Engikolai C. Krishnan

Breast Conservation Therapy with Tumor Bed Irradiation Alone in a Selected Group of Patients with Stage I Breast Cancer

Abstract: Radiotherapy after breast‐conserving surgery increases local control. We tested the feasibility of limited surgery with tumor bed irradiation only with 192Ir in a selected group of patients with stage I breast cancer. Twenty‐five breasts in 24 women more than 60 years old with low‐ or intermediate‐grade stage I tumors were treated with placement of interstitial catheters at the time of lumpectomy and axillary node dissection. This procedure was followed by after‐loading with low‐dose 192Ir to deliver 20–25 Gy to the tumor bed over 24–48 hours. There were neither local recurrences in the breast nor distant recurrences at a median follow‐up of 47 months (range 25–90 months). Cosmetic appearance ranged from very good to excellent. There were no long‐term complications. It is feasible to treat a select group of patients with tumor bed irradiation, using relatively low doses of interstitial irradiation, with excellent local control and no significant morbidity.

Consideration of physical parameters to predict thermal necrosis in acrylic cement implants at the site of giant cell tumors of bone

In the previous paper we had developed a general thermodynamic equation describing a polymethylmethacrylate implant at the site of giant cell tumors. In this paper we consider various characteristics of bone and methylmethacrylate crucial to the analysis such as thermal conductivity, specific heat, density, and heat generation. Also, an estimation of the temperature at which adjacent cells die is analyzed from literature. Finally, using the physical constants measured in laboratory situations a temperature profile is developed at various depths of bone that could facilitate predicting the zone of necrosis. These analyses show the maximum temperature attained in the acrylic cement-bone system depends primarily on the volume of the implant, the relative proportion of polymerization of the monomer, the temperature at which the monomer and polymer are mixed together, and the time lapse between the beginning of polymerization and implantation into the bone cavity. The temperature profile is shown to be relatively insensitive to the geometry of the system, greatly simplifying the analysis.

Renal cell carcinoma--angioinfarction.

In our experience the mortality rate in 46 patients who underwent angioinfarction for renal cell carcinoma was 4 per cent. Fever, ileus and leukocytosis were noted in 86 to 90 per cent of our patients. The use of absolute ethanol as a medium for renal infarction was associated with a significant incidence of damage to other organs. A 30 per cent decrease in tumor volume following angioinfarction using absorbable gelatin sponge and Gianturco coils was noted in 75 per cent of the patients. There was no evidence of metastatic tumor reduction and we could not document any significant decrease in operative time or blood loss. It would appear that there is some increased survival rate in patients with metastasis who are given adjuvant immune ribonucleic acid therapy. However, the numbers in our series are not significant to draw any definite conclusion. It is apparent that patients treated with infarction, delayed nephrectomy and medroxyprogesterone acetate did not have any significant survival over those treated with palliative nephrectomy or chemotherapy. The macrophage maturation assay may be useful during clinical followup.

Cosmetic results in early breast cancer treated with lumpectomy, peri-operative interstitial irradiation, and external beam radiation

Patients with operable breast cancer were treated at the University of Kansas Medical Center with lumpectomy, peri-operative interstitial Iridium, and external beam radiotherapy, and concomitant adjuvant chemotherapy in a majority of node positive cases. Examination of the cosmetic results in 85 breasts followed for at least 2 years, at a median of 41 months revealed 20% to be excellent, 44% to be very good, 24% good, 9% fair, and 4% to have poor results. In this paper cosmesis is analyzed with reference to the size of the primary, its location, age of the patient, whether the patient received adjuvant chemotherapy, and whether the regional nodes were treated. In this group of patients, the size and the site of the primary, patients age, and whether adjuvant chemotherapy was administered or not, did not adversely affect the aesthetic outcome. Treatment of the regional nodes gave a worse mean cosmetic score compared to the group in whom only the breast was treated (37.51 vs. 58.98 respectively, p less than 0.001). Among the 11 patients with fair/poor cosmesis, all had regional nodal treatment, 7/11 had inner quadrant lesions, and 7/11 had lesions greater than T1. Further follow-up and accrual would be needed to confirm our results and affirm if other factors would change.

Electron beam irradiation after reconstruction with silicone gel implant in breast cancer

Irradiation for breast cancer in the presence of a silicone gel breast prosthesis is sometimes necessary. There is a concern among radiation and other oncologists as to whether the presence of the prosthetic implant would interfere with delivery of the needed irradiation doses. Electron beams, with their finite penetration and rapid fall-off, offer a mode of adequately treating the recurrence and minimizing the radiation to the underlying normal structures, such as the lung and the heart. The dose distribution using 9–20 MeV electrons in the presence of a breast prosthesis is compared to the dose distribution without the implant in a tissue equivalent water phantom. The results reveal no significant difference in the dose delivered due to the presence of the prosthesis. Clinical verification of the dosimetry in the presence of the prosthesis confirmed that the presence of the silicone gel implant does not compromise treatment by irradiation in the management of breast cancer.

Effect of silicone gel breast prosthesis on electron and photon dose distributions

The effect of a silicone gel breast prosthesis on the absorbed dose distribution of 9-20 MeV electron beams and 1.25-15 MV photon beams was studied. Compared to water measurements, at depths smaller than the practical range of the electron beams, the central axis depth dose values below the prosthesis were lower for all energies by as much as 3.5%. However, at depths near the practical range, the central axis depth dose values for the prosthesis were greater than that of water by as much as 33%. Since this occurs near the end of the electron range, the resultant difference may not be clinically significant. Results of the effect of breast prosthesis on photon depth dose distributions reveal that no clinically significant perturbation is produced by the breast prosthesis using Co-60, 6- and 15-MV radiations.

Radiobiological advantages of an immediate interstitial boost dose in conservative treatment of breast cancer

Minimum surgery with irradiation is emerging as one of the main modalities of therapy for operable early breast cancer. Between June 1982 and June 1986, 110 breasts with Tis, T1 to T3 lesions have been treated at our institution with lumpectomy and interstitial irradiation to the tumor bed with Iridium-192 perioperatively followed by external beam irradiation. There have been two local recurrences at or near the vicinity of the primary, at a median follow-up of 60 months. To analyze the parameters that might have contributed to the local control, we have examined the treatment volumes, prescribed dose to the tumor bed, dose at the core of the tumor bed, and dose to the surrounding normal tissue. Immediate interstitial implant has the radiobiological advantage of delivering continuous low dose irradiation, immediately upon removal of gross tumor to residual foci. Implantation of the afterloading catheters intraoperatively facilitates accurate dose delivery and avoidance of geographical misses. By precise treatment of any residual foci, immediately upon removal of the gross mass, perioperative interstitial irradiation improves local control and by facilitating less radical surgical excision, leads to better cosmetic results.

Theoretical treatment of the distribution and degradation of vascular, interstitial and intracellular albumin.

Abstract The distribution and kinetics of albumin in the biological system is developed based on a catenary three-compartmental model, the three compartments representing the vascular pool, the intestitial pool and a third pool which is presumed to be intracellular. Solutions are derived to describe the behaviour of albumin in each of the three compartments in terms of transfer rate constants which can be calculated from the individual pool sizes. Then, the model is modified imposing certain constraints and appropriate solutions are derived. Finally, alternate models are proposed and analyzed. Though the theoretical model has been developed for the distribution and degradation of albumin, the same model can be applied to the distribution and degradation of other macromolecules in the biological system.

Quantitative radioimmunoassay of immunoglobulins on the surface of human tumor cells

Abstract Indirect radioimmunoassay can be used to detect surface immunoglobulins on tumor cells. In this study, 460–1140 ng of immunoglobulins per 10 6 cells was found on a variety of tumor cells. Peripheral lymphocytes also were assayed for surface immunoglobulins and from 340 to 1045 ng/10 6 cells were found. Cultured tumor cells, on the other hand, were found to contain only negligible quantities of immunoglobulin. The technique of radioimmunoassay of immunoglobulins on cells is described and the physiologic implications are discussed.

Breast conservation treatment with perioperative interstitial irradiation

Limited resection of the breast combined with radiation has proved to be as effective as more radical surgery in treating early breast cancer. At the University of Kansas Medical Center, the radiotherapy consists of an interstitial implant at the time of lumpectomy to deliver an interstitial boost dose to the tumor bed with iridium-192 immediately following the surgical procedure. An axillary node dissection is also performed at the time of lumpectomy. A dose of 2,000 cGy is delivered to the tumor bed between 40 and 60 h. Two to three weeks later, 4,500–5,000 cGy is delivered to the entire breast with external beam radiation over 5–5.5 weeks. One hundred breasts in 98 patients were so treated between June 1982 and February 1986, with 2 carcinomas in situ, 40 stage I, 51 stage II, and 7 stage III cancers, consisting of 2 TIS, 54 T1, 39 T2, and 5 T3 lesions. Locoregional control with a median follow-up of 31 months was 98%. One recurrence was in a different quadrant, and the other revealed predominantly the in situ component. Immediate implant did not compromise wound healing or cosmesis. The cosmetic result was graded as good to excellent in 88% of the breasts. Our preliminary results appear to suggest a better local control with immediate interstitial irradiation.