Treatment optimisation using external beam radiation in gynaecological cancers

The majority of patients with gynaecological cancers present with advanced stages in which external beam radiation forms a major component of the treatment. These patients undergo simulation for treatment planning prior to radiation. Currently the lower extent of the disease is evaluated by vaginal examination and marked using a lead wire on the anterior abdominal wall in the pelvic region. A 2 cm margin inferior to this level is used as the lower border of the treatment field. The suggested modified technique includes the placement of an indigenously designed perspex vaginal obturator with graduations at 1 cm distance from its tip. Following vaginal examination the obturator can be inserted into the vagina and fixed at the predefined length using a fixation device. The radio-opaque markers can be seen even in the lateral films. Twentyfive consecutive patients underwent the procedure and the differences between the two methods of marking the lower border were calculated. The external lead wire was inferior to the internal obturator in 19 patients (76%) ranging from 0.5 cm to 3 cm (median 1.5 cm, mean 1.37 cm). It was at the same level in 4 patients (16%) and 1 cm superior to the internal obturator in 2 (8%). With the modified technique using the internal obturator application for delineating the lower border of vaginal disease or vault, it was possible to decrease the length of field thereby reducing the chances of treatment-related toxicity, especially groin and vulval reactions, as well as avoiding treatment interruptions.

Vertebral height as the measure of lesion length in carcinoma of the oesophagus - is it accurate?

No abstract available.

Dosimetric characteristics with spatial fractionation using electron grid therapy

Recently, promising clinical results have been shown in the delivery of palliative treatments using megavoltage photon grid therapy. However, the use of megavoltage photon grid therapy is limited in the treatment of bulky superficial lesions where critical radiosensitive anatomical structures are present beyond tumor volumes. As a result, spatially fractionated electron grid therapy was investigated in this project. Dose distributions of 1.4-cm-thick cerrobend grid blocks were experimentally determined for electron beams ranging from 6 to 20 MeV. These blocks were designed and fabricated at out institution to fit into a 20 x 20-cm(2) electron cone of a commercially available linear accelerator. Beam profiles and percentage depth dose (PDD) curves were measured in Solid Water phantom material using radiographic film, LiF TLD, and ionometric techniques. Open-field PDD curves were compared with those of single holes grid with diameters of 1.5, 2.0, 2.5, 3.0, and 3.5 cm to find the optimum diameter. A 2.5-cm hole diameter was found to be the optimal size for all electron energies between 6 and 20 MeV. The results indicate peak-to-valley ratios decrease with depth and the largest ratio is found at Dmax. Also, the TLD measurements show that the dose under the blocked regions of the grid ranged from 9.7% to 39% of the dose beneath the grid holes, depending on the measurement location and beam energy.

Early growth response-1 gene: potential radiation response gene marker in prostate cancer

This study was undertaken to determine whether the transcription factor EGR-1 expression: (1) in the primary tumor, correlates with radiation response in terms of complete local tumor control with no evidence of disease or recurrence and no evidence of metastasis; (2) in the postirradiated biopsies correlates with residual tumor; and (3) correlates with the expression of Egr-1 target genes such as TP53, pRB, and Bax. The authors analyzed: (1) 25 pretreated surgically resected paraffin-embedded primary adenocarcinomas of the prostate for the presence of EGR-1 expression and mutation, and correlated this with clinical endpoints such as serum prostate-specific antigen levels and current clinical status; (2) 27 postirradiated biopsies of prostate for the presence of EGR-1 expression, and correlated these findings to the residual tumor status; and (3) 12 prospective prostate tumor specimens for EGR-1 expression and its target genes. EGR-1 expression was determined by immunohistochemistry and mutations were screened in two regions of the Egr-1 gene (trinucleotide AGC repeats in transactivation domain [TD] and poly A tract in 3'UTR) by polymerase chain reaction-single strand conformational polymorphism analysis. Of 25 patients, 18 patients showed expression of EGR-1. EGR-1 overexpression correlated with treatment failure. No correlation with EGR-1 overexpression and its target genes was found, which may indirectly suggest that overexpressed EGR-1 may lack transactivation function. In summary, EGR-1 overexpression in the mutant form may provide an indication of clinical failure (local recurrence or metastasis).

Low dose preoperative radiation in the treatment of carcinoma of the rectum

Recent advances in the treatment of cancer of the rectum show a steady improvement in survival. Newer surgical techniques and expanding options for adjunctive therapy appear to have had a significant impact on improving both local control and distant disease. Five-year survival of patients now ranges from 85-90% for stage I cancers and 50-55% for stage III cancers. Local recurrence of disease following curative surgical resections is dependent on the stage of the tumor and for some high-risk patients, stages T3/T4 and N+ disease, has been reported as high as 40-60%. In an attempt to lower the rate of local recurrence and improve survival, several approaches to adjuvant therapy have been utilized. Preoperative radiation was one approach that has been used extensively in the last decades. Recently, the large Swedish randomized studies using a short course (5 Gy x 5) of preoperative radiation have reported a clear improvement in local control and survival of patients. These results were achieved with no downstaging of disease since surgery was performed put immediately after irradiation. Therefore it should be presumed that preoperative radiation therapy resulted in the sterilization of tumor cells, which prevented both local and distant dissemination leading to the improved outcome. The question remains, therefore, as to what is the least and/or the most appropriate dose of preoperative irradiation that can achieve the beneficial effect of minimizing tumor cell dissemination at surgery. Low dose preoperative irradiation as a single fraction of 500 cGy appears to have a sound biological basis and in single institutional studies it was shown to be effective but in randomized studies it did not improve results. This is likely to be due to a poor design of trials and/or inappropriate patient selection for these studies. A well-designed study still remains to be done.

High-dose intra-arterial cisplatin boost with hyperfractionated radiation therapy for advanced squamous cell carcinoma of the head and neck

PURPOSE

To evaluate the tolerance and efficacy of intra-arterial (IA) cisplatin boost with hyperfractionated radiation therapy (HFX-RT) in patients with advanced squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Forty-two patients with locally advanced primary SCCHN were treated on consecutive phase I/II studies of HFX-RT (receiving a total of 76.8 to 81.6 Gy, given at 1.2 Gy bid) and IA cisplatin (150 mg/m(2) received at the start of and during RT boost treatment).

RESULTS

Acute grade 3 to 4 toxicities were as follows: grade 4 and grade 3 mucosal toxicity occurred in three (7%) and 31 patients (69%), respectively, and grade 3 hematologic, infectious, and skin events occurred in one patient each. Eight of 24 patients (33%) were unable to receive a second planned dose of IA cisplatin because of general anxiety (n = 5), nausea and/or emesis (n = 2), or asymptomatic occlusion of an external carotid artery (n = 1). Thirty-seven patients (88%) experienced complete response (CR) at primary site. Twenty-nine (85%) of 34 patients presenting with nodal disease experienced CR. The actuarial 2-year rates of locoregional control and disease-specific and overall survival are 73%, 63%, and 57%, respectively, with a median active follow-up of 30 months.

CONCLUSION

In this highly unfavorable subset of patients, these results seem superior to previously reported chemoradiation regimens in more favorable patients. Use of a second dose of IA cisplatin boost was associated with increased toxicity without obvious therapeutic gain. This novel strategy allows for an incremental increase in the treatment intensity of the HFX-RT regimen recently established as superior to once-a-day RT.

Ionizing radiation down-regulates p53 protein in primary Egr-1-/- mouse embryonic fibroblast cells causing enhanced resistance to apoptosis

In this study, we sought to investigate the mechanism of the proapoptotic function of Egr-1 in relation to p53 status in normal isogenic cell backgrounds by using primary MEF cells established from homozygous (Egr-1(-/-)) and heterozygous (Egr-1(+/-)) Egr-1 knock-out mice. Ionizing radiation caused significantly enhanced apoptosis in Egr-1(+/-) cells (22.8%; p < 0.0001) when compared with Egr-1(-/-) cells (3.5%). Radiation elevated p53 protein in Egr-1(+/-) cells in 3-6 h. However, in Egr-1(-/-) cells, the p53 protein was down-regulated 1 h after radiation and was completely degraded at the later time points. Radiation elevated the p53-CAT activity in Egr-1(+/-) cells but not in Egr-1(-/-) cells. Interestingly, transient overexpression of EGR-1 in p53(-/-) MEF cells caused marginal induction of radiation-induced apoptosis when compared with p53(+/+) MEF cells. Together, these results indicate that Egr-1 may transregulate p53, and both EGR-1 and p53 functions are essential to mediate radiation-induced apoptosis. Rb, an Egr-1 target gene, forms a trimeric complex with p53 and MDM2 to prevent MDM2-mediated p53 degradation. Low levels of Rb including hypophosphorylated forms were observed in Egr-1(-/-) MEF cells before and after radiation when compared with the levels observed in Egr-1(+/-) cells. Elevated amounts of the p53-MDM2 complex and low amounts of Rb-MDM-2 complex were observed in Egr-1(-/-) cells after radiation. Because of a reduction in Rb binding to MDM2 and an increase in MDM2 binding with p53, p53 is directly degraded by MDM2, and this leads to inactivation of the p53-mediated apoptotic pathway in Egr-1(-/-) MEF cells. Thus, the proapoptotic function of Egr-1 may involve the mediation of Rb protein that is essential to overcome the antiapoptotic function of MDM2 on p53.

The prognostic significance of midline shift at presentation on survival in patients with glioblastoma multiforme

PURPOSE

While patients with glioblastoma multiforme (GBM) who present with midline shift have a presumably worse prognosis, there is little literature evaluating the prognostic significance of this presentation in multivariate analysis in the context of other known prognostic factors.

METHODS AND MATERIALS

From March 1981 to September 1993, 219 patients underwent irradiation for intracranial glioma at our institution. One hundred fourteen patients with a diagnosis of a primary GBM were analyzed for the influence of the presence of midline shift at diagnosis on survival with respect to other known prognostic factors, including age, Karnofsky performance status (KPS), and extent of surgery. Eighty-five patients (74%) presented with midline shift. Surgical treatment consisted of subtotal/total resection in 86 patients (75%). Among patients presenting with midline shift, 68 (80%) underwent subtotal/total resection before irradiation.

RESULTS

Multivariate analysis of the entire cohort of patients found none of the potential prognostic factors analyzed to significantly influence survival. The overall median survival was 6 months. However, when multivariate analysis was limited to patients with a KPS of > or = 70, only the presence of midline shift and age were found to significantly influence survival. Patients with a KPS > or = 70 and with midline shift present at diagnosis had a median survival of 8 months, as compared to 14 months for those not having midline shift at presentation (p = 0.04). Patients with a KPS > or = 70 and age > 50 years had a median survival of 5 months as compared to 11 months for those < or = 50 (p = 0.02).

CONCLUSION

In this series, where 80% of patients who presented with a midline shift underwent decompressive resection of GBM before irradiation, the presence of midline shift at diagnosis remained an independent prognostic factor influencing survival among good performance status patients. While the role of decompressive surgery in this setting is likely of some benefit, the extent of this benefit remains to be defined.

Prognostic significance of postchemoradiation stage following preoperative chemotherapy and radiation for advanced/recurrent rectal cancers

PURPOSE

To evaluate the prognostic significance of postchemoradiation pathologic stage and implications for further therapy following preoperative chemoradiation and surgery for advanced/recurrent rectal cancer.

METHODS AND MATERIALS

Seventy-seven patients with advanced (fixed or tethered T4) or recurrent rectal cancer were treated with preoperative chemoradation followed by surgical resection of disease. Chemotherapy consisted of either of bolus 5-FU 500 mg/m(2) per day or continuous venous infusion 225 mg/m(2) per day for the duration of radiation. Radiation therapy was planned to be delivered to the whole pelvis to a dose of 45 Gy followed by a boost to the area of the tumor of 5-15 Gy. Total radiation doses ranged from 40 to 63 Gy with a median of 55.8 Gy. Surgical resection was then carried out 6-10 weeks following the completion of treatment (median, 7 weeks). Twenty-eight patients underwent abdominoperineal resection and and 49 patients had sphincter-sparing surgical procedures. None of the patients received postoperative chemotherapy. Follow-up in these patients ranges from 1 year to 8 years with a median of 3 years.

RESULTS

Significant downstaging of disease was observed with 12/77 (16%) having no residual disease(pT0) and 13% (10/77) found to have pT1-2, N0 disease, 31% (24/77) with pT3-4, N0 and 40% (31/77) for pT0-4, N1-2 cancers. Survival by pathologic stage was 100% for pT0-2, N0 cancers, 80% for pT3-4, N0 and 73% for pTx, N1-2. Local recurrence of disease was observed in 0% of patients with pT0-2, N0 as compared with 13% (3/24) in pT3-4, N0 and 16% (5/31) in pT0-4, N1-2 patients.

CONCLUSION

Downstaging following preoperative chemoradiation is a significant prognostic factor. Patients with pT0, T1, or T2 disease have an excellent prognosis and are unlikely to fail locally or with systemic disease. However, patient with T3/T4 or N+ disease may benefit from further adjuvant chemotherapy.

Low dose fractionated radiation enhances the radiosensitization effect of paclitaxel in colorectal tumor cells with mutant p53

BACKGROUND

The current study was undertaken to investigate the influence of wild-type or mutant p53 status on the radiosensitizing effect of paclitaxel in colorectal tumor cell lines.

METHODS

HCT-116 (contains wild-type p53) and HT-29 (contains mutant p53) established from moderately differentiated colorectal carcinomas were used in this study. Colony-forming assay was performed after exposure to either different radiation doses (0.5-6 gray [Gy]) or paclitaxel (1-10 nM) or in combination. Induction of p53 and p21(waf1/cip1) by these treatments were determined by immunocytochemistry and Western blot analysis.

RESULTS

Radiation caused an increase in nuclear p53 and p21(waf1/cip1) proteins in HCT-116 cells, indicating that p53 functionally induced p21(waf1/cip1). However, induction of nuclear p53 and p21(waf1/cip1) protein was not evident in HT-29 cells, suggesting that p53 was not functional in these cells. Survival data showed that the HCT-116 cells (survival fraction of exponentially growing cells that were irradiated at the clinically relevant dose of 2 Gy [SF(2)] = 0.383; dose required to reduce the fraction of cells to 37% [D(0)] = 223 centigray [cGy]) were significantly sensitive to ionizing radiation (P < 0.008) when compared with the HT-29 cells (SF(2) = 0.614; D(0) = 351 cGy). Paclitaxel caused a higher degree of clonogenic inhibition in HCT-116 (D(0) = 0.7 nM) than HT-29 (D(0) = 1.11 nM) cells (P < 0.06). When paclitaxel and radiation were combined, an enhanced radiosensitizing effect (P < 0.05) was observed in HCT-116 cells (SF(2) = 0.138; D(0) = 103 cGy), whereas in HT-29 cells no significant radiosensitization of paclitaxel was observed (SF(2) = 0.608; D(0) = 306 cGy). However, pretreatment with paclitaxel followed by multifractionated low dose radiation (0.5- or 1-Gy fractions for a total dose of 2 Gy) significantly enhanced the radiosensitizing effect in both HCT-116 and HT-29 cells.

CONCLUSIONS

The results of the current study suggested that multifractionated radiation given at very low doses after exposure of cells to paclitaxel conferred a potent radiation sensitizing effect irrespective of p53 status.

The feasibility of dose escalation using concurrent radiation and 5-fluorouracil therapy following pancreaticoduodenectomy for pancreatic carcinoma

We evaluated the feasibility of dose escalation using external beam radiation therapy (RT) and 5-fluorouracil (5-FU) following pancreaticoduodenectomy for pancreatic carcinoma. Fourteen patients who underwent pancreaticoduodenectomy for stage I-III adenocarcinoma of the pancreas received postoperative high-dose chemoradiation. RT was given at 1.8-Gy daily fractions to total doses of 54 Gy for patients with negative surgical margins (n = 12), and 64.8 Gy for those with gross residual disease (n = 2). Concurrent 5-FU was given as a continuous infusion (CI) at 225 mg/m2 per day (n = 9) beginning or day 1 and continuing until the completion of RT, or by bolus injection at 500 mg/m2 per day (n = 5) during weeks 1 and 4 of RT. Follow-up ranged from 32 to 36 months (median, 35 months). All patients were able to complete the planned high-dose postoperative chemoradiation and none required a treatment break. No grade 4 acute toxicity was observed. Grade 3 acute toxicity was limited to 2 patients. Two patients developed grade 3 (n = 1) or 4 (n = 1) subacute toxicity, all gastrointestinal-related. There have been no fatal toxicities and no grade 3 or 4 late toxicity has been observed. The 3-year survival is 21%. Dose escalation of postoperative 5-FU chemoradiation following pancreaticoduodenectomy for pancreatic carcinoma is well tolerated. Further dose-intensification of postoperative adjuvant therapy in these patients appears feasible and is being evaluated in a recently activated national trial.

High-dose intra-arterial cisplatin and concurrent hyperfractionated radiation therapy in patients with locally advanced primary squamous cell carcinoma of the head and neck: report of a phase II study

BACKGROUND

This phase II study evaluates the tolerability and efficacy of concurrent hyperfractionated radiation therapy (HFX-RT) and high-dose intra-arterial (IA) cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN).

METHODS

Between December 1995 and November 1997, 20 patients with locally advanced T4/T3 SCCHN were treated with HFX-RT (76.8-79.2 Gy at 1.2 Gy bid over 6-7 weeks) and high-dose IA cisplatin (150 mg/m(2) given at the start of RT boost treatment [start of week 6]). Seventeen patients (85%) had T4 disease, and 14 (70%) had N2/ N3 disease.

RESULTS

Grade 3-5 acute toxicity was limited to one grade 4 (5%) and 14 grade 3 (70%) mucosal events. No grade 3/4 hematologic toxicity was observed. Median weight loss during therapy was 9% (range, 2%-16%). Eighteen patients had complete response (90%) at the primary site; 14 were confirmed pathologically. Among 17 patients with positive neck disease, 16 (94%) achieved complete response in the neck, including 12 of 13 patients with N2/N3 disease who underwent planned neck dissection. Active follow-up ranges from 12 to 32 months (median, 20 months) with 11 patients alive without disease, 5 dead of disease, and 4 dead of intercurrent disease. Eighteen patients (90%) remained disease free at the primary site, and the locoregional control rate is 80%.

CONCLUSIONS

High-dose IA cisplatin and concurrent HFX-RT as used in this study is feasible and warrants further investigation. The high complete response rate and low grade 4 toxicity in this highly unfavorable subset of patients appears better than previously reported chemoradiation regimens for more favorable patients.

Four prognostic groups predict long-term survival from prostate cancer following radiotherapy alone on Radiation Therapy Oncology Group clinical trials

PURPOSE

Gleason score (GS), T stage, and pathologic lymph node status have been described as major independent predictors of death due to prostate cancer in men treated with external beam radiotherapy (XRT). In this analysis we combine these three factors to define prognostic subgroups that correlate with disease-specific survival (DSS) death from prostate cancer.

METHODS AND MATERIALS

Men entered on one of four Radiation Therapy Oncology Group (RTOG) Phase III randomized trials between 1975 and 1992, for clinically localized prostate cancer (CAP) (n = 1557), were selected for this analysis. Patients were included if: 1) they were evaluable, and eligible for the trial; 2) they received no hormonal therapy with their initial treatment; and 3) follow-up was available. For this study a DSS event was declared if: 1) death was certified as due to CAP; 2) death was due to complications of treatment; or 3) death was from unknown causes with active malignancy. The median follow-up for patients treated on early and late RTOG studies exceeded 11 and 6 years respectively. Subgroups were identified based on their pretreatment GS, T-stage, and lymph node such that patients with similar risk of dying from prostate cancer were combined.

RESULTS

By combining patients with similar DSS, four subgroups were identified. Risk Group 1 patients had a GS = 2-6, and T1-2Nx; Group 2: GS = 2-6, T3Nx; or GS = 2-6, N+, or GS = 7, T1-2Nx; Group 3: T3Nx, GS = 7; or N+, GS = 7, or T1-2Nx, GS = 8-10; and Group 4 patients were T3Nx, GS = 8-10, or N+, GS = 8-10. The 5-, 10-, and 15-year DSS was 96%, 86%, and 72%; 94%, 75%, and 61%; 83%, 62%, and 39%; and 64%, 34%, and 27% for Groups 1 through 4, respectively.

CONCLUSIONS

Recognition of these four risk groups provides a basis for estimating the long-term DSS for men treated with XRT alone and should facilitate the design of future prospective randomized trials.