Felix Leborgne

Hospital Italiano, Córdoba, Córdoba, Argentina

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Publications (37)97.66 Total impact

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    ABSTRACT: Now that the follow-up time has exceeded 5 years, an estimate of the α/β ratio can be presented. The additional late outcomes in patients treated with three-dimensional conformal external beam radiotherapy for localized prostate cancer using a hypofractionated vs. a standard fractionation regimen are reported from this prospective nonrandomized contemporary comparison. A total of 114 nonrandomized patients chose hypofractionation delivered in 20 fractions of 3 Gy or 3.15 Gy (mean 3.06 Gy) for localized prostate cancer within a median overall time of 32 days (range, 29-49) using four fractions weekly. A total of 160 comparable patients were contemporarily treated within a median of 55 days (range 49-66). The median follow-up was 66 months (range, 24-95) for the hypofractionated arm and 63 months (range, 36-92) for the standard arm. The percentage of patients in the low-, medium-, and high-risk groups was 36%, 46%, and 18% in the hypofractionated arm and 44%, 50%, and 6% in standard arm (2 Gy), respectively. The 5-year actuarial biochemical absence of disease (prostate-specific antigen nadir + 2 ng/mL) and disease-free survival rate was the same at 89% in both arms, making the α/β calculation unambiguous. The point ratio of α/β was 1.86 (95% confidence interval, 0.7-5.1 Gy). The 95% confidence interval was determined entirely by the binomial confidence limits in the numbers of patients. Rectal reactions of grade 3 and 4 occurred in 1 of 114 (hypofractionated) and 2 of 160 (standard) patients. The presented three-dimensional conformal regimen was acceptable, and the α/β value was 1.8, in agreement with other very recent low meta-analyses (reviewed in the "Discussion" section).
    International journal of radiation oncology, biology, physics 04/2011; 82(3):1200-7. · 4.59 Impact Factor
  • Felix Leborgne, Jack Fowler
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    ABSTRACT: To study retrospectively late complications and biochemical control in patients treated with three-dimensional conformal external-beam radiotherapy for localized prostate cancer administered using hypofractionation vs. a standard fractionation regimen. The hypofractionation regimen (Hypo) was designed to avoid more late rectal reactions and to be done in half as many treatment sessions. Eighty-nine nonrandomized patients chose Hypo delivered in 20 fractions of 3 Gy (n = 52) or 3.15 Gy (n = 37) for a median overall treatment time of 33 days. One hundred thirty comparable patients were contemporaneously treated with standard fractionation to a median dose of 78 Gy delivered over 55 days. The median follow-up time was 49 months (range, 24-73 months). The 5-year actuarial biochemical control rates were 96%, 84%, and 85% for low-, medium-, and high-risk disease in the Hypo group, respectively. The respective rates in the standard fractionation group were 98%, 84%, and 87%, with no statistical difference between the two groups. The rate of rectal Grade 2-4 complications was 5.5% in both treatment groups and of urinary Grade 2-4 complications was 5.6% in the Hypo and 3% in the standard group (p = 0.36). Similarly, there were no statistical differences in the rate of late complications between patients treated with 3 Gy/fraction vs. 3.15 Gy/fraction. Our preliminary results showed that the Hypo regimen is feasible and does not reduce biochemical control compared with standard fractionation. The incidence of late complications was not increased when the tumor normalized total doses at 2Gy/fraction was increased from 77.1 to 83.7 Gy in patients treated with either 3 or 3.15 Gy/fraction in the Hypo group, respectively.
    International journal of radiation oncology, biology, physics 05/2009; 74(5):1441-6. · 4.59 Impact Factor
  • Felix Leborgne, Jack Fowler
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    ABSTRACT: To prospectively study acute rectal and urinary reactions from three-dimensional conformal external beam radiotherapy for localized prostate cancer comparing two hypofractionation regimens with standard fractionation (standard). The hypofractionation regimens were designed to avoid more late reactions in the hypofractionation groups than in the standard group, with the advantage of one-half as many treatment sessions. A total of 56 nonrandomized patients chose hypofractionation delivered at 3 (n = 22) or 3.15 (n = 34) Gy/fraction, 4 d/wk, to a total dose of 60 or 63 Gy within 5 weeks. A total of 74 patients were contemporarily treated with standard fractionation at 2 Gy/fraction, 5 d/wk, to a total dose of 76 to 80 Gy. The differences within patients without complications were not statistically significant in the three groups. However, for acute complications of Grade 2 or worse, the Hypo3.15 group had significantly greater (p = 0.001) complication rates (50%) compared with the standard group (17%). The incidence of patients without acute rectal complications was significantly lower for the Hypo3.15 group compared with the Hypo3 and standard groups. The incidence of rectal Grade 2 or greater complications was correspondingly significantly greater for the Hypo3.15 group than for the Hypo3 and standard groups (p < 0.001). The incidence of patients with urinary complications was not significantly different among the three groups. Acute rectal reactions were more frequent and intense in the Hypo3.15 group than in the Hypo3 and standard groups. In our study, 60 Gy at 3 Gy/fraction within 5 weeks resulted in acute toxicity similar to that after standard fractionation.
    International journal of radiation oncology, biology, physics 04/2008; 72(3):770-6. · 4.59 Impact Factor
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    Felix Leborgne, José H. Leborgne, Bettys Ortega
    01/2008;
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    01/2004;
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    ABSTRACT: To investigate whether a predictive estimate can be obtained for a 'tolerance level' of acute oral and pharyngeal mucosal reactions in patients receiving head and neck radiotherapy, using an objective set of dose and time data. Several dozen radiotherapy schedules for treating head and neck cancer have been reviewed, together with published estimates of whether they were tolerated or (in a number of schedules) not. Those closest to the borderline were given detailed analysis. Total doses and biologically effective doses (BED or ERD) were calculated for a range of starting times of cellular repopulation and rates of daily proliferation. Starting times of proliferation from 5 to 10 days and daily cellular doubling rates of 1-3 days were considered. The standard published form of BED with its linear overall time factor was used: BED=nd(1 + d/(alpha/beta) - Ln2(T - T(k))/alpha T(p) (see text for parameters). A clear progression from acceptable to intolerable mucosal reactions was found, which correlated with total biologically effective dose (BED in our published modeling), for all the head and neck cancer radiotherapy schedules available for study, when ranked into categories of 'intolerable' or 'tolerable'. A review of published mechanisms for mucosal reactions suggested that practical schedules used for treatment caused stimulated compensatory proliferation to start at about 7 days. The starting time of compensatory proliferation had little predictive value in our listing, so we chose the starting time of 7 days. Very short and very long daily doubling rates also had little reliability, so we suggest choosing a doubling time of 2.5 days as a datum. With these parameters a 'tolerance zone of uncertainty' could be identified which predicted acute-reaction acceptability or not of a schedule within a range of about 2-10 Gy in total BED. If concurrent chemoradiotherapy is used, our provisional suggestion is that this zone should be reduced by up to roughly 3-5 Gy10 in BED, with a request for further evidence. It is suggested that total BED should be used, as specified above. Parameters of alpha=0.35 Gy-(1), alpha/beta=10 Gy, Tk=7 days and Tp=2.5 days are suggested. The 'acute/ tolerance zone' then turns out to be 59-61 Gy10 for radiation-only treatments. Further information about the decrement caused by concurrent head-and-neck cancer chemoradiotherapy, possibly 3-5 Gy10, is required.
    Radiotherapy and Oncology 12/2003; 69(2):161-8. · 4.52 Impact Factor
  • Francisco Leborgne, Felix Leborgne
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    ABSTRACT: We studied the feasibility of treating breast abscesses with sonographically guided aspiration, irrigation, and local instillation of antibiotics without placing indwelling catheters. Seventy-three patients with breast abscesses were seen from 1995 to 2001. Aspiration and irrigation were performed under sonographic guidance. Repeated aspiration was performed when deemed necessary. One gram of cephradine was injected into 29 abscesses measuring more than 25 mm. Six patients refused further treatment after failure of the first aspiration and elected surgical drainage. Of the remaining 67 patients who completed treatment, 38 required one aspiration for cure, 18 required two aspirations, and eight required more than two aspirations. The treatment failed and surgical drainage was required in only three of the 67 patients completing treatment. Ninety-six percent of patients completing treatment were cured with this procedure. Local instillation of antibiotics is probably beneficial.
    American Journal of Roentgenology 11/2003; 181(4):1089-91. · 2.90 Impact Factor
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    Felix Leborgne, Eduardo Zubizarreta
    International Journal of Radiation OncologyBiologyPhysics 01/2003; 54(5):1577; author reply 1577. · 4.52 Impact Factor
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    ABSTRACT: Using data collected for one series during 1987-1989 and data collected for another series during 1996, we sought to compare the frequency of and positive predictive value for carcinoma of the breast in nonpalpable, probably benign lesions that had been detected on and followed up with mammography. During 1996, mammography was performed in 18,435 women of whom 544 (3.0%) had lesions assigned to Breast Imaging Reporting and Data System (BI-RADS) category 3 for nonpalpable, probably benign lesions. The lesions in the women were assessed as BI-RADS category 3 after the patients had undergone a diagnostic study that included additional imaging, sonography, and a focused physical examination. Patients with BI-RADS category 3 lesions were recommended for mammographic surveillance. A minimum of 2 years of follow-up data was available for 511 patients, our study population. We compared the findings for our study population with those of the previous study. Ninety-seven percent of the follow-up mammograms showed stability or regression of the BI-RADS category 3 lesions. Fourteen patients (3%) had nonpalpable interval progression revealed on mammography and underwent biopsy. The breast cancer detection rate in category 3 lesions among the study population was 0.4% (2/511), which was 14% of the patients who had undergone biopsies because of interval progression of the lesions. The pathologic stage of the cancers in these two patients was T1b N0. Compared with the findings from the 1987-1989 study, the frequency of BI-RADS category 3 lesions has remained stable; patient compliance for follow-up has increased; and the positive predictive value of category 3 lesions for cancer has decreased from 1.7% to 0.4% (p = 0.04).
    American Journal of Roentgenology 10/2002; 179(3):691-5. · 2.90 Impact Factor
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    ABSTRACT: A retrospective study was undertaken to compare local tumor control and complications of external beam radiation therapy with and without interstitial 137Cs needle brachytherapy boost doses. Two hundred one consecutive patients with locally advanced (T3-T4) cancer of the tongue and floor of the mouth treated with definitive radiotherapy by external beam irradiation with (n = 78) or without (n = 123) low-dose-rate interstitial brachytherapy from 1974 to 1999 were analyzed retrospectively. External beam irradiation was administered with conventional fractionation in 105 patients and administered with accelerated hyperfractionation in 96 patients. The 8-year actuarial local control rates showed a trend toward improved results in the combined-treatment group as a whole and also when it was stratified into patients with base of tongue sites and those with oral tongue and floor of mouth sites. Cox regression analysis for local control showed that the only significant variable was overall treatment time. The use of brachytherapy boost doses was not a significant variable. The 8-year actuarial probability of Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer Grades 3-5 late effects was 25% and 35% for patients with and without brachytherapy, respectively (p = not significant), although the crude incidence of mandibular radiation osteonecrosis was 10% and 1.6%, respectively (p =0.001). This study showed a trend toward improved local control rates for brachytherapy after external beam radiotherapy. The incidence of mandibular osteonecrosis was increased.
    Brachytherapy 02/2002; 1(3):126-30. · 1.22 Impact Factor
  • Felix Leborgne, Eduardo Zubizarreta
    International Journal of Radiation Oncology Biology Physics - INT J RADIAT ONCOL BIOL PHYS. 01/2002; 54(5):1577-1577.
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    ABSTRACT: Optimal treatment duration of altered fractionation schedules in head and neck cancer is still undefined. A retrospective study on local tumor control, survival, and complications of accelerated hyperfractionated irradiation in head and neck cancer was undertaken to investigate whether there was an advantage in further shortening overall time from 6.5 weeks. Four hundred nineteen consecutive male patients treated with radiation alone for cure 1987-1998 were analyzed. Patients with stage I, or treated also with brachytherapy implants or chemotherapy, were excluded. Treatment with accelerated hyperfractionation was performed twice daily, at a median of 1.6 Gy/fraction, to a total median dose of 68 Gy in 39 days. The patient population was divided into two groups: those with < or =39 days overall treatment time (group A, n = 227; median, 33 days) and those with >39 days (group B, n = 192; median, 46 days). Group A received a significant median tumor dose reduction of 7% compared with group B. The 7-year actuarial local control (LC) rates were 59% and 48% for groups A and B, respectively (p =.02). The actuarial LC rates for T1-2 patients were 79% and 74% at 7 years for groups A and B, respectively (p = NS). Similarly, for T3-4 patients, they were 47% and 35% (p =.02), respectively. The 7-year actuarial disease-free survival (DFS) rates for groups A and B were 39% and 26% (p =.01), respectively. For stage II patients, DFS was 62% and 60% at 7 years (p = NS) for groups A and B, respectively. And similarly, for stage III-IV patients, DFS was 33% and 20% (p =.04), respectively, at 7 years. LC and DFS rates at 7 years for T4 and stage IV patients, respectively, were significantly improved in group A. Cox regression analyses for LC showed that both T stage and overall time were significant prognostic factors. Similarly, UICC clinical stage and overall time were significant prognostic factors for DFS. There was no difference in acute morbidity between the two groups: 3% of patients in both groups required tube or parenteral feeding. The 7-year actuarial probability of RTOG/EORTC grades 3-5 late effects was 15% and 13%, respectively, for each group (p = NS). This study, with the limitations of a retrospective study, has shown a significant improvement in local tumor control and disease-free survival, in patients treated with shorter overall treatment times (median, 33 days) with an accelerated hyperfractionated irradiation schedule compared with those treated with a median duration of 46 days. No significant enhancement of acute reactions and late morbidity were observed with the shorter schedule.
    Head & Neck 09/2001; 23(8):661-8. · 2.83 Impact Factor
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    ABSTRACT: The authors undertook a retrospective study on local tumor control, survival, and complications of conventional irradiation compared with accelerated hyperfractionated irradiation in women with selected head and neck tumor sites. One hundred eight consecutive women who were treated with radiation alone for cure during 1974-1998 were analyzed. Patients were excluded who had T1 tumors of the vocal cord and those who were treated with brachytherapy implants. Fifty-nine patients were treated with conventional fractionation once daily (QD) during 1974-1998 with a median dose of 2.1 grays (Gy) per fraction up to a total median dose of 69 Gy in a median overall time of 54 days. Forty-nine patients were treated with accelerated hyperfractionation twice daily (BID) during 1987-1998 at a median dose of 1.6 Gy per fraction BID, with an interfraction interval of 4-6 hours, for a total median dose of 66 Gy in 35 days. Patients were not randomized into the QD group or the BID group. The 7-year actuarial local control (LC) rates for T1-T2 tumors in QD-treated and BID-treated patients were 79% and 87%, respectively (P = not significant [NS]). For T3-T4 tumors, the LC rates at 7 years were 59% and 56% for the QD and BID groups, respectively (P = NS). A Cox regression analysis for LC showed that the significant variables were T classification and overall time. Schedule (QD or BID), total dose, dose per fraction, and patient age were not significant variables. For the QD and BID groups, the 7-year actuarial cause specific survival rates for patients with Stage I-II disease were 100% and 65%, respectively (P = 0.004), and, for patients with Stages III-IVA,IVB disease, the rates were 39% and 56%, respectively (P = NS), respectively. Acute morbidity was higher with the BID schedule: In the BID group, 8% of patients required tube or parenteral feeding, and 0% of patients in the QD group required such feeding (P = 0.04). The 5-year actuarial probability of Grade 3-5 late effects (according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer grading system) was 4% for the BID group and 0% for the QD group (P = NS). This study suggests that accelerated hyperfractionated irradiation for women with advanced carcinoma of the head and neck does not provide significantly better local tumor control or cause specific disease free survival compared with conventional fractionation. Women with these malignancies appear to have a better prognosis compared with men.
    Cancer 07/2001; 91(12):2353-60. · 5.20 Impact Factor
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    ABSTRACT: The objective of this study was to describe the results and complications of a prospectively designed high-dose-rate (HDR) brachytherapy schedule for early-stage cancer of the cervix, at 14 Gy/h to point A, based on the linear-quadratic model and our clinical experience. We used a combination of brachytherapy and external beam pelvic and parametrial irradiation in 88 consecutively seen patients with stage IB1-IIB treated by irradiation alone (1995-1998). The modeled HDR schedule consisted of three insertions on three treatment days separated by 10 days, with six 7 Gy planned brachytherapy fractions to point A, at 14 Gy/h, two on each treatment day with an interfraction interval of 6 h, plus an 18 Gy external whole-pelvic dose followed by additional parametrial irradiation. The calculated biologically effective dose (BED) was 92 Gy10 for tumor and 110 Gy3 for the rectum, equivalent to 77 and 66 Gy in 2 Gy fractions, respectively. The median overall treatment time was 41 days. The actuarial 4-year central recurrence-free rate, pelvic control, and disease-free survival rate were 97%, 93%, and 88% for stages IB-IIA and 79%, 75%, and 75% for stage IIB. The actuarial 4-year late complication rate for grades 2-3 was 4.7% (scale 0-3). We conclude that preliminary results of this HDR brachytherapy schedule for early-stage disease at a median follow-up of 52 months are as effective as the previously used low dose rate (LDR) at 0.44 Gy/h at point A. They are also as effective as medium-dose-rate schedules (MDR) at 1.6-1.5 Gy/h at this institution and do not require a further increase in fractionation of intracavitary treatments or in the whole-pelvic external beam irradiation dose common to standard HDR schedules. In addition, more patients per machine can be treated per day compared with MDR. Longer follow-up is required for a complete assessment of late complications.
    International Journal of Gynecological Cancer 01/2001; 11(6):445-53. · 1.94 Impact Factor
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    ABSTRACT: A retrospective study on local tumor control, survival, and complications of conventional irradiation vs. accelerated hyperfractionated irradiation in patients with selected head and neck cancer sites was undertaken. A total of 1,007 consecutive patients treated with radiation alone for cure from 1974-1997 were analyzed. Excluded were female patients, patients with T1 stage of the vocal cord, and patients also treated with brachytherapy implants. There were 637 patients treated with conventional fractionation once daily (QD) in 1974-1997, at a median 2.1 Gy/fraction, to a total median dose of 71.4 Gy in a median overall time of 54 days. As was common before the mid-1980s, 39% and 22% of patients had overall times exceeding 8 and 9 weeks, respectively; 370 patients were treated with accelerated hyperfractionation twice daily (BID) from 1987-1997, at a median of 1.6 Gy/fraction, with an interfraction interval of 4-6 h, to a total median dose of 68 Gy in 40 days. Both schedules were well-balanced with respect to their pretreatment characteristics. Patients were not randomized into QD or BID. The 10-year actuarial probability of local control was 37% vs. 56% for QD and BID, respectively (P < 0.001), which reflects an increase of 19% or a 51% reduction in the local failure rate. Multivariate analysis revealed that T-stage, QD or BID schedule, and overall treatment time were significant independent factors for achieving local tumor control. The 10-year actuarial probability of cause-specific disease-free survival was 25% and 30% for QD and BID, respectively (P = 0.012). Acute morbidity was slightly higher with the BID schedule: patients requiring tube or parenteral feeding were 2.4% for BID and 0.5% for QD (P = 0.01). The 10-year actuarial probability of RTOG/EORTC Grades 3-5 late effects was 13% for both QD and BID. The lack of increase in late complications was most probably due to the lower total dose and dose per fraction in the BID schedule. This study has shown that accelerated hyperfractionated irradiation using two doses of 1.6 Gy each treatment day for less than 6 weeks in advanced head and neck cancer in male patients provides significantly better local tumor control and cause-specific disease-free survival, without increased late morbidity, than conventional fractionation delivered at the previously relaxed overall times of 7 weeks, but sometimes exceeding 8 or 9 weeks. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 80-91, 2000.
    International Journal of Cancer 05/2000; 90(2):80-91. · 6.20 Impact Factor
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    International Journal of Radiation Oncology Biology Physics - INT J RADIAT ONCOL BIOL PHYS. 01/2000; 48(3):264-264.
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    ABSTRACT: To compare results and complications of our previous low-dose-rate (LDR) brachytherapy schedule for early-stage cancer of the cervix, with a prospectively designed medium-dose-rate (MDR) schedule, based on the linear-quadratic model (LQ). A combination of brachytherapy, external beam pelvic and parametrial irradiation was used in 102 consecutive Stage Ib-IIb LDR treated patients (1986-1990) and 42 equally staged MDR treated patients (1994-1996). The planned MDR schedule consisted of three insertions on three treatment days with six 8-Gy brachytherapy fractions to Point A, two on each treatment day with an interfraction interval of 6 hours, plus 18 Gy external whole pelvic dose, and followed by additional parametrial irradiation. The calculated biologically effective dose (BED) for tumor was 90 Gy10 and for rectum below 125 Gy3. In practice the MDR brachytherapy schedule achieved a tumor BED of 86 Gy10 and a rectal BED of 101 Gy3. The latter was better than originally planned due to a reduction from 85% to 77% in the percentage of the mean dose to the rectum in relation to Point A. The mean overall treatment time was 10 days shorter for MDR in comparison with LDR. The 3-year actuarial central control for LDR and MDR was 97% and 98% (p = NS), respectively. The Grades 2 and 3 late complications (scale 0 to 3) were 1% and 2.4%, respectively for LDR (3-year) and MDR (2-year). LQ is a reliable tool for designing new schedules with altered fractionation and dose rates. The MDR schedule has proven to be an equivalent treatment schedule compared with LDR, with an additional advantage of having a shorter overall treatment time. The mean rectal BED Gy3 was lower than expected.
    International Journal of Radiation OncologyBiologyPhysics 04/1999; 43(5):1061-4. · 4.52 Impact Factor
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    ABSTRACT: Patients with head and neck cancer were randomized in a double-blind manner to receive 40 mg/day prednisone (n = 32) or placebo (n = 34). The prescribed daily tumour dose was 1.6 Gy twice daily with an interfraction interval of > or =6 h. Treatment interruptions were at the discretion of the radiation oncologists. The primary study end-point was the total duration of treatment. A mean 4.4 day reduction was observed in the total elapsed treatment duration for the prednisone arm, 34.3 versus 29.9 days (P = 0.013), which paralleled a significantly lower median total tumour and biologically effective dose (BED) Gy10 in this arm. A trend favouring shorter treatment interruptions in the prednisone arm was also found, but not a reduction in the intensity or duration of mucositis.
    Radiotherapy and Oncology 05/1998; 47(2):145-8. · 4.52 Impact Factor
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    ABSTRACT: The amount of dose reduction on changing from low dose rate (LDR) brachytherapy to medium dose rate (MDR) or high dose rate (HDR) afterloading has been the subject of much debate. The magnitude of reduction depends, together with other possible factors, on two radiobiological parameters: the alpha/beta ratio and the half-time of repair of the relevant tissues. In an attempt to extract these radiobiological parameters for the late rectal complications observed in our previously published clinical results four different schedules using MDR and one using LDR are analyzed. The percentage incidence of complications was a function of increasing biologically effective dose (BED), but would yield nonsense scattergrams if plotted against raw total dose. In addition, for three other published MDR series, three LDR series, and two HDR series, the incidence of rectal complications is plotted against BED to examine the predictive potential of using BED as the surrogate of total dose. Our own results were published in 1996, consisting of 102 patients treated at the LDR of 0.44 Gy/hr and 88 patients treated by four different schedules using an MDR of 1.6-1.7 Gy/hr. Follow-up is at least 3 years in all schedules. The linear quadratic formula including the "g" dose rate factor was used to analyze them, assuming exponential repair of the repairable beta term. First, multivariate and profile likelihood analyses were carried out to obtain estimates of alpha/beta and T1/2 for rectal late responding tissues. Then graphs of incidence of rectal complications vs. BED were constructed, assuming alpha/beta = 3 Gy and T1/2 = 1.5 hr, values which had not been contradicted by the multivariate analysis. Graphs were drawn both for "all grades including mild reactions" (grades 1 + 2 + 3) and for "serious" complications (grade 3 in our system). In addition, other published cervical brachytherapy series were reviewed, with calculation of their BEDs if not published by the authors. It was necessary to review and compare their grading systems, so that "mild and moderate" (grades 1 and 2) could be contrasted with "serious" (grades 3 and 4 or 5 in various systems). Comparisons were made with other published results, including three LDR, three MDR, and two HDR series spanning from 1982 to 1997. The BEDs at which the incidence of rectal complications rose above the arbitrary level of 10% were compared for all three ranges of dose rate. The multivariate analysis gave estimates of alpha/beta and T1/2 which were not significantly different from 3 Gy and 1.5 hr, respectively, so these values were used to compute the BEDs for the subsequent comparisons. It was found that the graphs of incidence of rectal complications for "all grades including mild" agreed rather better between all series than might have been expected, within a provisional (10%) threshold BED of range 100-123 Gy3 (60-74 Gy given as 2 Gy fractionated external beam or as LDR). The dose-response curves diverged above these values, as expected until common grading systems such as SOMA/ LENT become more widely used. For "serious" complications the 10% incidence occurred at a median BED of 140 Gy3 (84 Gy given as 2 Gy fractionated external beam or as LDR), range 124-155 Gy3. The use of BED (or extrapolated response dose), assuming alpha/beta = 3 Gy and T1/2 = 1.5 hr, instead of total dose, enabled incidence of late rectal complications in cervical brachytherapy with LDR, MDR, and HDR to be plotted in a reasonably consistent way. This does not mean that those parameter values have been definitively determined, but they appear to be provisional values that may be of use in comparing the expected effects of new schedules until better values are obtained from greater use of common grading systems.
    Radiation Oncology Investigations 02/1997; 5(6):289-99.
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    ABSTRACT: This study assessed the effectiveness and toxicity of induction chemotherapy (CT) and radiation therapy (RT) in the treatment of locally advanced carcinoma of the cervix with data provided by a pilot study and a randomized trial. Eighty-six patients with International Federation of Gynecology and Obstetrics (FIGO) Stage IB-IVA (Stage IB >4-cm tumor diameter) (Group A) were entered in a pilot study and treated with cisplatin (50 mg/m2), vincristine (1 mg/m2 on days 1, 11, and 21), bleomycin (25 mg/m2 infusion on days 1-3, 11-13, and 21-23), and standard RT. Ninety-six patients were randomized to either this same CT regimen and RT, or RT alone (Group B: CT plus RT or RT). In Group A, 58% responded to induction CT. With a mean follow-up of 78 months, 73% achieved pelvic control (LRC), and 55% were disease-free survivors. Response to CT was not a marker for ultimate LRC or increased disease-free survival (DFS). In Group B, 62% responded to CT. With a mean follow-up of 43 months, LRC was 68% and 65% for all randomized patients in the CT plus RT and RT arms, respectively (p = NS). In patients who completed treatment, 78% and 70%, respectively, achieved LRC (p = NS). Disease-free survival rates were 38% and 49% for randomized patients in the CT plus RT and RT arms (p = NS), respectively, and 44% and 52% in those patients completing treatment (p = NS), respectively. Complications were acceptable. Data from this study did not prove the efficacy of induction CT before definitive RT in locally advanced cancer of the cervix. Induction CT with the currently used combinations and modes of administration should not be considered standard therapy.
    International Journal of Radiation OncologyBiologyPhysics 02/1997; 37(2):343-50. · 4.52 Impact Factor