Update on the Hong Kong Reference Framework for Hypertension Care for Adults in Primary Care Settings-review of evidence on the definition of high blood pressure and goal of therapy.

The Hong Kong Reference Framework for Hypertension Care for Adults in Primary Care Settings is updated regularly to ensure it reflects the latest medical development and best practice. In 2017, guidelines from the United States included a major change, adopting the lower blood pressure values of 130/80 mm Hg in defining hypertension, in contrast to the prevailing international consensus of 140/90 mm Hg. After thorough review of the literature and international guidelines, the Advisory Group on Hong Kong Reference Framework for Care of Diabetes and Hypertension in Primary Care Settings (Advisory Group) recommends that the definition of hypertension adopted in the Reference Framework should remain unchanged as a blood pressure of ≥140/90 mm Hg, as there is currently inadequate evidence and lack of general consensus to support such change in Hong Kong. The Advisory Group agrees on individualised treatment goals, and recommends that the initial blood pressure goal for individuals with uncomplicated hypertension should be <140/90 mm Hg; for those who can tolerate it, the goal should be ≤130/80 mm Hg. A lower blood pressure is advisable for young or overweight/obese patients, smokers, and patients with other cardiovascular risk factors.

Thermal dosimetry and clinical requirements.

Major problems in clinical hyperthermia include (a) inhomogeneity of heat distribution in designated tumor volumes due to tissue characteristics and differential blood flow, (b) limitations of heat delivery and control systems for adequate depth penetration and adjustments of temperatures, and (c) the lack of capability of accurate temperature measurements, especially in the area of noninvasive techniques for deep-seated tumors. Examples were given to illustrate the clinical requirements of hyperthermia of superficial, intermediate, and deep-seated tumors.

Down-regulation of the low-density lipoprotein receptor by dietary cholesterol.

To determine the effect of dietary cholesterol on the low-density lipoprotein (LDL) receptor of circulating mononuclear cells, nine adults (six men, three women) consumed a natural diet consisting of 45% of the calories as carbohydrate, 40% as fat, and 15% as protein, polyunsaturated/saturated fatty acid ratio 0.80 to 0.84, and either 137 +/- 25 mg cholesterol per day (low cholesterol phase) or 1034 +/- 25 mg cholesterol per day (high cholesterol phase). The study lasted 2 months with 1 month in each phase and used a cross-over design. The levels of plasma triglyceride, plasma cholesterol, very low-density and high-density lipoprotein cholesterol, and apolipoproteins B, A-I, and A-II were similar in the two diet phases. The high cholesterol diet was associated with an 11 +/- 9% increase (p less than 0.02) in LDL cholesterol level and a 41 +/- 14% decrease in LDL receptor activity (p less than 0.05, n = 6). The percentage decrease in LDL receptor activity correlated with the percentage increase in LDL cholesterol (r = -0.796, p = 0.06, n = 6). Thus, high levels of dietary cholesterol can down-regulate the LDL receptor in humans.

LOCATE: an application of computed tomography in radiation therapy treatment planning with emphasis on tumor localization.

Computed tomography can provide precise information for radiation therapy treatment planning. However, inaccuracies in radiation field design may occur when the radiation oncologist attempts to transfer information about tumor location from the transverse plane of the CT scan to the longitudinal plane of the simulation film. This report describes a new computer program, LOCATE, which addresses this problem. The program uses operator generated information from the cross sectional CT images to draw an outline of tumor on AP and lateral longitudinal scanned projection radiographs. The resultant images are useful because they are in the same plane as radiographs obtained on a therapy simulator. The impact of LOCATE on radiation treatment planning for 26 patients is discussed along with several cases in which LOCATE was particularly helpful.

Complications resulting from spurious fields produced by a microwave applicator used for hyperthermia.

Microwave hyperthermia applicators are generally characterized at two or three frequencies. These frequencies usually are at the extremes of the applicator's operating range. However, such applicators are often used at arbitrary frequencies within their range. The most common reason for choice of frequency is to achieve acceptable coupling in the clinical configuration with a given patient. Occasionally a spurious transmission pattern will result from the frequency chosen that can lead to undetected high power densities well away from the target volume. In the present report, such a situation is discussed. The transmission pattern resembled "horns" reported at the field edge of certain accelerators. This pattern resulted in the inability to heat the target volume and the production of thermal blisters outside that volume. Such an occurrence underscores the need to characterize the transmission characteristics of a microwave hyperthermia applicator at all the frequencies used.

Effects of fat thickness on heating patterns of the microwave applicator MA-151 at 631 and 915 MHz.

Previous studies showed that the surface heating patterns of the MA-151 applicator on a 2 cm fat and 10 cm thick muscle phantom had center heating at 581 and 930 MHz and two hot spots near the edges of the applicator at 657 and 779 MHz. The hot spots at 657 MHz were consistent with two blisters on a patient's thigh. Since the heating patterns on muscle only showed good center elliptical heating at all frequencies, in this study we have investigated the effects of fat thickness on the heating patterns. Thermograms of fat and muscle surfaces were taken on phantoms with 0, 0.25, 0.5, 1, and 2 cm thick fat exposed to 631 or 915 MHz energy. The 631 MHz was selected to provide reasonable energy coupling for all phantoms. At 631 MHz, two hot spots were evident on all fat surfaces. The pattern on the muscle surface under the 0.25 cm fat did not show two hot spots, but the heating was elongated in the E-field direction. At 915 MHz, the heating was elongated on the surface of the 0.25 and 2 cm fat, and two hot spots were observed on the 0.5 and 1 cm fat surfaces. However, the muscle heating was elliptical in all cases. The ratio of muscle to fat heating decreased as the fat thickness increased. At 0.5 cm fat the ratio was about 1. These results indicate that fat thickness influences heating in muscle. During treatment with this applicator, surface temperature probes should be placed over potential hot spots. Surface cooling is desirable for heating tumors beneath the fat.

Combined radiation and hyperthermia: comparison of two treatment schedules based on data from a registry established by the Radiation Therapy Oncology Group (RTOG).

A registry established by the Radiation Therapy Oncology Group provides data for assessing the impact of clinical heating in a set of non-randomized patients treated with hyperthermia in participating member institutions from 1/77 to 6/81. This analysis focuses on tumor response when localized hyperthermia is produced by microwave and applied pursuant to two distinctly different treatment schedules. Hyperthermia treatments were biweekly and combined with daily radiation treatments in one patient group, and combined with biweekly radiation treatment in another. Sample X consists of 65 patients who received a course of therapy using combined hyperthermia and radiation in consecutive treatment sessions each separated by at least 48 hours, but no more than 96 hours. Sample Y consists of 34 patients who received further radiation after the start of a course of combined therapy--either between or at the end of a series of combined treatment sessions. The average length of heat treatment was 72 minutes for Sample X and 32 minutes for Sample Y patients. None of the patients received concurrent chemotherapy; all received between 3 and 13 hyperthermia treatments; all had superficial, measurable tumors. On the average, Sample X patients received 704 total minutes of heat compared to Sample Y patients who received 233 total minutes of heat. Total tumor radiation doses ranged from 17.0 Gy to 44.0 Gy among Sample X patients with 92.3% receiving radiation at either 3 Gy or 4 Gy per fraction. In Sample Y the range for total tumor dose was 16.0 Gy to 70.2 Gy with 73.4% of the patients receiving radiation at 2.5 Gy or less per fraction. Generally, the two treatment schedules achieved similar levels of tumor response. Among treated tumors in Sample X and Sample Y, complete regression rates were 52.4 and 61.8%, respectively, and partial regression rates were 16.9 and 14.7%. Adenocarcinoma and squamous cell carcinoma in both samples responded well to these combined treatments. Only in Sample X was there a statistically significant trend of decreasing complete regression rate when the treated tumor sizes increased. Best responses to treatment generally occurred between 28 and 84 days after completion of the combined therapy course. There were no differences between the two samples with respect to median days to best response or response duration. Blister, ulcer or wet desquamation were reported in 47.7% of Sample X as the maximum skin reaction. In contrast, only 20.6% of Sample Y had these complications.(ABSTRACT TRUNCATED AT 400 WORDS)

Design and thermometry of an intracavitary microwave applicator suitable for treatment of some vaginal and rectal cancers.

The construction of a modified coaxial cable as an intracavitary microwave applicator suitable for use in some vaginal and rectal cancers is presented. Thermometry was performed for microwave frequencies of 300, 400, 650, and 915 MHz. Temperature profiles in tissue phantoms were obtained with non-perturbing temperature probes and thermography, and the data were compared with those obtained in dogs. The temperature profiles were dependent on the frequency of the microwaves and the insertion depth of the applicator. In addition, an acrylic cylindrical spacer external to the applicator also altered the heating pattern. Therefore, with proper combinations of frequency, insertion depth and spacer, the applicator can be used for heating tumors in some clinical situations.

Adenocarcinoma of the cecum: natural history and clinical patterns of recurrence following radical surgery.

One hundred and forty-three patients with previously untreated primary adenocarcinomas of the cecum were analyzed. Fifty-three patients manifesting disseminated disease at diagnosis were analyzed to define mechanisms of disease spread. Ninety patients were analyzed following attempted curative resection to determine anatomical distribution of initial clinical recurrences. Twenty-eight patients recurred (31%), of whom 9 underwent a second laparotomy. Nineteen of the 28 patients who recurred (68%) demonstrated an initial pattern of relapse clinically confined to the abdomen, liver, and retroperitoneum. Analysis was performed to determine the influence of stage and grade of the primary tumor on prognosis. Implications for adjuvant therapy are discussed.

Adenocarcinoma of the retroperitoneal ascending and descending colon: sites of initial dissemination and clinical patterns of recurrence following surgery alone.

One hundred twenty-seven patients with previously untreated primary carcinomas of proximal, retroperitoneal large bowel were retrospectively analyzed. Sites of involvement in 33 patients with surgically incurable (disseminated) disease were analyzed to define patterns of initial spread. Ninety-four patients were analyzed following attempted curative resection to determine anatomical distribution of initial clinical recurrences. Thirty-one patients recurred (33%). Twenty-four of these patients (77.5%) demonstrated an initial pattern of relapse clinically confined to the abdomen and retroperitoneum. Analysis was performed to identify factors of prognostic significance. Implications for adjuvant therapy are discussed.

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.

To boost or not to boost: decreasing radiation therapy in conservative breast cancer treatment when "inked" tumor resection margins are pathologically free of cancer.

A retrospective study was performed to compare local treatment approaches for 108 treated breasts in 105 patients with Stage I or II breast cancer. Six cases with intraductal carcinoma have shown no evidence of recurrence. The other 102 cases had invasive cancer. In 54 treated breasts in 53 patients, the treatment approach involved surgical resection of the primary tumor, pathological determination of tumor-free "inked" specimen margins and 5000 cGy to the whole breast. Local radiation therapy (RT) boosts to the primary site were not given. This approach produced a 100% local control rate (mean follow-up of 38 months). In 28 treated breasts in 27 patients, the treatment approach involved tumor excision without evaluation of specimen margins followed by RT which included a local boost by either interstitial Iridium-192 implant or electron beam. This approach yielded an actuarial local control rate of 87% at 48 months (mean follow-up of 47 months). The difference in local control rate between the two groups was statistically significant (p less than 0.03). Among patients with clear surgical margins who received a local RT boost, 1 of 9 developed a local recurrence. Among those with tumor involving specimen margins who received a local boost, 1 of 8 developed local recurrence. Local recurrence developed more frequently among patients with poorly differentiated cancers (2 of 11 cases) than among those with other invasive cancers (3 of 91 cases). Comparison of treatment approaches was limited since poorly differentiated cancer was present in 25% of cases with unknown specimen margins, as compared with only 2% of those with clear surgical margins who did not receive a local RT boost. Our preliminary findings suggest that when "inked" primary tumor resection margins are pathologically free of cancer, 5000 cGy whole breast RT appears to be highly effective for local tumor control in patients with Stage I or II disease. Our results are inconclusive as to whether patients with poorly differentiated cancers should receive a local RT boost even when surgical margins are clear.

The reverse hockey stick technique: postmastectomy radiation therapy for breast cancer patients with locally advanced tumor presentation or extensive loco-regional recurrence.

A combination of photon and electron radiation therapy (RT) fields was devised to treat patients with initial or recurrent breast cancer presentations which extensively involved the chest wall (CW) and/or the axilla. The ipsilateral supraclavicular, infraclavicular, axillary, and lateral CW regions are treated in continuity by anterior and posterior opposed photon beam "reverse hockey stick" fields. The internal mammary and medial chest wall regions are treated by an anterior electron beam field which is tightly junctioned to the photon beam fields. Electron beam energy and thickness of applied bolus are selected so that the electron beam 80% depth isodose curve matches the anterior pleural surface and/or deepest extent of tumor. The goal of treatment is to deliver 4400-5000 cGy to regions at risk of microscopic tumor with local boosts to 6000-7500 cGy to sites of gross disease. Between January 1977, and June 1985, this technique was selectively used in 46 patients, 31 patients with loco-regional tumor recurrence and 15 post-mastectomy patients who initially presented with locally advanced disease. A minimum tumor dose of 4400 cGy was delivered in all except five patients. A diffuse moist skin reaction developed in 31 of the 44 (70%) patients who received at least 3800 cGy. This healed in less than 1 month in all except seven. Frequency of CW diffuse moist skin reaction within the electron beam field was related to the daily applied RT dose. Diffuse moist skin reactions were also noted to be more frequent among patients who had received prior or concurrent Adriamycin. Significant complications included symptomatic arm lymphedema in seven; CW ulcer in two; and acute radiation pneumonitis; steroid-withdrawal radiation pneumonitis, pleuritis, and marked thrombocytopenia in one patient each. With a follow-up of 36-100 months, there was no evidence of loco-regional tumor relapse in 55% of patients treated for recurrent disease and in 73% treated following mastectomy for locally advanced presentations. In summary, we find the reverse hockey stick technique to be a simple, highly reproducible and effective RT approach for postmastectomy breast cancer patients with extensive initial presentation or recurrent disease.

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.

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 patient's 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.

Wound-healing complications following biopsy of the irradiated breast.

A retrospective review evaluated results of 38 posttreatment biopsies (with resulting benign pathologic findings) that were performed on 32 irradiated breasts or axillae in 31 of 232 patients who underwent conservation treatment of early-stage breast cancer. Postbiopsy wound-healing complications developed in eight (30%) of 27 patients who were undergoing open biopsies but in none of 11 who underwent only needle biopsies. Wound-healing complications occurred in two of five patients who underwent incisional skin biopsy, three of five who underwent mammographic needle-localized excisional biopsy, and three of 17 who underwent other types of open biopsies. Frequency of wound-healing complications following open biopsy was not related to patient age, diabetes mellitus, cigarette smoking, or use of chemotherapy. Wound-healing complications were related to breast size, developing in four (67%) of six patients with large breasts (brassiere cup size D or DD) as compared with that in only four (19%) of 21 patients with smaller breasts. Significant worsening of cosmetic breast retraction was frequently associated with wound-healing complications, especially wounds that took more than 1 month to heal.

Carcinoma of penis. Review of cases treated by surgery and radiation therapy 1960-1977.

Cases of squamous cell carcinoma of the penis treated by surgery and radiation therapy at Moffitt Hospital, University of California, and Mount Zion Hospital and Medical Center are reviewed. Only cases followed for more than three years or with autopsy findings are presented. For the primary lesion, over-all surgical control rate locally was 15/17 or 88 per cent. Over-all control rate with radiation therapy alone was 9/12 (75 per cent), and with surgical salvage 11/12 (92 per cent). Radiation therapy appears to be the treatment of choice for early stage lesions, reserving surgery for salvage. Prophylactic ilioinguinal lymph node dissection for N0 lesions is not warranted. The role of chemotherapy needs further investigation.

Thermographically determined specific absorption rate patterns of 434-MHz applicators.

The specific absorption rate (SAR) patterns of two 434-MHz hyperthermia applicators, models TCA 434-1 (9 X 20 cm) and TCA 434-2 (13 X 25 cm), were evaluated thermographically using a phantom model. The phantom model consisted of a 2-cm-thick layer of fat and a 10-cm depth of muscle contained in a 30 X 30 cm base Plexiglas box. The model was bisected in the middle. Polyester screens at the interface allowed the synthetic gel to make electrical contact between the two halves of the muscle tissue. Octyl alcohol was applied to the fat interface to ensure continuity of dielectric properties. Thermograms were taken for both applicators over the following areas of the exposed model: (1) fat surface, (2) internal surface with E-field parallel to interface, and (3) internal surface with E-field perpendicular to interface. SAR's were calculated from the temperature rise (8 degrees C maximum), net input power (550-650 W), exposure time (15-60 s), and specific heat of the muscle (0.86 kcal/kg degrees C). A factor of 0.42 needs to be multiplied to correct for the specific heat of fat. High localized SAR's along the broad sides of the applicators were seen when the applicators were in direct contact with the phantom. With the use of a 0.8-cm polystyrene foam spacing, the SAR's within the aperture of the applicators were relatively uniform. The patterns of the two applicators were quite similar. However, the TCA 434-1 applicator is smaller and more applicable for clinical conditions.

Heating patterns of microwave applicators in inhomogeneous arm and thigh phantoms.

Heating rate (HR) patterns in cylindrical structures were studied with inhomogeneous limb phantoms. These phantoms, arm and thigh models consisting of fat, bone, and muscle material, were heated with Clini-Therm L, M, and MS applicators at 915 MHz. The thigh model is 18 cm in diameter with 2.65-cm-thick fat on the outside and a 4-cm-diam bone in the center. The arm model is 9 cm in diameter with 1.35-cm-thick fat and 2-cm-diam bone. All models are 29 cm long with phantom muscle in the space between fat and bone and were heated with their long axes parallel or perpendicular to the E field. HR patterns in the transverse and longitudinal planes were obtained thermographically. A large water bolus, with the water channels parallel to the E field, was used in every case. In the thigh model, maximum heating was in the muscle for both L and M applicators when the E field was parallel to the long axis. When it was perpendicular, the maximum heating occurred in the fat layer. However, the peak HR in the fat remained about the same for both E field orientations. For the small applicator, heating was mostly in the fat, and the two field orientations did not cause much difference in the heating pattern. In the arm model, the maximum heating of all three applicators occurred mostly in the muscle for both E-field orientations. However, the maximum HR was reduced by a factor of 2 to 3 when the E field was perpendicular rather than parallel to the long axis.(ABSTRACT TRUNCATED AT 250 WORDS)