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Dive into the research topics where Derek Jenkin is active.

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Featured researches published by Derek Jenkin.


International Journal of Radiation Oncology Biology Physics | 1990

Posterior fossa medulloblastoma in childhood: Treatment results and a proposal for a new staging system

Derek Jenkin; Karen Goddard; Derek Armstrong; Laurence Becker; Martin Berry; Helen S. L. Chan; Mary Doherty; Mark T. Greenberg; Bruce Hendrick; Harold J. Hoffman; Robin P. Humphreys; Marilyn Sonley; Sheila Weitzman; Al Zipursky

Seventy-two children with posterior fossa medulloblastoma were diagnosed at the Hospital for Sick Children, Toronto, from 1977 to 1987 and treated by standard methods. The 5- and 10-year survival and disease-free survival rates were 71% and 63%, and 64% and 63%, respectively. Total tumor resection, as determined by the surgeon was the most significant favorable prognostic factor. Post-operative meningitis, a residual enhancing mass lesion on the post-operative, pre irradiation CT scan and dissemination to the brain or cord at diagnosis were unfavorable factors. These four easily definable factors were used to define a staging system with prognostic significance. Five-year disease-free survival rates were for Stage I (total resection, no adverse factor) 100%, Stage II (total resection with one or more adverse factor or less than total resection with no other adverse factor) 78%, and Stage III (less than total resection with one or more adverse factor) 18%. Evaluation of treatment results in medulloblastoma requires that these prognostic factors be known.


International Journal of Radiation Oncology Biology Physics | 1993

Optic glioma in children : surveillance, resection, or irradiation ?

Derek Jenkin; Steven Angyalfi; Laurence Becker; Martin P. Berry; Raymond Buncic; Helen S. L. Chan; Mary Doherty; James M. Drake; Mark T. Greenberg; Bruce Hendrick; Harold J. Hoffman; Robin P. Humphreys; Sheila Weitzman

Eighty-seven consecutive children with newly diagnosed optic glioma were managed at University of Toronto hospitals 1958-1990. Overall the 10-year survival, relapse-free survival and freedom from second relapse rates were 84%, 68% and 85%. Twenty-seven patients relapsed or progressed, of whom 40% were free of a second relapse 10 years after the first relapse. Fourteen patients had a second relapse. Thirteen are dead. None survived 5 years after second relapse. Patients with anteriorly located tumors (N = 35), which involved the optic nerve, or chiasm and optic nerves, fared better than those with posteriorly located tumors (N = 52) with spread beyond the chiasm, 10-year survival 95% versus 76%, (p = .02), 10-year relapse-free survival 80% versus 59% (p = .02), respectively. For posterior tumors primary irradiation was more effective than primary subtotal resection for prevention of subsequent relapse, 10-year relapse-free survival 75% versus 41% (p = .02), but salvage therapy was, in part, successful and multivariate analysis of prognostic factors influencing survival for posterior tumors indicated that neither primary resection nor primary irradiation were significant factors. For first relapse, primary irradiation and the presence of neurofibromatosis were the significant favorable factors. Since 1977 and for posterior optic glioma subtotal resection or surveillance were used in 21/29 (72%) patients compared with 4/23 (17%) previously. Ten-year survival rates before and after 1977 were 78% and 67% and 10-year relapse-free survival 64% and 56%, respectively.


Pediatric Neurosurgery | 1993

Optic pathway/hypothalamic gliomas : A dilemma in management

Harold J. Hoffman; Robin P. Humphreys; James M. Drake; James T. Rutka; Laurence E. Becker; Derek Jenkin; Mark T. Greenberg

Optic pathway gliomas follow an unpredictable course. Some remain static for years; others increase rapidly in size and often lead to death. This unpredictability, along with the histological similarity of these tumors, has resulted in controversy about their management. We have reviewed the results of management of all 62 patients with a diagnosis of optic pathway/hypothalamic glioma treated at The Hospital for Sick Children during the years 1976-1990. Twelve patients received no direct treatment, and 3 only a biopsy. Six patients were treated with radiotherapy alone. Eight patients received radiotherapy following a biopsy. Seventeen patients were treated by resection alone and 16 had a resection followed by radiotherapy. Eight patients received chemotherapy in addition to other therapy, and in 5 of them the chemotherapy was given as an initial therapy. Forty-eight patients are well with their visual deficits but 7 of them are receiving hormone replacement therapy. Six patients have significant neurologic deficits and 8 have died.


International Journal of Radiation Oncology Biology Physics | 1990

Pineal region germinomas in childhood treatment considerations

Derek Jenkin; Martin P. Berry; Helen S. L. Chan; Mark T. Greenberg; Bruce Hendrick; Harold J. Hoffman; Robin P. Humphreys; Marilyn Sonley; Sheila Weitzman

From 1967-1986, 21 children were treated for pineal germinoma, including 16 biopsy-proven, 2 biopsy non-diagnostic, and 3 metastatic unbiopsied (marker negative) patients. Ten of 18 (56%) biopsied patients underwent partial or sub-total tumor resection. Twenty patients were irradiated, 19 of whom are alive. No irradiated patient died of progressive germinoma, but two patients relapsed in the spinal cord and required treatment intensification for salvage. Long-term survivors have significant morbidity. Determination of the minimum effective treatment remains the chief therapeutic challenge.


International Journal of Radiation Oncology Biology Physics | 2003

OPTIC GLIOMAS: A RETROSPECTIVE ANALYSIS OF 50 CASES

Yasser Khafaga; Maher Hassounah; Alaa Kandil; Imaduddin Kanaan; Ayman Allam; Gamal El Husseiny; Amani Kofide; Abdulaziz Belal; Mohammed Al Shabanah; Henrik Schultz; Derek Jenkin

PURPOSE Gliomas of the optic pathways are rare childhood central nervous system tumors. The treatment approach is controversial because of its rarity and the slow and unpredictable growth rates of these lesions. METHODS AND MATERIALS We reviewed 50 patients with the diagnosis of optic pathway low-grade gliomas treated between January 1980 and December 1995 at King Faisal Specialist Hospital and Research Center, Saudi Arabia. Thirty-five patients presented with chiasmatic/hypothalamic (posterior tumors), and 15 with optic nerve gliomas with or without chiasmal involvement (anterior tumors). Evidence of neurofibromatosis was present in 18 patients. Twenty-nine patients underwent surgery (total or partial resection), and 12 of these received postoperative radiotherapy (RT). Sixteen patients were treated with primary RT. The radiation dose varied between 42 and 54 Gy (median dose 50). RESULTS The overall actuarial survival rate was 87.5% at 5 years and 75% at 10 years, and the corresponding progression-free survival (PFS) rates were 69% and 62%. Patients with anterior tumors fared better than those with posterior tumors, with a 10-year PFS rate of 72% and 58%, respectively; the difference, however, was not statistically significant (p = 0.58). A PFS advantage was found in favor of patients with posterior tumors treated with RT (primary or postoperative) compared with no RT, with 5-year PFS rates of 68% vs. 42% (p = 0.03). This, however, did not translate into a survival advantage because of the success of salvage treatment. CONCLUSION In multivariate analysis, age (<3 vs. >3 years) emerged as the only significant determinant for PFS with patients <3 years old faring worse (p = 0.03). Neurologic and endocrine dysfunction are significant problems that need to be addressed.


Medical and Pediatric Oncology | 1998

Subsequent quality of life for children irradiated for a brain tumor before age four years.

Derek Jenkin; Cyril Danjoux; Mark T. Greenberg

BACKGROUND We wanted to evaluate survival and functional morbidity following radiation treatment of brain tumors in children less than 4 years old. PROCEDURE Outcome was evaluated for 222 children who were less than 4 years old when they were irradiated at University of Toronto Centres, 1958-1995. The status of the survivors with regard to focal neurological defects, vision, hearing, and education at last follow-up was recorded. In 23 adult survivors older than 21 years at last follow-up, information was obtained with regard to higher education, occupation, and living arrangements. RESULTS The overall 10-year survival rate was 40%, not significantly different than the 45% for 776 4-16-year-olds with irradiated brain tumors treated at the same institutions. Forty-five percent of the survivors had no major focal neurological, visual, or hearing defects. There were no major differences in the frequencies of these criteria or of schooling between 0-2- and 2-4-year-olds. Among adult survivors, older than 21 at last follow-up, 26% successfully completed higher education, 31% were in full-time employment, and 37% had never been employed. For medulloblastoma, the 5-year survival rate was 61% for 30 children less than 3 years old and treated from 1975-1995. This compared favorably with recent reports of survival following primary chemotherapy with delayed or omitted radiation treatment. SUMMARY Radiation treatment of a young child with a brain tumor was associated with cure in 1 of every 3 patients. Unfortunately, quality of life for many survivors was not good. Only one of every 3 adult survivors was able to have a normal life-style. This shortfall was the result of focal neurological defects which were present from the time of first treatment, and of the long-term effects of radiation treatment. CONCLUSIONS The search for less toxic treatment remains appropriate, but is experimental and researchers must recognize that there may be a trade-off between morbidity and mortality.


Journal of Clinical Oncology | 2006

Survival and Late Effects in Children With Hodgkin's Lymphoma Treated With MOPP/ABV and Low-Dose, Extended-Field Irradiation

Lionel M.L. Chow; Paul C. Nathan; David C. Hodgson; Derek Jenkin; Sheila Weitzman; Ronald Grant; David Manson; Adee Bross; John Doyle; Cyril Danjoux; Mark T. Greenberg

PURPOSE Reduced-intensity protocols for pediatric Hodgkins lymphoma are aimed at preserving excellent relapse-free survival while decreasing the incidence of late effects. PATIENTS AND METHODS We retrospectively reviewed the outcome of 123 children treated consecutively for Hodgkins lymphoma at a single institution. Patients with stages I-IIIB disease received three cycles of mechlorethamine, vincristine, procarbazine, and prednisone (MOPP)/ doxorubicin, bleomycin, and vinblastine (ABV) followed by 15 Gy of extended-field irradiation, while those with stage IV disease were treated with six to eight cycles of MOPP/ABV chemotherapy with or without radiotherapy. RESULTS At a median follow-up of 8.5 years (range, 1.4 to 15.5 years), the estimated 10-year overall survival and event-free survival are 94% (SE, 2.2%) and 88% (SE, 3.1%) respectively. There have been 12 treatment failures and six disease-related deaths. A very large mediastinal mass ( 50% of the maximal thoracic diameter) was associated with a 10-year event-free survival of 50% (SE, 14%) compared with 91% (SE, 4.0%) for smaller masses (P < .001). Late cardiopulmonary toxicity is largely absent, and the incidence of hypothyroidism is 14%. There have been no cases of secondary leukemia and four secondary solid malignancies observed to date. CONCLUSION MOPP/ABV and low-dose, extended-field radiotherapy is an effective treatment for pediatric Hodgkins lymphoma. With median follow-up of 8.5 years, late cardiopulmonary effects and secondary malignancies from this treatment regimen are infrequent. Continued longitudinal observations, particularly for breast cancer in female patients and gonadotoxicity, will determine whether the goal of decreasing treatment-related complications while maintaining excellent survival has been achieved.


International Journal of Radiation Oncology Biology Physics | 1995

Brain tumors in children: Long-term survival after radiation treatment

Derek Jenkin; Mark T. Greenberg; Harold J. Hoffman; Bruce Hendrick; Robin P. Humphreys; Annette Vatter

PURPOSE To determine the cause of death in children who survive more than 5 years after radiation treatment of a brain tumor. METHODS AND MATERIAL Nine hundred and twelve consecutive children with a primary brain tumor irradiated at the Princess Margaret Hospital or Toronto-Bayview Regional Cancer Center from 1958 to 1991, were evaluated for long-term outcome. RESULTS Overall 10- and 20-year survival rates were 44% and 37%. Subsequent survival of 377 5-year survivors was, at an additional 10 and 20 years, 78% and 67%. Most (83%) deaths that occurred more than 5 years from diagnosis were a result of relapse of the original tumor. The 10-year survival rate subsequent to relapse was 9% when the first relapse occurred less than one year from diagnosis, 17% for 1-2 years, and 31% when the time to relapse was 3 years or greater. The cumulative actuarial incidence of, and death from, second malignant tumors at 30 years from diagnosis was 18% and 13%, respectively. CONCLUSIONS Death later than 5 years from diagnosis of a brain tumor in children is common and is usually due to progressive disease in slowly evolving low grade tumors. Death from a second malignant tumor becomes more frequent than death from the original tumor after 15 years from diagnosis.


Medical and Pediatric Oncology | 1996

Second malignant tumours in childhood Hodgkin's disease

Derek Jenkin; Mark T. Greenberg; Annette Fitzgerald

This study was undertaken to determine the treatment-specific incidence of second malignant tumours (SMT) in childhood Hodgkins disease. The institutional databases at The Hospital for Sick Children, the Princess Margaret Hospital, and the Toronto-Bayview Regional Cancer Centre were reviewed for the years 1958-1993. Three hundred and forty-three consecutive newly diagnosed children were evaluated. The overall 30 year cumulative SMT incidence was 31%. The 20 year SMT incidence was greater for patients who relapsed (n = 129), 27%, compared with patients who remained relapse free (n=214), 13%. For patients with stage 1-3B disease who remained relapse free, the 10 year SMT rate was 7% for patients who were surgically staged and treated with extended field radiation treatment (EF RT) (35 G), compared with 3% in clinically staged patients treated with MOPP (six cycles) and EF RT (25-30 G). To date there is no significant difference in the oncogenicity of these treatment protocols. However, EF RT alone was less effective in disease control. For stages 1-3B, 62% of patients relapsed after EF RT alone compared with 18% after bimodal treatment. Therefore treatment intensification due to relapse was more frequent in the former group. The overall 10 year SMT incidence for patients treated with these protocols was 11% and 3%, respectively. The 20 year SMT incidence following EF RT alone was 24%. We conclude that SMTs were a common late complication in childhood Hodgkins disease and are a limiting factor in the achievement of cure. The incidence of SMTs was increased in children who required retreatment and was minimal in children who remained in a first complete remission. Therefore the initial treatment strategy in childhood Hodgkins disease must be to minimize the risk of relapse, in order to avoid the morbidity and mortality associated with both relapse and SMT induction, and to achieve this objective with a primary treatment protocol of low oncogenicity.


Cancer | 1980

Soft-tissue sarcomas in the young. Medical treatment advances in perspective

Derek Jenkin; Marilyn Sonley

One hundred and sixty‐two patients with all types of soft tissue sarcoma, less than 21 years old and diagnosed at a single institution during the period 1958 through 1976, were studied. The major histologic subset comprised 115 patients with either embryonal rhabdomyosarcoma or undifferentiated sarcoma. In this group, responses of patients with stage I‐II disease to local treatment alone indicated that at least half had no occult metastatic disease. Responses to irradiation alone in stage III disease indicated that only about a quarter of these patients had no occult disease. Sustained local control at the primary site by irradiation was observed in 68% of the patients given doses of 4500 rad or greater compared with 22% at lower doses. The effectiveness of adjuvant chemotherapy was best seen in patients with stage III disease as a decrease in relapse rate and a lengthening of the time to first relapse. In these patients it appeared that occult metastatic disease could be eradicated in approximately half of the patients affected.

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Mark T. Greenberg

Pennsylvania State University

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