Pharmacokinetics of the hypoxic radiosensitizers misonidazole and demethylmisonidazole after intraperitoneal administration in humans.

The hypoxic radiosensitizers misonidazole or demethylmisonidazole were administered i.p. in a 2-liter volume to 6 patients affected by advanced ovarian carcinoma, and the pharmacokinetic course of the two drugs was studied. The clearance of misonidazole and demethylmisonidazole from the peritoneal fluid was 19.1 and 12.4 ml/min, respectively. At 3 hr after drug administration, both radiosensitizers had peritoneal fluid concentrations more than 8 times larger than in the plasma. The concentration x time exposure in the peritoneal fluid was 3.2 times larger than in plasma for misonidazole and 7.6 times for demethylmisonidazole. The advantage of i.p. delivery compared with systemic delivery decreases with distance from the peritoneal surface, but the advantage may be maintained for up to 1 mm or 100 cell layers. These differences between the two routes of administration provide a rational basis for the expectation that a substantial increase of the therapeutic benefits of misonidazole and demethylmisonidazole in potentiating radiation therapy or chemotherapy can be expected in treating tumors confined to the i.p. space.

The impact of primary irradiation treatment of localized breast cancer on the ability to administer systemic adjuvant chemotherapy.

The impact of primary irradiation of localized breast cancer on the ability to administer Adriamycin-cytoxan adjuvant chemotherapy to patients with stage II breast cancer was examined. Patients were prospectively randomized to receive either irradiation or mastectomy as local therapy and did not differ with respect to other prognostic variables that might influence tolerance to chemotherapy. All of the patients received chemotherapy dose escalations (or reductions) until maximal tolerated drug doses were established. Patients receiving irradiation had minimally greater myelosuppression which was nearly totally explainable by lymphopenia. Irradiated patients required dose reduction nearly twice as often as mastectomy patients although commonly their dose could be reescalated. Patients managed with radiotherapy received slightly less drug than patients treated with mastectomy when treated to an identical degree of bone marrow suppression. The primary management of breast cancer by irradiation does not induce substantial changes in the ability of patients to tolerate adjuvant chemotherapy.

Pulmonary toxicity with combined modality therapy for limited stage small-cell lung cancer.

To assess the pulmonary toxicity of radiation therapy combined with chemotherapy v chemotherapy alone, we reviewed the clinical course of 80 patients with limited stage small-cell lung cancer treated in a randomized prospective trial. Life-threatening pulmonary toxicity, defined as bilateral pulmonary infiltrates extending beyond radiation ports with symptoms requiring hospital admission, developed in 11 patients (28%) receiving combined modality therapy and in two (5%) receiving chemotherapy alone. Eight of these 13 patients died from pulmonary complications with no clinical evidence of tumor in five. Pulmonary toxicity initially presented at a median of 63 days (range, 21 to 150 days) after the start of combined modality therapy and at a median of 217 days after chemotherapy alone. Biopsies obtained in 11 patients with severe toxicity revealed only interstitial fibrosis with no evidence of an infectious agent. Review of pretreatment parameters such as age, performance status, and radiation portal area failed to reveal any significant differences between patients with or without pulmonary complications. However, initial pulmonary function tests (PFTs) revealed a significantly lower vital capacity (P = .03) and forced expiratory volume (FEV/1.0 second) (P = .04) in patients with subsequent pulmonary complications. Pulmonary toxicity was significantly more common with combined modality therapy than with chemotherapy alone (P = .017) and worse than expected with radiotherapy alone. Six- or 12-month PFTs in completely responding patients revealed improvement within the chemotherapy alone group and no clear trend within the combined modality group. For the group treated with radiation therapy and chemotherapy, there was significantly less improvement after 6 or 12 months in the forced vital capacity (P less than .005) and FEV/1.0 second (P less than .005) than observed for the group treated with chemotherapy alone. Despite the increased incidence of pulmonary toxicity, overall survival favored the combined modality arm (P = .07). Enhanced local control and disease-free survival appeared to compensate for the initial increased pulmonary morbidity and mortality in the group with combined modality therapy.

Complete axillary lymph node dissection for stage I-II carcinoma of the breast.

We reviewed the complete axillary dissection specimens of 136 patients with stage I-II breast cancer to clarify the distribution of axillary lymph node metastases in this disease. Our series included 71 patients undergoing axillary dissection as part of a modified radical mastectomy (MRM) and 65 patients undergoing axillary dissection in conjunction with conservative surgery of the breast and definitive postoperative breast radiotherapy (CAD). These two groups of patients were comparable according to age, menopausal status, tumor size, and clinical stage. In all patients the pectoralis minor muscle was excised and all axillary tissue removed. Each specimen contained a median of 23 lymph nodes. The axillary levels (I, II, III) were determined according to the relationship of axillary tissue to the pectoralis minor muscle (lateral, inferior, medial). Thirty-nine percent of the lymph nodes were contained in level I, 41% in level II, and 20% in level III. There were no significant differences noted in the number of lymph nodes or in the distribution of lymph nodes according to axillary level between dissections performed as part of the MRM or those done as a single procedure (CAD). Sixty-five patients (47.8%) had one or more positive lymph nodes in their axillary specimen. The clinical and pathologic stage was determined and compared for all patients. Among patients judged to have a clinically negative axilla, 37.6% had histologically positive lymph nodes (clinical false-negative rate). For patients with a clinically positive axilla, 11.1% had, histologically, no evidence of metastatic disease (clinical false-positive rate). When the distribution of lymph node metastases according to axillary level was studied, it was found that 29.2% of lymph node-positive patients (or 14.0% of all patients) had metastases only to level II and/or III of the axilla, with level I being negative (skip metastases). This incidence of skip metastases was greater among clinically node-negative than among clinically node-positive patients, but was not related to the size or location of the primary tumor in the breast. In addition, it was found that 20.0% of lymph node-positive patients (or 9.6% of all patients) were converted from three or fewer to four or more positive nodes by analysis of lymph nodes contained in levels II and III. This conversion from three or fewer to four or more positive nodes was due primarily to information contained in level II, with level III contributing to a smaller degree.(ABSTRACT TRUNCATED AT 400 WORDS)

Mastectomy versus breast-conserving therapy in the treatment of stage I and II carcinoma of the breast: a randomized trial at the National Cancer Institute.

PURPOSE: Mastectomy versus excisional biopsy (lumpectomy) plus radiation for the treatment of stage I and II breast cancer was compared in a prospective randomized study. PATIENTS AND METHODS: From 1979 to 1987, 247 women were randomized and 237 were treated on this study. All patients received a full axillary dissection and all node-positive patients received adjuvant chemotherapy with cyclophosphamide and doxorubicin. Radiation consisted of external-beam therapy to the whole breast with or without supraclavicular nodal irradiation followed by a boost to the tumor bed. RESULTS: The minimum time on the study was 18 months and the median time on the study was 68 months. No differences in overall survival or disease-free survival were observed. Actuarial estimates at 5 years showed that 85% of mastectomy-treated patients were alive compared with 89% of the lumpectomy/radiation patients (P2 = .49; 95% two-sided confidence interval [CI] about this difference, 0% to 9% favoring lumpectomy plus radiation). The probability of failure in the irradiated breast was 12% by 5 years and 20% by 8 years according to actuarial estimates. Of 15 local breast failures, 14 were treated with and 12 were controlled by mastectomy; the ultimate local-regional control was similar in both arms of the trial. CONCLUSION: These data add further weight to the conclusion that breast conservation using lumpectomy and breast irradiation is equivalent to mastectomy in terms of survival and ultimate local control for stage I and II breast cancer patients.

Influence of patient characteristics, socioeconomic factors, geography, and systemic risk on the use of breast-sparing treatment in women enrolled in adjuvant breast cancer studies: an analysis of two intergroup trials.

PURPOSE: To investigate the frequency of breast-sparing treatment among breast cancer patients subsequently enrolled in national cooperative group studies of adjuvant chemotherapy. PATIENTS AND METHODS: A data base was formed of 5,172 patients randomized onto two intergroup trials. Lumpectomy rates were analyzed within study-defined risk strata and across geographic regions. Significant predictors of lower lumpectomy usage were determined in multivariate analyses with variables that described patient and disease characteristics, systemic risk strata, geographic region, and socioeconomic indicators based on zip code of residence. RESULTS: Breast-conservation rates were 30% in the node-negative and 15% in the node-positive trials, with a wide geographic variation within each study (range, 14% to 49% and 9% to 31%, respectively). Lumpectomy use declined with increasing tumor size and did not exceed 40% even for tumors < or = 1 cm with negative nodes. With increasing risk of systemic relapse, frequency of lumpectomy declined (rates for five strata in order of increasing systemic risk: 41%, 33%, 24%, 18%, and 11%), even though these strata were not known at the time of the surgical decision. A logistic model confirmed the joint significance of geographic region and systemic risk. An exploratory model that adjusted for all important variables identified the following significant predictors of lower lumpectomy use: positive nodes; many positive nodes, increased systemic risk; tumor size > or = 2.0 cm; older age; South, Central or non-New England regions; and either lack of college degree or lower income levels. CONCLUSION: Breast-sparing therapy was used in the minority of women subsequently accrued to two national adjuvant breast cancer studies, even though this cohort and their referring surgeons represented a select population. Although multiple concrete factors were independent predictors of lower lumpectomy rates, prospective research is needed into how patients and their physicians approach the mastectomy versus lumpectomy decision.

Dose escalation in non-small-cell lung cancer using three-dimensional conformal radiation therapy: update of a phase I trial.

PURPOSE: High-dose radiation may improve outcomes in non-small-cell lung cancer (NSCLC). By using three-dimensional conformal radiation therapy and limiting the target volume, we hypothesized that the dose could be safely escalated. MATERIALS AND METHODS: A standard phase I design was used. Five bins were created based on the volume of normal lung irradiated, and dose levels within bins were chosen based on the estimated risk of radiation pneumonitis. Starting doses ranged from 63 to 84 Gy given in 2.1-Gy fractions. Target volumes included the primary tumor and any nodes >or= 1 cm on computed tomography. Clinically uninvolved nodal regions were not included purposely. More recently, selected patients received neoadjuvant cisplatin and vinorelbine. RESULTS: At the time of this writing, 104 patients had been enrolled. Twenty-four had stage I, four had stage II, 43 had stage IIIA, 26 had stage IIIB, and seven had locally recurrent disease. Twenty-five received chemotherapy, and 63 were assessable for escalation. All bins were escalated at least twice. Although grade 2 radiation pneumonitis occurred in five patients, grade 3 radiation pneumonitis occurred in only two. The maximum-tolerated dose was only established for the largest bin, at 65.1 Gy. Dose levels for the four remaining bins were 102.9, 102.9, 84 and 75.6 Gy. The majority of patients failed distantly, though a significant proportion also failed in the target volume. There were no isolated failures in clinically uninvolved nodal regions. CONCLUSION: Dose escalation in NSCLC has been accomplished safely in most patients using three-dimensional conformal radiation therapy, limiting target volumes, and segregating patients by the volume of normal lung irradiated.

Phase III randomized intergroup trial of subtotal lymphoid irradiation versus doxorubicin, vinblastine, and subtotal lymphoid irradiation for stage IA to IIA Hodgkin's disease.

PURPOSE: The management of early-stage Hodgkin's disease in the United States is controversial. To evaluate whether staging laparotomy could be safely avoided in early-stage Hodgkin's disease and whether chemotherapy should be a part of the treatment of nonlaparotomy staged patients, a phase III intergroup trial was performed. PATIENTS AND METHODS: Three hundred forty-eight patients with clinical stage IA to IIA supradiaphragmatic Hodgkin's disease were randomized without staging laparotomy to treatment with either subtotal lymphoid irradiation (STLI) or combined-modality therapy (CMT) consisting of three cycles of doxorubicin and vinblastine followed by STLI. RESULTS: The study was closed at the second, planned, interim analysis because of a markedly superior failure-free survival (FFS) rate for patients on the CMT arm (94%) compared with the STLI arm (81%). With a median follow-up of 3.3 years, 10 patients have experienced relapse or died on the chemoradiotherapy arm, compared with 34 on the radiotherapy arm (P <.001). Few deaths have occurred on either arm (three deaths on CMT and seven deaths on STLI). Treatment was well tolerated, with only one death on each arm attributed to treatment. CONCLUSION: These results demonstrate that it is possible to obtain a high FFS rate in a large group of stage IA to IIA patients without performing staging laparotomy and that three cycles of chemotherapy plus STLI provide a superior FFS compared with STLI alone. Extended follow-up is necessary to assess freedom from second relapse, overall survival, late toxicities, patterns of treatment failure, and quality of life.

Late intensive combined modality therapy followed by autologous bone marrow infusion in extensive-stage small-cell lung cancer.

To attempt to improve the poor prognosis of extensive-stage small-cell lung cancer (SCLC) patients, we tried to administer late intensive combined modality therapy (LICMRX) to patients with good tumor regression after 12 weeks of conventional chemotherapy. Twenty-nine consecutive extensive-stage SCLC patients received 6 weeks of cyclophosphamide, methotrexate, and lomustine (CMC) induction therapy, followed by 6 weeks of vincristine, doxorubicin, and procarbazine (VAP). After restaging for assessment of tumor response, autologous bone marrow (ABM) was collected in patients in good medical condition with complete response (CR) or partial response (PR) and no tumor on marrow examination. LICMRX consisted of irradiation with 2,000 rad in five fractions for five days to sites of initial tumor involvement, followed by cyclophosphamide, 60 mg/kg for 2 days, and etoposide, 200 mg/m2 for 3 days and then by ABM infusion. Prophylactic cranial irradiation (PCI) was administered thereafter, but no further chemotherapy was used. Due to lack of tumor regression or poor medical condition, only ten of the original 29 patients were eligible for LICMRX; two refused, so only eight (28%) received therapy. Three patients who began LICMRX in CR developed recurrence of SCLC after an additional 4, 8, and 15 months. Of five patients with PR, one attained CR but relapsed at 3 months, two remained in PR and progressed at 2 and 4 months, and two died of infection without recovery from LICMRX. Mean time from ABM infusion to recovery of granulocyte count to 500/microL was 15.8 days in the six surviving patients (range, 12-22). The major non-hematologic toxicity of LICMRX was severe esophagitis. Among all 29 patients, there were six CRs (21%) and no 2-year survivors, compared with a CR rate of 36% and 10% 2-year survivors in 78 extensive-stage patients previously treated with CMC plus VAP without LICMRX. We conclude that the LICMRX given in this study can be administered to only a minority of extensive-stage SCLC patients and is very unlikely to yield substantial improvement in the fraction of 2-year survivors (95% confidence limits for 2-year survival 0% to 10%).

Effect of gonadotropin secretion rate on the radiosensitivity of the rat luteinizing hormone-releasing hormone neuron and gonadotroph.

To test the hypothesis that the functional state of hypothalamic LHRH neurons and pituitary gonadotrophs might alter their radiosensitivity, we determined the experimental conditions under which the gonadotropin response to castration could be impaired by a single dose of cranial irradiation. Single doses of cranial irradiation greater than 2000 rads were lethal to unshielded rats. Shielding of the oropharynx and esophagus allowed the animals to survive doses up to 5000 rads. Doses between 2000 and 5000 rads had no effect on basal gonadotropin levels for as long as 3 months after irradiation. Irradiation caused a dose- and time-dependent impairment, however, in the gonadotropin response to castration. Impairment of the gonadotropin levels of castrate animals occurred in animals that were irradiated either before or after castration. However, rats irradiated in the castrate state showed a decreased susceptibility to irradiation damage. Additionally, stimulation of the pituitary by LHRH agonist (LHRHa) 3 h before irradiation significantly reduced the impairment of gonadotropin secretion 12-20 weeks after irradiation (P less than 0.05). Thus, increased functional activity of the rat hypothalamus or pituitary at the time of irradiation, induced by either castration or acute LHRHa administration, was associated with some protection against the gonadotropin-lowering effect of irradiation. Based upon these data, we hypothesize that stimulation of gonadotropin secretion at the time of therapeutic cranial irradiation in humans might protect against subsequent impairment of gonadotropin secretion.

Carcinomatous leptomeningitis in small cell lung cancer: a clinicopathologic review of the National Cancer Institute experience.

CLM developed in 60 of 526 patients (11%) with SCLC seen at the NCI between August 1969 and June 1980. Life table analysis revealed an overall 25% risk of CLM at 3 years. CLM was diagnosed during all phases of the patients' clinical course, but the majority (83%) were cases diagnosed at the time of progressive systemic disease. Univariate log rank analysis indicated that pretreatment factors associated with the development of CLM included: involvement of the brain, spinal cord, bone marrow, liver or bone; extensive disease; and male sex. Patients who did not obtain a complete response to systemic therapy were at greater risk of developing CLM than complete responders. Multivariate analysis of these factors indicated that liver metastases were most strongly associated with the time to development of CLM, followed in order of importance by bone and CNS metastases. Patients usually presented with signs and symptoms reflecting involvement of multiple areas of the neuraxis including the cerebrum, cranial nerves and spinal cord; 51 of the 60 patients had intracerebral metastases and 27 had spinal cord lesions during their clinical course. Autopsy features including focal or diffuse involvement of the leptomeninges with infiltration of the Virchow-Robin spaces were similar to meningeal lymphoma and leukemia, except that CLM was rarely the sole manifestation of CNS tumor. Median survival following the diagnosis of CLM was 7 weeks. However, most deaths were attributed to systemic disease, and treatment with intrathecal chemotherapy and irradiation often provided palliation. With the increased awareness of this complication, an antemortem diagnosis increased from 39% prior to 1977, to 88% of patients after 1977.

Optimization and clinical use of multisegment intensity-modulated radiation therapy for high-dose conformal therapy.

Intensity-modulated radiation therapy (IMRT) may be performed with many different treatment delivery techniques. This article summarizes the clinical use and optimization of multisegment IMRT plans that have been used to treat more than 350 patients with IMRT over the last 4.5 years. More than 475 separate clinical IMRT plans are reviewed, including treatments of brain, head and neck, thorax, breast and chest wall, abdomen, pelvis, prostate, and other sites. Clinical planning, plan optimization, and treatment delivery are summarized, including efforts to minimize the number of additional intensity-modulated segments needed for particular planning protocols. Interactive and automated optimization of segmental and full IMRT approaches are illustrated, and automation of the segmental IMRT planning process is discussed.

The residency match in radiation oncology.

Centralized matching of postgraduate training positions has been successfully implemented nationwide since 1951. Specialty and subspecialty matches have proliferated in the 1970's and early 1980's, and Radiation Oncology was the last residency program that did not have a centralized match arrangement. Responding to pressures from training program directors who were dissatisfied with the non-centralized matching of resident applicants, made especially acute by a rapid increase in the number of students interested in Radiation Oncology, the first centralized matching program for Radiation Oncology--the Radiation Oncology Matching Program (ROMP)--began in 1989. Two years of experience with the ROMP are summarized in this paper. Interest in training positions in Radiation Oncology remains high, with approximately 1.3 to 1.5 qualified applicants per each residency position. The major problem with the current arrangement in ROMP is lack of full participation. In 1989, approximately 70% of first year positions were offered through ROMP, and in 1990 this was closer to 60%. While the majority of programs desire and participate in a centralized match, participation at less than an 85 to 90% level will likely cause the centralized match to disband. Reasons for and against a centralized matching process and a history of matching programs in other specialties are discussed.

Pleural-based changes on chest X ray after irradiation for primary breast cancer: correlation with findings on computerized tomography.

In treating breast cancer with excisional biopsy and irradiation, a volume of lung underlying the breast and chest wall receives significant doses of irradiation. This irradiation can produce pleural and pulmonary changes that can be seen on routine chest radiographs. In five such cases, we have examined pre and post-treatment computerized tomograms of the chest and show that these radiographic changes are pleural-based and lie within the high dose radiation volume. Failure to correct radiation treatment plans for the influence of lung density results in an increased dose to lung and pleura that could, in theory, exacerbate pulmonary and pleural radiation effects.

A large screen digitizer system for radiation therapy treatment planning.

PURPOSE: This paper describes a new technique for manually drawing contours of anatomy over image data for the purposes of radiation therapy treatment planning. METHODS AND MATERIALS: A large area rear-projectible digitizer tablet is used together with a projection TV system to display computer graphics and image data. Large images of computed tomography or magnetic resonance cross-sections are displayed and the digitizer is used to directly trace outlines of important organs. Digitizer menus allow multiple functions for selecting images and structures, for changing the grayscale level and window, and for zooming and roaming the image. RESULTS: This device has been in clinical operation for many years and has proven to greatly increase the speed of entering cross-sectional outlines defined for serial computed tomography images sets. A small timing study of clinical usage demonstrates up to a factor of ten improvement in the speed of contour entry. CONCLUSION: For 3-dimensional radiation therapy, tumor, and target volumes, as well as important critical organs, must be delineated from serial sets of computed tomography or magnetic resonance images. Often 30 or more slices must be considered and the process of outlining structures on this number of slices can represent a significant fraction of the total treatment planning time. The device described in this paper greatly improve the ease and speed of manual contour entry for 3-dimensional radiation therapy planning.

Potential improvement in the results of irradiation for prostate carcinoma using improved dose distribution.

Results for radiation treatment of prostate carcinoma indicate that nearly one-third of Stage C patients fail locally. This number will likely increase as occult failures are discovered by monitoring serum prostate specific antigen levels. Thus, there is need for techniques that would increase the local control of prostatic carcinoma. Using cross-sectional imaging and 3-dimensional treatment planning, dose distributions for photon irradiation can be created that conform more closely to the shape of the prostate and seminal vesicles, sparing additional dose to portions of bladder and rectum. A dose escalation trial is underway to investigate whether these techniques will lead to increased local control without unacceptable increases in bladder and rectal complications. While zero local failures is probably an unattainable goal, reduction in local failure in prostate cancer would likely increase the overall cure rate in this disease.

Full integration of the beam's eye view concept into computerized treatment planning.

A complete set of beam's eye view (BEV) and beam portal design features have been integrated into a computerized 3-dimensional radiotherapy treatment planning system. Among the features implemented is the ability to mix BEV graphics with gray-scale images such as simulator and verification radiographs, and digital reconstructed radiographs. Image processing techniques have been developed to both enhance verification images and to detect radiation field boundaries. These portal simulation and presentation techniques are being used clinically to design and verify radiation fields with manual or automatically-designed field shaping blocks. The ability to perform computer dose calculations for planes which are parallel or perpendicular to a specified beam's central axis is available and this feature has also proven useful for treatment plan evaluation and optimization. Finally, direct comparison of computer-generated portal images with actual simulation and verification radiographs is also possible. These techniques allow the direct integration of "CT-directed treatment planning" with block design, simulator films and port films, and other Beam's Eye View-type displays.

Dose to the contralateral breast due to primary breast irradiation.

The radiation dose received by the contralateral breast during primary breast irradiation is of concern because breast tissue is subject to cancer induction from low to moderate doses of radiation. In this paper the dose to the opposite breast has been studied in detail for common breast treatment techniques. Measurements have been made on 16 patients, a water phantom, a polystyrene phantom with cork inserts to simulate lung tissue, and a body-shaped phantom with wax breasts. Thermoluminescent dosimeters (TLD), ion chambers, diodes, and film have been used in the various configurations. The patient measurements have shown that there is a wide variation in the opposite breast dose received by patients, even when all are treated with, for example, tangential fields alone. Addition of more radiation fields, such as supraclavicular/axillary and internal mammary fields, may increase the dose to the opposite breast for a particular patient. Variations in the details of the technique such as what wedges are used, the use of blocks, and the orientation of the field edges are all important to the final dose received by the patient's contralateral breast. With the phantom measurements, it has been possible to determine the contributions to the opposite breast dose from each of the relevant factors. This makes it possible to explain the wide variation in patient dose measurements, and to make some relatively simple recommendations that will allow the reduction of the dose to the opposite breast from several hundred cGy to about 50 cGy for a typical treatment course dose of 5000 cGy.

Preservation of parotid function after external beam irradiation in head and neck cancer patients: a feasibility study using 3-dimensional treatment planning.

PURPOSE: Radiation-induced xerostomia is a frequent complication and major cause of morbidity in head and neck cancer patients. The severity of xerostomia is related to radiation dose and the amount of parotid tissue included in the irradiated volume. To reduce this side-effect and preserve salivary function, we have evaluated the use of 3-dimensional (3-D) treatment planning to spare the contralateral parotid gland in twelve patients undergoing radiation therapy for head and neck cancers. METHODS AND MATERIALS: In each case, beam's eye view displays were used to design beam and blocking arrangements that excluded the contralateral parotid. Ten patients were treated with 2 nonopposing oblique fields in the axial and non-axial plane while two patients required a non-axial, non-coplanar 3-field arrangement. These 3-D treatment plans were also compared with conventional 2-dimensional (2-D) plans. The 2-dimensional plans were designed independently of the 3-D treatment planning information using the orthogonal radiographs and hard copies of the computed tomography scans. RESULTS: An average of 1.8% (range, 0-7%) of the target volume was underdosed with the 95% isodose level for the 3-D plans compared with 18.8% (range, 2.0-36.6%) for the 2-D plans. This was due to improved identification of the target volumes and better design of blocked fields with beam's eye view treatment planning. Furthermore, the mean dose to the opposite parotid was 3.9 Gy for the 3-D plans vs 28.9 Gy for the conventional plans. With a minimum follow-up of 4 months, only 2 of 12 patients have complained of a dry mouth. CONCLUSION: These encouraging results suggest that this approach is feasible in many cases. 3-D treatment planning may allow the use of parotid sparing techniques in patients who otherwise would not have been considered candidates using conventional radiotherapy techniques.