- Email: [email protected]
In response to Drs. Chu and Solin
1268
I. J. Radiation
Oncology
0 Biology
0 Physics
our analyses (and, for that matter, from Dr. Ben-Josef’s recalculated curve); that is, that radiation oncologists should appreciate that the dose-response for subclinical disease is different from that for macroscopic disease, and that subclinical disease can be eliminated in a proportion of patients even when normal tissue intolerance demands the use of less than optimal doses. H. RODNEY WITHERS, M.D., LESTER J. PETERS, M.D.’
D.Sc.’
JEREMY M. G. TAYLOR, PH.D.’ ‘Department of Radiation Oncology Jonsson Comprehensive Cancer Center UCLA Los Angeles, CA 90095-1714 ‘Department of Radiotherapy M.D. Anderson Cancer Center Houston, TX 77030, 310 825-8278 1. Ben-Josef, 31:353-359;
CONFORMAL THE
and
Volume
32, Number IN
4, 1995
RESPONSE
TO
CANCER ET AL..
AND
SOLIN
PATRICK D. HIGGINS, PH.D. Department of Therapeutic Radiology University of Minnesota Minneapolis, MN 55455
OF COMBINING CANCER
To the Editor: The paper by Higgins et al. (3) describes an analysis on dose distributions within a cylindrical phantom containing spherical target volumes simulating cancer of pancreas. We have reported an analysis of three-dimensional treatment planning in 4 patients with cancer of the pancreas. The study was presented during the ASTRO meeting in 1989 (2) and we have subsequently published the results of the study in 1992 ( 1) In contrast to the study by Higgins et al., we compared the noncoplanar, opposed treatment techniques with the conventional coplanar treatments on both the target coverage and the dose to the normal tissues. Our studies were performed on 4 patients with target volumes ranging from 18-367 cm3 and the results indicated that at least 99% of all target volumes received IOO108% of the prescribed dose for all treatment field arrangements. We also found that the ability of a particular treatment technique to spare normal tissues varies from patient to patient and is dependent upon the particular normal tissue considered. For example, compared with standard 4-field treatment technique, a noncoplanar 4-field oblique technique delivers lower dose to the right kidney in only 3 of the 4 patients studied; the fourth patient would have received a higher right kidney dose if treated with the noncoplanar technique. In addition, the oblique fields may include other critical organs not included in standard treatment fields, such as heart, lung, and colon. Complex noncoplanar beam arrangements can be used to deliver radiation therapy on modem treatment machines. Phantom studies may be useful to provide preliminary guidelines for the delivery of such treatments. However, the patient-specific data are important and should be considered when evaluating the potential benefit of noncoplanar beams or other new treatment techniques. JAMES C. H. CHU, PH.D. Department of Medical Physics Rush Presbyterian St. Luke’s Medical Chicago, IL 60612
CHU
To the Editor: We agree completely with Chu and Solin’s comment that conformal treatment planning is a customized process specific to each patient. As such it is difficult to make generalized comparisons between different optimized approaches because the target volumes, target locations (with respect to critical structures), and target spatial distributions all contribute to the problem of building a conformal plan. Although we had a patient database of about 50 patients that could have been included in this analysis, we felt that the goal of this simple comparison, to demonstrate that equivalent conformal plans could be generated using a systematic method for the disposition of either low or high energy beams, combined with an example of the corresponding positioning errors, could be best presented in a phantom model. We did not intend to imply that conformal treatment planning of the pancreas was a simple procedure, but only to demonstrate the systematic approach we have used to provide flexibility in machine/energy selection.
E. Letter to the editor. Regarding Withers et al. IJROBI’ 1995. Int. J. Radiat. Oncol. Biol. Phys. 32:1267; 1995.
TREATMENT PLANNING FOR PANCREAS: REGARDING HIGGINS ZJROBP 31:605-669; 1995
DRS.
Center
FORCES OF THE FORASTIERE,
FOR TREATMENT HEAD AND NECK: ZJROBP 31:679-680;
To rhe Editor: Dr. Forastiere’s editorial ( 1) on the concurrent use of radiation and cisplatin represents the sort of joint oncologic thinking that deserves commendation. These patients are often hard enough to get through treatment with a sole modality. At the National Cancer Institute (NCI) we began a pilot project with 1.5 BID fractionation and continuous iododeoxyuridine and were essentially the only service that functioned on a day-to-day basis in the giving of chemotherapy and evaluating the patients. More sharing of the responsibilities, interest, and publication of results would have been beneficial. The pilot project, by nature of the drug, was a one-department effort that could have involved other subspecialties. We tried to do our best. We obtained biopsy samples to assure drug uptake and spent significant time with the patients. Toxicity was quite significant although the patients were not infrequently referred by good physicians, often academic who recognized pathology beyond a reasonable chance of control. The results were reasonably favorable as can be read in the Dec. 1995 JNCI. The pilot has nonetheless ended. Advanced head and neck cancer is a full-time job and there is the potential for significant need in patient aid. The disorder needs a team approach, with physicians from different disciplines-to get aggressive treatment-from diagnostic help in delineating tumor borders and potential grafting in huge but sterilized fields, to surgeons prepared to place gastric feeding tubes, to medical oncologists, especially able to determine when and what chemotherapy is optimal. Advanced head and neck cancer is a miserable way to die. Yet the patients seem hesitant to go through one modality and then on to another. Radiation oncologists have seen patients refuse treatment, drink alcohol during treatment, and get through one cancer modality only to say they do not want another. Dr. Forastiere is to be complimented on the ability to overcome many of the personality differences these patients have. Moreover, her call for further study, hopefully a large and unified study. of these diseases is key to some coherence in treatment.
LAWRENCE J. SOLIN, M.D. Department of Radiation Oncology Hospital of the University of Pennsylvania Philadelphia, PA 19104 Chu, J. C. H.; Solin, L. J.; Hwang, C. C.; Kessler, H.; Hanks, G. E. Three-dimensional dosimetric comparison of the radiation therapy treatment olannine. of the pancreas. Med. Dosim. 17:199-203; 1992. Chu, J.; S&n, L.;i-Iwang, c.; Kessler, H.; Hanks, G. Three-dimensional dosimetric comparison of the radiation therapy treatment techniques for carcinoma of pancreas. Int. J. Radiat. 011~01. Biol. Phys. (abstract) 17:142; 1989. Higgins, P. D.; Sohn, .I. W.; Fine, R. M.; S&U, M. Three-dimensional confomal pancreas treatment: Comparison of the four- to six-field techniques. Int. J. Radiat. Oncol. Biol. Phys. 31:605-669; 1995.
OF ADVANCED REGARDING 1995
THOMAS E. GOFFMAN, M.D. 1650 Jonquil St., NW Washington, DC 20012 I. Forastiere, A. A. Concurrent cisplatinum and radiation for advanced head and neck cancer. Int. J. Radiat. Oncol. Biol. Phys. 31:679680; 1995.
LETTER To the Editor: work of Withers
TO THE EDITOR ET AL., ZJROBP
REGARDING 31:865-873;
We wish to correct and clarify et al. that was cited as reference
STEPHENS 1995 our reference to the #39 in the discussion
I. J. Radiation
Oncology
0 Biology
0 Physics
our analyses (and, for that matter, from Dr. Ben-Josef’s recalculated curve); that is, that radiation oncologists should appreciate that the dose-response for subclinical disease is different from that for macroscopic disease, and that subclinical disease can be eliminated in a proportion of patients even when normal tissue intolerance demands the use of less than optimal doses. H. RODNEY WITHERS, M.D., LESTER J. PETERS, M.D.’
D.Sc.’
JEREMY M. G. TAYLOR, PH.D.’ ‘Department of Radiation Oncology Jonsson Comprehensive Cancer Center UCLA Los Angeles, CA 90095-1714 ‘Department of Radiotherapy M.D. Anderson Cancer Center Houston, TX 77030, 310 825-8278 1. Ben-Josef, 31:353-359;
CONFORMAL THE
and
Volume
32, Number IN
4, 1995
RESPONSE
TO
CANCER ET AL..
AND
SOLIN
PATRICK D. HIGGINS, PH.D. Department of Therapeutic Radiology University of Minnesota Minneapolis, MN 55455
OF COMBINING CANCER
To the Editor: The paper by Higgins et al. (3) describes an analysis on dose distributions within a cylindrical phantom containing spherical target volumes simulating cancer of pancreas. We have reported an analysis of three-dimensional treatment planning in 4 patients with cancer of the pancreas. The study was presented during the ASTRO meeting in 1989 (2) and we have subsequently published the results of the study in 1992 ( 1) In contrast to the study by Higgins et al., we compared the noncoplanar, opposed treatment techniques with the conventional coplanar treatments on both the target coverage and the dose to the normal tissues. Our studies were performed on 4 patients with target volumes ranging from 18-367 cm3 and the results indicated that at least 99% of all target volumes received IOO108% of the prescribed dose for all treatment field arrangements. We also found that the ability of a particular treatment technique to spare normal tissues varies from patient to patient and is dependent upon the particular normal tissue considered. For example, compared with standard 4-field treatment technique, a noncoplanar 4-field oblique technique delivers lower dose to the right kidney in only 3 of the 4 patients studied; the fourth patient would have received a higher right kidney dose if treated with the noncoplanar technique. In addition, the oblique fields may include other critical organs not included in standard treatment fields, such as heart, lung, and colon. Complex noncoplanar beam arrangements can be used to deliver radiation therapy on modem treatment machines. Phantom studies may be useful to provide preliminary guidelines for the delivery of such treatments. However, the patient-specific data are important and should be considered when evaluating the potential benefit of noncoplanar beams or other new treatment techniques. JAMES C. H. CHU, PH.D. Department of Medical Physics Rush Presbyterian St. Luke’s Medical Chicago, IL 60612
CHU
To the Editor: We agree completely with Chu and Solin’s comment that conformal treatment planning is a customized process specific to each patient. As such it is difficult to make generalized comparisons between different optimized approaches because the target volumes, target locations (with respect to critical structures), and target spatial distributions all contribute to the problem of building a conformal plan. Although we had a patient database of about 50 patients that could have been included in this analysis, we felt that the goal of this simple comparison, to demonstrate that equivalent conformal plans could be generated using a systematic method for the disposition of either low or high energy beams, combined with an example of the corresponding positioning errors, could be best presented in a phantom model. We did not intend to imply that conformal treatment planning of the pancreas was a simple procedure, but only to demonstrate the systematic approach we have used to provide flexibility in machine/energy selection.
E. Letter to the editor. Regarding Withers et al. IJROBI’ 1995. Int. J. Radiat. Oncol. Biol. Phys. 32:1267; 1995.
TREATMENT PLANNING FOR PANCREAS: REGARDING HIGGINS ZJROBP 31:605-669; 1995
DRS.
Center
FORCES OF THE FORASTIERE,
FOR TREATMENT HEAD AND NECK: ZJROBP 31:679-680;
To rhe Editor: Dr. Forastiere’s editorial ( 1) on the concurrent use of radiation and cisplatin represents the sort of joint oncologic thinking that deserves commendation. These patients are often hard enough to get through treatment with a sole modality. At the National Cancer Institute (NCI) we began a pilot project with 1.5 BID fractionation and continuous iododeoxyuridine and were essentially the only service that functioned on a day-to-day basis in the giving of chemotherapy and evaluating the patients. More sharing of the responsibilities, interest, and publication of results would have been beneficial. The pilot project, by nature of the drug, was a one-department effort that could have involved other subspecialties. We tried to do our best. We obtained biopsy samples to assure drug uptake and spent significant time with the patients. Toxicity was quite significant although the patients were not infrequently referred by good physicians, often academic who recognized pathology beyond a reasonable chance of control. The results were reasonably favorable as can be read in the Dec. 1995 JNCI. The pilot has nonetheless ended. Advanced head and neck cancer is a full-time job and there is the potential for significant need in patient aid. The disorder needs a team approach, with physicians from different disciplines-to get aggressive treatment-from diagnostic help in delineating tumor borders and potential grafting in huge but sterilized fields, to surgeons prepared to place gastric feeding tubes, to medical oncologists, especially able to determine when and what chemotherapy is optimal. Advanced head and neck cancer is a miserable way to die. Yet the patients seem hesitant to go through one modality and then on to another. Radiation oncologists have seen patients refuse treatment, drink alcohol during treatment, and get through one cancer modality only to say they do not want another. Dr. Forastiere is to be complimented on the ability to overcome many of the personality differences these patients have. Moreover, her call for further study, hopefully a large and unified study. of these diseases is key to some coherence in treatment.
LAWRENCE J. SOLIN, M.D. Department of Radiation Oncology Hospital of the University of Pennsylvania Philadelphia, PA 19104 Chu, J. C. H.; Solin, L. J.; Hwang, C. C.; Kessler, H.; Hanks, G. E. Three-dimensional dosimetric comparison of the radiation therapy treatment olannine. of the pancreas. Med. Dosim. 17:199-203; 1992. Chu, J.; S&n, L.;i-Iwang, c.; Kessler, H.; Hanks, G. Three-dimensional dosimetric comparison of the radiation therapy treatment techniques for carcinoma of pancreas. Int. J. Radiat. 011~01. Biol. Phys. (abstract) 17:142; 1989. Higgins, P. D.; Sohn, .I. W.; Fine, R. M.; S&U, M. Three-dimensional confomal pancreas treatment: Comparison of the four- to six-field techniques. Int. J. Radiat. Oncol. Biol. Phys. 31:605-669; 1995.
OF ADVANCED REGARDING 1995
THOMAS E. GOFFMAN, M.D. 1650 Jonquil St., NW Washington, DC 20012 I. Forastiere, A. A. Concurrent cisplatinum and radiation for advanced head and neck cancer. Int. J. Radiat. Oncol. Biol. Phys. 31:679680; 1995.
LETTER To the Editor: work of Withers
TO THE EDITOR ET AL., ZJROBP
REGARDING 31:865-873;
We wish to correct and clarify et al. that was cited as reference
STEPHENS 1995 our reference to the #39 in the discussion