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T A Rich

Publications and source records attributed to T A Rich.

At least 37 records · Page 2Linked to original sources
PubMed1999

Chemoradiation for pancreatic and biliary cancer: current status of RTOG studies.

Chemoradiation for gastrointestinal cancers is actively under study in the Radiation Therapy Oncology Group (RTOG) and consists of external irradiation combined with simultaneously administered chemotherapy given to provide radiation sensitization and to attack micro metastatic disease. Two national protocols for the treatment of patients with pancreatic and biliary cancers are now active. RTOG 97-04 is a phase III post-operative combined modality program for patients with resected pancreatic cancer. All patients receive protracted infusional 5-fluorouracil (5-FU) combined with 50.4 Gy given in 28 fractions. Prior to and after chemoradiation all patients are randomized to receive multiple cycles of either infusional 5-FU or Gemcitabine to determine the effect on survival. In the other study (RTOG 98-12) patients with unresectable pancreatic cancer are given 50.4 Gy combined with weekly Paclitaxel (50 mg/m2) to examine the efficacy of this active combination in a phase II trial in a multi-institutional setting. Both of these trials have recently been opened to accrual. A third RTOG study for patients with biliary cancer will examine the efficacy of giving pre-operative chronomodulated infusional 5-FU chemoradiation. The background and the rationale for these studies is based on the long history of 5-FU radiation sensitization in the treatment of cancers of these anatomic sites and will be summarized. A brief review of recently published trials using chemoradiation in conjunction with new irradiation treatment techniques "3D" conformal therapy for these diseases will be discussed.

Antineoplastic Agents↗
PubMed1999

Infusional chemoradiation for rectal and anal cancers.

Combined-modality therapy, including irradiation and concurrently administered chemotherapy, has become the mainstay of therapy for anal and rectal cancers. Several important lessons have been learned from clinical trials over the last several decades. Simultaneous delivery of large (bolus) doses of 5-fluorouracil with irradiation is associated with improved survival compared to irradiation alone, but at a price of increased normal tissue toxicity. These side effects can be ameliorated by using protracted venous infusion for chemotherapy, which is analogous to the observations in radiation oncology that fractionation spares late tissue toxicity. The protracted venous infusion approach is efficacious, has a wide therapeutic index, and permits concurrent systemic treatment of micrometastatic disease and radiation sensitization. Protracted venous infusion chemoradiation is also used in the preoperative management of rectal cancer and in the nonoperative management of anal cancers. Newer radiosensitizing agents, three-dimensional radiotherapy planning, and conformal radiotherapy treatment offer additional hope for the future that even more patients with rectal and anal cancers may benefit from combined-modality therapy with acceptable toxicity.

Anal Gland Neoplasms↗
PubMed1998

Locally advanced rectal cancer: surgical complications after infusional chemotherapy and radiation therapy.

PURPOSE: To compare the surgical complication rate after further experience with infusional chemotherapy and radiation therapy for locally advanced rectal cancer. MATERIALS AND METHODS: Preoperative radiation therapy (45 Gy in 25 fractions over 5 weeks) and concurrent continuous infusion of 5-fluorouracil (300 mg.m-2.d-1) were given to 117 patients with rectal cancer. Approximately 6 weeks after therapy, surgery was performed. RESULTS: The histopathologic cancer stages were Tis-2N0 in 30 patients (26%), T2N1 in six (5%), T3N0 in 24 (21%), T3N1 in 18 (15%), T4N0 in six (5%), and T4N1 in one (1%); a complete response to preoperative therapy was histopathologically confirmed in 32 patients. A decrease in cancer stage allowed a sphincter-saving procedure in 68 patients (58%) and abdominoperineal resection in 49 patients (42%). Only one patient developed fistula; nine patients, perioperative wound complications; and four patients, pelvic infection. In the authors' previously reported chemotherapy and radiation therapy results (same protocol), eight (22%) of 37 patients developed fistulas and five (14%) developed pelvic abscess; in the authors' previous experience with preoperative radiation therapy only (median total dose, 45 Gy; dose range, 40.0-59.4 Gy), results were similar. CONCLUSION: Surgical complications after chemotherapy and radiation therapy are statistically significantly (P < .05) reduced with further experience.

Actuarial Analysis↗
PubMed1998

Rapid-fractionation preoperative chemoradiation, pancreaticoduodenectomy, and intraoperative radiation therapy for resectable pancreatic adenocarcinoma.

PURPOSE: To evaluate the toxicities, radiographic and pathologic responses, and event-free outcomes with combined modality treatment that involves preoperative rapid-fractionation chemoradiation, pancreaticoduodenectomy, and electron-beam intraoperative radiation therapy (EB-IORT) for patients with resectable pancreatic adenocarcinoma. PATIENTS AND METHODS: Patients with radiographically resectable localized adenocarcinoma of the pancreatic head were entered onto a preoperative protocol that consisted of a 2-week course of fluorouracil (5-FU) 300 mg/m2 daily 5 days per week and concomitant rapid-fractionation radiation 30 Gy, 3 Gy daily 5 days per week. Radiographic restaging was performed 4 weeks after chemoradiation, and patients with localized disease underwent pancreaticoduodenectomy with EB-IORT 10 to 15 Gy. RESULTS: Thirty-five patients were entered onto the study and completed chemoradiation, 34 (97%) as outpatients. Three patients (9%) experienced grade 3 nausea and vomiting; no other grade 3 or 4 toxicities were observed. Of the 27 patients taken to surgery, 20 patients (74%) underwent pancreaticoduodenectomy with EB-IORT. All patients had a less than grade III pathologic response to preoperative chemoradiation. At a median follow-up of 37 months, the 3-year survival rate in patients who underwent combined modality therapy was 23%. CONCLUSION: Combined modality treatment with preoperative rapid-fractionation chemoradiation, pancreaticoduodenectomy, and EB-IORT is associated with minimal toxicity and excellent locoregional control. This represents one approach to maximize the proportion of patients who receive all components of combined modality therapy and avoids the toxicity of pancreaticoduodenectomy in patients found to have metastatic disease at the time of restaging.

Adenocarcinoma↗
PubMed1998

Camptothecin radiation sensitization: mechanisms, schedules, and timing.

Based on high tumoricidal activity of the camptothecin analogs topotecan (Hycamtin), irinotecan (CPT-11[Camptosar]), and 9-aminocamptothecin (9-AC) in preclinical studies, clinical trials began testing these agents against human cancers. The cytotoxic activity of camptothecins in the clinic has been lower than predicted from the laboratory, however, and new approaches are needed. One method that holds promise is the use of the camptothecins as radiation sensitizers. The camptothecin dose, schedule, method of administration, and timing of administration, when given with irradiation, are likely to be important factors for these new S-phase radiation sensitizers. Phase I trials of the camptothecins as radiation sensitizers have begun, and multicenter phase II studies are planned by the Radiation Therapy Oncology Group (RTOG). One new approach based on preclinical observations that deserves clinical evaluation is chronomodulated camptothecin delivery with irradiation in order to widen the therapeutic window.

Animals↗
PubMed1997

Preirradiation PSA predicts biochemical disease-free survival in patients treated with postprostatectomy external beam irradiation.

PURPOSE: To assess the clinical outcome and prostate-specific antigen (PSA) response and to determine prognostic factors for biochemical disease-free survival in patients treated with external beam radiotherapy following radical prostatectomy without hormonal therapy. METHODS AND MATERIALS: Forty-eight patients were treated after prostatectomy with radiotherapy between March, 1988 and December, 1993. Seven patients had undetectable PSA (<0.2) and the remainder had detectable PSA at the time of irradiation (overall: median 2.7, range 0-24.9). Nine patients had biopsy proven local recurrence, palpable local disease, or positive preirradiation imaging. No patients received hormonal therapy prior to irradiation. Median follow-up was 55 months. A median dose of 60 Gy (range 58-66) was given to the prostate bed. Survival was analyzed using the life-table method. Actuarial biochemical disease-free survival was the primary endpoint studied. RESULTS: In patients with detectable PSA, 51% had levels return to undetectable after irradiation. The actuarial 5-year freedom from biochemical failure for all patients was 24%. A significant difference in biochemical disease-free survival was seen for patients irradiated with preirradiation PSA that was undetectable (p < 0.001), or preirradiation PSA that was < or =2.7 (p = 0.002), vs. preirradiation PSA that was >2.7. Five-year actuarial biochemical disease-free survival values were 71, 48, and 0%, respectively, for the three groups. Biochemical disease-free survival was not affected by preoperative PSA level, clinical stage, Gleason's score, pathologic stage, surgical margins, presence of undetectable PSA after surgery, surgery to radiation interval, total dose, or presence of clinically suspicious local disease. Based on digital rectal exam, there were no local failures. CONCLUSION: Biochemical disease-free survival after postprostatectomy radiation is predicted by the PSA at the time of irradiation. Clinical local control is excellent, but distant failure remains a significant problem in this population. The addition of concomitant systemic therapy should be investigated in patients with PSA >2.7.

Adenocarcinoma↗
PubMed1997

Potentiation of murine MCa-4 carcinoma radioresponse by 9-amino-20(S)-camptothecin.

9-Amino-20(S)-camptothecin (9-AC) has demonstrated efficacy against several human cancer xenografts, including cancers of the colon, breast, lung, ovary, and stomach and malignant melanoma, and is currently undergoing Phase I clinical trials. In vitro data indicate that the addition of topoisomerase I inhibitors shortly after irradiation causes conversion of single-strand breaks to double-strand breaks, resulting in synergistic lethality to cultured log-phase or quiescent malignant cells. In our study, the efficacy of 9-AC as a potential radiosensitizing agent in vivo was assessed in C3Hf/Kam female mice bearing 7.6-8-mm MCa-4 mammary tumors implanted i.m. into the right posterior thigh. In one series of experiments to determine the dose dependence of 9-AC, mice were injected twice a week with either 0.5, 1.0, or 2.0 mg/kg 9-AC (total doses of 2, 4, and 8 mg/kg, respectively) either alone or 1 h before irradiation. In a second series of experiments, the schedule dependence of 9-AC was determined by giving a constant total dose of 4 mg/kg 9-AC once (2 mg/kg), twice (1 mg/kg every third day), or four (0.5 mg/kg every other day) times per week for 2 weeks, either alone or combined with radiation. The same radiation regimen was used in all experiments: 2-Gy fractions daily for 14 consecutive days, giving a total dose of 28 Gy to the tumor-bearing leg only. Tumor response was assessed by regrowth delay and dose modification factors (DMFs) obtained by comparing regrowth delay in the groups given 9-AC alone with those given the same dose of 9-AC and radiation. 9-AC significantly delayed tumor growth when combined with radiation, and this effect was dependent on drug dose; DMFs of 2.4 [95% confidence interval (CI), 2.0-3.1], 3.7 (95% CI, 3.1-4.6), and 3.3 (95% CI, 2.7-4.1) were obtained for groups treated with total drug doses of 2.0, 4.0, and 8.0 mg/kg 9-AC, respectively. In addition, the same total dose of 4 mg/kg 9-AC was more effective when given either twice or four times a week compared with once a week, giving DMFs of 2.8 (95% CI, 2.2-3.9), 2.6 (95% CI, 2.0-3.6), and 1.7 (95% CI, 1.3-2.4), respectively. The effect of 9-AC and radiation on normal tissue toxicity was assessed in two normal tissues, jejunum and skin, in separate groups of mice. Jejunal crypt cell survival was decreased in those mice given single doses of 9-AC ranging from 0.5-4.0 mg/kg and 12.5 Gy of total body radiation compared with those given 12.5 Gy of total body irradiation alone. The same regimen of drug and radiation did not modify acute skin reactions. These results suggest that 9-AC is an effective in vivo radiosensitizing agent when given in divided doses with fractionated irradiation. In addition, the gastrointestinal tract but not skin could be a critical target tissue for the use of 9-AC combined with radiation.

Animals↗
PubMed1997

Pelvic exenteration for locally advanced rectal carcinoma: factors predicting improved survival.

BACKGROUND: The purpose of this retrospective review was to determine whether a number of clinicopathologic factors (age, gender, type of exenteration, tumor extent, adjuvant therapy, tumor DNA ploidy, and S-phase fraction) that could be determined before operation were useful in predicting survival in patients undergoing pelvic exenteration for rectal cancer. METHODS: Between 1983 and 1992, 40 patients (15 male and 25 female) at our institution underwent pelvic exenteration for rectal adenocarcinoma in which tumor-free pathologic margins were obtained. Twenty-nine patients presented with primary tumors; 11 had recurrent disease. A total exenteration was performed in 20 patients, posterior exenteration in 18 patients, and an anterior exenteration in 2 patients. RESULTS: By multivariate (Cox proportional hazards regression) analysis, age, preoperative chemoradiation therapy, and an S phase of 10% or greater were found to be significant predictors of survival. Age older than 55 years was associated with a relative risk for cancer-related death (RR) of 0.13 (p = 0.02), and chemoradiation had an RR of 0.05 (p = 0.01), indicating their beneficial effect. An S-phase fraction of 10% or greater had an RR of 16.97 (p = 0.03), indicating a poor survival. The clinicopathologic factors listed above were used to derive a prognostic index (PI). A PI of less than 1.37 was associated with a 5-year survival rate of 65% (low risk), whereas patients with a PI of 1.37 or greater had a 5-year survival rate of 20% (high risk) (p = 0.005). CONCLUSIONS: These results indicate that adjuvant chemoradiation may significantly improve survival in patients who require pelvic exenteration for resection of locally advanced rectal carcinoma. An S-phase fraction of 10% or greater is also predictive of a poor outcome. Use of these factors allowed the generation of a PI that identifies high- and low-risk patients. Consideration of the ability to deliver chemoradiation and the determinates of the tumor S-phase fraction in patients requiring pelvic exenteration for rectal cancer may be helpful in predicting outcome and planning therapy.

Adenocarcinoma↗
PubMed1997

Preoperative and postoperative chemoradiation strategies in patients treated with pancreaticoduodenectomy for adenocarcinoma of the pancreas.

PURPOSE: The effects of preoperative versus postoperative fluorouracil (5-FU)-based chemotherapy and irradiation on treatment toxicity, duration of treatment, tumor recurrence, and survival were compared in patients who underwent potentially curative therapy for adenocarcinoma of the pancreatic head during a 5-year period. METHODS: From July 1990 to July 1995, 142 patients with localized adenocarcinoma of the pancreatic head deemed resectable on the basis of radiographic images were treated with curative intent using a multimodality approach involving either preoperative or postoperative chemoradiation. Patients with biopsy confirmation of adenocarcinoma and a low-density mass in the pancreatic head identified by computed tomography (CT) received preoperative chemoradiation. Patients without a mass on CT or in whom the preoperative biopsy was negative underwent pancreaticoduodenectomy with planned postoperative chemoradiation. Protocol-based preoperative chemoradiation consisted of external-beam irradiation at a dose of 50.4 Gy (standard fractionation; 1.8 Gy/d, 5 d/wk) or 30 Gy (rapid fractionation; 3 Gy/d, 5 d/wk) combined with continuous infusion 5-FU (300 mg/m2/d, 5 d/wk). Postoperative chemoradiation combined 50.4 Gy of external-beam irradiation (standard fractionation) with continuous-infusion 5-FU. RESULTS: No patient who received preoperative chemoradiation experienced a delay in surgery because of chemoradiation toxicity, but six of 25 eligible patients (24%) did not receive postoperative chemoradiation because of delayed recovery after pancreaticoduodenectomy. No significant differences in toxicities from chemoradiation were observed between groups. Patients treated with rapid-fractionation preoperative chemoradiation had a significantly (P < .01) shorter duration of treatment (median, 62.5 days) compared with patients who received postoperative chemoradiation (median, 98.5 days) or standard-fractionation preoperative chemoradiation (median, 91.0 days). At a median followup of 19 months, no significant differences in survival were observed between treatment groups. No patient who received preoperative chemoradiation and pancreaticoduodenectomy experienced a local recurrence; peritoneal (regional) recurrence occurred in 10% of these patients. Local or regional recurrence occurred in 21% of patients who received pancreaticoduodenectomy and postoperative chemoradiation. CONCLUSION: Delivery of preoperative and postoperative chemoradiation in patients who underwent potentially curative pancreaticoduodenectomy for adenocarcinoma of the pancreatic head resulted in similar treatment toxicity, patterns of tumor recurrence, and survival. Rapid-fractionation preoperative chemoradiation ensured the delivery of all components of therapy to all eligible patients with a significantly shorter duration of treatment than with standard-fractionation chemoradiation given either before or after pancreaticoduodenectomy. Prolonged recovery after pancreaticoduodenectomy prevents the delivery of postoperative adjuvant chemoradiation in up to one fourth of eligible patients.

Adenocarcinoma↗
PubMed1997

Infusional chemoradiation for operable rectal cancer: post-, pre-, or nonoperative management?

The use of adjuvant irradiation combined with systemic chemotherapy, or "chemoradiation," in the management of patients with operable rectal cancer has enabled more conservative surgery to be performed. Chemoradiation has been employed in both postoperative and preoperative settings, and also has been used as sole therapy in selected patients. Of the various schedules of postoperative chemoradiation evaluated to date, a protracted infusion of fluorouracil (5-FU) combined with irradiation appears to maximize control of both local and distant micrometastatic disease. Preoperative infusional chemoradiation is highly effective in patients with advanced rectal cancer. Data also suggest that it may be possible to treat selected patients with low-lying rectal cancers with radical chemoradiation alone, thus obviating the need for a permanent colostomy. Future studies of preoperative and nonoperative infusional chemoradiation are warranted.

Chemotherapy, Adjuvant↗
PubMed1997

p53 immunohistochemical staining predicts residual disease after chemoradiation in patients with high-risk rectal cancer.

This study was conducted to investigate the value of p53 immunohistochemical staining of pretreatment biopsy specimens in predicting the response of rectal cancer to chemoradiation. The study group comprised 42 patients with high-risk rectal cancer treated between July 1990 and July 1995 with a preoperative chemoradiation regimen of 45 Gy of external-beam irradiation and continuous-infusion 5-fluorouracil followed by surgical resection. p53 immunohistochemical staining was performed on pretreatment biopsy specimens. p53 immunohistochemical staining pattern and standard clinical and pathological parameters were correlated with extent of residual cancer in the surgical specimen. Twenty tumors were positive for p53 on immunohistochemical staining, 19 were negative, and 3 were focally positive. Thirteen patients experienced a complete response to chemoradiation. Aberrant p53 protein accumulation, as measured by immunohistochemical staining, correlated inversely with a complete pathological response to chemoradiation (P = 0.005; correlation coefficient = -0.43) and directly with an increased likelihood of residual cancer in the lymph nodes of surgical specimens (P = 0.02; correlation coefficient = 0.39). p53 immunohistochemical staining of pretreatment biopsy specimens correlates with the extent of residual disease after chemoradiation in patients with high-risk rectal cancer.

Adult↗
PubMed1996

Preoperative chemoradiation, pancreaticoduodenectomy, and intraoperative radiation therapy for adenocarcinoma of the pancreatic head.

BACKGROUND: Local recurrence in the bed of the resected pancreas is the most common site of tumor recurrence following a standard pancreaticoduodenectomy (PD) for adenocarcinoma of the pancreatic head. In an attempt to improve local and regional disease control and thereby enhance the quality and length of survival in patients undergoing potentially curative PD, we have used a protocol of preoperative multimodality therapy. PATIENTS AND METHODS: All patients were treated with external-beam radiation (30.0 or 50.4 Gy) and concomitant 5-fluorouracil (300 mg/m2 per day) prior to PD. Electron-beam intraoperative radiation therapy was given to the bed of the resected pancreas before reconstruction. Patients were assessed for recurrence by physical examination, chest roentgenography, and computed tomography scan performed at 3-month intervals following treatment. RESULTS: Thirty-nine patients completed all therapy; 1 perioperative death occurred. Thirty-eight tumor recurrences have been documented in 29 patients at a median of 11 months from the date of diagnosis; 23 patients died of disease. The liver was the most frequent site of recurrence, and liver metastases were a component of treatment failure in 53% of patients. Isolated local or peritoneal recurrences were documented in only 4 patients (11%). The only significant clinical or pathologic variable predictive of local-regional recurrence was a previous laparotomy and intraoperative biopsy. The median survival of all 39 patients was 19 months, and the 4-year actuarial survival rate was 19%. CONCLUSIONS: Preoperative chemoradiation, PD, and electron-beam intraoperative radiation therapy for adenocarcinoma of the pancreatic head have resulted in improved local-regional tumor control, with distant metastatic disease becoming the predominant site of tumor recurrence. Future treatment strategies should incorporate effective multimodality therapy for local-regional disease as demonstrated in this study. Major improvements in overall survival will likely await the development of systemic or regional therapy for liver metastases.

Adenocarcinoma↗
PubMed1996

Preoperative infusional chemoradiation, selective intraoperative radiation, and resection for locally advanced pelvic recurrence of colorectal adenocarcinoma.

OBJECTIVE: The results of preoperative infusional chemoradiation, resection, and selective intraoperative radiation (IORT) boost in 43 previously nonirradiated patients with locally advanced pelvic recurrence of colorectal adenocarcinoma are described. SUMMARY BACKGROUND DATA: After surgery alone 10% to 30% of patients with carcinoma of the distal colon and rectum will develop isolated pelvic recurrence. In most cases, the disease is locally advanced and not amenable to curative resection. Preoperative infusional chemoradiation has been shown to increase resectability and decrease local recurrence in primary locally advanced colorectal cancer. Based on this experience, we initiated a multimodality treatment protocol to treat patients with pelvic recurrence of colorectal adenocarcinoma. METHODS: Forty-three consecutive patients with histologically proven pelvic recurrence of colorectal adenocarcinoma were enrolled on a multimodality treatment protocol. The treatment plan consisted of 5 weeks of concurrent pelvic external beam radiotherapy (45 Gy) with continuous intravenous infusion of 5-fluorouracil and/or cisplatin. This was followed by surgery that included IORT boost (10-20 Gy) for 21 patients and brachytherapy for 4 patients. RESULTS: Forty patients (93%) underwent operation and 33 (77%) underwent resection with curative intent. There were 29 (88%) margin-negative resections. Fifteen patients (48%) underwent sphincter-preserving operations. There were no treatment-related deaths. Twenty-two patients experience perioperative complications. Median follow-up for the 43 patients was 26 months. The local recurrence rate was 36%. Median survival for the patients who underwent resection was 34 months, and actuarial 5-year disease-free and overall survival were 37% and 58%, respectively. CONCLUSIONS: Tumor cytoreduction by preoperative chemoradiation can increase resectability and enable sphincter-preserving surgery in patients with locally advanced pelvic recurrence of colorectal cancer.

Adenocarcinoma↗
PubMed1995

Preoperative chemoradiation for adenocarcinoma of the pancreas: excessive toxicity of prophylactic hepatic irradiation.

PURPOSE: In an effort to reduce relapse in the liver and improve survival in patients with potentially resectable adenocarcinoma of the pancreatic head, we combined whole-liver irradiation with our standard preoperative chemoradiation regimen. METHODS AND MATERIALS: Eleven patients with biopsy-proven, potentially resectable adenocarcinoma of the pancreatic head were treated with 50.4 Gy of external beam irradiation to the pancreas (1.8 Gy/day, 5 days/week) and concurrent continuous infusion 5-fluorouracil (300 mg/m2 per day). The liver was treated with 23.4 Gy on Days 8 through 21 (13 fractions; 1.8 Gy/fraction). Patients, who upon restaging with radiography and computed tomography were considered to have resectable tumors, were subsequently taken to surgery. If, at surgery, tumors were resectable, pancreaticoduodenectomy was performed, and 10 Gy of intraoperative electron-beam radiation therapy was delivered to the bed of the resected pancreas. RESULTS: All 11 patients completed chemoradiation. Two treatment-related deaths occurred following chemoradiation, prompting premature termination of the study. Of seven patients taken to surgery, four underwent resection. Seven patients have died of disease, five with liver metastases. CONCLUSIONS: Prophylactic hepatic chemoradiation, as given in this study, was associated with two treatment-related deaths and a higher than expected incidence of subsequent liver metastases. Our data do not support the use of this treatment program in patients with adenocarcinoma of the pancreas.

Adenocarcinoma↗
PubMed1995

5-Fluorouracil-radiation interactions in human colon adenocarcinoma cells.

PURPOSE: To determine the effect of cellular proliferation and cell cycle stage on the ability of postirradiation 5-fluorouracil (5-FU) to radiosensitize cultured human colon adenocarcinoma Clone A cells. METHODS AND MATERIALS: Cell survival curves were generated for irradiated: (a) log- and plateau-phase Clone A cells; and (b) Clone A cells separated by centrifugal elutriation into the various phases of the cell cycle; with and without postirradiation treatment with 100 micrograms/ml 5-FU. RESULTS: Postirradiation treatment with 5-FU sensitized proliferating cells to a greater degree than it sensitized cells growing in plateau phase. The beta component of cell kill in log-phase cells was increased by a factor of 1.5 with a sensitizer enhancement ratio of 1.21 at the 0.01 survival level. Plateau-phase cells showed less radiosensitization (sensitizer enhancement ratio of 1.13 at the 0.01 survival level); however, there was a mild increase in both alpha and beta kill in plateau-phase cells. Elutriated G1 cells were the most radiosensitive, independent of treatment with 5-FU. The phase of the cell cycle had little effect on the ability of fluorouracil to radiosensitize Clone A cells. CONCLUSION: Proliferating cells are more susceptible to radiosensitization with 5-FU than plateau-phase cells are, but this effect appears to be independent of the phase of the cell cycle.

Adenocarcinoma↗
PubMed1995

Preoperative infusional chemoradiation therapy for stage T3 rectal cancer.

PURPOSE: To evaluate preoperative infusional chemoradiation for patients with operable rectal cancer. METHODS AND MATERIALS: Preoperative chemoradiation therapy using infusional 5-fluorouracil (5-FU), (300 mg/m2/day) together with daily irradiation (45 Gy/25 fractions/5 weeks) was administered to 77 patients with clinically Stage T3 rectal cancer. Endoscopic ultrasound confirmed the digital rectal exam in 63 patients. Surgery was performed approximately 6 weeks after the completion of chemoradiation therapy and included 25 abdominoperineal resections and 52 anal-sphincter-preserving procedures. RESULTS: Posttreatment tumor stages were T1-2, N0 in 35%, T3 N0 in 25%, and T1-3, N1 in 11%; 29% had no evidence of tumor. Local tumor control after chemoradiation was seen in 96% (74 out of 77); 2 patients had recurrent disease at the anastomosis site and were treated successfully with abdominoperineal resection. Overall, pelvic control was obtained in 99% (76 out of 77). The survival after chemoradiation was higher in patients without node involvement than in those having node involvement (p = n.s.). More patients with pathologic complete responses or only microscopic foci survived than did patients who had gross residual tumor (p = 0.07). The actuarial survival rate was 83% at 3 years; the median follow-up was 27 months, with a range of 3 to 68 months. Acute, perioperative, and late complications were not more numerous or more severe with chemoradiation therapy than with traditional radiation therapy (XRT) alone. CONCLUSIONS: Excellent treatment response allowed two-thirds of the patients to have an anal-sphincter-sparing procedure. Gross residual disease in the resected specimen indicates a poor prognosis, and therapies specifically targeting these patients may improve survival further.

Adenocarcinoma↗