John O. Archambeau

Breast retraction assessment: an objective evaluation of cosmetic results of patients treated conservatively for breast cancer☆

Breast Retraction Assessment (BRA) is an objective evaluation of the amount of cosmetic retraction of the treated breast in comparison to the untreated breast in patients who receive conservative treatment for breast cancer. A clear acrylic sheet supported vertically and marked as a grid at 1 cm intervals is employed to perform the measurements. Average BRA value (+/- standard deviation) in 29 control patients without breast cancer was 1.2 cm (+/- 0.7 cm). Average BRA value in 27 patients treated conservatively for clinical Stage I or II unilateral breast cancer was 3.7 cm (+/- 2.1 cm). BRA values in breast cancer patients ranged from 0.0 to 8.5 cm. Statistical analysis revealed that tumor size, employment of adjuvant chemotherapy and use of separate radiation lymph node fields were not factors in breast retraction. Patients who received a local radiation boost to the primary tumor bed site had statistically significantly less retraction than those who did not receive a boost. Patients who had an extensive primary tumor resection had statistically significantly more retraction than those who underwent a more limited resection. In comparison to qualitative forms of cosmetic analysis, BRA is an objective test that can quantitatively evaluate factors which may be related to cosmetic retraction in patients treated conservatively for breast cancer.

Interstitial implant with interstitial hyperthermia

A Phase I Pilot Study combining interstitial or intracavitary irradiation using 192Ir or 137Cs and interstitial hyperthermia in advanced or recurrent tumors is underway at the City of Hope National Medical Center. Hyperthermia is performed using 0.5 megahertz RF (500 kilohertz) radiofrequency localized current fields. In the implanted volume, a temperature of 41° to 45°C is maintained for 30 to 40 minutes. Hyperthermia is performed prior to irradiation in all patients. All patients had either failed previous conventional treatments, including surgery, chemotherapy and/or radiation therapy, or had advanced malignant tumors which were not felt to be controllable by conventional means. Sixteen lesions were implanted in 15 patients. Of the 16 lesions, 11/16 (68%) achieved complete response, and three had no response or recurred locally. The six patients (100%) receiving interstitial implant and hyperthermia as the primary therapy achieved complete response. Normal tissue complications were minimal. Range of response was three to 13 months. Interstitial thermoradiotherapy appears to be a safe and promising mode of therapy in advanced or recurrent accessible malignant tumors.

Interstitial hyperthermia and interstitial iridium 192 implantation: A technique and preliminary results

Abstract A simple technique using interstitial hypertbermia in combination with interstitial Iridium 192 implantation is described in detail. This technique was initially tested on swine and later successfully tested on seven patients. The preliminary results of the City of Hope Interstitial Hyperthermia Pilot protocol are stated. The authors feel that this simple technique could be used by any radiation oncologist while performing interstitial implants in selected sites.

Critical evaluation of the role of nutritional support for radiation therapy patients

Nutritional intake or absorption may be compromised by radiation therapy (RT) when large portions of the gastrointestinal tract are treated. Dietary counseling, oral supplements, tube feedings and intravenous hyperalimentation (IVH) have been employed to limit weight loss and lessen intestinal RT side effects. Unfortunately, no prospective study reviewed has shown improved tumor control or patient survival. Special diets and IVH have also been employed in select patients to relieve chronic malabsorption from severe radiation enteritis.

Use of variable thickness bolus to control electron beam penetration in chest wall irradiation

Abstract Construction of a variable thickness bolus modifies the electron beam penetration to accomodate differences in target thickness. This technique reduces the integral dose to underlying sensitive normal tissues, and permits increased flexibility in dose delivery to the designated volume. The technique has been found useful in electron beam irradiation of large chest wall lesions in 18 patients with recurrent, residual or suspected breast carcinoma post-mastectomy. The great flexibility shows individually tailored therapy. Patients tolerate the 5006–5600 rad delivered to the skin and the 4000–4500 delivered at depth in 6 weeks. Except for skin, which is at risk, there are no adverse reactions. Residual disease received local boost irradiation. The pattern of response following this program is similar to that found for photon therapy.

FIELD SIZE DEPENDENCE OF RADIATION SENSITIVITY AND DOSE FRACTIONATION RESPONSE IN SKIN

Four sets of data from the literature were analyzed to assess the effects of field size on dose tolerance and dose fraction size dependence in irradiated skin. The data consisted of combinations of total dose and dose per exposure (or number of fractions) required to yield a given degree of visible damage to the skin, for fields of different sizes. Putative cell survival curves were constructed, under the assumptions that the isoeffect represents a fixed cell survival, and that each exposure during a course of fractionated irradiation has equal effect on cell survival. The analysis showed that overall sensitivity to radiation, and dependence on dose per exposure, both increase with field size. To account for these results we describe a model that can be qualitatively related to the geometric properties of the dermal vascular network. First, vascular function after irradiation should depend on the length of the vessels exposed to the radiation. This directly predicts an increasing sensitivity in large irradiated fields. Furthermore, if vascular function determines radiation response, the shape of the shoulder (low-dose) region of the effective survival curve will depend on the average number of vessels nourishing each cell, with a more pronounced shoulder for a high multiplicity of vessels. The model predicts a greater fractionation sensitivity in large than in small fields, in agreement with our analysis of the isoeffect data. It is therefore possible that the advantages of hyperfractionation in reducing late effects in normal tissues may be related to vascular architecture, and not to inherent differences between late and acutely responding cell populations.

The development of metastases within a field of previous irradiation: A case report

The development of metastatic chest wall growths from a primary nasopharyngeal carcinoma is described. The growths developed only in areas previously irradiated prophylactically and sharply outlined the treatment portals. The adjacent skin appeared completely normal. The possible mechanisms underlying this phenomenon are reviewed.

Lack of correlation between basal cell survival and gross response in irradiated swine skin

The relationship between basal cell survival and gross response in irradiated swine skin was tested by comparing dose survival curves derived from time-dose isoeffect data with curves obtained directly from basal cell counts in histological sections. Assuming equal effect per exposure and constant cell survival at isoeffect, best-fitting single-hit multi-target and linear-quadratic response curves were determined for time-dose schedules resulting in non-healing of 50% of irradiated fields. Basal cell survivals for single doses of 970, 1649, 2231, and 2619 rad were estimated 1) by counting regenerating islands and 2) by monitoring total basal cell counts through time. The dose survival curve derived from the isoeffect data was steeper than the curve obtained from direct basal cell counts. Furthermore, the direct basal cell survival curve extrapolates to less than 100% at zero dose, indicating the presence of a resistant basal cell subpopulation. The data show that the isoeffect in this case is not strongly coupled to basal cell survival. Rather, the probability of healing of an irradiated field is more sensitive to the dose per fraction than is basal cell survival, implying a contribution to non-healing from damage to stromal elements such as the capillary endothelium.

Acute normal tissue tolerance to 7 day per week accelerated fractionation.

Fifty-six sites in 49 patients were irradiated by a 7 day/week accelerated fractionation schedule to conventional tumor doses. Daily doses were 180 to 200 rad in 85% of sites. Patients were analyzed for normal tissue tolerance. A 7 day/week accelerated fractionation appears clinically tolerable at 180 rad per fraction.