K.H. Luk

Arm lymphedema in patients treated conservatively for breast cancer: Relationship to patient age and axillary node dissection technique

Arm lymphedema (ALE) was evaluated in 74 patients treated conservatively for breast cancer. ALE was defined based upon measurements performed upon 35 volunteer subjects who did not have and were never treated for breast cancer. Multiple variable statistical analysis of 74 breast cancer patients revealed that age at diagnosis was the most important factor related to the subsequent development of ALE. ALE appeared in 7 of 28 patients (25%) 60 years of age or older but in only 3 of 46 (7%) younger patients (p less than 0.02). Axillary node dissection (AND) was the only other statistically significant factor. For the younger patients, obesity and post-operative wound complications appeared to be contributing factors. For the older patients, AND technique was the only significant factor. ALE developed in only 1 of 10 (10%) of the older patients who underwent AND without splitting the pectoralis minor muscle (PMM), but in 6 of 11 (55%) who underwent AND with PMM split (p less than 0.03). Splitting the PMM during AND did not yield more lymph nodes for pathological analysis nor did it yield a higher incidence of patients with nodal metastases. Neither the use of lymph node radiation therapy fields, radiation to the full axilla, nor systemic chemotherapy was associated with ALE. We conclude that older patients are at higher risk of ALE and that this complication can possibly be reduced by not splitting the PMM during axillary node dissection.

Hyperthermia quality assurance guidelines

These Hyperthermia Quality Assurance guidelines are a result of a joint workshop of the Hyperthermia Committee of the American College of Radiology and the Hyperthermia Physics Center, which is the national quality assurance program under Contract No. N01-CM-37512 with the National Cancer Institute. Hyperthermia technology presently lacks the kind of standardization in equipment, treatment procedures, patient monitoring, and treatment documentation available in radiotherapy. Therefore, preventing unacceptable variability in treatment data demands a strong commitment to in-house quality control procedures and to centralized quality assurance reviews in cooperative multi-institutional trials. This paper presents a set of test procedures necessary to ensure proper operation of equipment, suggests a frequency for such tests, and also includes guidelines on quality control procedures to be used during treatment to improve the safety, effectiveness, and reproducibility of hyperthermia treatments. A set of forms are presented to indicate the minimum data, albeit incomplete, that must be collected for acceptable documentation of treatment. These guidelines should be valuable not only to the new entrants in the field but also to those participating in multi-institutional cooperative hyperthermia trials. They have been approved by the Hyperthermia Committees of American College of Radiology, American Society for Therapeutic Radiology and Oncology, Radiation Therapy Oncology Group and the American Association of Physicists in Medicine.

Factors affecting cosmetic outcome in breast-conserving cancer treatment : objective quantitative assessment

SummaryA battery of objective measurements of cosmetic outcome was performed on 114 patients who had been treated by breast-preservation techniques for breast cancer. Cosmetic breast retraction, as determined by Breast Retraction Assessment (BRA) measurements, was significantly greater in patients who underwent extensive primary tumor resection, were more than 60 years old, weighed more than 150 lbs, or had a primary tumor in an upper breast quadrant. While use of a local RT boost, per se, was not a significant factor, those patients with high dose and/or large volume local boosts more frequently had marked retraction. Breast telangiectasia and depigmentation (T/D) was related to use of a local RT boost, patient age greater than 60 years, and use of separate nodal RT fields. Breast T/D was significantly more frequent with use of electron beam local RT boost which delivered a boost skin dose exceeding 1600 cGy.Objective quantitative assessments, such as BRA and T/D area measurements, provide data to determine factors related to each type of cosmetic change and thus provide guidelines for optimizing cosmetic outcome. Limiting the extent of primary tumor resection may minimize the amount of breast retraction. Omitting the local RT boost, particularly large volume, high dose boosts, may reduce the frequency of marked cosmetic retraction and skin T/D.

Total skin electron irradiation for mycosis fungoides: relationship between acute toxicities and measured dose at different anatomic sites

From June 1978 to June 1986, 50 patients with primary and recurrent mycosis fungoides were treated with total skin electron irradiation (TSEI), using the Stanford technique, to a total dose of 3600 cGy. TSEI was used alone, or in combination with low dose total body photon irradiation, or MOPP. Thermoluminescent dosimeter (TLD) measurements of the prescribed skin dose were obtained on twenty patients. The dorsum of the foot was 24% higher. The axillae, the bottom, and the arch of the foot were significantly underdosed. Frequencies of acute toxicities noted at 2000 cGy were: Skin, Grade I-II (RTOG) 80%. Partial epilation: scalp, 100%; eyebrows and at eyelashes, 20%. Nail dystrophy, 48%. Edema: hands and feet, 44%. Bullae: dorsum of feet, 8%; hands, 4%; and 3600 cGy: Skin, grade III 22%. Total epilation: scalp, 66%; eyebrows and eyelashes, 56%. Nail loss, 38%. Edema: hands and feet, 76%. Bullae: dorsum of feet, 34%; hands, 12%. Conjunctivitis, 4%. Large bullae, were more significant on the dorsum of the feet. Severe moist desquamation occurred in eight patients who had ulcerated lesions on initial presentation. Three patients were hospitalized due to ulceration and skin infection. All patients completed treatment after a short to moderate break. No patient developed skin necrosis, or corneal ulceration. No correlation exists between dose level, degree and onset of toxicity with previous chemotherapy or TBI. We conclude that the overall toxicity of TSEI is well tolerated.

Changes in heating patterns of interstitial microwave antenna arrays at different insertion depths

The changes in heating patterns of interstitial microwave antennas at different insertion depths were investigated in a static phantom at 915 MHz. Antennas for the Clini-Therm Mark VI system were inserted 5-15 cm into muscle-equivalent material, through nylon catheters. The phantom was heated with arrays of antennas at 2 cm spacings for 60 s at 15 W per antenna. Midplane and transverse heating patterns were determined thermographically with the antennas inserted parallel or perpendicular to the split of the phantom. Hot spots, independent of heating near the junction plane, were observed in the midplane of the 2 x 2 and 2 x 4 arrays at 2.8 cm from the insertion end. The magnitudes of these hot spots were reduced by 40-45 per cent as insertion depth was increased from 7 to 10.5 cm. With insertion depths of more than 11.5 cm the hot spots gradually diminished and heating occurred mostly near the junction plane. The observed heating patterns were caused by changes in impedance of the antenna arrays at different insertion depths. The impedance mismatch had resulted in different wave propagation within the tissue material which produced different radiation patterns. During treatments, because heating varies with insertion depth, great care must be exercised in monitoring temperatures.

Intracatheter hyperthermia and iridium-192 radiotherapy in the treatment of bile duct carcinoma.

We report a case of a patient with locally advanced bile duct carcinoma treated with 4500 cGy external beam radiotherapy, followed 3 weeks later by intracatheter 915 MHz microwave hyperthermia and radiotherapy delivered through a biliary U-tube placed at the time of surgery. Heating was to 43-45 degrees C for 1 hour followed immediately by intracatheter Iridium-192 seeds to deliver 5000 cGy over a 72 hour period. Prior to treatment, a thermal dosimetry study in phanton was conducted, using the same type of U-tube catheter tubing as in the patient. Orthogonal X rays of the patients porta hepatis region were used to reconstruct the catheter geometry in the phantom. Proper insertion depth was determined thermographically to obtain maximum heating at the center of the tumor. The maximum SAR was 8.8 watts per kilogram per watt input. During the treatment, the average power applied was 30 W. Six months after therapy, the patient is asymptomatic. Although alkaline phosphatase, SGOT and SGPT have remained elevated, bilirubin has returned to normal and computerized tomographic scans and cholangiograms remain stable. A duodenal ulcer developed after therapy and is healing well with conservative medical management. This case demonstrates that hyperthermia applied through biliary drainage catheters is technically feasible and clinically tolerated. We believe the use of intracatheter hyperthermia in conjunction with external and/or intracatheter radiotherapy in selected patients with unresectable bile duct carcinomas warrants further study.

Changes in heating patterns due to perturbations by thermometer probes at 915 and 434 MHz

The changes in heating patterns due to perturbations by thermometer probes in microwave fields were investigated in static phantoms at 915 and 434 MHz. Thermograms taken parallel to the plane of E and H fields, at depths of up to 2 cm, indicated heating changes of +25 to -45 per cent at 915 MHz and +/- 15 per cent at 434 MHz. The amount of perturbation is dependent on the length, size and location of the probes in the RF fields and their orientations to the electric field. If proper probe placement techniques are not observed when metallic probes are involved, hot and cool spots can be generated and shifted to sites that are not measured. Therefore misleading temperatures can result when changes in heating patterns are not detected. Perturbation also varies with applicator designs and phantom geometry. If thermistors and thermocouples are used, the effects of perturbation should be investigated with individual applicators under applicable clinical conditions.

Perturbations due to the use of catheters with non-perturbing thermometry probes

Perturbations due to the use of catheters with non-perturbing thermometry probes were investigated in static phantom at 915 MHz. Fibre optic probes for the Luxtron and Clini-Therm thermometry systems, and Vitek probes for the BSD hyperthermia systems, were inserted in closed-end catheters at depths up to 2 cm in the phantom and exposed parallel to the E-field. The probes alone produced 0-12 per cent changes in heating and catheters alone were 0-20 per cent. When the probes were inserted in catheters, perturbations were 0-12 per cent at the surface and 1 cm depth, and 5-15 per cent at 2 cm depth. Even with non-perturbing probes it is important to place catheters perpendicular to the E-field during microwave hyperthermia.

Evaluation of captive bolus applicators

Three square (L, M, MS) and one rectangular (HN) applicators with captive boluses were provided by the Clini-Therm Corporation for evaluation. Surface cooling is achieved by attaching a mineral oil captive bolus to the built in water-circulating tubes at the aperture of the applicators. These applicators were tested on a phantom with a 2-cm fat slab over 10-cm-thick muscle. Surface and sagittal heating patterns were obtained using a thermograph. All captive-bolus applicators have heating patterns similar to that of the regular Clini-Therm applicators. Due to hot spots at the edges of the applicators where the E fields terminate, these modified applicators should not be placed in direct contact with patients when boluses are not used. Tests with Clini-Therm regular water bolus instead of the captive oil bolus indicated that the orientation of water flow should be parallel to the E field to minimize perturbation of the heating patterns. Thermal conduction studies showed that the captive bolus reacts too slowly for skin temperature control. The modified captive bolus applicators did not improve the performance of the system.

Fractionated total body irradiation and high dose cyclophosphamide: a preparative regimen for bone marrow transplantation for patients with hematologic malignancies in first complete remission

SummaryWe treated 73 patients with hematologic malignancies in first complete remission (acute lymphoblastic leukemia = 23 patients; acute nonlymphoblastic leukemia = 25 patients; chronic myelogenous leukemia in first chronic phase = 20 patients, and high grade lymphoma = five patients) with a uniform preparative regimen consisting of fractionated total body irradiation (1 320 cGy) and high dose cyclophosphamide (100 mg/kg), followed by allogeneic bone marrow transplantation. By radiation dosimetry we demonstrated that the calculated doses were delivered accurately and reproducibly. Actuarial survival rates (± SEM) in complete remission were as follows: Acute lymphoblastic leukemia = 74±9%; acute nonlymphoblastic leukemia = 50±11%; and chronic myelogenous leukemia = 55±11%. Actuarial relapse rates for these three diagnoses were 19±9%, 17±11%, and 0% respectively. Three of the five lymphoma patients are alive in complete remission at 22+, 28+, and 54+ months. Overall probability of survival for the 73 patients was 59±7%. Interstitial pneumonia, usually associated with cytomegalovirus infection and graft-versus-host disease, and relapse of the underlying malignancy were the major causes of death.