ADT Use and Nodal Irradiation in Men Receiving Post-Prostatectomy Salvage Radiotherapy within a Statewide Radiation Oncology Quality Consortium

PURPOSE/OBJECTIVE(S)

For men with biochemical recurrence after radical prostatectomy, salvage radiotherapy (SRT) is a standard of care. Outcomes are improved when SRT is delivered at lower PSA levels, and there has been increased emphasis on more timely treatment. With early SRT, however, there remains uncertainty as to the optimal use and duration of androgen deprivation therapy (ADT) and pelvic lymph node radiation (PLNRT). Moreover, PET imaging and genomic classifiers have emerged as tools to guide treatment decisions, but their uptake in routine practice is unknown. To address these questions, we analyzed a contemporary cohort treated with SRT within the Michigan Radiation Oncology Quality Consortium (MROQC). We hypothesized that ADT and PLNRT practices would reflect recent trial results in this setting.

MATERIALS/METHODS

Eligible patients receiving SRT at an MROQC center were enrolled from 06/09/20 to 11/04/22. Data was prospectively collected via patient-, physician-, and physicist-completed forms. Patients were matched to the Michigan Urological Surgery Improvement Collaborative (MUSIC) database for additional treatment- and patient-related data. Univariable (UVA) and multivariable analyses (MVA) were performed to test associations between patient/tumor factors and ADT or PLNRT use.

RESULTS

A total of 191 patients across 26 centers were enrolled in the MROQC database. Of these, 116 were matched to the MUSIC database. Median time from RP to SRT was 17 months (IQR 8 - 33 months). The median post-RP PSA prior to SRT was 0.25 (IQR 0.16 - 0.60). Early SRT was defined as pre-SRT PSA ≤0.5, and 27% (n = 31/116) had a pre-SRT PSA >0.5. Twenty-eight were pT3b/T4, 97% were pN0/NX, and 51% had positive surgical margins. Fractionation was conventional (>28 fractions) in 58% and moderate hypofractionation (20-28 fractions) in 38%. Table 1 describes the patients receiving ADT and/or PLNRT. Median ADT duration was 6 mo (IQR 6 - 7 mo). MVA revealed pre-SRT PSA >0.5 (OR 5.05 [1.89 - 15.33]) and pT3b/T4 disease (OR 4.23 [1.40 - 14.56]) were significantly associated with ADT use (p <0.05), but not grade group (GG) or margin status. PLNRT was significantly associated with pre-SRT PSA >0.5 (OR 3.04 [1.21 - 8.42], p <0.05) but not pT stage, margin status, or GG. PET imaging was performed in 37% of men (52% negative, 21% prostate bed alone uptake, and 26% lymph node positivity) and genomic classifiers were performed in 24%.

CONCLUSION

Nearly 75% of biochemically recurrent prostate cancer patients within MROQC received early SRT, and about half received ADT. A pre-SRT PSA >0.5 was strongly associated with ADT and PLNRT. With prostate bed SRT alone, very few received ADT. Given the considerable heterogeneity in treatment, additional studies may help identify patients who most benefit from ADT + PLNRT, and who may be spared potential added toxicity.

Androgen Deprivation Therapy Use among Intermediate Risk Prostate Cancer Patients Undergoing Radiation Therapy across a Statewide Radiation Oncology Quality Consortium

PURPOSE/OBJECTIVE(S)

For men with intermediate (INT) risk prostate cancer, the addition of androgen deprivation therapy (ADT) reduces risk of PSA failure, distant metastasis, and cancer-related mortality. Moreover, the relative reduction in cancer-related adverse outcomes with ADT use appears consistent across all INT risk subgroups. The absolute benefit of ADT, however, varies by baseline risk. In contemporary practice, it is unknown which clinical factors are most strongly associated with intended ADT use. Therefore, we sought to identify such factors within the diverse practices of the Michigan Radiation Oncology Quality Consortium (MROQC).

MATERIALS/METHODS

Patients with localized prostate cancer undergoing definitive radiation therapy were enrolled from 6/9/20 to 11/4/22 (n = 599). Standardized patient, physician, and physicist forms were used to collect baseline and follow-up information. Intended ADT use, defined by the treating physician, was prospectively collected and is the primary outcome of this analysis. Univariable (UVA) and multivariable analyses (MVA) associations with patient (age, race, comorbidities), tumor (T stage, Gleason, percent cores positive, and PSA), and practice-related (academic vs private) factors were performed. In addition, advanced modality testing (PET, MRI, and genomic classifiers) was available as of March 2021, and subgroup analysis were performed where appropriate.

RESULTS

A total 351 patients across 26 centers were enrolled with INT risk disease. ADT use was intended for 46% of men (n = 162/351) which differed by men with NCCN favorable INT (21%, n = 22/105) vs unfavorable INT risk disease (57%, n = 140/246), p<0.001. Sixty two percent (n = 100/162) had an intended ADT duration of 4-6 months and 21% (n = 34/162) had ≥12 months. Older age was associated with ADT use (70 vs 67, p < 0.01); there were no significant differences by race or comorbidities number. MVA showed Gleason 4+3 (OR 4.61 [2.91 - 7.42]) and > = 50% positive cores (2.56 [1.52 - 4.37]) were significantly associated with ADT use. No significant differences were noted based on practice setting. Pelvic MRI was obtained for 71% of men (n = 197/279), genomic classifiers in 47% (n = 130/279), and PET in 2% (n = 6/282). In the subset with MRI (n = 197), adverse features (ECE, SVI, or equivocal LNs) were associated with intended ADT use (OR 3.0 [1.4 - 7.1]) after adjustment for NCCN favorable/unfavorable INT risk classification.

CONCLUSION

Within a state-wide consortium, intended ADT use for intermediate prostate cancer is most strongly associated with Gleason score, ≥50% positive cores, NCCN unfavorable intermediate risk classification, and adverse features on MRI. Nearly half of men had genomic classifier testing underscoring the importance ongoing trials such as NRG/GU 010.

Prostate magnetic resonance imaging for brachytherapists: Diagnosis, imaging pitfalls, and post-therapy assessment

Optimal integration of multiparametric MRI (mp MRI) into prostate brachytherapy practice necessitates an understanding of imaging findings pertinent to prostate cancer detection and staging. This review will summarize prostate cancer imaging findings and tumor staging on mp MRI, including an overview of the Prostate Imaging Reporting and Data System (PIRADS)-structured reporting schema, mp MRI findings observed in the post-therapy setting including cases of post-treatment recurrence, and MRI concepts integral to successful salvage brachytherapy.

A randomized trial of a single-dose rasburicase versus five-daily doses in patients at risk for tumor lysis syndrome

BACKGROUND

Tumor lysis syndrome (TLS) is a life-threatening disorder characterized by hyperuricemia and metabolic derangements. The efficacy of rasburicase, administered daily for 5 days, has been well established. However, the optimal duration of therapy is unknown in adults.

PATIENTS AND METHODS

We evaluated the efficacy of rasburicase (0.15 mg/kg) administered as single dose followed by as needed dosing (maximum five doses) versus daily dosing for 5 days in adult patients at risk for TLS.

RESULTS

Eighty of the 82 patients enrolled received rasburicase; 40 high risk [median uric acid (UA) 8.5 mg/dl; range, 1.5-19.7] and 40 potential risk (UA = 5.6 mg/dl; range, 2.4-7.4). Seventy-nine patients (99%) experienced normalization in their UA within 4 h after the first dose; 84% to an undetectable level (<0.7 mg/dl). Thirty-nine of 40 (98%) patients in the daily-dose arm and 34 of 40 (85%) patients in single-dose arm showed sustained UA response. Six high-risk patients within the single-dose arm required second dose for UA >7.5 mg/dl. Rasburicase was well tolerated; one patient with glucose-6-phosphate dehydrogenase deficiency developed methemoglobinemia and hemolysis.

CONCLUSIONS

Rasburicase is highly effective for prevention and management of hyperuricemia in adults at risk for TLS. Single-dose rasburicase was effective in most patients; only a subset of high-risk patients required a second dose.

Defining High Risk Prostate Cancer With Risk Groups and Nomograms: Implications for Designing Clinical Trials

PURPOSE

Death from prostate cancer is usually preceded by metastases and it usually occurs in men with high risk disease who experienced biochemical failure with a short prostate specific antigen doubling time. We developed a model for determining disease specific survival in prostate cancer.

MATERIALS AND METHODS

We used the model for defining high risk prostate cancer that was developed by the Radiation Therapy Oncology Group and combined it with the Kattan nomogram for predicting the risk of metastases. We selected 414 Radiation Therapy Oncology Group intermediate and high risk patients who were treated with external beam radiotherapy alone. Excluded were patients with low risk disease. The Kaplan-Meier product limit method was used to estimate the probability of freedom from biochemical failure, overall survival and disease specific survival.

RESULTS

A significant difference was observed in freedom from biochemical failure, disease specific survival and overall survival among the 3 tertiles created by the nomogram using the cutoff points less than 8.5%, 8.5% to 15% and greater than 15% (p <0.001, 0.0002 and 0.0003, respectively). Only the risk of metastases using the categorized nomogram score (less than 8.5% and 8.5% to 15% vs greater than 15%), not preradiotherapy prostate specific antigen or Radiation Therapy Oncology Group risk (Radiation Therapy Oncology Group 2 vs 3), was a significant predictor of disease specific and overall survival for intermediate/high risk patients and intermediate/high risk with 15% or less risk for metastases.

CONCLUSIONS

We combined a risk group stratification scheme for disease specific survival with a nomogram predicting the risk of metastases and created a model that may be useful for designing phase III trials with metastases and disease specific survival as study end points.

What does postradiotherapy PSA nadir tell us about freedom from PSA failure and progression-free survival in patients with low and intermediate-risk localized prostate cancer?

OBJECTIVES

To determine whether the post-external beam radiotherapy (RT) prostate-specific antigen nadir (nPSA) improves our ability to predict freedom from PSA failure, progression-free survival (PFS), and overall survival. Controversy regarding the importance of nPSA after external beam RT as a prognostic indicator for patients with localized prostate cancer has continued.

METHODS

This analysis was based on the data from 748 patients with low and intermediate-risk localized prostate cancer treated with external beam RT alone. Patients were categorized by nPSA quartile groups with cutpoints of less than 0.3, 0.3 to less than 0.6, 0.6 to less than 1.2, and 1.2 ng/mL or greater. Both univariate and multivariate analyses were used to determine the significance of nPSA on PSA failure (American Society for Therapeutic Radiology Oncology consensus definition), PFS (death after PSA failure), and overall survival (death from any cause).

RESULTS

Freedom from PSA failure was strongly associated with nadir quartile groups (P <0.0001). PFS was also significantly different statistically among nadir quartile groups (P = 0.02). No statistically significant difference was found in overall survival associated with nPSA at this point.

CONCLUSIONS

nPSA is a strong independent predictor of freedom from PSA failure and PFS in patients with low and intermediate-risk localized prostate cancer treated with RT alone. Longer follow-up and larger patient numbers are required to confirm these observations.

Comparison of MRI pulse sequences in defining prostate volume after permanent implantation

PURPOSE

To determine the relative value of three MRI pulse sequences in defining the prostate volume after permanent implantation.

METHODS AND MATERIALS

A total of 45 patients who received a permanent 125I implant were studied. Two weeks after implantation, an axial CT scan (2 mm thickness) and T1-weighted, T1-weighted fat saturation, and T2-weighted axial MRI (3-mm) studies were obtained. The prostate volumes were compared with the initial ultrasound planning volumes, and subsequently the CT, T1-weighted, and T1-weighted fat saturation MRI volumes were compared with the T2-weighted volumes. Discrepancies in volume were evaluated by visual inspection of the registered axial images and the registration of axial volumes on the sagittal T2-weighted volumes. In a limited set of patients, pre- and postimplant CT and T2-weighted MRI studies were available for comparison to determine whether prostate volume changes after implant were dependent on the imaging modality.

RESULTS

T1-weighted and T1-weighted fat saturation MRI and CT prostate volumes were consistently larger than the T2-weighted MRI prostate volumes, with a volume on average 1.33 (SD 0.24) times the T2-weighted volume. This discrepancy was due to the superiority of T2-weighted MRI for prostate definition at the following critical interfaces: membranous urethra, apex, and anterior base-bladder and posterior base-seminal vesicle interfaces. The differences in prostate definition in the anterior base region suggest that the commonly reported underdose may be due to overestimation of the prostate in this region by CT. The consistent difference in volumes suggests that the degree of swelling observed after implantation is in part a function of the imaging modality. In patients with pre- and postimplant CT and T2-weighted MRI images, swelling on the T2-weighted images was 1.1 times baseline and on CT was 1.3 times baseline, confirming the imaging modality dependence of prostate swelling.

CONCLUSION

Postimplant T2-weighted MRI images provided superior prostate definition in all critical regions of the prostate compared with CT and the other MRI sequences tested. In addition to defining an optimal technique, these findings call two prior observations into question. Under dosing at the anterior base region may be overestimated because of poor definition of the prostate-bladder muscle interface. The swelling observed after implantation was lower on T2-weighted images as well, suggesting that a fraction of postimplant swelling is a function of the imaging modality. These findings have implications for preimplant planning and postimplant evaluation. As implant planning techniques become more conformal, and registration methods become more efficient, T2-weighted MRI after implantation will improve the accuracy of postimplant dosimetry.

Influence of 3D-CRT pelvic irradiation on outcome in prostate cancer treated with external beam radiotherapy

PURPOSE

The role of pelvic irradiation (PRT) in the treatment of prostate cancer remains unclear. We reviewed our institution's experience with three-dimensional conformal external beam radiotherapy (3D-CRT) during the prostate-specific antigen era to determine the influence of PRT on the risk of biochemical recurrence in patients who have a predicted risk of lymph node involvement.

METHODS AND MATERIALS

Between March 1985 and January 2001, 1832 patients with clinically localized prostate cancer were treated with definitive 3D-CRT. All treatments involved CT planning to ensure coverage of the intended targets. Treatment consisted of prostate-only treatment, prostate and seminal vesicle treatment, or PRT of lymph nodes at risk followed by a boost. To create relatively homogenous analysis groups, each patient's percentage of risk of lymph node (%rLN) involvement was assigned by matching the patient's T stage, Gleason score, and initial prostate-specific antigen level to the appropriate value as described in the updated Partin tables. Three categories of %rLN involvement were defined: low, 0-5%; intermediate, >5-15%; and high, >15%. Biochemical recurrence was defined as the first occurrence of either the American Society for Therapeutic Radiology and Oncology consensus definition of prostate-specific antigen failure or the initiation of salvage hormonal therapy for any reason.

RESULTS

The risk status (%rLN) could be determined for 709 low-risk, 263 intermediate-risk, and 309 high-risk patients. The actuarial freedom from biochemical recurrence (bNED) and the log-rank test for the similarity of the control and treatment survival functions are reported for each risk group. Multivariate analysis demonstrated a statistically significant benefit for the entire population treated with PRT, with a relative risk reduction of 0.72 (95% confidence interval 0.54-0.97). Although the multivariate analysis could not determine the patient population that would most benefit from PRT, the beneficial effect appeared to be most pronounced within the intermediate-risk group. Univariate analysis revealed that the intermediate-risk patients treated with PRT had an improved 2-year bNED rate, 90.1% vs. 80.6% (p = 0.02), and both low-risk and high-risk patients treated with PRT had statistically similar 2-year bNED rates compared with those who did not receive it.

CONCLUSION

Pelvic 3D-CRT appears to improve bNED in prostate cancer patients. Additional studies are needed to elucidate the %rLN population for which this treatment should be recommended.

Overall survival after prostate-specific-antigen-detected recurrence following conformal radiation therapy

PURPOSE

To study the significance, in terms of overall and cause-specific survival, of biochemical failure after conformal external-beam radiation therapy (RT) for prostate cancer.

METHODS AND MATERIALS

Of the 1844 patients in the Radiation Oncology prostate cancer database, 718 were deemed eligible. Patients excluded were those with N1 or M1 disease, those treated after radical prostatectomy, those who received hormone therapy before radiation therapy, and those who died, failed clinically, or had no PSA response in the first 6 months after RT. Patients included were required to have a minimum of 2 post-RT PSAs separated by at least 1 week. Biochemical relapse was defined as 3 consecutive PSA rises. This resulted in 154 patients with biochemical failure. Survival was calculated from the third PSA elevation. The rate of rise of PSA was calculated by fitting a regression line to the four rising PSAs on a ln PSA vs. time plot.

RESULTS

There were 41 deaths among the 154 patients with failure in 23 of the 41 due to prostate cancer. The overall survival after failure was 58% at 5 years, while the cause-specific failure was 73% at 5 years. Among the 154 failures, several factors were evaluated for an association with overall survival: age at failure, pre-RT PSA, PSA at second rise, PSA nadir, time from RT to failure, time to nadir, Gleason score, T-stage, and rate of rise, both from the nadir and from the beginning of the rise. None of these factors were significantly associated with an increased risk of death. As expected, the group of patients with biochemical failure have significantly worse prognostic factors than those without biochemical failure: median pre-RT PSA 15.9 vs. 9.0 (p < 0.001), and Gleason score of 7 or greater for 48% of subjects vs. 40% (p = 0.1). Relative PSA rise and slope of ln PSA vs. time were associated with cause-specific mortality (p < 0.001 and p = 0.007, respectively).

CONCLUSION

Overall survival after conformal radiotherapy for prostate cancer remains high 5 years after biochemical failure. This high survival rate occurs even though the group of patients with biochemical failure has worse than average adverse preradiation prognostic factors. Thus, although biochemical failure can identify patients who have recurrent disease after RT, the ultimate relationship between this endpoint and death remains to be better defined.

Prostate position late in the course of external beam therapy: patterns and predictors

PURPOSE

To examine prostate and seminal vesicles position late in the course of radiation therapy and to determine the effect and predictive value of the bladder and rectum on prostate and seminal vesicles positioning.

METHODS AND MATERIALS

Twenty-four patients with localized prostate cancer underwent a computerized tomography scan (CT1) before the start of radiation therapy. After 4-5 weeks of radiation therapy, a second CT scan (CT2) was obtained. All patients were scanned in the supine treatment position with instructions to maintain a full bladder. The prostate, seminal vesicles, bladder, and rectum were contoured. CT2 was aligned via fixed bony anatomy to CT1. The geometrical center and volume of each structure were obtained and directly compared.

RESULTS

The prostate shifted along a diagonal axis extending from an anterior-superior position to a posterior-inferior position. The dominant shift was to a more posterior-inferior position. On average, bladder and rectal volumes decreased to 51% (+/-29%) and 82% (+/-45%) of their pretreatment values, respectively. Multiple regression analysis (MRA) revealed that bladder movement and volume change and upper rectum movement were independently associated with prostate motion (p = 0.016, p = 0. 003, and p = 0.052 respectively).

CONCLUSION

Patients are often instructed to maintain a full bladder during a course of external beam radiation therapy, in the hopes of decreasing bladder and small bowel toxicity. However, our study shows that large bladder volumes late in therapy are strongly associated with posterior prostate displacement. This prostate displacement may result in marginal miss.

3D conformal radiation therapy (3DCRT) for high grade prostate cancer: a multi-institutional review

PURPOSE

To evaluate the results of 3DCRT and the effect of higher than traditional doses in patients with high grade prostate cancer, we compiled data from three institutions and analyzed the outcome of this relatively uncommon subset of prostate cancer patients.

METHODS AND MATERIALS

The 180 patients with Gleason score 8- 10 adenocarcinoma of the prostrate were treated with 3DCRT at the Univer sity of Michigan Health System, University of California-San Francisco, or Fox Chase Cancer. Eligible patients had T1-T4 NO or NX MO adenocarci noma with a pretreatment PSA. Pretreatment characteristics included: me dian age 72 years, 60.6% Gleason score 8 tumors, 57.6% T1-T2, and median pretreatment PSA 17.1 ng/ml (range 0.3-257.1). The total dose received was <70 Gy in 30%, 70-75 Gy in 37%, and >75 Gy in 33%, 27% received adju vant or neoadjuvant hormonal therapy. The median follow-up was 3.0 years for all patients and 16% of patients were followed up for at least 5 years.

RESULTS

The 5-year freedom from PSA failure was 62.5% for all patients and 79.3% in T1-T2 patients. Univariate analysis revealed that T-stage (T1-T2 vs. T3-T4), pretreatment PSA, and RT dose predicted for freedom from PSA failure. A 5-year overall survival for all patients was 67.3%. Only RT dose was predictive of 5-year overall survival on univariate analysis. Because a significant association was seen between T-stage and RT dose, the Cox proportional hazards model was performed separately for T1-T2 and T3-T4 tumors. None of the prognostic factors reached statistical significance for overall survival or freedom from PSA failure in T3-T4 patients or for overall survival in T1-T2 patients. Lower RT dose and higher pretreatment PSA predicted for PSA failure on multivariate analysis in T1-T2 patients.

CONCLUSION

This retrospective study from three institutions with experience in dose escalation suggests a dose effect for PSA control above 70 Gy in patients with T1-T2 high grade prostate cancer. These results are superior to surgery and emphasize the need for dose escalation in treating Gleason 8-10 prostate cancer.

Permanent implantation of 125I sources in the prostate: radical limits of simplicity

PURPOSE

To determine the effect of reducing the number of sources per implantation on the dose coverage of the prostate volume.

MATERIALS AND METHODS

Idealized source distributions were planned for four, eight, 16, 24, 32, and 48 sources. The peripheral loading technique was used to plan a uniform, conformal dose distribution to the target volume, which was the prostate volume as visualized at ultrasonography. Source-placement error was estimated by using measured error magnitudes and was expressed with systematic and random components. The relative sensitivities of the plans to the source-placement error were studied.

RESULTS

Idealized planned target coverage can be adequately achieved with comparable dose distributions with eight or more sources. The sensitivity to source-placement error is comparable for plans with 16 or more sources.

CONCLUSION

It is theoretically possible to radically simplify implantation without compromising target coverage or error tolerance.

The effect of patient position and treatment technique in conformal treatment of prostate cancer

PURPOSE

The relative value of prone versus supine positioning and axial versus nonaxial beam arrangements in the treatment of prostate cancer remains controversial. Two critical issues in comparing techniques are: 1) dose to critical normal tissues, and 2) prostate stabilization.

METHODS AND MATERIALS

Ten patients underwent pretreatment CT scans in one supine and two prone positions (flat and angled). To evaluate normal tissue exposure, prostate/seminal vesicle volumes or prostate volumes were expanded 8 mm and covered by the 95% isodose surface by both 6-field axial and 4-field nonaxial techniques. A total of 280 dose-volume histograms (DVHs) were analyzed to evaluate dose to rectal wall and bladder relative to patient position and beam arrangement. A CT scan was repeated in each patient after 5 weeks of treatment. Prostate motion was assessed by comparing early to late scans by three methods: 1) center of mass shift, 2) superior pubic symphysis to anterior prostate distance, and 3) deviation of the posterior surface of the prostate.

RESULTS

For prostate (P) or prostate/seminal vesicle (P/SV) treatments, prone flat was advantageous or equivalent to other positions with regard to rectal sparing. The mechanism of rectal sparing in the prone position may be related to a paradoxical retraction of the rectum against the sacrum, away from the P/SV. Although there was no clear overall preference for beam arrangement, substantial improvements in rectal sparing could be realized for individual patients. In this limited number of patients, there was no convincing evidence prostate position was stabilized by prone relative to supine position.

CONCLUSIONS

Prone flat positioning was advantageous over other positions and beam arrangements in rectal sparing. This study suggests that patient position is a more critical a factor in conformal therapy than beam arrangement, and may improve the safety of dose escalation.

Antibiotic treatment of gastric lymphoma of mucosa-associated lymphoid tissue. An uncontrolled trial

BACKGROUND

Gastric lymphoma of mucosa-associated lymphoid tissue (MALT) is related to Helicobacter pylori infection and may depend on this infection for growth.

OBJECTIVE

To determine the response of gastric MALT lymphoma to antibiotic treatment.

DESIGN

Prospective, uncontrolled treatment trial.

SETTING

University hospital referral center and three collaborating university and community hospitals.

PATIENTS

34 patients with stage I or stage II N1 gastric MALT lymphoma.

INTERVENTION

Two of three oral antibiotic regimens--1) amoxicillin, 750 mg three times daily, and clarithromycin, 500 mg three times daily; 2)tetracycline, 500 mg four times daily, and clarithromycin, 500 mg three times daily; or 3) tetracycline, 500 mg four times daily, and metronidazole, 500 mg three times daily--were administered sequentially (usually in the order written) for 21 days at baseline and at 8 weeks, along with a proton-pump inhibitor (lansoprazole or omeprazole) and bismuth subsalicylate.

MEASUREMENTS

Complete remission was defined as the absence of histopathologic evidence of lymphoma on endoscopic biopsy. Partial remission was defined as a reduction in endoscopic tumor stage or 50% reduction in the size of large tumors.

RESULTS

34 patients were followed for a mean (+/-SD) of 41 +/- 16 months (range, 18 to 70 months) after antibiotic treatment. Of 28 H. pylori-positive patients, 14 (50% [95% CI, 31% to 69%]) achieved complete remission, 8 (29%) achieved partial remission (treatment eventually failed in 4 of the 8), and 10 (36% [CI, 19% to 56%]) did not respond to treatment. Treatment failed in all 6 (100% [CI, 54% to 100%]) H. pylori-negative patients. Patients with endoscopic appearance of gastritis (stage I T1 disease) were most likely to achieve complete remission within 18 months. Tumors in the distal stomach were associated with more favorable response than tumors in the proximal stomach.

CONCLUSIONS

A subset of H. pylori-positive gastric MALT lymphomas, including infiltrative tumors, may respond to antibiotics. The likelihood of early complete remission seems to be greatest for superficial and distal tumors.

Hodgkin's disease with lymphocyte predominance: long-term results based on current histopathologic criteria

PURPOSE

To define the disease course, therapeutic strategies, patterns and rates of relapse and causes of death for patients with Hodgkin's disease with lymphocyte predominance (LPHD) and to assess prognostic factors including nodular and diffuse histologic patterns.

PATIENTS AND METHODS

The records of all previously untreated patients with LPHD who received initial treatment at the University of Texas M. D. Anderson Cancer Center (UTMDACC) from 1960 through 1992 were reviewed. Clinical and histopathologic characteristics, specifically nodular and diffuse LPHD, and treatment groups were assessed by overall and relapse-free survival, patterns of relapse, and causes of death.

RESULTS

Of 70 patients, 58 (83%) had nodular LPHD and 12 (17%) had a diffuse pattern: clinical characteristics were similar between the two subtypes. The median age of all patients was 25 years, 79% were male, 96% presented with stage I or II disease and 93% were free of B symptoms. Laparotomy (23 patients) failed to upstage any patient with a negative lymphogram. With a median follow-up of 12.3 years for alive patients, 19 (27%) patients have relapsed. All 3 relapses among the patients with diffuse subtype occurred within 3 years while 9 of 16 relapses occurred after 5 years with nodular subtype. However, we did not detect any statistically significant difference in relapse free survival or survival between the subtypes in our patient population. There was some suggestion that patients aged 40 and older experienced shorter survival; no other pretreatment characteristics were noted to be associated with relapse free survival or survival. Though there were no relapses within the radiation fields, no effect of extent of radiation therapy on relapse rate was observed. Thirteen (19%) patients have died, 6 (8.6%) of whom succumbed to LPHD. Two patients developed diffuse large cell lymphoma.

CONCLUSIONS

Patients with LPHD usually present with localized and asymptomatic disease. Laparotomy is unnecessary if the lymphogram is negative. Nodular histology occurred in the majority of patients. Though all relapses from diffuse subtype occurred within 3 years in contrast to some late relapses observed for nodular subtype, there was no statistically significant difference in relapse free survival or survival between the subtypes. The extent of irradiation had no effect on relapse free survival or survival. We could not find any evidence that LPHD should be treated any different from the classical Hodgkin's disease at this point despite suggestions that it be classified as a non-Hodgkin's B-cell lymphoma.

Bromodeoxyuridine improves the cytotoxic effect of cisplatin: a comparison with 5-fluorouracil

We compared the effects of the radiosensitizers, 5-bromo-2'-deoxyuridine (BUdR) and 5-fluorouracil (5-FU) alone and in combination and cis-diamminedichloroplatinum (cisplatin, DDP) on the growth of B16 amelanotic melanoma (B16a) tumors in mice. In a preliminary study, tumor growth was significantly inhibited in the presence of BUdR and was further reduced with the combination of BudR and DDP. In a second experiment, BUdR was found to be more effective than 5-FU when used in combination with DDP. At the completion of the study, tumor volumes as a percentage of control values in mice treated with a single drug were as follows: 5-FU (50 mg/kg per day for 7 days) 76.5% (P < 0.05), BUdR (100 mg/kg per day for 7 days) 68% (P < 0.05) and DDP (5 mg/kg x 3) 54% (P < 0.01). Combining 5-FU and DDP at these dosages reduced volumes to 38% (P < 0.01), while BUdR + DDP-treated mice had tumor volumes only 28% (P < 0.001) the size of untreated controls. Furthermore, the toxicity, as demonstrated by a decrease in body weight and an increase in mortality, was more severe in mice receiving 5-FU than in those receiving in BUdR. DDP interacts synergistically with either BUdR or 5-FU in its cytotoxic action in vivo. No such relationship could be demonstrated in vitro, suggesting that the pharmacologic activity of these drugs may be responsible for the antitumor activity than direct cytotoxic effects. We propose that BUdR is more effective than 5-FU as a potentiator of DDP in this murine melanoma model.

Impact of ultrasound and computed tomography prostate volume registration on evaluation of permanent prostate implants

PURPOSE

Ultrasound (US)-guided permanent prostate implants typically use US prostate volumes to plan the implant procedure and CT prostate volumes for 3D dosimetric evaluation of the implant. Such a protocol requires that CT and US prostate volumes be registered. We have studied the impact of prostate volume registration on postimplant dosimetry for patients with low-grade prostate cancer treated with combined US and fluoroscopic-guided permanent implants.

METHODS AND MATERIALS

A US image set was obtained with the patient in the lithotomy position to delineate the prostate volume that was subsequently used for treatment planning. Each plan was customized and optimized to ensure complete coverage of the US prostate volume. After implant, a CT scan was obtained for postimplant dosimetry with the patient lying supine. Sources were localized on CT by interactively creating orthogonal images of small cubes, whose dimensions were slightly larger than the source, to assure unique identification of each seed. Ultrasound and CT 3D surfaces were registered using either (a) the rectal surface and base of the prostate, or (b) the Foley balloon and urethra as the alignment reference. A dose distribution was assigned to the US prostate volume based on the CT source distribution, and the dose-volume histogram (DVH) was calculated.

RESULT

Prostate volumes drawn from US images differ from those drawn from CT images with the CT volumes being typically larger than the US volumes. Urethral registration of the prostate volume based on aligning the prostatic urethra generates a dose distribution that best follows the preimplant plan and is geometrically the preferable choice for dosimetry.

CONCLUSION

The dose distribution and the DVH for the US prostate is sensitive to the mode of registration limiting the ability to determine if acceptable dose coverage has been achieved.

Rate of PSA rise predicts metastatic versus local recurrence after definitive radiotherapy

OBJECTIVE

A rising prostate specific antigen (PSA) following treatment for adenocarcinoma of the prostate indicates eventual clinical failure, but the rate of rise can be quite different from patient to patient, as can the pattern of clinical failure. We sought to determine whether the rate of PSA rise could differentiate future local versus metastatic failure.

METHODS AND MATERIALS

Two thousand six hundred sixty-seven PSA values from 400 patients treated with radiotherapy for localized adenocarcinoma of the prostate were analyzed with respect to PSA patterns and clinical outcome. Patients had received no hormonal therapy or prostate surgery and had > 4 PSA values post-treatment. PSA rate of rise, determined by the slope of the natural log, was classified as gradual [< 0.69 log(ng/ml)/year, or doubling time (DT) > 1 year], moderate [0.69-1.4 log(ng/ml)/year, or DT 6 months-1 year], or rapid [> 1.4 log(ng/ml)/year, or DT < 6 months].

RESULTS

Sixty-one percent of patients had non-rising PSA following treatment; 25% of patients with rising PSA developed clinical failure, and 93% of patients with clinical failure had rising PSA. The rate of rise discerned different clinical failure patterns. Local failure occurred in 23% of patients with moderate rate of rise versus 7% with gradual rise (p = 0.0001). Metastatic disease developed in 46% of those with rapid rise versus 8% with moderate rise (p < 0.0001). By multivariate analysis, in addition to rate of rise, PSA nadir and rate of decline predicted local failure; those with post-treatment nadir of 1-4 ng/ml were five times more likely to experience local failure than nadir < 1 ng/ml (p = 0.0002). Rapid rate of rise was the most significant independent predictor of metastatic failure.

CONCLUSIONS

The rate of PSA rise following definitive radiotherapy can predict clinical failure patterns, with a rapidly rising PSA indicating metastatic recurrence and moderately rising PSA local recurrence. This information could potentially direct therapy; if the rise predicts metastatic failure hormonal therapy could be considered, while aggressive salvage therapy may benefit subclinical local recurrence identified by a moderate rate of PSA rise.

Results of 3D conformal radiotherapy in the treatment of localized prostate cancer

PURPOSE

3D conformal radiotherapy (3D CRT) has been shown to decrease acute morbidity in the treatment of prostate cancer. Therapeutic outcome and late morbidity data have been accumulating. To evaluate the results of 3D CRT for the treatment of prostate cancer, we analyzed the outcome of a large series of patients treated with conformal techniques.

MATERIAL AND METHODS

From January 1987 through June 1994, 707 patients with localized prostate cancer were treated with 3D CRT. Patients with pathologically-confirmed pelvic lymph node metastasis, treated with pre-irradiation (preRT) androgen ablation, or treated post-prostatectomy were excluded. All had CT obtained specifically for treatment planning, multiple structures contoured on the axial images, and beam's-eye view conformal beams edited to provide 3D dose coverage. Median follow-up is 36 mos; 70 patients have been followed longer than 5.5 years. Six hundred three had T1-T2 tumors. PreRT prostate specific antigen (PSA) was available for 649 patients: median preRT PSA was 12.9 ng/ml, 209 patients had preRT PSA > 20 ng/ml. The median dose of radiation was 69 Gy; 102 patients received > or = 69 Gy. Biochemical failure was defined as: 1) two consecutive PSA rises over 2.0 ng/ml if nadir PSA < or = 2.0 ng/ml, 2) two consecutive PSA rises over nadir if nadir PSA > 2.0 ng/ml, or 3) initiation of hormonal therapy after RT. Complications were graded using the RTOG system.

RESULTS

PreRT PSA and Gleason score emerged as independent indicators of biochemical control (bNED). Patients with preRT PSA > 10 had a significantly worse bNED at 5 years than patients with preRT PSA < or = 10. Five-year bNED was determined according to preRT PSA: PSA < or = 4, 88%; PSA > 4 < or = 10, 72%; PSA > 10 < or = 20, 43%; and PSA > 20, 30%. Patients with Gleason score > or = 7 also had a significantly worse bNED than patients with Gleason score < 7. Patients were divided into two prognostic groups: a favorable group with PSA < or = 10, Gleason score < 7, and T1-T2 tumors, and an unfavorable group with PSA > 10, Gleason score > or = 7 or T3-T4 tumors and studied for the effect of dose on bNED status. The bNED at 5 years was 75% for the favorable group and 37% for the unfavorable group. In addition, a group that might be considered a surgical subset was reviewed: patients with PSA < or = 10, Gleason score < or = 7, and T1-T2 tumors who were < 70 years old. This subset had an 84% 5-year bNED rate and 98% 5-year overall survival. Complications with the techniques used here are very low: 3% risk at 7 years of Grade 3-4 complications and 1% risk at 7 years of Grade 3 bladder complications (no Grade 4).

CONCLUSION

3D CRT allows for treatment of prostate cancers with a very low risk of complications. Patients with relatively early disease as defined by preRT PSA, Gleason score < 7, and T1-2 tumors and patients who are candidates for radical prostatectomy have excellent 5-year bNED rates. Patients with adverse prognostic factors have a high risk of biochemical recurrence and are candidates for innovative therapy.

Impact of differences in ultrasound and computed tomography volumes on treatment planning of permanent prostate implants

PURPOSE

Both ultrasound (US) and computerized tomography (CT) images have been used in the planning of prostate interstitial therapy. Ultrasound images more clearly define the apex and capsule of the prostate, while CT images define seed positions for postimplant dosimetry. Proper registration of the US volume with the CT volume is critical to the assessment of dosimetry. We therefore compared US and CT prostate volumes to determine if differences were significant.

METHODS AND MATERIALS

Ten consecutive patients entered in an interstitial implant program were studied by pretreatment US. In addition, pretreatment CT scans were obtained and three physicians independently outlined the dimensions of the prostate on these images. The patients subsequently underwent placement of radioactive 125I or 103Pd. Postimplant CT images were obtained the next day and the postimplant prostate volumes were outlined by the same three physicians. Seven of 10 patients underwent late CT scans 9-14 months postimplant for comparison of preimplant and immediate postimplant CT studies.

RESULTS

There were differences between US and CT volumes. Although the physician-to-physician variation was significant, the trends were consistent, with US prostate volume typically smaller (47%) than the preimplant CT volume and markedly smaller (120%) than the postimplant CT volume. Prostate volumes derived from late CT images did not consistently return to preimplant levels.

CONCLUSIONS

Significant differences in volume of the prostate structure were found between US and CT images. The data suggests that: (a) Implants planned on CT tend to overestimate the size of the prostate and may lead to unnecessary implantation of the urogenital diaphragm and penile urethra. (b) Registration of initial US and postimplant CT prostate volumes required for accurate dosimetry is difficult due to the increased volume of prostate secondary to trauma. (c) Further study to determine the optimal time for the postimplant CT is necessary.

Source placement error for permanent implant of the prostate

The performance of ultrasound (US) and fluoroscopic-guided permanent 125I source implant of the prostate using CT identification of the source positions has been evaluated. Marker seeds were implanted during the planning study to assist in the alignment of the US and CT prostate volumes for treatment planning and to guide the placement of needles. The relative positions of the needles and marker seeds were checked by fluoroscopy. A postimplant CT study was used to input the radioactive source positions and to register the sources relative to the preimplant CT and US prostate volumes and the planned source distribution. Source placement errors observed were categorized as: (1) source-to-source spacing differences; (2) needle placement error, both depth and position; and (3) seed splaying, particularly near the prostate periphery. Errors due to source splaying and spacing were in part attributed to prostate motion. Later refinements included fixed-spaced string sources, for which placement errors were smaller than for unattached sources. However, source placement errors due to needle placement error and prostate motion remained unchanged.

Preliminary experience with paclitaxel for the treatment of relapsed and refractory Hodgkin's disease

PURPOSE

To determine the activity of paclitaxel (Taxol; Bristol-Myers Squibb Co., Princeton, NJ) in patients with relapsed and primary treatment-refractory Hodgkin's disease.

PATIENTS AND METHODS

Fifteen patients with relapsed (n = 8) or primary treatment-refractory (n = 7) Hodgkin's disease were treated at two cancer centers. Patients received paclitaxel 200 mg/m2 intravenously over three hours every three weeks. All patients also received premedication with dexamethasone, cimetidine, and diphenhydramine. The median age was 33 years (range 19 to 69 years), and the median number of prior treatment regimens was three. Seven patients had previously received treatment with autologous bone marrow transplantation.

RESULTS

Fourteen patients were evaluable for response after receiving one to six courses (median, two courses) of paclitaxel. Two patients (14%) had partial remissions; both of them had relapsed after achieving a complete remission with high-dose therapy and autologous bone marrow transplantation. One of these patients was given involved field radiation to consolidate the partial remission and remains free of disease two years after paclitaxel therapy. Three patients had stable disease, and nine had progressive disease. Therapy was well tolerated, with a toxicity profile similar to that previously reported for paclitaxel in patients with non-Hodgkin's lymphoma.

CONCLUSION

Paclitaxel, at this dose and schedule, has modest activity in this group of heavily pretreated patients. Studying its activity in patients with more favorable disease characteristics is warranted.

Optimal placement of radioisotopes for permanent prostate implants

PURPOSE

To determine which of four loading techniques most efficiently yields the prescribed dose to the prostate volume while limiting dose to the central urethral volume.

MATERIALS AND METHODS

The four techniques included (a) equal activity and equal spacing with nomogram, (b) differential loading, (c) peripheral loading, and (d) spiked loading of the lobes. They were evaluated with regard to target coverage urethra dose, tolerance to error, and complexity of procedure.

RESULTS

All ideal plans delivered the prescribed dose of 160 Gy to 99% of the prostate volume. With prostate-volume expansion and source-placement errors, all strategies indicated that at least 71% of the target volume received the prescribed dose and greater than 92% of the target volume received 120 Gy.

CONCLUSION

With source-placement errors and glandular swelling, peripheral loading yields the best target coverage while limiting dose to the central urethral volume.

Three dimensional conformal radiotherapy for the treatment of prostate cancer: low risk of chronic rectal morbidity observed in a large series of patients

PURPOSE

Three dimensional conformal radiotherapy (3D CRT) may provide a technique to increase the dose delivered to target tissues while sparing uninvolved normal structures. To evaluate the role of 3D treatment in reducing the treatment toxicity, we analyzed the chronic rectal morbidity observed in a large group of patients undergoing radiotherapy for prostate cancer.

METHODS AND MATERIALS

From 1987 through 1992, 721 prostate cancer patients were treated with 3D CRT at the University of Michigan or Providence Hospital. All had axial computed tomography (CT) specifically for RT planning, multiple structures contoured on the axial images, and beam's-eye-view conformal beams edited to provide 3D dose coverage. Using current American Joint Commission (AJCC) staging, 537 patients had T1-T2 tumors, 123 had T3-T4 tumors, and 60 were treated postprostatectomy. Pelvic lymph nodes were treated in 462 patients. Prostate boosts were delivered with four-field axial, six-field axial, or four-field oblique, nonaxial fields. The median dose was 68.40 Gy (range 59.4-80.4). Median follow-up was 20.4 months; 175 were followed more than 3 years. All complications have been graded conservatively using the RTOG system.

RESULTS

Using a Cox proportional hazard's model, patient age, T-stage, prescribed dose, pelvic treatment, and boost technique were analyzed. The factor most strongly related to risk of morbidity was dose (p = 0.05); however, the boost technique was also related: the four-field oblique field had the lowest relative risk. Most episodes of rectal morbidity have been mild: 82 Grade 1 or 2. There have been only 14 more serious complications including 12 Grade 3 and 2 Grade 4. The actuarial risk of a Grade 3 or 4 complication is 3% at 3 and 5 years.

CONCLUSIONS

A very small proportion of patients treated with 3D CRT had significant rectal morbidity related to RT, supporting the use of conformal treatment planning and dose delivery as a mechanism to minimize complications in the treatment of prostate cancer.

Long term assessment of patterns of treatment failure and survival in patients with stage I or II follicular lymphoma

BACKGROUND

Follicular lymphoma is a clearly defined type of malignant lymphoma. The many treatment approaches reported in the literature attest to the lack of agreement on its best management. The treatment experiences of patients with Stage I or II follicular lymphoma who were at risk for at least 5 years were reviewed to assess their survival, disease free survival, and patterns of failure.

METHODS

Between 1974 and 1988, 144 patients with Stage I or II follicular lymphoma were treated at The University of Texas M. D. Anderson Cancer Center. Initial staging studies included lymphangiography in 87% of the patients, computerized tomography of the abdomen and pelvis in 60%, bone marrow biopsy in 98%, and diagnostic or staging laparotomy in 33%. Forty-five patients were treated with regional radiotherapy, 84 patients with combined chemotherapy and radiotherapy, and 15 patients were treated with chemotherapy alone.

RESULTS

With a median follow-up of 8.7 years (range, 48-182 months) the actuarial survival rates at 5, 10, and 15 years were 81, 69, and 63%, respectively. The freedom from relapse (FFR) rates were 66, 56, and 46%, respectively. The FFR rate was better for patients treated with chemotherapy-radiotherapy than for patients treated with radiotherapy alone (63 vs. 35% at 15 years). In addition, there were no relapses after 7.5 years in patients treated with chemotherapy-radiotherapy, but relapses continued even beyond 15 years in patients treated with radiotherapy alone. Univariate analysis for each of the treatment groups revealed age to be the only significant prognostic factor. There was no significant difference in survival or disease free survival rates for the three histologic subtypes of follicular lymphoma.

CONCLUSION

The addition of chemotherapy to radiotherapy may have increased the probability of cure for patients with Stages I or II follicular lymphoma.

Bromodeoxyuridine-mediated radiosensitization in human glioma: the effect of concentration, duration, and fluoropyrimidine modulation

PURPOSE

To define the relative influence of duration of exposure, concentration, and modulation by fluorodeoxyuridines (FdUrd) on the incorporation of 5-bromo-2-deoxyuridine (BrdUrd) into DNA of a human malignant glioma line (D-54) in vitro and in vivo.

MATERIALS AND METHODS

IN VITRO STUDIES

an established human malignant glioma line (D-54) was exposed to a clinically achievable concentration of BrdUrd to model intravenous (1 microM BrdUrd) and intraarterial (4 microM BrdUrd) conditions. The influence of modulation was assessed using 1 nM FdUrd. Incorporation of BrdUrd, radiosensitization, and cytotoxicity were determined after 24, 72, and 120 h drug exposures. In Vivo studies: nude mice bearing D-54 xenografts were infused with BrdUrd at 100 mg/kg/day for 7 and 14 days or BrdUrd at 400 mg/kg/day for 5 days. The influence of modulation was assessed by combining 100 mg/kg/day of BrdUrd with 0.1, 0.3, and 1 mg/kg/day FdUrd for 7 days. Incorporation of BrdUrd into the DNA of tumor, gut, and marrow were determined.

RESULTS

In Vitro: thymidine replacement and radiosensitization were a function of concentration, and incorporation began to plateau after 2 to 3 population doublings. Modulation with 1 nM FdUrd significantly increased incorporation. Radiosensitization was a linear function of thymidine replacement under all conditions tested. In Vivo: infusion with 400 mg/kg/day for 5 days resulted in greater tumor incorporation (10.3 +/- 0.4% thymidine replaced) than treatment with 100 mg/kg/day for 14 days (6.0 +/- 0.6% of thymidine replaced). Infusion of FdUrd with BrdUrd increased normal tissue incorporation of BrdUrd, but failed to increase BrdUrd incorporation in tumor cells.

CONCLUSION

These results suggest that relatively short, high dose rate infusions may be preferable to long, low dose rate infusions. The potential benefit of FdUrd modulation demonstrated in vitro may be difficult to realize using continuous systemic infusions.

Intensive induction chemotherapy and radiation for organ preservation in patients with advanced resectable head and neck carcinoma

PURPOSE

We designed a protocol to evaluate the possibility of organ preservation in patients with advanced, resectable carcinoma of the head and neck. The regimen consisted of intensive chemotherapy followed by radiation therapy alone for patients with good response to treatment. The end points of the study were response rate, organ preservation, toxicity, and survival.

PATIENTS AND METHODS

Forty-two eligible patients with carcinoma of the oral cavity, oropharynx, hypopharynx, larynx, and paranasal sinuses were enrolled. Induction chemotherapy consisted of three cycles of mitoguazone, fluorouracil (5-FU), and high-dose continuous infusion cisplatin. Patients who had a complete response to chemotherapy, or whose tumor was downstaged to T1N1, were treated with definitive radiation therapy, to a total dose of 66 to 73.8 Gy. Patients with residual disease greater than T1N1 underwent surgery and postoperative radiation.

RESULTS

The overall response rate to chemotherapy was 84%, with a 43% complete response rate, and a 68% complete response rate at the primary tumor site. Sixty-nine percent of patients (29 of 42) were initially spared surgery to the primary tumor site, and four of these patients (14%) required neck dissection only, after radiation therapy. These tumor sites included oral cavity, oropharynx, hypopharynx, larynx, and sinuses. Eventually, five of these patients (17%) required salvage surgery and eight patients (28%) had unresectable or metastatic relapses. With a median follow-up duration of 38.5 months, 36% of all patients have had preservation of the primary tumor site and remain disease-free. The median survival duration is 26.8 months. Toxicity was substantial, with a 70% incidence of grade 3 to 4 granulocytopenia and two septic deaths.

CONCLUSION

Organ preservation without apparent compromise of survival was achieved in patients with selected nonlaryngeal sites of head and neck carcinoma. Larger site-specific trials with less toxic regimens conducted in randomized fashion are required to extend these data.

Localization of the prostatic apex for radiation therapy using implanted markers

PURPOSE

This report concentrates on the localization of the prostatic apex using implantable markers, and a comparison to localization defined by computed tomography (CT) and retrograde urethrography.

METHODS AND MATERIALS

Fifteen patients were entered into a prospective trial and scheduled to undergo (a) pelvic CT, (b) retrograde urethrogram, and (c) transrectal ultrasound with placement of radiodense markers. Three markers were implanted: one was placed at the trapezoid area (prostatic apex), and the others placed lateral to the base of each seminal vesicle. The retrograde urethrogram was performed using standard technique. The superior-inferior distance between the apex identified by the marker placed at the prostatic apex and the other studies was measured.

RESULTS

CT and urethrogram overestimated the inferior extent of the prostatic apex when compared to the location as defined by the implanted marker. With CT, the average distance from the marker to the CT-defined apex was 0.6 cm (95% C.I.--0.4-0.8 cm). With urethrogram, the average distance from the marker to the urethrogram-defined apex was 1.3 cm (95% C.I.--0.7-1.9 cm). When CT and urethrogram were compared, CT was more accurate in identifying the prostatic apex.

CONCLUSION

Under ultrasound guidance, radiodense markers have been implanted into the prostate. This has revealed that the apex is localized superior to the apical margin as defined by retrograde urethrogram and CT, and that CT may be more accurate than retrograde urethrogram. In addition, the placement of multiple markers yields spatial information on prostatic position that can be extracted from megavoltage portal images.

Halogenated pyrimidine sensitization of low dose rate irradiation in human malignant glioma

PURPOSE

To determine the potential advantage of combining halogenated pyrimidine radiosensitization and continuous low dose rate irradiation in human malignant glioma.

METHODS AND MATERIALS

An established glioma line (U-251) was incubated with 5-bromo-2-doxyuridine (BrdUrd) at clinically achievable concentrations at three dose rates of interest--100 cGy/min (typical of external beam therapy), 43 cGy/hr (typical of temporary afterloaded implants), and 12 cGy/hr (typical of permanent implants).

RESULTS

After exposure to 1 microM BrdUrd, the greatest enhancement ratio was seen at the 12 cGy/hr dose rate, implying a BrdUrd induced inverse dose rate effect independent of a G2M block. Under these conditions, the mean inactivation dose after 1 microM BrdUrd exposure was equivalent for 100 cGy/min and 12 cGy/hr.

CONCLUSION

These results support the use of halopyrimidines as sensitizers of temporary afterloaded and permanent implants.

Frequency of residual neoplasm in the prostate following three-dimensional conformal radiotherapy

The incidence of residual neoplastic cells on prostatic biopsy following conventional external beam radiotherapy is reported to range from 40-90%. As a result, it has been stated that current modalities of radiotherapy may carry an unacceptable local failure rate even in patients irradiated for low stage disease. In order to assess the potential benefits of three-dimensional (3-D) treatment planning, an unselected, consecutive group of patients with localized adenocarcinoma of the prostate was evaluated. This study was designed to determine the frequency of residual cancer in the prostate two years following definitive external beam radiotherapy designed, using a 3-D planning system. Between February 1988 and February 1989, 30 consecutive patients with localized (Stage T1-T3NxMo) adenocarcinoma of the prostate received definitive external beam radiotherapy. All treatment fields were designed with a computed tomography (CT)-based 3-D treatment planning system, resulting in a static conformal radiotherapy plan. The minimum dose delivered to the target volume, which included the prostate, periprostatic tissues, and a 1 cm margin, was between 65 and 69 cGy. Twenty-six patients had Stage T1, T2NxMo primary tumors and four were T3NxMo. Two years following the completion of treatment, all patients underwent digital rectal examination, transrectal ultrasound examination of the prostate with multiple biopsies, bone scan, and serum prostate specific antigen (PSA) determinations. Residual prostate cancer was proven by biopsy in six of 30 patients (20%). Four of 26 (15%) with Stage T1 and T2 tumors had a positive biopsy. However, two of the four Stage T3 tumors had postradiation biopsies positive for cancer (50%). Only one patient with a positive biopsy had an abnormal rectal examination. Five of the eight patients with elevated serum PSA levels after two years had residual neoplasia identified on biopsy. One of six patients with an abnormal postradiation ultrasound had residual tumor. Only one of the 22 patients (5%) with a normal serum PSA at two years had a positive postradiation biopsy. In patients with localized prostate cancer, the use of 3-D static conformal radiotherapy followed by multiple ultrasound guided biopsies confirmed the efficacy of external beam radiotherapy in low stage disease. We believe that the low incidence of positive biopsies in this study resulted from the benefits of 3-D treatment planning as well as the fact that all patients were evaluated, whereas past studies have been in selected patient groups when suspicion of residual disease existed prior to biopsy.(ABSTRACT TRUNCATED AT 400 WORDS)

Tumor burden assessment and its implication for a prognostic model in advanced diffuse large-cell lymphoma

Previously untreated adult patients who presented with advanced diffuse large-cell lymphoma (DLCL) at diagnosis were studied to identify possible prognostic factors. One hundred five patients were seen between 1974 and 1981; 45 patients were stage III and 60 patients were stage IV. All patients received cyclophosphamide, doxorubicin, vincristine, prednisone, and bleomycin (CHOP-Bleo). Stage III patients also received radiation therapy alternated with chemotherapy. Overall survival was 50% at 5 years and 43% at 8 years. Seventy-four patients achieved a complete remission (CR) and 37 are alive and disease-free with a median follow-up of 72 months. There was no difference in clinical outcome between stage III and stage IV. However, a proportional hazards model identified lactic dehydrogenase (LDH) level and tumor burden, among all clinical factors studied, as independent risk factors for survival. These two factors were also important for achievement of remission and relapse-free survival. Three distinct patient risk groups were identified with 5-year survival rates of 87%, 48%, and 20%, respectively. The measure of tumor burden proposed herein, along with LDH level, can be used for developing treatment programs, and for meaningful comparison of different treatment regimens, as well as assessment of prognosis.