Biomedical subjects

L Souhami

Publications and source records attributed to L Souhami.

At least 55 records · Page 3Linked to original sources

PubMed1993

Accelerated fractionation in inoperable non-small cell lung cancer. A phase I/II study.

BACKGROUND: A prospective, single-treatment-arm, Phase I/II trial was performed to determine the tumor response to an accelerated regimen and assess the feasibility and toxic effects of this approach in patients with inoperable non-small cell lung cancer (NSCLC). METHODS: Thirty-seven previously untreated patients with inoperable NSCLC who had no evidence of metastatic disease entered the study. All patients were able to walk and had disease that was measurable or assessable. Patients with palpable supraclavicular disease and weight loss were also eligible. Radiation therapy consisted of an altered fractionation regimen with a concomitant boost technique. The original lung volume received a dose of 40 Gy in 20 daily fractions to the computerized axial tomography (CT)-defined primary tumor and mediastinal nodes. The boost dose (10 Gy) was administered concomitantly with the last five fractions of the original volume treatments, with an interfraction interval of 6-8 hours. The maximal allowed dose to the cord was 46 Gy. RESULTS: At a median follow-up of 36 months, complete response was achieved in 29% (9 of 31) of the patients and a partial response in 42% (13 of 31). The overall survival rate at 36 months was 10% (median survival time, 8 months). Survival rates were 25%, 8%, and 0% for the complete responders, partial responders, and nonresponders, respectively. Local failure alone was observed in 35.5% of all patients, local and distant failure in 42%, and distant failure only in 13%. Treatments were well tolerated, and all patients were able to complete the planned regimen. Grade 1 and 2 esophagitis occurred in 65% and 26% of the patients, respectively. The clinical condition of two patients (6%) was compatible with radiation pneumonitis. Moist desquamation of the skin occurred in two patients, but most had either mild (55%) or moderate (19%) skin erythema. Late complications have been limited to radiologically detected lung fibrosis. CONCLUSIONS: The accelerated fractionation schedule used in this trial was well tolerated with shortening of overall treatment time. Local tumor control and overall survival are similar to those resulting from conventional fractionation without an increase in normal tissue effects. These results are encouraging, and additional studies testing higher tumor doses are warranted.

Aged↗

PubMed1993

Clinical experience with electron pseudoarc therapy.

Between November 1986 and June 1990, 24 patients were treated with electron pseudoarc therapy at McGill University. There were 21 females and three males aged 27 to 81 years (median 62 years). 17 patients, nine of whom had received previous conventional locoregional irradiation, were treated palliatively for locally extensive breast carcinoma. Eight of these 17 patients achieved a complete, and six a partial, response to treatment; nine subsequently developed evidence of progressive disease within the treatment field after intervals of one to 27 months (median 5 months) following therapy. Eight patients developed moist desquamation of the treated chest wall, which was extensive in four; one of these patients developed chronic ulceration of the skin. The latter and one additional patient developed radiation pneumonitis. Seven patients were treated with radical intent, two following mastectomy for breast carcinoma, and one each for chest wall lymphoma, chest wall sarcoma, scalp angiosarcoma, scalp lymphoma and posterior cervical soft tissue sarcoma. Local control was achieved in six of these seven patients with minimal toxicity. Electron pseudoarc therapy is a treatment option for selected breast carcinoma patients for palliation of extensive chest wall disease, although morbidity may be considerable. The technique may, however, play a more useful role in other situations where the superficial portion of large curved surfaces is to be treated with curative intent.

Adult↗

PubMed1993

A halo-ring technique for fractionated stereotactic radiotherapy.

Stereotactic radiosurgery has become established as an effective treatment modality for certain non-malignant brain diseases such as arteriovenous malformations. This paper describes an extension of our linear accelerator-based radiosurgical technique to fractionated treatment of intracranial disease. The fractionated stereotactic radiotherapy technique expands the use of the modality by sparing normal cells within the treatment volume thus improving the therapeutic ratio. The first treatment is given using a stereotactic frame both for target localization and patient immobilization. The frame is then removed and subsequent treatments use a standard neurosurgical halo-ring for patient immobilization. The halo-ring is left in place on the skull for the duration of the course of treatment. Thus the physical requirements for fractionation pertain firstly to the patient immobilization and target localization using the halo-ring and secondly to the stringent quality assurance procedures required to maintain spatial accuracy under these new conditions. We describe a sensitive and effective technique for checking the rotational beam parameters and collimator alignment which we use immediately prior to treatment to ensure adequate accuracy of dose delivery to the target volume.

Equipment Design↗

PubMed1993

Early and late complications following dynamic stereotactic radiosurgery and fractionated stereotactic radiotherapy.

Between December 1986 and June 1990, 112 patients (116 lesions), underwent treatment with dynamic stereotactic radiosurgery at McGill University. Of the treated lesions, 59 were arteriovenous malformations and 53 were a variety of other neoplastic conditions. In 86 lesions, the treatment was delivered in a single fraction and the treatment of the remaining 30 lesions was fractionated. Complications attributed to treatment developed in seven of the 112 patients (6.3%). No relationship was found between complications and prescribed dose, fractionation, collimator diameter, type and anatomical region of the lesion that was treated, or previous irradiation. Although extensive clinical experience will be necessary to determine optimal total doses, the potential role of fractionated treatment, and the tolerance of critical structures to radiosurgery, the relatively low incidence of complications in our series allows us to conclude that radiosurgery is well tolerated by the vast majority of patients.

Adolescent↗

PubMed1992

Dynamic stereotactic radiosurgery in the palliative treatment of cerebral metastatic tumors.

From October 1988 to April 1990, 9 patients with metastatic brain disease (11 lesions) underwent stereotactic radiosurgery. All patients but two had recurrent metastatic disease after previous brain irradiation. The patients were treated with a single dose of 20 Gy, delivered to spherical target volumes ranging in diameters from 10 mm to 30 mm and prescribed to the 90% isodose surface. All tumors treated showed a favorable response to the treatment, with 4 patients achieving a complete radiological disappearance of the tumor. The majority of the patients experienced a rapid clinical improvement of their symptoms. No complications attributable to the radiosurgical treatment were seen. Stereotactic radiosurgery appears to be an effective and safe treatment for patients with recurrent metastatic brain disease.

Adult↗

PubMed1992

Clinical experience with a single field rotational total skin electron irradiation technique for cutaneous T-cell lymphoma.

Between October 1981 and December 1989, 44 patients with cutaneous T-cell lymphoma (CTCL) were treated with a single field rotational total skin electron irradiation (RTSEI) technique developed in the McGill University, Department of Radiation Oncology. Only 11 (25%) of the 44 patients had received no prior treatment. Three-quarters (33/44) had advanced (T3 or T4) disease. Complete responses were seen in 32/44 (73%) of patients (91% T2, 71% T3 and 58% T4), but only 3/11 (27%) of patients with T2 disease and 3/21 (14%) of patients with T3 disease remain in continuous complete remission in the skin, after median intervals of 58 and 35 months, respectively. Median cause-specific survival for the whole group is 43 months and survival at 5 years is 38%. Survival was significantly better for patients with T2 disease than for patients with T3 disease (relative risk 4.3; 95% CI 1.4-13.2) and patients with T4 disease (relative risk 3.1; 95% CI 0.8-12.1). The RTSEI technique used at McGill has depth-dose characteristics and photon contamination similar to other commonly used TSEI techniques. It is relatively simple and provides a homogenous dose distribution over the entire skin surface in a short treatment time. Results of treatment are similar to those obtained with other techniques. For T2 disease, TSEI is an effective treatment modality with a possibility of long-term tumor control. For more advanced disease, more aggressive treatment, which may include TSEI, is necessary.

Adult↗

PubMed1992

Radiation therapy of testicular seminoma: a 15-year survey.

A retrospective review of 69 patients with testicular seminoma, stage I and II, treated by orchiectomy and adjuvant irradiation at McGill University Hospitals from 1972 to 1987 was performed. All patients underwent either lymphangiogram or computed axial tomography scan for evaluation of retroperitoneal disease. There were 52 stage I (75%), 13 stage IIA (11%), 2 stage IIB (3%), and 2 stage IIC (Royal Marsden Hospital staging criteria). Median follow-up time was 6.2 years. The 10-year actuarial survivals were 94% and 93% for stages I and II, respectively. Only two stage I patients failed treatment, and both died from metastatic disease. Interestingly, both developed biopsy-proven metastatic brain disease and had no evidence of intra-abdominal recurrence. In stage II disease, only one patient failed the treatment. There was no serious acute toxicity and no late complications have been encountered. Radiation therapy following orchiectomy is the treatment of choice for stage I and for most stage II patients with testicular seminoma. The controversial aspects of radiographic retroperitoneal staging, the use of prophylactic mediastinal irradiation for stage II patients, and the role of surveillance only for stage I patients are discussed.

Adolescent↗

PubMed1992

Fractionated stereotactic radiotherapy for intracranial neoplasms.

Fractionated stereotactic radiotherapy is a method which attempts to combine the radiobiological advantages offered by dose fractionation with a technique for focal delivery of radiation. At McGill University, fractionated stereotactic radiotherapy is given with a linear accelerator-based dynamic stereotactic radiosurgery unit. The first treatment is given using the stereotactic frame for target localization and head immobilization. Subsequent treatments are given using skin tattoos and laser alignment for target placement within the isocenter of the linear accelerator, and a modified portable halo-ring device is used for skull immobilization. Typically, a marginal dose of 42 Gy was prescribed at the margins of the lesion, divided in 6 fractions and given over a 2-week period. We report the pathological profile and treatment results in a series of 21 patients with a variety of intracranial tumors, treated in this manner between May 1987 and April 1990. Fractionated stereotactic radiotherapy appears to be a worthwhile procedure for the treatment of well-selected patients with intracranial neoplasms.

Adult↗

PubMed1992

Photon radiosurgery: a clinical review.

The term radiosurgery has been used to describe a variety of radiotherapy techniques which deliver high doses of radiation to small, stereotactically defined intracranial targets in such a way that the dose fall-off outside the targeted volume is very sharp. Proton, charged particle, gamma unit, and linear accelerator-based techniques appear to be equivalent from the standpoint of accuracy, dose distributions, and clinical results. However, capital and operating costs associated with the use of linear accelerators in general clinical use are much lower. Radiosurgery has an established role in the treatment of arteriovenous malformations and acoustic neurinomas. Interest in these techniques is increasing in neurosurgical and radiation oncological communities, as radiosurgery is rapidly assuming a place in the management of several other conditions, including craniopharyngiomas, meningiomas, and selected malignant lesions.

Humans↗

PubMed1991

Fractionated stereotactic radiation therapy for intracranial tumors.

In stereotactic radio surgery, a single, large dose of radiation is delivered to a small, well-defined, stereotactically localized intracranial lesion. In contrast to conventional radiation therapy, in radio surgery no attempt is made to spare normal cells within the target volume by fractionating the tumor dose. In 1987, the authors began a program of fractionated stereotactic radiation therapy for selected tumors involving sensitive brain structures. Their objective was to improve the therapeutic index and study the feasibility of the fractionated technique. Fifteen patients were treated with a multifraction regimen typically consisting of six fractions of 700 cGy each, given on alternate days for 2 weeks (total tumor dose, 4200 cGy). All patients were treated with the dynamic stereotactic radio surgical technique. A head ring ("halo frame") was used for immobilization and setup during radiation treatments. At a median follow-up time of 27 months, the symptoms of the majority of the patients improved clinically; this improvement usually occurred within a few weeks after completion of the treatment. The radiologic response was much slower. Currently, only two patients have had complete radiologic disappearance of their lesions; the majority of the patients have only had a decrease in tumor size. The treatments were well tolerated by the patients and no acute complications were observed. One patient who had a vasogenic edema 11 months after treatment fully recovered after steroid therapy. Fractionated stereotactic radiation therapy is a feasible treatment technique and may prove to be useful for selected patients with intracranial tumors. Although the preliminary data are encouraging, this technique should still be considered experimental. A larger number of patients and a longer follow-up time are necessary to determine whether the results of this technique are actually better than those of conventional radiation therapy.

Adolescent↗

PubMed1991

Accelerated fractionation for high-grade cerebral astrocytomas. Preliminary treatment results.

A Phase I/II accelerated fractionation study for high-grade cerebral astrocytomas began in October 1987. Forty-two patients, 25 men and 17 women, were entered in the study. Median age was 58.5 years of age (range, 32 to 78 years). Performance status was 0, 1, 2, and 3 on Eastern Cooperative Oncology Group (ECOG) scale for 13, 19, 9, and 1 patients, respectively. Thirty-six patients had undergone partial resection, and six had stereotactic biopsy only. All patients had histologically proven astrocytomas (6 Grade 3, and 36 Grade 4). Treatment consisted of radiation therapy doses of 4400 cGy in 22 daily fractions to the whole brain plus a boost of 1600 cGy in 8 fractions given concomitantly with the last 8 whole-brain treatments using a twice daily schedule with an interfraction interval of 8 hours. Median survival time was 57 weeks from the date of starting irradiation. Survival was 50% and 28% at 1 and 2 years, respectively. Alopecia and scalp erythema were seen in all patients; nine patients had localized areas of moist desquamation in the retroauricular region. Decreased hearing and serous otitis media were seen in five patients within 1 to 2 months from the end of treatment. Increasing somnolence was marked in eight patients with progressive deterioration of performance status; computerized axial tomography (CAT) scan studies in all eight patients showed evidence of disease recurrence with associated brain edema and mass effect. Three patients had a second resection for a recurrent tumor with no evidence of brain necrosis at craniotomy. To date, the accelerated fractionation schedule appears to be well tolerated with valuable shortening of overall treatment time. The preliminary results are encouraging, and longer follow-up time is required to evaluate tumor control and toxicity.

Adult↗

PubMed1991

A randomized trial comparing radiation therapy versus concomitant radiation therapy and chemotherapy in carcinoma of the thoracic esophagus.

From September 1982 to December 1985, 59 previously untreated patients with Stage II squamous cell carcinoma of the thoracic esophagus were randomly assigned to receive radiation therapy (RT) alone versus the concomitant use of RT and chemotherapy (CT) with 5-fluorouracil (5-FU), mitomycin C, and bleomycin (RT + CT). Thirty-one patients were randomized to the RT regimen and 28 to the RT + CT regimen. The complete local response rate was 58% for the RT group and 75% for the RT + CT group (P = 0.77). The median duration of response was 8 months for both groups. The overall 5-year survival rates were 6% and 16% (P = 0.16) for the RT and RT + CT groups, respectively. Acute toxicities were more pronounced in the RT + CT group. This clinical trial did not detect a difference in outcome with combined-technique therapy. This result must be interpreted with caution because of the small number of patients entered in this trial. Confirmation of the value or lack of value for combined therapy will require additional larger clinical trials.

Adult↗

PubMed1991

High dose rate afterloading intracavitary therapy in carcinoma of the cervix.

From January 1984 through December 1986, 87 patients with previously untreated carcinoma of the cervix received external beam pelvic irradiation and high dose rate intracavitary therapy (HDRT). There were 18 Stage IIA patients, 39 Stage IIB, and 30 Stage IIIB. The median age was 60 years and the median follow-up time was 42 months for patients at risk. Radiotherapy consisted of external megavoltage irradiation to the whole pelvis (median dose 4600 cGy) combined with one (6 patients), two (51 patients), or three (30 patients) HDRT insertions. A high dose rate remote afterloading unit with 60Co sources was used to deliver the HDRT. The prescribed dose to point A was between 800 and 1000 cGy per treatment. The dose rate at point A initially was approximately 150 cGy/min and dropped to approximately 100 cGy/min during the duration of the study. Treatments with multiple fractions were given at weekly intervals. The overall actuarial survival at 5 years was 88% for Stage IIA, 64% for Stage IIB and 32% for Stage IIIB patients. Pelvic recurrence remained the major cause of failure. Grade III and IV late complications included proctitis and bowel obstruction in six patients each. We conclude that HDRT results are similar to those obtained with conventional low dose rate intracavitary systems. HDRT is cost effective and minimizes exposure to personnel. Several questions, such as the total number of insertions required, dose per HDRT insertion, and optimal HDRT insertion schedule remain unanswered and further experience is needed to better clarify these issues.

Adult↗

PubMed1991

Physical aspects of the angle-beta concept in electron arc therapy.

A technique for the determination of treatment parameters that are required to achieve a desired depth dose distribution in electron arc therapy is discussed and a method for calculating isodose distributions is presented. Both the treatment technique and the dose calculation method rely on the angle beta concept, which uniquely describes the dependence of the radial percentage depth doses in electron arc therapy on the nominal field width, isocenter depth, and virtual source-axis distance. The angle beta concept is discussed in detail and the electron pseudo-arc therapy technique used at McGill is described. Also presented is the method used to achieve dose homogeneity in target volumes treated with the pseudo-arc technique.

Electrons↗

PubMed1991

Prospective randomized trial comparing hyperfractionated versus conventional radiotherapy in stages III and IV oropharyngeal carcinoma.

From April 1986 to May 1989, 112 patients seen at a single institution with previously untreated squamous cell oropharynx carcinoma, Stages III and IV, were randomly assigned to 66 Gy in 33 fractions of 2 Gy each (conventional RT) versus 70.4 Gy in 64 fractions of 1.1 Gy given twice a day with a minimal interfraction interval of 6 hours (hyperfractionated RT). The overall time for both arms was 6 1/2 weeks. Patients were stratified by site (base of the tongue vs others), T stage (T1/T2 vs T3 vs T4), N stage (N0/N1 vs N2 vs N3), and lymphnode size (less than 6 cm vs greater than 6 cm). As of January 1990, an analysis was performed in 98 patients (8 patients in the conventional arm and 6 in the hyperfractionation not included). The groups were balanced by age, performance status, stage, and site of the primary disease. The median follow-up time was 25 months. The probability of complete loco-regional response was 62% in the hyperfractionation arm and 52% for the conventional fractionation (p = 0.28). There was no difference in the control of lymphnodal disease (hyperfractionated = 55%, conventional = 57%; p = 0.92), but the disease control in the oropharynx only was significantly improved in the hyperfractionation arm (84% vs 64%, p = 0.02). Overall survival rate at 42 months was 27% for the hyperfractionation arm and 8% for the conventional (p = 0.03). Survival rates for hyperfractionated versus conventional RT were 40% versus 18% (p = 0.06), respectively, for Stage III patients and 16% versus 0% (p = 0.15), respectively, for Stage IV. There was significant improvement in survival in favor of the hyperfractionation arm in patients with lesions outside the base of the tongue (31% vs 15%, p = 0.02), for those with a 50-70% Karnofsky status (19% vs 0%, p = 0.006) and for patients with N0/N1 disease (38% vs 15%, p = 0.03). Acute toxicities were of similar magnitude, although both skin and mucosal reactions appeared earlier on the hyperfractionation scheme. To date, no differences in late toxicity have been observed. We conclude that in a subset group of patients with locally advanced carcinoma of the oropharynx, hyperfractionated radiotherapy appears to provide improved survival without adding to increased toxicity.

Adult↗

PubMed1991

Is post-operative intracavitary therapy a necessary component of treatment for carcinoma of the endometrium?

The role of intracavitary therapy in combination with external pelvic radiotherapy for endometrial carcinoma remains controversial. To determine the pelvic failure rat in patients receiving only external pelvic radiotherapy following total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAHBSO) for carcinoma of the endometrium, we undertook a retrospective review of all patients referred to the Radiation Oncology Department from January 1977 through December 1984. Patients with grade I, superficially invading tumors were excluded from this analysis. 52 patients were eligible for the study. Three patients who were lost to follow-up immediately after completion of external beam irradiation were excluded, leaving a total of 49 evaluable patients. The median follow-up time is 61 months. Pelvic failure was seen in only 2 patients (4%), both of them occurring concurrent with distant disease. No vaginal vault failures were observed. Overall actuarial survival at 5 years was 82%. We conclude that external beam pelvic radiotherapy alone without intracavitary boost appears to be an adequate treatment for patients undergoing TAHBSO for carcinoma of the endometrium.

Adenocarcinoma↗

PubMed1991

A randomized trial of chemotherapy followed by pelvic radiation therapy in stage IIIB carcinoma of the cervix.

Because of the poor results in stage III B carcinoma of the cervix with standard treatment using radiotherapy alone, we designed a randomized trial to determine whether administration of chemotherapy before pelvic irradiation would improve survival. Between May 1984 and August 1986, 107 patients with previously untreated squamous cell carcinoma were randomly assigned, after stratification by age (less than 50 v greater than 50 years), extent of parametrial involvement (unilateral v bilateral), and lymphangiographic findings (negative v positive) to pelvic radiotherapy (RT; arm A) or three cycles of chemotherapy (CT; bleomycin, vincristine, mitomycin, and cisplatin [BOMP]), followed by the same radiotherapy regimen (CT + RT; arm B). The groups were balanced by age, performance status, extent of parametrial involvement, bulkiness of cervical disease, nodal involvement, and presence of hydronephrosis. Minimal follow-up is 34 months. A complete local response was observed in 32.5% of the patients in arm A and in 47% of the patients in arm B (P = .19). Overall 5-year survival rates were 39% for the RT arm and 23% for the CT + RT approach (P = .02). Toxicity was severe in arm B and included fatal pulmonary toxicity in four patients. Locoregional and distant failures were similar in both groups. We conclude that, despite a satisfactory response rate, neoadjuvant BOMP chemotherapy adversely affects survival in stage III B cervical cancer and is associated with unacceptable toxicity.

Aged↗

PubMed1990

Dynamic stereotactic radiosurgery in arteriovenous malformation. Preliminary treatment results.

From December 1986 through August 1988, 25 patients with intracranial arteriovenous malformations underwent radiosurgery with the dynamic stereotactic irradiation technique. The prescribed dose at isocenter ranged from 50 Gy to 55 Gy, given as a single fraction in 92% of the patients. Field sizes, defined at the 90% isodose surface, varied from 5 mm to 25 mm and were chosen in order to deliver 20 to 25 Gy at the periphery of the malformation. To date, 14 angiographic studies were repeated at 1 year posttreatment. In six patients (43%) a complete obliteration of the lesion was achieved. Late side effects were observed in three patients. Our initial analysis, at 1 year posttreatment, suggests that our results are comparable with those previously reported for other radiosurgical techniques. The linac-based dynamic stereotactic technique appears to be a valid alternative to radiosurgery with the Gamma unit or with heavy-charged particle beams.

Adolescent↗