a later stage of therapy: 8-year survival 90% versus 55% (P = 0.00); 8-year DFS 87% versus 59% (P = 0.01). The attainment of a complete ERC was adversely affected by lymphocyte depletion (LD) histologic type (P = 0.01) and MRD less than 65% (P = 0.04). However, when a multivariate regression analysis was used, ERC was the only significant prognostic variable for survival and DFS and its predictive value was confirmed even after correction by MRD. These data suggest that the rapidity of response to chemotherapy could be an important prognostic factor in high-risk Stage II and III Hodgkin's disease.

[Total cutaneous irradiation with low energy electrons and mycosis fungoides. Technic and dosimetry]. / Irradiazione cutanea totale con elettroni di bassa energia e micosi fungoide. Tecnica e dosimetria.

Mycosis fungoides initially involves the epidermis and the superficial layers of derma at a depth of about 1 cm. Wide field irradiation with low energy electrons is therefore the treatment of choice in the initial stages of the disease. In our Institute, total skin electron beam irradiation is delivered with Therac 20 linear accelerator: the lowest available energy is 6 MeV. A lucite sheet of 0.6 cm thickness is used to decrease the energy of the beam. We used film dosimetry to evaluate the homogeneity of dose distribution in an Alderson-Rando phantom with different arrangements of the fields and the lucite sheet: 4 and 6 fields techniques have been compared with different positions of the lucite filter, near the phantom and near the collimator. Six fields yield a better dose distribution: homogeneity is within +/- 3.7%, while with four fields it is within +/- 6%. X-rays contamination is less than 2%. "In vivo" dosimetry has been performed using thermoluminescent dosimeters: homogeneity is within +/- 15%.

[Technic and dosimetry in total body irradiation with 18 MeV photons]. / Tecnica e dosimetria nell'irradiazione corporea totale con fotoni da 18 MeV.

Total body irradiation (TBI) is used in our Institution in the conditioning regimen for bone marrow transplantation. The fractionation pattern consists of two daily fractions of 1.65 Gy repeated for 4 days (total dose 13.20 Gy in 8 fractions). Lung dose is reduced by means of lead custom shaped shields directly strapped to the patient surface. TBI is delivered by a THERAC 20 linear accelerator with two opposing AP-PA photon beams with a maximum energy of 18 MeV. Treatment distance is 340 cm and the patient is treated in a semi-standing position. Dosimetry studies in a homogeneous phantom were performed in the treatment geometry and consisted in the determination of: tissue maximum ratios (TMR) at different depths, absorbed dose along the median axis and the diagonal of the field, variation of the absorbed dose in the prescription point with different volumes of scattering material, and transmission of shielding and compensating material. A semi-empiric formula for the calculation of absorbed dose in a point has been obtained. A subsequent study in a Rando phantom with termoluminescent dosimeters (TLD) has shown a +/- 5% agreement between calculated and measured values and a +/- 7% homogeneity.

[Mantle irradiation with 18 MeV photons. Measurement and calculation of dose distribution]. / L'irradiazione a mantellina con fotoni da 18 MeV. Misura e calcolo della distribuzione della dose.

Dose distribution in mantle fields irradiated with 18 MeV photons has been studied in an Alderson-Rando phantom with thermoluminescent dosimeters. The treatment was also simulated on an RT-plan 7000 computer; calculated and measured doses in anatomical sites of major interest were compared. Doses in all significant points were within +/- 7% of the doses at the reference point. Calculated and measured doses agreed within +/- 5% except points situated near unhomogeneous tissues. The authors discuss their results and present conclusions about algorithms for computer dose calculation in irregular field treatments.