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Biomedical subjects

J D Cox

Publications and source records attributed to J D Cox.

At least 109 records · Page 6Linked to original sources
PubMed1995

Influence of a sampling review process for radiation oncology quality assurance in cooperative group clinical trials--results of the Radiation Therapy Oncology Group (RTOG) analysis.

The Radiation Therapy Oncology Group (RTOG) designed a random sampling process and observed its influence upon radiotherapy review mechanisms in cooperative group clinical trials. The method of sampling cases for review was modeled from sampling techniques commonly used in pharmaceutical quality assurance programs, and applied to the initial (on-study) review of protocol cases. 'In control' (IC) status is defined for a given facility as the ability to meet minimum compliance standards. Upon achieving IC status, activation of the sampling process was linked to the rate of continued patient accrual for each participating institution in a given protocol. The sampling design specified that > or = 30% cases not in compliance would be detected with 80% power. A total of 458 cases was analyzed for initial review findings in four RTOG Phase III protocols. Initial review findings were compared with retrospective (final) review results. Of the 458 cases analyzed, 370 underwent initial review at on-study, while 88 did not require review as they were enrolled from institutions that had demonstrated protocol compliance. In the group that had both initial and final review, 345/370 (93%) were found to have followed the protocol or had a minor variation. Of the exempted cases, 79/88 (90%) were found to be per protocol or a minor variant. The sampling process proved itself to be cost-effective and resulted in a noticeable reduction in the workload, thus providing an improved approach to resource allocation for the group. Continued evaluation of the sampling mechanism is appropriate as study designs and participants vary over time, and as more data become available to study.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Protocols↗
PubMed1995

Limited-stage small-cell lung cancer: patient survival after combined chemotherapy and radiation therapy with and without treatment protocols.

PURPOSE: To compare survival of patients who undergo treatment in protocols versus survival of patients not in protocols. MATERIALS AND METHODS: Records of 81 adult patients with small-cell lung cancer who underwent chemotherapy and radiation therapy in 1987-1992 were reviewed retrospectively. Forty-one patients were in a protocol; 40 patients were not. Patient demographics and prognostic factors were not statistically significantly different. RESULTS: Median overall survival was 16.7 months in the nonprotocol group versus 29.0 months in the protocol group (P = .0023). Median disease-specific survival was 18.3 months in the nonprotocol group versus 27.1 months in the protocol group (P = .0176). Survival was not statistically significantly influenced by Karnofsky performance status, weight loss, or thoracic radiation dose. CONCLUSION: There was a highly statistically significant difference in survival outcome in the nonprotocol group versus the protocol group (P = .0023). Differences in chemotherapy-radiation therapy timing and other treatment-related factors may have contributed substantially to the improved survival in the protocol group.

Adult↗
PubMed1994

Analysis of the probability and risk of cause-specific failure.

PURPOSE: Kaplan-Meier curves are frequently misused in the analysis of nonsurvival endpoints, such as time to local failure or time to late complications. More appropriate analyses are available and described. METHODS AND MATERIALS: Cumulative incidence is an unbiased estimate of probability of cause-specific failure. Cumulative conditional probability of cause-specific failure reflects risk to patients remaining at risk. Hazard rates also measure risk. RESULTS: Kaplan-Meier curves overestimate the probability of late complications when there is a high mortality rate. Cumulative incidence and cumulative conditional probability accurately give the probability and risk of cause-specific failure. CONCLUSION: Kaplan-Meier analysis of cause-specific failure should be avoided because of its misinterpretation as an estimate of probability, in favor of appropriate methods.

Colorectal Neoplasms↗
PubMed1994

Thymoma. A retrospective study of 87 cases.

BACKGROUND: The authors retrospectively analyzed 87 patients with malignant thymoma treated at M.D. Anderson Cancer Center between 1951 and 1990. The analysis examined the clinical stages, histologic types, and treatment modalities and attempted to determine if chemotherapy had an impact on survival. METHODS: The patients were divided into three groups by their year of treatment and treatment modality. Patients treated between 1951 and 1975 were in Group I; patients treated between 1976 and 1980 were in Group II; and patients treated between 1981 and 1990 were in Group III. Most of the patients (18 [72%] in Group I; 16 [62%] in Group II; and 18 [50%] in Group III) had surgical resection alone or with radiotherapy. Patients with advanced-stage disease in Group I received single-agent chemotherapy, whereas patients with advanced-stage disease in Group II received a different, combination chemotherapy regimen, and those in Group III were treated primarily with cisplatin- and doxorubicin-based combination chemotherapy, e.g., the cyclophosphamide doxorubicin, and cisplatin with or without prednisone. The 17 patients treated with cisplatin with or without prednisone were separately evaluated for survival according to their response. RESULTS: Twenty-eight patients (5 [20%] in Group I; 6 [23%] in Group II; and 17 [47%] in Group III) received chemotherapy alone or after surgery or radiotherapy. The cisplatin with or without prednisone regimen was used in 17 Group III patients for initial treatment or for relapse. The overall response rate among the patients receiving the cisplatin with or without prednisone regimen was 64%; 6 (35%) had a complete response, and 5 (29%) had a partial response. Thirty-one (36%) of the 87 total patients had 45 recurrent tumors; the lung (29%), pleura (22%), and mediastinum (18%) were the most common sites of recurrence, whereas bone was the most common distant metastatic site. The 5-year survival rate was 70% in patients with Stage I disease, 71% in patients with Stage II or III disease, and 46% in patients with Stage IV disease. The 10-year survival rate was 70% in patients with Stage I disease, 47% in patients with Stage II or III disease, and 21% in patients with Stage IV disease. Statistical analysis indicated a significant difference among the survival rates of patients with noninvasive Stage I, invasive Stage II plus III (P = 0.033), and Stage II plus III and IV tumors (P = 0.056), but not between patients with Stage II or III tumors. Patients with a major response to the cisplatin with or without prednisone regimen had a significant survival improvement compared to those with no response (P = 0.002, log-rank test). CONCLUSIONS: Because thymoma is a chemosensitive tumor and frequently recurs in patients with Stage II or greater disease, chemotherapy carries a potential survival benefit and should be incorporated into the multimodality approach to prolong disease-free survival.

Adolescent↗
PubMed1994

Continuous split course irradiation for stage I and II Hodgkin's disease: 20 year experience at the Medical College of Wisconsin.

Between January 1970 and December 1989, 153 consecutive patients with stage I or II Hodgkin's disease were treated at the Medical College of Wisconsin Affiliated Hospitals. Eighty-eight patients were clinically staged and 65 patients underwent staging laparotomy. Ninety-nine patients were treated using continuous split course irradiation (CSCI) technique. Overall survival (OS) at 5, 10, and 15 years was 89%, 79%, and 68%, respectively. Disease-free survival (DFS) at 5, 10, and 15 years was 75%, 72%, and 68%, respectively. No significant differences were found in OS or DFS when comparing pathologically and clinically staged patients or when comparing patients treated using CSCI with those treated with the standard technique. Patients treated using CSCI tended to complete therapy in a shorter time, without increased morbidity.

Adolescent↗
PubMed1994

Dose intensity of radiation therapy in non-small cell carcinoma of the lung: a review of RTOG data and strategies.

Prospective trials exploring questions of dose intensity for control of the local-regional tumor have been conducted by the Radiation Therapy Oncology Group for 20 years. Early studies established radiation therapy with a total dose of 60 Gy in 30 fractions as standard (STD) for unresectable non-small cell carcinomas of the lung (NSCCL). Hyperfractionated radiation therapy (HFX) with 1.2 Gy twice daily permitted higher total doses without increased normal tissue effects and led to comparison of STD vs. HFX (total dose 69.6 Gy in 58 fractions). Induction chemotherapy followed by STD, induction followed by concurrent chemotherapy and STD, and concurrent chemotherapy and HFX, have been explored in successive trials. Preliminary results of STD combined with chemotherapy suggest that increases in dose intensity increase local-regional control and survival. Confirmatory trials of increased dose intensity by combining chemotherapy with STD and HFX have been completed or are progressing.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Hodgkin's disease with a mediastinal mass greater than 10 cm: results of four different treatment approaches.

BACKGROUND: Management of Hodgkin's disease (HD) and large mediastinal adenopathy (LMA) usually includes intensive chemotherapy (CT) with or without radiation therapy (XT) regardless of stage. PATIENTS AND METHODS: One hundred and eighteen evaluable patients received one of four treatment regimens: (1) 6 cycles of MOPP or similar CT and XT; (2) 2 of MOPP followed by XT; (3) 6 of CVPP/ABDIC (cyclophosphamide, vincristine, procarbazine, prednisone/doxorubicin, bleomycin, decarbazine, prednisone, lomustine) followed by XT; or (4) 3 of NOVP (mitoxantrone, vincristine, vinblastine, procarbazine) and XT. XT doses included 30-40 Gy to areas of nodal involvement noted prior to therapy. RESULTS: Complete remission (CR) rates for groups 1, 2, 3, and 4 were 100%, 85%, 87%, and 96%. Respective 3-year freedom from progression (FFP) results were 88%, 66%, 82%, and 88%, and 3-year freedom from tumor mortality (FTM) results were 100%, 84%, 84%, and 100%. The presence of B symptoms and stage IV disease was correlated with lower CR and 3-year FFP rates but similar 3-year survival. CONCLUSIONS: Results of this study suggest that patients with stage I-III Hodgkin's disease and LMA greater than 10 cm treated with 3 NOVP and XT have results similar to those obtained for a similar group of patients treated with 2 to 6 MOPP or 6 CVPP/ABDIC and XT. NOVP has also been reported to produce limited toxicity in this trial and should be considered as an alternative to MOPP or doxorubicin-containing regimens in treatment of patients with early-staged disease and LMA greater than 10 cm.

Adolescent↗
PubMed1993

Interruptions of high-dose radiation therapy decrease long-term survival of favorable patients with unresectable non-small cell carcinoma of the lung: analysis of 1244 cases from 3 Radiation Therapy Oncology Group (RTOG) trials.

PURPOSE: To determine if prolonged treatment time adversely affects survival for patients with inoperable non-small cell carcinoma of the lung. METHODS AND MATERIALS: Patients enrolled on three randomized studies (RTOG 8311, 8321, 8403) between 1983-1989 formed the database. Previous analyses found that the addition of thymosin (8321) or prophylactic cranial irradiation (8403) failed to prolong survival: both studies used thoracic irradiation with standard fractionation to 55-60 Gy in 30 fractions. In 8311, patients were treated by hyperfractionated radiation therapy to randomly assigned total doses of 60.0 Gy, 64.8 Gy, 69.6 Gy, 74.4 Gy or 79.2 Gy, 1.2 Gy twice daily, 5 days per week. Patients analyzed received +/- 4% of the assigned total dose and lived > 90 days (to ensure that all patients would have completed treatment). Completion < 5 days beyond protocol specifications was classified as "per protocol." Elapsed treatment time exceeding specifications by 5-9 days was a minor deviation, 10-13 days was a major deviation-acceptable, and > or = 14 days was a major deviation-unacceptable. Absolute survival was the endpoint to evaluate the effect of delays. The log rank statistic was used to test for survival differences in the univariate setting, the Cox regression model was used in the multivariate setting. RESULTS: Of 293 patients treated with standard fractionation, eight (2.7%) had deviations from the specified treatment time (six minor, two major-acceptable). With hyperfractionation, 90 (15%) patients had deviations (40 minor, 21 major-acceptable, 29 major-unacceptable). As the assigned dose increased, the deviation rate increased (9.7% for 60.0 Gy vs. 20.8% for 79.2 Gy). Survivals for hyperfractionation patients with any deviations in treatment time were significantly shorter than those treated "per protocol" (p = 0.16): estimated 2- and 5-years rates were 24% and 10% versus 13% and 3%, respectively. Multivariate analyses showed the delay effect to be entirely in patients treated with 69.6 Gy or higher; there was also dependence upon the patients' prognosis. In patients with favorable prognosis (KPS 90-100, weight loss < or = 5%, no N3), the difference in survival was pronounced (33% and 15% vs. 14% and 0% at 2- and 5-years, respectively). Such differences were not found in patients with unfavorable prognostic factors. CONCLUSIONS: Interruptions delaying completion of planned radiation therapy were more frequent with higher total doses (> or = 69.6 Gy). Favorable patients (high KPS, little weight loss, < N3 nodal metastasis) had markedly adverse effects on long-term survival associated with delays to completion of the planned total dose.

Adult↗
PubMed1993

The influence of field size and other treatment factors on pulmonary toxicity following hyperfractionated irradiation for inoperable non-small cell lung cancer (NSCLC)--analysis of a Radiation Therapy Oncology Group (RTOG) protocol.

PURPOSE: The risk of pulmonary toxicity, observed in an Radiation Therapy Oncology Group Phase I/II randomized dose escalation trial of hyperfractionated irradiation for nonsmall cell lung cancer, was analyzed with regard to custom vs. hand blocking and compliance to protocol specified treatment field parameters. MATERIALS AND METHODS: There were 832 evaluable cases analyzed. The protocol required field margins 2 cm beyond primary tumor and involved nodes. In 674, the field margins were considered "per protocol" or as having minor protocol variations. In 94, margins exceeded protocol specification ("excessive margin" group). In this group, the area (cm2) of the effective (blocked) field and the portion including lung was measured from simulator films with a computer scanning device. Based on size and location of the primary and nodal disease, "per protocol" fields were constructed and the area (cm2) of lung included beyond these margins was estimated. Patients from both groups who received less than 30 Gy to normal lung were excluded from analysis of pulmonary toxicity. RESULTS: Grade 1 acute lung toxicity was higher (p = .009) in the "excessive margin" group compared to the "per protocol" group, whereas late lung toxicity was not significantly different (p = .94). The risk of Grade 2 or greater acute toxicity increased as area of excess irradiated lung increased. Overall lung toxicity, defined as the greater of either acute or late toxicity, was evaluated by multivariate analysis, in relation to assigned dose, effective treated field area, and type of shielding. Overall maximum lung toxicity (> or = Grade 2) was significantly greater in the "excessive margin" group, when lung treated beyond protocol margins exceeded an area of 35 cm2, than in the "per protocol" group, but only when the effective treated field size was > or = 180 cm2 (68% vs. 37%; p = .02). This effect was independent of assigned total dose or type of shielding. CONCLUSION: For nonsmall cell lung cancer treated with hyperfractionated irradiation, the risk of overall pulmonary toxicity was increased for patients treated with field sizes in excess of protocol specified margins of tumor coverage in comparison to patients treated with protocol specified margins. This effect was seen only when the area of lung treated beyond protocol margins exceeded 35 cm2 and when the overall field size was below 180 cm2.

Carcinoma, Non-Small-Cell Lung↗
PubMed1993

Central lymphatic irradiation for stage III nodular malignant lymphoma: long-term results.

PURPOSE: To report the long-term results of central lymphatic irradiation for stage III nodular malignant lymphoma. PATIENTS AND METHODS: Between 1969 and 1985, 34 patients (26 with nodular poorly differentiated lymphoma, four with nodular mixed lymphocytic/histiocytic lymphoma, and four with nodular histiocytic lymphoma) were treated with central lymphatic irradiation. Median age of the group was 51 years (range, 30 to 73). There were 15 men and 19 women. Staging work-up included a physical examination and bone marrow biopsy in all patients. Seventy-four percent had a lymphangiogram (LAG) and 44% a laparotomy (LAP). Eighty-two percent had either a LAP or a LAG. Thirty-two patients were Ann Arbor stage IIIA and two were stage IIIB. All patients received lymphatic irradiation that encompassed cervical, supraclavicular, axillary, mediastinal, paraaortic, mesenteric, pelvic, and femoral lymphatics to total doses ranging from 20 to 30 Gy in 1.0- to 1.8-Gy fractions. Waldeyer's ring was initially treated in 17 patients. Follow-up information is available on all 34 patients. Median follow-up is 9 years, 8 months (range, 15 to 244 months). RESULTS: Life-table actuarial overall, disease-free, and cause-specific survival rates at 15 years are 28%, 40%, and 46%, respectively. Only one relapse was observed after 9 years. Disease-free survival was significantly improved in patients with five or fewer sites of involvement (P = .02). Age, sex, B symptoms, histology, and technique of irradiation were not prognostically significant. Salvage therapy, including further irradiation and/or chemotherapy, was delivered to 20 patients. Ten percent of these patients remain alive without evidence of disease. Toxicity data were available for the patients treated at the Medical College of Wisconsin (MCW). Radiation Therapy Oncology Group (RTOG) acute hematologic, gastrointestinal, and salivary toxicity scores were < or = 2 in 83% of patients. Late toxicity scores were < or = 2 in 96%. Persistent xerostomia was noted in 23% of patients who received initial treatment to Waldeyer's ring. CONCLUSION: These results suggest that initial comprehensive central lymphatic irradiation may be the preferred approach to achieve a durable relapse-free interval for this group of patients.

Adult↗
PubMed1992

Comparison of prognostic factors and survival among black patients and white patients treated with irradiation for non-small-cell lung cancer.

BACKGROUND: Many studies have reported differences in cancer incidence and survival between populations of Blacks and Whites. A 45% higher death rate from lung cancer for Black men and a survival duration for Black patients with lung cancer that is generally shorter than that for White patients have also been reported. PURPOSE: The purpose of this study was to evaluate whether race affects known prognostic factors for non-small-cell lung cancer in Black versus White patients. This analysis attempts to determine which prognostic factors may contribute to the reported differences in disease outcome. METHODS: We used data from 1565 patients with non-small-cell lung cancer treated in four randomized prospective trials conducted by the Radiation Therapy Oncology Group (RTOG). The data were pooled for a retrospective analysis of survival and prognostic factors by race. RESULTS: Univariate analysis showed significant differences between Blacks and Whites with regard to sex, weight loss, histology, and RTOG T stage (P < .05), but the only clinically significant difference (P < or = .01) was weight loss. Despite these findings, overall survival for Blacks and Whites did not differ significantly (P = .67). Median survival for Blacks and Whites with a Karnofsky performance status (KPS) of 90 or more was 12.1 and 11.3 months, respectively (P = .45). Survival for Blacks and Whites with a KPS of less than 90 was 7.8 and 6.8 months, respectively. Cause of death did not differ between the two races. For both races, KPS, age, sex, weight loss, and RTOG T and N stages were significant prognostic factors for survival (P < .01), but race was not a significant prognostic factor. CONCLUSION: Further studies of the differential in cancer survival for Blacks and Whites may be indicated, but greater impact may be achieved by addressing socioeconomic factors, lifestyle and occupational risk factors, health education, and access to adequate health care.

Black People↗