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Biomedical subjects

M C Ryoo

Publications and source records attributed to M C Ryoo.

16 recordsLinked to original sources
PubMed1993

Outcome of care. Complications from radiation therapy treatment.

This study was undertaken to examine radiation treatment complications. From September 1987 through December 1989, 29,380 patients were screened at their follow-up visits for possible radiation complications. Of these patients, 1,380 were singled out for further study. These 1,380 charts were examined by a radiation oncologist and physicist to determine if there was a radiation complication, the severity of the complication, and whether a calculation or setup error could account for the complications. Of the 1,380 patients studied, 178 (3% of new patients treated each year) were determined to have radiation complications. These complications were divided into four categories of severity and entered into our computerized tumor registry as follows: complication type R1, complete recovery from symptoms, n = 59; R2, injury requiring medications to control injury, n = 104; S1, surgical intervention for one organ, n = 12; and S2, surgical intervention for two organs, n = 3. We believe that a baseline complication rate of 5% is acceptable in radiation oncology practices. However, the examination and documentation of the outcome of care in the form of radiation complications can help improve patient care and keep the radiation oncologist abreast of treatment outcome trends in the department.

Dose-Response Relationship, Radiation↗
PubMed1991

Large cell lymphoma stage IA/IAE.

Fifty-two patients with large cell lymphoma stage IA/IAE were retrospectively reviewed for the purpose of evaluation of treatment methods. All pathology slides were reviewed by one pathologist with a special interest in lymphoma. There were 24 patients at stage IA and 28 at stage IAE. Twenty-six patients were treated with radiation alone (10 IA, 16 IAE) and 26 patients were treated with radiation therapy and chemotherapy (13 IA, 13 IAE). Patients treated with radiation therapy alone and those with combined modality therapy (CMT) have similar survival curves with p values greater than 0.05. Recurrence patterns are similar for either method of treatment. While the majority of the literature recommends CMT for large cell lymphoma, our study of 52 patients reveals no difference in survival or recurrence patterns for these patients by either method of treatment. We recommend radiation therapy alone for stage IA/IAE large cell lymphoma, with chemotherapy held in reserve for failure.

Aged↗
PubMed1989

Treatment selection for base of tongue carcinoma.

Sixty-two previously untreated patients with squamous cell carcinoma of the base of tongue were retrospectively analyzed. The American Joint Committee on Cancer (AJCC) Stage distribution was I-3, II-7, III-24, and IV-28. The choice of treatment was nonrandomized. The local control was 10/18 with high-dose preoperative radiation, 17/30 with external beam radiation only, and 4/14 with external beam plus interstitial implantation. The median survival for the three treatment regimens were 63, 51, and 13 months, respectively. Preoperative radiation is suggested for tumors with inferior (laryngeal) spread or those with extensive superior extension (to tonsillar fossa and beyond). For centrally placed lesions in the base of the tongue (with or without lateral hypopharyngeal wall spread), radiation alone is recommended. An interstitial implantation should be restricted to lesions equal to or less than 4 x 3 x 2.5 cm3. Since this insertion is technically more demanding than for tumors of the mobile tongue, they should be performed by the more experienced brachytherapist.

Brachytherapy↗
PubMed1989

Prognostic factors for recurrence and cosmesis in 393 patients after radiation therapy for early mammary carcinoma.

Between 1978 and 1985, 393 of 2,765 (14%) patients with operable cancer of the breast (clinical stage T0-3N0-2M0) were irradiated after excisional biopsy and staging axillary dissection. Of 77 patients with microscopic axillary metastases, 68 received systemic adjuvant therapy. Treatment failed locally in 26 cases, and there were seven patients with distant metastasis. The three major factors for increased local treatment failure were (a) age below 40 years (P = .003), (b) negative estrogen receptor assay result (P = .03), and (c) failure to deliver a radiation boost dose when tumor was present at the margin of the specimen (P = .002). The size of the tumor, the nodal status, the progesterone receptor assay result, and the presence of ductal carcinoma in situ mixed with infiltrating carcinoma did not show a significant influence on local recurrence. In 274 of 393 (70%) patients, cosmesis was evaluated. The four major factors affecting cosmesis favorably were (a) utilization of a wedge (P less than .0001); (b) treatment of two fields a day (P less than .0001); (c) failure to use a separate treatment port to the regional lymph nodes, so as to avoid field junctions (P = .0003); and (d) small size of specimen (less than 50 cm2) (P = .0171). A second or third cancer was found in 39 of the 393 (10%) patients; contralateral breast cancer was the most common form (n = 23), followed by genitourinary cancer (n = 5). The most frequent complication was arm edema (6%).

Adult↗
PubMed1987

Observations on the treatment of mediastinal masses in Hodgkin's disease emphasizing site of failure.

Of 244 patients with Hodgkin's disease, 126 (52%) had an abnormal mediastinum. Sixty-four patients were treated with radiation, 36 with radiation and chemotherapy, and 25 with chemotherapy alone as an initial treatment. Twenty of 52 (38%) with stage I or II who received initially radiation alone relapsed, and 70% (14 of 20) of them were salvaged with chemotherapy. Therefore, the ultimate failure rate was 12% (6 of 52). Forty percent (8 of 20) of these patients failed within or at the margin of the radiation portal, and 60% failed predominantly outside of the radiation field. Even though we did not treat the whole lung prophylactically, there was only one true peripheral lung recurrence. Nine of 20 (45%) recurred in more than one site. Of 36 patients treated with combined radiation and chemotherapy, 21 patients had stage I, II, or IIIA disease. Of these, two patients relapsed. Of 86 patients with accessible x-ray films, 30 patients had large masses with a ratio of mass to transverse diameter greater than .33 at the broadest level. Fifty-six patients had small masses. Survival at 96 months in patients with stages I-IIIA with either large or small masses is 94% (p = 0.80). Their relapse-free survival at 96 months is 79% for large masses and 95% for small masses (p = 0.18). The site of relapse is discussed in detail in the text. There were five treatment-related deaths; three patients died of acute myelogenous leukemia. Our data do not support the role of whole-lung prophylactic irradiation or initial combined radiotherapy and chemotherapy in patients with large mediastinal masses.

Adolescent↗
PubMed1986

Proposed method to study the factors affecting local control with combined external beam and interstitial implantation of mobile tongue and floor of mouth.

Twenty-seven patients with squamous cell carcinoma of the mobile tongue and floor of the mouth were treated with external beam and interstitial radiation. Good prognostic factors were T1N0, T2N0, superficial tumors, tumor shrinkage by 75% with external beam, and no apparent tumor clinically 2 months after treatment. On the other hand, T3N0, T1-3N1, and deeply necrotic tumors had a poor prognosis. We recommend using a flexible afterloading system to implant the initial local tumor volume (not just the residual nidus) that does not exceed 45 cm3. The minimum (reference) dose was prescribed to a surface 1/2 cm beyond the most peripheral rim of radioactive sources. For acceptable local control and complication rates, our suggested minimum (reference) doses are less than or equal to 7,500 rads for T1 (or a time-dose-fractionation [TDF] of 131-140), less than or equal to 8,000 rads for T2 (TDF of 131-140), and probably less than 8,500 rads for T3 (TDF of less than or equal to 150). These guidelines should be considered preliminary.

Brachytherapy↗
PubMed1984

Reassessment of technical and biological factors in paranasal sinus carcinoma.

Twenty-seven patients with paranasal sinus carcinoma were analyzed. Local control with radiation alone was poor, with most patients failing centrally within the primary site. With preoperative radiation local control is 60%. Previous reports have emphasized failure at superior sites--particularly the orbit. The pattern of local failure in our series is predominantly various medial sites inclusive of intact or exenterated orbit. The surgically nonremovable medial structures are best encompassed by a three-field radiotherapy technique (weighted anterior and two laterals).

Adult↗
PubMed1984

Management of gastrointestinal lymphoma.

A study was made of 65 patients with primary gastrointestinal (GI) lymphoma. The occurrence was 40 (62%) in stomach, 15 (23%) in the small intestine, and 10 (15%) in colorectum. The majority of patients had their histology classified according to Rappaport's classification. Diffuse histiocytic type had the worst prognosis (median survival 13.8 months), and nodular histology had the best prognosis. A modified staging system proposed by Blackledge et al. was used. Patients who had their disease confined to one viscus (Stage I) or with spread to regional lymph nodes (Stage II) had an excellent prognosis, with a 5-year survival of 87 and 67%, respectively. However, those who had distant nodal involvement (Stage III, e.g., para-aortic nodes) or spread to adjacent organs within the abdomen (Stage IV) had worse prognosis, with 5-year survival of 40 and 13%, respectively. In Stage I, radiotherapy alone was as effective as surgical resection. None of the 11 patients treated by radiotherapy alone had perforation or bleeding. The 5-year disease-free survival was 51%.

Adolescent↗
PubMed1982

The changing role of external-beam irradiation in the management of malignant tumors of the major salivary glands.

Postoperative irradiation reduces the local recurrence rate for malignant salivary gland tumors. Less extensive surgery followed by immediate radiotherapy is possible without decreasing local control; moreover, cosmetic appearance and physiological function are preserved. Local tumor control was achieved in 16 out of 17 patients without gross tumor using a dose of 6,000 rad/6 wk. Combined photon and electron beams give better cosmetic and functional results than either modality alone. Irradiation with greater than or equal to 7,000 rad should be employed in unresectable cases and may effect tumor control.

Adult↗
PubMed1980

External irradiation for malignant thyroid tumors.

Thirty-eight patients with residual or recurrent primary thyroid cancers which did not take up 1-131 were treated with external beam irradiation. Excluding 5 patients with malignant lymphoma, there were 23 patients with local disease and 10 with distant metastases. Doses ranged from 3,500 to 7,000 rads (35-70 Gy) among the 23 with local disease; local tumor control was achieved in 8. Six are alive and well 2-11 years later. External beam irradiation should be considered in locally advanced, incompletely resected, recurrent and metastatic thyroid malignancies of all histological types without 1-131 uptake. Reviewed are the age and sex distribution, histology, stage, extent of surgery, and dose and radiotherapy technique as they affect survival and patterns of failure.

Adenocarcinoma↗
PubMed1979

Irradiation of primary brain-stem tumors.

Of 40 patients treated for brain-stem tumors, 20 had lesions of the thalamus and midbrain (group A) and 20 had lesions of the pons and medulla (group B). Performance status measured 1 month after irradiation improved in 16 of 20 group A and 11 of 20 group B patients and was a valuable prognostic factor. The survival rate at 5 years was 40% (8/20) in group A and 30% (6/20) in group B. All recurrences appeared within 3 years and were predominantly locoregional. Treatment factors, including dose and field size, are analyzed.

Adolescent↗
PubMedDate not supplied

Local control of T1 vocal cord cancer with radiation therapy: the importance of tumor character vs. treatment parameters.

Ninety-one patients with T1 vocal cord carcinoma received primary irradiation treatment. The 5- and 10-year determinate disease-free survival was 80%; the 5- and 10-year determinate survival including surgical salvage was 92%. Tumors involving more than one-half of a vocal cord or involving the anterior commissure or exhibiting an exophytic growth pattern had numerically, but not statistically, higher local failure rates than tumors without these characteristics. Precise radiation treatment technique appears more important for local control (LC) than tumor character. The crucial treatment factors for high LC with few radiation complications are reproducible daily patient positioning, use of contour-compensating devices (wedges), field size of 5 X 5 cm, and a radiation prescription with a time-dose fractionation value of 101 to 106.

Carcinoma, Squamous Cell↗