03603016/92 $5.00 + .oO Copyright 0 1992 Pergamon Press Ltd.
1111.I Rodiomn Oncology Bwl. Phys.. Vol. 24. pp. 805-807 Printed in the U.S.A. All nghts reserved.
??Correspondence
nostic indicators of Gleason’s category. Dr. Hanks (4) has shown through Current Patterns of Care studies that radiation is equal to surgery in early stages of prostate cancer. There is little survival difference in radiation of the prostate versus prostatectomy. With more accurate staging, survival should be at the highest means, and therefore there should be less complications overall. With the advent of further staging, I feel that radiation can show less complications that previously shown through studies. With the combination of Iaproscopic sampling and other metastatic work up, radiation therapy would be of great value in treating many patients, with less side effects and complications.
BLOCK MOUNTING SOLVENTS To fhe Editor: In a technical note published in the Journal in 1987 ( I), we described a method of attaching shielding blocks to patient blocking trays using a high-strength double-stick tape. At the time, most blocking trays were made of methyl methacrylate (e.g., Lucite, Perspex) and we recommended that the reasonably non-toxic solvent acetone be used to remove adhesive residue from the trays. In recent years, the use of polycarbonate (e.g., Lexan) trays has dramatically increased. Acetone cannot be used on this plastic without damaging the surface, and we have learned that some potential users of the technique have been dissuaded from this approach because of that problem. This letter is intended to advise the community that naphtha is a suitable solvent for tape removal on polycarbonate trays. It is also relatively non-toxic and is widely available because of its common use as a paint thinner.
L. SHULTZ,D.O. Dept. of Radiation Oncology Macomb Hospital Center I 1800 E. Twelve Mile Rd. Warren, MI 48093
GARY
ROBERTJ. BARISH,PH.D. The Cancer Institute Catholic Medical Center of Brooklyn & Queens Jamaica, NY 11432
KEITH
SHULTZ
University of Iowa Medical School Iowa City, IA 52242 1. Arduino, L. J.; Glucksman, M. A. Lymph node metastasis in early carcinoma of the prostate. J. Ural. 8:91;1962. 2. Brausi, M.; Soloway, M. Progression and complications after externalbeam radiation therapy for carcinoma of the prostate. Ural. 34: 11S119;1989. 3. Flocks, R. H.; Gulp, D.; Poto, R. Lymphatic spread from prostatic cancer. J. Ural. 81:194;1959. 4. Hanks, G. E. External-beam radiation therapy for clinically local&d prostate cancer: Patterns of care studies in the United States. Consensus Development Conference of the Management of Clinically Localized Prostate Cancer. NC1 Monog. 7:75-84;1988. 5. Kuban, D. A.; El-Mandi, A. M.; Schellhammer, P. F. Prognosis in patients with local recurrence atter definitive irradiation for prostatic carcinoma. Cancer 63:242 l-2425; 1989.
I. Barish, R. J. Shielding block mounting with double-stick tape. Int. J. Radiat. Oncol. Biol. Phys. 13:133-134;1987.
EXTERNAL RADIATION THERAPY VERSUS PROSTATECTOMY To the Edifor: Historically, patients with early prostatic carcinoma have been treated with external radiation therapy or radical prostatectomy surgery. There is a great controversy as to the appropriate treatment of choice. External radiation therapy versus prostatectomy have shown to be equal in results. I feel that the difference in any study has been due to the staging; the radiation therapy to the prostate has been done without evaluating the lymph nodes. This has not been done secondary to the morbidity associated with a pelvic lymphectomy. A recent technological alternative has been pelvic lymph node sampling through laproscopic examination. It has a distinct advantage of: a short hospital stay, less debilitating, and the ability to obtain results to be used to complete the patient’s staging. Several studies, including Dr. Flock’s and Associates ( 3), aswell as Dr. Arduino and Dr. Glucksman ( 1) have shown pelvic staging lymphectomy to be a definitive value as a predictor of prognosis. Whitmore and Associates report 40% of the patient’s who have had lymph node involvement fail within 2 years. Hilaris and Associates show that 75% of the patient’s with lymph node involvement will have metastatic disease within five years of treatment. Recently, it has been shown that pelvic dissection versus sampling has not been a curetive procedure. Sagerman and Associates show evidence that a dissection is only a prognostic predicator. With the advent of laproscopic sampling, we can assure a better and more accurate staging for our definitive radiation therapy. Studies have shown that small field irradiation subsides with the acute reactions, allowing less acute cystitis, diarrhea and interruptions of the patient’s treatment schedule. The Joint Center for Radiation Therapy’s recent study shows a significantly higher complication rate with a large field technique compared to a small field technique. An 8.7 versus 1.6% complication rate showed that the small field technique was better tolerated by the patients. In the past measures have condemned definitive radiation therapy to the prostate as having decreased survival compared to surgical prostatectomy. There are several indicators showing false dam in these series. This allowed the older patient to be treated by radiation for poorer prog-
OXYGEN ENHANCEMENT RATIO OF A MURINE FIBROSARCOMA To the Editor: In a recent article in the Int. J. Radial. Oncol. Biol. Phys.,Abe et al. ( 1) presented excellent experimental data on the response of a murine fibrosarcoma to a fractionated irradiation treatment. From their results, the authors claimed that the oxygen enhancement ratio was greater than 3.0. We do not agree with this conclusion, since it is not feasible to calculate the OER by dividing the a/@ ratios of the hypoxic and oxic dose response curves. The oxygen enhancement ratio is defined as the ratio of the doses that are required to achieve a given effect of radiation under absence and presence of oxygen. Since the dose response curves are not linear the OER is a function of dose. This function can be calculated using the linear-quadratic model: -log(SF) Boeffectivity is achieved if:
805
= ad + @d2.
(1)
1111.I Rodiomn Oncology Bwl. Phys.. Vol. 24. pp. 805-807 Printed in the U.S.A. All nghts reserved.
??Correspondence
nostic indicators of Gleason’s category. Dr. Hanks (4) has shown through Current Patterns of Care studies that radiation is equal to surgery in early stages of prostate cancer. There is little survival difference in radiation of the prostate versus prostatectomy. With more accurate staging, survival should be at the highest means, and therefore there should be less complications overall. With the advent of further staging, I feel that radiation can show less complications that previously shown through studies. With the combination of Iaproscopic sampling and other metastatic work up, radiation therapy would be of great value in treating many patients, with less side effects and complications.
BLOCK MOUNTING SOLVENTS To fhe Editor: In a technical note published in the Journal in 1987 ( I), we described a method of attaching shielding blocks to patient blocking trays using a high-strength double-stick tape. At the time, most blocking trays were made of methyl methacrylate (e.g., Lucite, Perspex) and we recommended that the reasonably non-toxic solvent acetone be used to remove adhesive residue from the trays. In recent years, the use of polycarbonate (e.g., Lexan) trays has dramatically increased. Acetone cannot be used on this plastic without damaging the surface, and we have learned that some potential users of the technique have been dissuaded from this approach because of that problem. This letter is intended to advise the community that naphtha is a suitable solvent for tape removal on polycarbonate trays. It is also relatively non-toxic and is widely available because of its common use as a paint thinner.
L. SHULTZ,D.O. Dept. of Radiation Oncology Macomb Hospital Center I 1800 E. Twelve Mile Rd. Warren, MI 48093
GARY
ROBERTJ. BARISH,PH.D. The Cancer Institute Catholic Medical Center of Brooklyn & Queens Jamaica, NY 11432
KEITH
SHULTZ
University of Iowa Medical School Iowa City, IA 52242 1. Arduino, L. J.; Glucksman, M. A. Lymph node metastasis in early carcinoma of the prostate. J. Ural. 8:91;1962. 2. Brausi, M.; Soloway, M. Progression and complications after externalbeam radiation therapy for carcinoma of the prostate. Ural. 34: 11S119;1989. 3. Flocks, R. H.; Gulp, D.; Poto, R. Lymphatic spread from prostatic cancer. J. Ural. 81:194;1959. 4. Hanks, G. E. External-beam radiation therapy for clinically local&d prostate cancer: Patterns of care studies in the United States. Consensus Development Conference of the Management of Clinically Localized Prostate Cancer. NC1 Monog. 7:75-84;1988. 5. Kuban, D. A.; El-Mandi, A. M.; Schellhammer, P. F. Prognosis in patients with local recurrence atter definitive irradiation for prostatic carcinoma. Cancer 63:242 l-2425; 1989.
I. Barish, R. J. Shielding block mounting with double-stick tape. Int. J. Radiat. Oncol. Biol. Phys. 13:133-134;1987.
EXTERNAL RADIATION THERAPY VERSUS PROSTATECTOMY To the Edifor: Historically, patients with early prostatic carcinoma have been treated with external radiation therapy or radical prostatectomy surgery. There is a great controversy as to the appropriate treatment of choice. External radiation therapy versus prostatectomy have shown to be equal in results. I feel that the difference in any study has been due to the staging; the radiation therapy to the prostate has been done without evaluating the lymph nodes. This has not been done secondary to the morbidity associated with a pelvic lymphectomy. A recent technological alternative has been pelvic lymph node sampling through laproscopic examination. It has a distinct advantage of: a short hospital stay, less debilitating, and the ability to obtain results to be used to complete the patient’s staging. Several studies, including Dr. Flock’s and Associates ( 3), aswell as Dr. Arduino and Dr. Glucksman ( 1) have shown pelvic staging lymphectomy to be a definitive value as a predictor of prognosis. Whitmore and Associates report 40% of the patient’s who have had lymph node involvement fail within 2 years. Hilaris and Associates show that 75% of the patient’s with lymph node involvement will have metastatic disease within five years of treatment. Recently, it has been shown that pelvic dissection versus sampling has not been a curetive procedure. Sagerman and Associates show evidence that a dissection is only a prognostic predicator. With the advent of laproscopic sampling, we can assure a better and more accurate staging for our definitive radiation therapy. Studies have shown that small field irradiation subsides with the acute reactions, allowing less acute cystitis, diarrhea and interruptions of the patient’s treatment schedule. The Joint Center for Radiation Therapy’s recent study shows a significantly higher complication rate with a large field technique compared to a small field technique. An 8.7 versus 1.6% complication rate showed that the small field technique was better tolerated by the patients. In the past measures have condemned definitive radiation therapy to the prostate as having decreased survival compared to surgical prostatectomy. There are several indicators showing false dam in these series. This allowed the older patient to be treated by radiation for poorer prog-
OXYGEN ENHANCEMENT RATIO OF A MURINE FIBROSARCOMA To the Editor: In a recent article in the Int. J. Radial. Oncol. Biol. Phys.,Abe et al. ( 1) presented excellent experimental data on the response of a murine fibrosarcoma to a fractionated irradiation treatment. From their results, the authors claimed that the oxygen enhancement ratio was greater than 3.0. We do not agree with this conclusion, since it is not feasible to calculate the OER by dividing the a/@ ratios of the hypoxic and oxic dose response curves. The oxygen enhancement ratio is defined as the ratio of the doses that are required to achieve a given effect of radiation under absence and presence of oxygen. Since the dose response curves are not linear the OER is a function of dose. This function can be calculated using the linear-quadratic model: -log(SF) Boeffectivity is achieved if:
805
= ad + @d2.
(1)
