Genetic variants of NPAT-ATM and AURKA are associated with an early adverse reaction in the gastrointestinal tract of patients with cervical cancer treated with pelvic radiation therapy.

PURPOSE: This study sought to associate polymorphisms in genes related to cell cycle regulation or genome maintenance with radiotherapy (RT)-induced an early adverse reaction (EAR) in patients with cervical cancer. METHODS AND MATERIALS: This study enrolled 243 cervical cancer patients who were treated with pelvic RT. An early gastrointestinal reaction was graded using the National Cancer Institute Common Toxicity Criteria, version 2. Clinical factors of the enrolled patients were analyzed, and 208 patients were grouped for genetic analysis according to their EAR (Grade ≤1, n = 150; Grade ≥2, n = 58). Genomic DNA was genotyped, and association with the risk of EAR for 44 functional single-nucleotide polymorphisms (SNPs) of 19 candidate genes was assessed by single-locus, haplotype, and multilocus analyses. RESULTS: Our analysis revealed two haplotypes to be associated with an increased risk of EAR. The first, comprising rs625120C, rs189037T, rs228589A, and rs183460G, is located between the 5' ends of NPAT and ATM (OR = 1.86; 95% CI, 1.21-2.87), whereas the second is located in the AURKA gene and comprises rs2273535A and rs1047972G (OR = 1.75; 95% CI, 1.10-2.78). A third haplotype, rs2273535T and rs1047972A in AURKA, was associated with a reduced EAR risk (OR = 0.42; 95% CI, 0.20-0.89). The risk of EAR was significantly higher among patients with both risk diplotypes than in those possessing the other diplotypes (OR = 3.24; 95% CI, 1.52-6.92). CONCLUSIONS: Individual radiosensitivity of intestine may be determined by haplotypes in the NPAT-ATM and AURKA genes. These variants should be explored in larger association studies in cervical cancer patients.

Can MRI predict local control rate of uterine cervical cancer immediately after radiation therapy?

PURPOSE: To evaluate the utility of measuring the volumes of areas of high signal intensity on T(2)-weighted magnetic resonance (MR) images immediately after irradiation for predicting the local control rate of uterine cervical cancer. MATERIALS AND METHODS: From our departmental database, we identified 109 patients with cervical cancer who underwent MR imaging before irradiation and just before or just after completion of radiation therapy from 1994 to 2007. We included 46 of the 109 patients in this study, 5 patients with local recurrence and 41 patients who were free of disease for more than 2 years. Fifteen received radiation therapy alone, and 28 patients received concurrent chemoradiation therapy. We measured the volumes of areas of high signal intensity involving the uterine cervix on T(2)-weighted MR images before radiation therapy and just before or just after its completion. We measured the 3 orthogonal diameters to calculate the volume as an ellipsoid and evaluated proportional tumor volume and the rate of reduction. We analyzed statistics with Student's t-test. RESULTS: In patients with local recurrence, the mean volume of the areas of high signal intensity on T(2)-weighted MR images just before completion of irradiation therapy or just after was 19.70 cm(3), which was significantly larger than that in patients without recurrence (1.77 cm(3), P<0.05). The proportional tumor volume was also significantly larger (P<0.05). CONCLUSIONS: Although areas of high signal intensity on T(2)-weighted MR images include acute radiation change, their volume and the proportional tumor volume after irradiation can be useful clues in predicting the local control rate of uterine cervical cancer.

Limited thymectomy for stage I or II thymomas.

BACKGROUND: Once an anterior mediastinal tumor has been diagnosed as a thymoma, complete excision including the thymic gland and perithymic fat is currently the procedure of choice. However, little is known about the clinical outcome of grossly encapsulated thymomas excised only with the surrounding tissue while leaving a part of the thymic gland. METHODS: A retrospective historical comparative study was conducted on 79 patients who had received surgery for stage I (n=25) or stage II (n=54) thymomas. Total thymectomy was performed in 61 patients (Total Thymectomy Group), whereas resection of tumors with only the surrounding tissue was carried out in 18 (Limited Thymectomy Group). The follow-up interval was longer in the Limited Thymectomy Group because these patients were treated longer ago (104.2+/-58.1 months vs 67.3+/-54.8 months, p<0.05). RESULTS: One case in the Limited Thymectomy Group showed postoperative myasthenia gravis (5.6%). Two patients with multiple thymomas (2.5%) were treated with total thymectomy. One case in the Limited Thymectomy Group, which had been diagnosed as Masaoka stage II and WHO type B3 at initial surgery, recurred. None died of tumor progression in this study. Disease free survival rates at 10 years did not differ between the Limited Thymectomy and Total Thymectomy Groups (85.7% and 82.0%, respectively). There were no statistical differences in the incidence of postoperative myasthenia gravis and disease free survival between the two groups. CONCLUSION: Resection of thymomas with surrounding tissue instead of total thymectomy can be indicated for stage I or II thymomas in light of disease free and overall survival, post-operative onset of MG, and the incidence of multiple lesions.

Malignant myoepithelioma in the maxillary sinus: case report and review of the literature.

Malignant myoepithelioma of the head and neck usually arises in the salivary glands. We experienced a rare case with malignant myoepithelioma in the maxillary sinus. A 47-year-old woman with malignant myoepithelioma in the maxillary sinus underwent partial maxillectomy. However, local recurrence occurred 28 months after surgery and she was subsequently treated with radiation therapy with proton beams. The recurrent tumor showed complete response and the patient was alive with no evidence of disease 30 months after irradiation. No therapy-related severe toxicities were observed. A rare case with malignant myoepithelioma in the maxillary sinus was successfully treated with radiation therapy.

Comparison of tumor regression rate of uterine cervical squamous cell carcinoma during external beam and intracavitary radiotherapy.

PURPOSE: We compared the radioresponse of cervical carcinoma that was closely related to local disease control by the tumor regression rate (RR) during intracavitary radiotherapy (ICRT) and external beam radiotherapy (EBRT) on the presumption that ICRT has a stronger treatment impact than EBRT because of its specific dose distribution. MATERIALS AND METHODS: A total of 37 patients were treated by EBRT at 45.0 Gy over 5 weeks, followed by high-dose-rate ICRT at 6.0 Gy per weekly insertion at point A three to five times and by boost EBRT. RR was defined as the slope (day(-1)) of the tumor-volume shrinkage curve fit to an exponential regression equation. Assuming that the tumors were ellipsoid, the tumor volume was estimated using magnetic resonance (MR) images obtained before treatment, after 45.0 Gy of EBRT, and after the third ICRT insertion. RRs were compared based on the radiotherapy method. RESULTS: RR ranged between -0.008 to 0.093 day(-1) (median 0.021 day(-1)) during EBRT and -0.001 to 0.097 day(-1) (median 0.018 day(-1)) during ICRT, showing no significant difference or correlation between treatments. CONCLUSION: Contrary to expectations, RR did not directly relate to the impact of physical treatment. RR could be related to biological factors, such as the amount of tumor clearance and changes in tumor consistency during treatment.

Pathologic radioresponse of preoperatively irradiated invasive thymomas.

BACKGROUND: We have been applying preoperative radiotherapy (RT) to Masaoka stage III thymomas intending to make surgical resection more complete by reducing mass volume, to prevent possible dissemination caused by surgical manipulation and to get better survival as a result. However, the radioresponses vary from tumor to tumor. We hypothesized that thymoma is a variable radioresponsive tumor depending on pretreatment histology. MATERIALS AND METHODS: Twenty-one of stage III thymomas underwent preoperative RT plus surgery followed by postoperative RT between 1982 and 2004. Reduction ratios, histopathologic changes according to WHO histologic criteria, resectability, long-term survival, and disease control, by preoperative RT were analyzed. RESULTS: Pretreatment WHO subtypes were type AB (n = 1), B1 (5), B2 (6), B3 (4), and unclassified (5). Sixteen tumors (76.2%) decreased in size after preoperative RT with a mean (median) reduction ratio of 30.8% (27.0%). Type B1or B2 group had higher reduction ratio than type B3 group (mean value of 39.7%, 31.8%, and 21.0%, respectively, p < 0.01). Histopathologically, lymphocyte diminished markedly in type B1 thymoma, and both lymphocyte and epithelial cells diminished in type B2, whereas none of the B3 tumors showed any histologic change. The values of all the cases is 90.5% in complete resection, 19.0% in no combined resection of the adjacent organs, and 77.6% and 83.6% in overall and disease-free 10-year survival, respectively, and these value do not differ according to the WHO histologic criteria. CONCLUSIONS: This modality at modest doses was macroscopically and histopathologically effective on tumors particularly in WHO B1 and B2 thymomas than WHO B3 thymoma. The therapeutic benefit of preoperative RT followed by surgery and postoperative RT for stage III thymomas should be defined thoroughly.

Proton beam therapy for hepatocellular carcinoma adjacent to the porta hepatis.

PURPOSE: To evaluate the efficacy and safety of proton beam therapy (PBT) for patients with hepatocellular carcinoma (HCC) located adjacent to the porta hepatis. METHODS AND MATERIALS: Subjects of the study were 53 patients with HCC located within 2 cm of the main portal vein. All patients had tumor confined to the radiation field with no evidence of metastatic disease. All patients had hepatic function levels of a Child-Pugh score of 10 or less, Eastern Cooperative Oncology Group performance status of 2 or less, and no uncontrolled ascites. Patients underwent PBT of 72.6 GyE in 22 fractions from Sept 2001 to Dec 2004. RESULTS: After 3 years, the actuarial survival rate was 45.1% and local control rate was 86.0%. Prognostic factors for survival included Child-Pugh score, number of tumors, and alpha-fetoprotein levels. No late treatment-related toxicity of Grade 2 or higher was observed. CONCLUSIONS: The PBT delivering 72.6 GyE in 22 fractions appears to be effective and safe for HCC adjacent to the porta hepatis.

Classical tandem-source dwelling covering the entire uterus: essential in modern intracavitary radiotherapy for cervical cancer?

PURPOSE: We investigated whether conventional tandem-source dwelling to cover the entire uterus, classically regarded as the target volume, is necessary in modern intracavitary radiotherapy (ICRT) for cervical cancer. MATERIALS AND METHODS: The study included 95 cervical squamous cell carcinoma patients treated by high-dose-rate ICRT (point A dose was 6.0 Gy, with three to five insertions per patient) after external beam radiotherapy (EBRT), with central pelvic doses of 12-50 Gy. The tandem-source dwell length was adjusted to the target volume specified by magnetic resonance (MR) imaging. A tandem applicator was inserted as far as the uterine fundus in accordance with the post-EBRT MR-assessed cavity length. The pre-EBRT MR-specified target volume was used for the dwell-length adjustment. The safety of the dwell-length adjustment was assessed in terms of treatment failure. RESULTS: The dwell-length adjustment was made in 248 of 366 total insertions with a dwell-length reduction of 5-55 mm (median 15 mm) at the corpus. Pelvic failure was identified in 22 patients with a 2-year pelvic disease-free survival rate of 75.6% but without evidence of failure at dwelling-skipped corpuses. CONCLUSION: Given after pelvic EBRT and ICRT of full-length dwelling in part, which may have eradicated possible subclinical extension, adjustment of the tandem-source dwell length to the MR-specified target volume appeared to be safe.

Proton irradiation in a single fraction for hepatocellular carcinoma patients with uncontrollable ascites. Technical considerations and results.

PURPOSE: To present technical considerations and results of proton irradiation in a single fraction for hepatocellular carcinoma (HCC) patients with uncontrollable ascites. PATIENTS AND METHODS: Three HCC patients with uncontrollable ascites underwent proton irradiation of 24 Gy in a single fraction. Hepatic tumors were solitary in two patients, and multiple in one, and tumor sizes were 30, 30, and 33 mm in maximum diameter. No patient had lymph node or distant metastases. The center position of radiation fields was determined and the beam range was adjusted, using CT data taken immediately before irradiation to compensate for changes in the volume of ascites. Adjustment of the beam range was within 6 mm in water-equivalent thickness. RESULTS: All irradiated tumors showed objective responses, and were controlled during the follow-up period. Of the three patients, two were alive with no evidence of disease at 13 and 30 months, respectively, after treatment. The remaining patient died of ruptured esophageal varices 6 months after treatment. No therapy-related toxicity of grade 3 or more was observed. CONCLUSION: Proton beams were successfully adjusted immediately before irradiation. Single-dose irradiation with precisely adjusted proton beams may be tolerable for HCC patients with uncontrollable ascites.

Proton beam therapy for hepatocellular carcinoma with inferior vena cava tumor thrombus: report of three cases.

Three patients with hepatocellular carcinoma (HCC) and inferior vena cava tumor thrombus (IVCTT) were treated using proton beam therapy at the University of Tsukuba, Japan. A total dose of 50-70 Gy in 10-35 fractions was given to the primary tumor and IVCTT. All the patients survived for more than 1 year from the beginning of proton beam therapy (13-55 months) and no treatment-related toxicity of grade 3 or higher was observed. These cases suggest that proton beam therapy is safe and effective for patients with HCC associated with IVCTT.

Explanation for the failure of neoadjuvant chemotherapy to improve outcomes after radiotherapy for locally advanced uterine cervical cancer from the standpoint of the tumor regression rate.

PURPOSE: Treatment outcomes for patients with locally advanced cervical cancer are no better with neoadjuvant chemotherapy (NAC) combined with radiotherapy (RT) than with RT alone. We investigated the reason for this failure from the standpoint of the tumor regression rate (RR). MATERIALS AND METHODS: A total of 48 patients with clinical stage IIB-IVA cervical squamous cell carcinoma were treated clinically with cisplatin-based NAC plus RT (n = 15) or RT alone (n = 33). The RR was defined as the slope of a tumor shrinkage curve derived with magnetic resonance images. The local control rate (LCR) and disease-free rate (DFR) were estimated by clinical stage (IIB vs. III-IVA), pretreatment volume (< or = median vs. > median), lymph node status (negative vs. positive), treatment type, overall treatment time (< or =8 weeks vs. >8 weeks), and RR (< or = median vs. > median) using univariate and multivariate analyses. RESULTS: RR during NAC or during NAC and RT (n = 15) was not significantly higher than RR by RT alone (n = 33). Low RR and positive nodal status were significantly powerful prognostic factors for both the LCR and DFR, whereas the others were not. CONCLUSION: Although effective in reducing tumor volume prior to RT, NAC showed no overall effect in increasing the RR, which was shown to be the most powerful prognostic factor.

Hypofractionated high-dose proton beam therapy for stage I non-small-cell lung cancer: preliminary results of a phase I/II clinical study.

PURPOSE: To present treatment outcomes of hypofractionated high-dose proton beam therapy for Stage I non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: Twenty-one patients with Stage I NSCLC (11 with Stage IA and 10 with Stage IB) underwent hypofractionated high-dose proton beam therapy. At the time of irradiation, patient age ranged from 51 to 85 years (median, 74 years). Nine patients were medically inoperable because of comorbidities, and 12 patients refused surgical resection. Histology was squamous cell carcinoma in 6 patients, adenocarcinoma in 14, and large cell carcinoma in 1. Tumor size ranged from 10 to 42 mm (median, 25 mm) in maximum diameter. Three and 18 patients received proton beam irradiation with total doses of 50 Gy and 60 Gy in 10 fractions, respectively, to primary tumor sites. RESULTS: Of 21 patients, 2 died of cancer and 2 died of pneumonia at a median follow-up period of 25 months. The 2-year overall and cause-specific survival rates were 74% and 86%, respectively. All but one of the irradiated tumors were controlled during the follow-up period. Five patients showed recurrences 6-29 months after treatment, including local progression and new lung lesions outside of the irradiated volume in 1 and 4 patients, respectively. The local progression-free and disease-free rates were 95% and 79% at 2 years, respectively. No therapy-related toxicity of Grade > or =3 was observed. CONCLUSIONS: Hypofractionated high-dose proton beam therapy seems feasible and effective for Stage I NSCLC. Proton beams may contribute to enhanced efficacy and lower toxicity in the treatment of patients with Stage I NSCLC.

Proton beam therapy for hepatocellular carcinoma patients with severe cirrhosis.

BACKGROUND AND PURPOSE: Hepatocellular carcinoma (HCC) patients with severe cirrhosis are usually treated with supportive care because of their poor prognosis. However, the survival of severe cirrhotic patients has recently improved due to advanced treatments. The aim of this study was to define the role of proton beam therapy for HCC patients with severe cirrhosis. PATIENTS AND METHODS: 19 HCC patients with Child-Pugh class C cirrhosis received proton beam therapy. The hepatic tumors were solitary in 14 patients and multiple in five, and the tumor size was 25-80 mm (median 40 mm) in maximum diameter. No patient had regional lymph node or distant metastasis. Total doses of 50-84 Gy (median 72 Gy) in ten to 24 fractions (median 16) were delivered to the tumors. RESULTS: Of the 19 patients, six, eight and four died of cancer, liver failure and intercurrent diseases, respectively, during the follow-up period of 3-63 months (median 17 months) after treatment. A remaining patient was alive with no evidence of disease 33 months after treatment. All but one of irradiated tumors were controlled during the follow-up period. Ten patients had new intrahepatic tumors outside the irradiated volume. The overall and progression-free survival rates were 53% and 47% at 1 year, respectively, and 42% each at 2 years. Performance status and Child-Pugh score were significant prognostic factors for survival. Therapy-related toxicity of grade 3 or more was not observed. CONCLUSION: Proton beam therapy for HCC patients with severe cirrhosis was tolerable. It may improve survival for patients with relatively good general condition and liver function.

Sequential evaluation of hepatic functional reserve by 99mTechnetium-galactosyl human serum albumin scintigraphy after proton beam therapy: a report of three cases and a review of the literatures.

The treatment strategy for malignant liver tumors should be appropriately determined because post-treatment quality of life greatly depends on the patients' residual hepatic function. In this report, we present three patients with malignant liver tumors treated by proton beam therapy in whom pre- and post-therapeutic hepatic functional reserves were evaluated sequentially for more than a year by 99mTechnetium-galactosyl human serum albumin (99mTc-GSA) scintigraphy. All three patients exhibited the distinctive time course of 99mTc-GSA uptake efficiency, which suggested a transient decline in the ratio of liver activity to heart and liver activity at 15 minutes (LHL15) 3-6 months after proton beam therapy. This change was not in parallel with that expected from a functioning normal liver tissue volume. In a year after proton beam therapy, LHL15 recovered nearly to the pre-treatment level in all three patients. Our observations may be related to the up-regulation of receptor-mediated 99mTc-GSA uptake during hepatic regeneration after proton beam therapy.

Proton beam therapy for hepatocellular carcinoma with limited treatment options.

BACKGROUND: The authors conducted a retrospective review to define the usefulness of proton beam therapy for patients who had hepatocellular carcinoma (HCC) with limited treatment options. METHODS: Twenty-one patients with HCC for whom other treatment modalities either were contraindicative or were unfeasible because of coexisting diseases and unfavorable conditions received proton beam therapy. Four patients had renal failure, 2 patients had severe heart disease, 9 patients had severe cirrhosis, 1 patient had aplastic anemia, 1 patient had a dissecting abdominal aortic aneurysm before treatment, and 4 patients had bleeding tendency or unresectable tumors. Moreover, 2 of the latter 4 patients were allergic to iodine, and 2 other patients were unable to be catheterized for transcatheter arterial chemoembolization. Hepatic tumors were solitary in 14 patients and multiple in 7 patients, and the tumors ranged in greatest dimension from 25 mm to 100 mm (median, 40 mm). No patient had regional lymph node or distant metastasis. Total doses of 63 grays (Gy) to 84 Gy (median, 73 Gy) in 13 to 27 fractions (median, 18 fractions) were used for tumor treatments. RESULTS: All but 1 of the irradiated tumors were controlled at a median follow-up of 3.3 years. The objective response rate was 81%, and the primary site-control rate was 93% at 5 years. Eleven patients had intrahepatic recurrences, and 2 patients had distant metastases in the lungs. Four of 11 patients with intrahepatic recurrences received a second course of proton beam therapy, and all recurrent tumors were controlled. The overall and cause-specific survival rates were 62% and 82% at 2 years, respectively, and 33% and 67% at 5 years, respectively. Grade > or =3 therapy-related toxicities were not observed. CONCLUSIONS: Proton beam therapy was safe and effective for a variety of patients with HCC. The current results suggested that this method was tolerable and effective, even for patients with HCC who had limited treatment options.

Proton beam therapy for invasive bladder cancer: a prospective study of bladder-preserving therapy with combined radiotherapy and intra-arterial chemotherapy.

PURPOSE: To present outcomes of bladder-preserving therapy with proton beam irradiation in patients with invasive bladder cancer. METHODS AND MATERIALS: Twenty-five patients with transitional cell carcinoma of the urinary bladder, cT2-3N0M0, underwent transurethral resection of bladder tumor(s), followed by pelvic X-ray irradiation combined with intra-arterial chemotherapy with methotrexate and cisplatin. Upon completion of these treatments, patients were evaluated by transurethral resection biopsy. Patients with no residual tumor received proton irradiation boost to the primary sites, whereas patients demonstrating residual tumors underwent radical cystectomy. RESULTS: Of 25 patients, 23 (92%) were free of residual tumor at the time of re-evaluation; consequently, proton beam therapy was applied. The remaining 2 patients presenting with residual tumors underwent radical cystectomy. Of the 23 patients treated with proton beam therapy, 9 experienced recurrence at the median follow-up time of 4.8 years: local recurrences and distant metastases in 6 and 2 patients, respectively, and both situations in 1. The 5-year overall, disease-free, and cause-specific survival rates were 60%, 50%, and 80%, respectively. The 5-year local control and bladder-preservation rates were 73% and 96%, respectively, in the patients treated with proton beam therapy. Therapy-related toxicities of Grade 3-4 were observed in 9 patients: hematologic toxicities in 6, pulmonary thrombosis in 1, and hemorrhagic cystitis in 2. CONCLUSIONS: The present bladder-preserving regimen for invasive bladder cancer was feasible and effective. Proton beam therapy might improve local control and facilitate bladder preservation.

Repeated proton beam therapy for hepatocellular carcinoma.

PURPOSE: To retrospectively evaluate the safety and effectiveness of repeated proton beam therapy for newly developed or recurrent hepatocellular carcinoma (HCC). METHODS AND MATERIALS: From June 1989 through July 2000, 225 patients with HCC underwent their first course of proton beam therapy at the University of Tsukuba. Of them, 27 with 68 lesions who had undergone two or more courses were retrospectively reviewed in this study. Median interval between the first and second course was 24.5 months (range 3.3-79.8 months). Median total dose of 72 Gy in 16 fractions and 66 Gy in 16 fractions were given for the first course and the rest of the courses, respectively. RESULTS: The 5-year survival rate and median survival period from the beginning of the first course for the 27 patients were 55.6% and 62.2 months, respectively. Five-year local control rate for the 68 lesions was 87.8%. Of the patients, 1 with Child-Pugh class B and another with class C before the last course suffered from acute hepatic failure. CONCLUSIONS: Repeated proton beam therapy for HCC is safe when the patient has a target in the peripheral region of the liver and liver function is Child-Pugh class A.

Predictive factors for the histologic response to preoperative radiotherapy in advanced oral cancer.

PURPOSE: Preoperative radiotherapy and chemotherapy are important in treating advanced oral cancer. We attempted to elucidate predictive factors for the histologic response to preoperative radiotherapy or chemoradiotherapy. PATIENTS AND METHODS: Forty-three patients with locally advanced cancer of the oral cavity and oropharynx were treated preoperatively with radiotherapy (50 Gy); surgery included modification of the resected area to preserve organ function. RESULTS: Hemoglobin level and histologic differentiation were independent factors significantly associated with the histologic response by multivariate analysis. Locoregional failure occurred only in patients with poor histologic response, and there was a significant difference in the 5-year survival rate between patients with good and poor responses (84% vs 32%). Multivariate analysis indicated that the histologic response at the primary site and the number of metastatic lymph nodes were prognostic factors. CONCLUSION: We identified predictive factors for a good response to preoperative therapy and found a high survival rate in patients with a good response.

Early determination of uterine cervical squamous cell carcinoma radioresponse identifies high- and low-response tumors.

PURPOSE: To investigate whether early-assessed radioresponse of tumors corresponds with late-assessed radioresponse, which is associated with local disease control in radiotherapy (RT) for cervical cancer. METHODS AND MATERIALS: This prospective study included 12 patients with cervical squamous cell carcinoma treated by RT with or without concurrent cisplatin. Tumor volume was estimated by scheduled magnetic resonance imaging before (preRT), 3 to 4 weeks after (early assessment), and 6 to 7 weeks after (late assessment) RT initiation. Radioresponse was assessed with tumor shrinkage curves based on these volumes. Radioresponse for each tumor was calculated as the slope (day(-1)) of the shrinkage curve by fitting to an exponential equation. RESULTS: Early-assessed radioresponse ranged from 0.001 to 0.106 day(-1) (median, 0.021 day(-1)) and late-assessed radioresponse from 0.009 to 0.091 day(-1) (median, 0.021 day(-1)), with no significant difference between them (p = 0.1191). The early-assessed radioresponse correlated with the late-assessed radioresponse (R(2) = 0.714, p = 0.0005). CONCLUSIONS: Correspondence between early- and late-assessed radioresponse in a series of tumors showing a wide range of radioresponse was not particularly close overall. However, early assessment of radioresponsiveness did seem to be useful for characterizing those tumors with high or low radioresponsiveness.