Predicting long-term survival, and the need for hormonal therapy: a meta-analysis of RTOG prostate cancer trials

PURPOSE

To assess the impact of short-term and long-term androgen suppression on the disease-specific and overall survival of 2200 men treated with radiotherapy on one of 5 prospective randomized trials when stratified by prognostic risk groups.

METHODS AND MATERIALS

Between 1975 and 1992, 2742 men were treated for clinically localized prostate cancer on one of 5 consecutive prospective Phase III randomized trials. Patients were selected for this analysis if they were deemed evaluable and eligible for the trial, and if follow-up information was available. For this analysis patients were stratified into four previously described prognostic risk groups: Group 1 patients had a Gleason score (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 median pretreatment prostate-specific antigen (PSA) was 25 ng/ml for the 434 evaluable patients for whom this information was available. The median follow-up times for patients treated on early studies exceeded 11 years, and for more recent studies 6 years.

RESULTS

Risk group 2 patients with "bulky" or T3 disease appeared to have a disease-specific survival benefit at 8 years with the addition of 4 months of goserelin and flutamide. Group 3 and 4 patients were noted to have an approximately 20% higher survival at 8 years with the addition of long-term hormonal therapy (p < or =0.0004).

CONCLUSIONS

Based on this meta-analysis of RTOG trials, subsets of patients can be identified who either do not appear to benefit from the use of hormonal therapy, benefit from short-term hormonal therapy, or who benefit only from long-term hormonal therapy. These observations should be confirmed by prospective randomized trials before they can be considered conclusive. In the meantime, however, these observations provide rational guidelines for deciding who should receive hormonal therapy and for how long.

Characterization of a newly established human pancreatic carcinoma cell line, UK Pan-1

BACKGROUND

A highly tumorigenic cell line designated as UK Pan-1 was established in a surgically removed human pancreatic adenocarcinoma and characterized as having many of the genotypic and phenotypic alterations commonly found in pancreatic tumors.

METHODS

The cell line was characterized by its morphology, growth rate in monolayer culture and soft agar, tumorigenicity in nude mice, and chromosomal analysis. Furthermore, the status of p53, Ki-ras mutation and transforming growth factor (TGF)-/receptor expression were determined. The characteristics of UK Pan-1 were compared with those of other commonly used pancreatic carcinoma cell lines.

RESULTS

Quiescent UK Pan-1 cells could be stimulated to proliferate in growth factor free nutrient media, indicating a growth factor independent phenotype. UK Pan- 1 cells grew in soft agar and rapidly formed tumors in nude mice. This cell line possesses a mutation at codon 12 of the c-Ki-ras-2 gene that is commonly found in pancreatic carcinoma. Fluorescence in situ hybridization showed that two alleles of p53 tumor suppressor gene were present in UK Pan-1. However, sequencing analysis revealed a mutation in one allele at exon 8, codon 273 (G to A; Arg to His). Additional growth assays indicated that the cell line was insensitive to negative growth regulation induced by exogenous TGF-beta. Molecular analysis of the TGF-beta signaling pathway showed that UK Pan-1 did not express appreciable levels of the TGF-beta receptor type I, II, or III mRNAs, but did express DPC4 mRNA. Karyotype analysis revealed an 18q21 deletion indicating a possible loss of heterozygosity for DPC4, as well as other chromosomal deletions and rearrangements.

CONCLUSIONS

This study indicates that UK Pan-1 is a highly tumorigenic cell line possessing a molecularly complex pattern of mutations that may be used as a model to further the understanding of the mechanisms responsible for the development of pancreatic carcinoma.

Preoperative chemoradiation in fixed distal rectal cancer: dose time factors for pathological complete response

PURPOSE

Preoperative chemoradiation is being utilized extensively in the treatment of rectal cancer. However, a variety of dose time factors in both delivery of chemotherapy and irradiation remain to be established. This study was undertaken to examine the impact of dose time factors on pathological complete response (pCR) rates following preoperative chemoradiation for fixed rectal cancer.

METHODS AND MATERIALS

Thirty-three patients with fixed rectal cancers were treated with combined 5-fluorouracil (5-FU) chemotherapy and pelvic radiation. Twenty-one patients received bolus 5-FU during the first 3-5 days of radiation and repeated on days 28-33 of their radiation treatment. Twelve patients were treated with continuous infusion (CI) 5-FU, 225 mg/m(2) for the duration of the pelvic radiation. Fifteen patients received a planned total radiation dose of 45 to 50 Gy and 18 patients received a dose of 55 to 60 Gy. Surgical resection was then carried out 6-8 weeks after completion of treatment.

RESULTS

Diarrhea was the most frequent acute toxicity. Grade 3 diarrhea was observed in 6 patients requiring treatment interruption and was not related to the chemotherapy regimen. There was no Grade 4 or 5 toxicity. pCR was observed in 2 of 21 (10%) patients treated with bolus 5-FU as compared to 8 of 12 (67%) for patients treated with CI (p = 0.002). pCR were observed in 8 of 18 (44%) patients receiving radiation dose > or = 5500 cGy as compared to 2 of 15 (13%) patients treated to a dose < or = 5000 cGy (p = 0.05). In the high-dose radiation (> or = 5500 cGy) group, a significant difference in pCR rate was observed in patients treated with CI, 8 of 12 (67%) (p = 0.017) as compared with bolus 5-FU (0 of 6). There was no significant difference in operative morbidity or in wound healing between patients treated with bolus 5-FU or CI or within the groups treated with low or high doses of radiation. Three patients have developed local recurrence at 14 and 24 months, two in the low-dose group treated with bolus 5-FU and one patient in the CVI group. The overall 5-year survival for the whole group is 71%.

CONCLUSION

Dose intensity of 5-FU and dose of radiation correlate significantly with the likelihood of achieving a pCR. Continuous infusion 5-FU (CI) and a preoperative radiation dose of 5500 cGy or higher can achieve pCR rates of approximately 50%, even in fixed cancers of the rectum.

Outcomes of patients receiving radiation for carcinoma of the rectum. Results of the 1988-1989 patterns of care study

BACKGROUND

Clinical trials of surgical adjuvant treatment for patients with rectal carcinoma (RC) indicate that postoperative radiation therapy with concurrent chemotherapy (CRT) is superior to postoperative radiation alone (RT) or surgery alone. Whether preoperative treatment is superior to postoperative treatment is controversial. This Patterns of Care Study (PCS) surveyed patients with RC treated with radiation during the years 1988-1989 to determine the national practice standards and outcomes and to compare these results with those of clinical trials.

METHODS

A national survey of 73 institutions was conducted using 2-stage cluster sampling, and specific information on 406 patients with RC who received radiation at 69 facilities was collected. Follow-up information on 215 patients was subsequently collected by mail survey. There were no significant differences between the known prognostic indicators or treatment-related variables for patients for whom follow-up was available compared with the variables for patients for whom follow-up was not available. Follow-up ranged from 0 to 8.44 years with a median of 4 years. One hundred fifty-four patients (71%) received postoperative treatment, either RT (37%) or CRT (34%); and 40 (18%) received preoperative treatment, either RT (15%) or CRT (3%). Ninety-six patients (45%) received chemotherapy, and for 86% of those patients chemotherapy was administered concurrently with radiation.

RESULTS

Survival was stage-dependent (85% Stage I, 69% Stage II, and 54% Stage III at 5 years, P = 0.04). Survival was also substage-dependent, and patients with C(1) cancer had significantly higher 5-year survival than those with C(2)/C(3) cancer (89% vs. 48%, P = 0.008). Local failure was similar for Stage II and Stage III patients (10% vs. 11% at 5 years, respectively). In multivariate analyses, only stage and use of chemotherapy were significant to survival (Stage III vs. Stage I and II, relative risk [RR] = 2.52, and chemotherapy vs. no chemotherapy, RR = 0.46). A significantly higher 5-year survival rate was seen with postoperative CRT than with postoperative RT (69% vs. 50%, P = 0. 011). Preoperative radiation resulted in a significantly higher 5-year survival rate than postoperative radiation (85% vs. 50%, P = 0.0006), but not compared with postoperative CRT. Survival and local failure did not differ according to radiation therapy interruption or the interval between surgery and radiation.

CONCLUSIONS

Stage is an important prognostic indicator for survival, and among patients with Stage III malignancies survival in the substage C(1) is significantly higher than in the substages C(2) and C(3). As has been demonstrated in randomized trials, adjuvant postoperative CRT is superior to postoperative RT for patients with RC in this national study. These nationwide results of adjuvant treatment are comparable to those reported in randomized trials. The use of CRT was the only treatment-related factor that resulted in a significant reduction in the risk of death.

Differential expression of transforming growth factor beta receptors in human pancreatic adenocarcinoma

BACKGROUND

Many cancer cells show resistance to transforming growth factor beta (TGF-beta)-mediated growth inhibition. This resistance to TGF-beta is associated with an increased tumorigenic phenotype.

OBJECTIVE

In this study, we determined whether a loss in expression of TGF-beta receptors or DPC4, an important down stream target of TGF-beta signaling, might account for this lack of TGF-beta sensitivity in pancreatic adenocarcinoma.

MATERIALS AND METHODS

To accomplish this, six established pancreatic cancer cell lines, twenty-six surgically resected tumor specimens of pancreatic adenocarcinoma and ten non-tumor pancreas tissues were analyzed for the mRNA expression of the three TGF-beta receptors (RI, RII, and RIII) and DPC4.

RESULTS

We report here that five of six pancreatic cancer cell lines were not sensitive to TGF-beta. All the ten non-tumor specimens of pancreas showed expression of RI, and DPC4; while nine of ten showed expression of RIII and eight of ten showed expression of RII. Five of six pancreatic cancer cell lines and 23 of 26 tumor specimens showed expression of RI. Two cell lines and about half (46%) of the tumor specimens did not express RII. Only two cell lines showed appreciable levels of RIII expression; while ten of 26 (38%) tumor specimens did not show expression of RIII. DPC4 expression was observed in three of the six (50%) cell lines and 19 of 24 (79%) tumor specimens.

CONCLUSION

This study indicates that apart from the functional loss of DPC4 due to mutations or homozygous deletion, a lack of the TGF-beta receptors, particularly RII and RIII, may contribute to a loss of TGF-beta signaling in a population of pancreatic cancers.

Outcomes of patients receiving radiation for carcinoma of the rectum. Results of the 1988-1989 patterns of care study

BACKGROUND

Clinical trials of surgical adjuvant treatment for patients with rectal carcinoma (RC) indicate that postoperative radiation therapy with concurrent chemotherapy (CRT) is superior to postoperative radiation alone (RT) or surgery alone. Whether preoperative treatment is superior to postoperative treatment is controversial. This Patterns of Care Study (PCS) surveyed patients with RC treated with radiation during the years 1988-1989 to determine the national practice standards and outcomes and to compare these results with those of clinical trials.

METHODS

A national survey of 73 institutions was conducted using 2-stage cluster sampling, and specific information on 406 patients with RC who received radiation at 69 facilities was collected. Follow-up information on 215 patients was subsequently collected by mail survey. There were no significant differences between the known prognostic indicators or treatment-related variables for patients for whom follow-up was available compared with the variables for patients for whom follow-up was not available. Follow-up ranged from 0 to 8.44 years with a median of 4 years. One hundred fifty-four patients (71%) received postoperative treatment, either RT (37%) or CRT (34%); and 40 (18%) received preoperative treatment, either RT (15%) or CRT (3%). Ninety-six patients (45%) received chemotherapy, and for 86% of those patients chemotherapy was administered concurrently with radiation.

RESULTS

Survival was stage-dependent (85% Stage I, 69% Stage II, and 54% Stage III at 5 years, P = 0.04). Survival was also substage-dependent, and patients with C(1) cancer had significantly higher 5-year survival than those with C(2)/C(3) cancer (89% vs. 48%, P = 0.008). Local failure was similar for Stage II and Stage III patients (10% vs. 11% at 5 years, respectively). In multivariate analyses, only stage and use of chemotherapy were significant to survival (Stage III vs. Stage I and II, relative risk [RR] = 2.52, and chemotherapy vs. no chemotherapy, RR = 0.46). A significantly higher 5-year survival rate was seen with postoperative CRT than with postoperative RT (69% vs. 50%, P = 0. 011). Preoperative radiation resulted in a significantly higher 5-year survival rate than postoperative radiation (85% vs. 50%, P = 0.0006), but not compared with postoperative CRT. Survival and local failure did not differ according to radiation therapy interruption or the interval between surgery and radiation.

CONCLUSIONS

Stage is an important prognostic indicator for survival, and among patients with Stage III malignancies survival in the substage C(1) is significantly higher than in the substages C(2) and C(3). As has been demonstrated in randomized trials, adjuvant postoperative CRT is superior to postoperative RT for patients with RC in this national study. These nationwide results of adjuvant treatment are comparable to those reported in randomized trials. The use of CRT was the only treatment-related factor that resulted in a significant reduction in the risk of death.

High-dose spatially-fractionated radiation (GRID): a new paradigm in the management of advanced cancers

PURPOSE

With the advent of megavoltage radiation, the concept of spatially-fractionated (SFR) radiation has been abandoned for the last several decades; yet, historically, it has been proven to be safe and effective in delivering large cumulative doses (> 100 Gy) of radiation in the treatment of cancer. SFR radiation has been adapted to megavoltage beams using a specially constructed grid. This study evaluates the toxicity and effectiveness of this approach in treatment of advanced and bulky cancers.

METHODS AND MATERIALS

From January 1995 through March 1998, 71 patients with advanced bulky tumors (tumor sizes > 8 cm) were treated with SFR high-dose external beam megavoltage radiation using a GRID technique. Sixteen patients received GRID treatments to multiple sites and a total of 87 sites were irradiated. A 50:50 GRID (open to closed area) was utilized, and a single dose of 1,000-2,000 cGy (median 1,500 cGy) to Dmax was delivered utilizing 6 MV photons. Sixty-three patients received high-dose GRID therapy for palliation (pain, mass, bleeding, or dyspnea). In 8 patients, GRID therapy was given as part of a definitive treatment combined with conventionally-fractionated external beam irradiation (dose range 5,000-7,000 cGy) followed by subsequent surgery. Forty-seven patients were treated with GRID radiation followed by additional fractionated external beam irradiation, and 14 patients were treated with GRID alone. Thirty-one treatments were delivered to the abdomen and pelvis, 30 to the head and neck region, 15 to the thorax, and 11 to the extremities.

RESULTS

For palliative treatments, a 78% response rate was observed for pain, including a complete response (CR) of 19.5%, and a partial response (PR) of 58.5% in these large bulky tumors. A 72.5% response rate was observed for mass effect (CR 14.6%, PR 52.9%). The response rate observed for bleeding was 100% (50% CR, 50% PR) and for dyspnea, a 60% PR rate only. A relatively higher response rate (CR 23.3%, PR 60%) was observed in patients who received GRID treatment in the head and neck area. No grade 3 late skin, subcutaneous, mucosal, GI, or CNS complications were observed in any patient in spite of these high doses. In the 8 patients who received GRID treatment for definitive treatment, a clinical CR was observed in 5 patients (62.5%) and a pathological complete response was confirmed in the operative specimen in 4 patients (50%).

CONCLUSION

The efficacy and safety of using a large fraction of SFR radiation was confirmed by this study and substantiates our earlier results. In selected patients with bulky tumors (> 8 cm), SFR radiation can be combined with fractionated external beam irradiation to yield improved local control of disease, both for palliation and selective definitive treatment, especially where conventional treatment alone has a limited chance of success.

Postoperative radiation therapy for primary vs. recurrent squamous cell carcinoma of the head and neck: results of a comparative analysis

BACKGROUND

There is little literature comparatively evaluating the results of postoperative radiation therapy (RT) for patients with squamous cell carcinoma (SCC) of the head and neck treated for primary versus recurrent disease.

METHODS

Between 1981 and 1993, 174 patients with SCC of the head and neck, 143 with primary and 31 with recurrent disease, were treated with standard postoperative RT.

RESULTS

Patients treated for primary disease had 5-year local-regional control (LRC) and disease-specific survival (DSS) rates of 69% and 54%, respectively, as compared with 46% and 32%, respectively, for patients treated for recurrent disease (P = 0.03 and 0.04, respectively). On multivariate analysis, only tumor type (primary vs recurrent) significantly influenced LRC (P = 0.003) and only primary tumor site (oral cavity vs nonoral cavity) significantly influenced DSS (P = 0.04). Among the patients treated for recurrent disease, site of recurrence (undissected vs dissected tissue) significantly influenced both LRC and DSS (P = 0.008 and 0. 001, respectively).

CONCLUSIONS

Patients with recurrent SCC of the head and neck do poorly as compared with those with primary disease when treated with standard postoperative RT, particularly when the recurrence is within previously dissected tissue. This patient group should be targeted for alternative treatment strategies.

Long-term survival after radiotherapy alone: radiation therapy oncology group prostate cancer trials

PURPOSE

We assess the relative importance of the several pretreatment characteristics in predicting death from prostate cancer in patients treated with curative intent with external beam radiotherapy alone.

MATERIALS AND METHODS

Patients entered on 4 prospective phase III randomized trials conducted by the Radiation Therapy Oncology Group between 1975 and 1992 were selected for this analysis if they were deemed evaluable and eligible for the trial, they had received no hormonal therapy with initial treatment and followup information was available. A disease specific survival event was declared if death was certified as due to prostate cancer, complications of treatment or unknown causes with clinically active malignancy. Median followup for patients treated on early and late studies exceeded 11 and 6 years, respectively.

RESULTS

Most of the patients (1,557) had tumors clinically staged as T3 (59%), and 87 (36%) with clinically staged T1-2 tumors had pathologically positive lymph nodes. On multivariate analysis Gleason score, clinical stage and nodal status were associated with a less favorable overall and disease specific survival, whereas others factors, such as age and race, were not. A Gleason score of 8 to 10 was associated with a high risk of dying of prostate cancer in the first 5 years (risk ratio 20.0, p = 0.0001). The 10-year disease specific survival for patients with a Gleason score of 2 to 5, 6 to 7 and 8 to 10 was 87, 75 and 44%, respectively, following radiotherapy. Based on published reports these rates were higher than expected with observation alone.

CONCLUSIONS

In the first 10 years Gleason score was the single most important predictor of death. Gleason score should be incorporated into the current clinical staging system.

Significance of pretreatment hemoglobin level in patients with T1 glottic cancer

Recent reports have suggested that pretreatment hemoglobin level (Hgb) is significantly associated with local control (LC) and overall survival (OS) in patients with T1 and T2 squamous cell carcinoma of the glottic larynx. To further evaluate the association of pretreatment Hgb level and other factors with outcome, we performed a retrospective review limited to patients with T1 squamous cell carcinoma of the glottic larynx treated with external beam radiation therapy. One-hundred thirty-nine patients with T1 squamous cell carcinoma of the glottic larynx were analyzed. Median follow-up was 5 years (range 2-22). Median pretreatment Hgb was 14.4 gm/dl (range 8.2-17.2). The following parameters were analyzed for their impact on LC, OS, and disease specific survival (DSS): age; gender; pretreatment Hgb; tumor grade; anterior commissure involvement; field size; total dose; dose per fraction; and overall treatment time. Five-year actuarial LC was 84%. Pretreatment Hgb was not a significant predictor for LC when assessed as a continuous variable (P = 0.38), nor as a dichotomous variable with a cutoff at 13 gm/dl. Local control was 82% for patients with Hgb >13 vs. 92% for Hgb < or = 13 (P= 0.13). No other factor was significant for LC. Five-year actuarial OS was 74%. Univariate analysis revealed that, pretreatment Hgb, total dose, and patient age were significant factors for OS. Overall survival was 78% for patients with pretreatment Hgb > 13 gm/dl vs. 68% for patients with Hgb < or = 13 gm/dl (P = 0.004). Overall survival was 77% for patients treated with > 66 Gy vs. 67% for those treated with < or =66 Gy (P = 0.0013), and 80% for patients < or =61 years as opposed to 69% for patients older than 61 years (P = 0.017). Multivariate analysis revealed that only age (P = 0.014) and Hgb concentration (P = 0.001) retained significance. Five-year actuarial DSS was 92%. Pretreatment Hgb was not a prognostic factor for DSS, nor were any other analyzed factors. Pretreatment Hgb is not a significant prognostic factor for LC in patients with T1 squamous cell carcinoma of the glottic larynx, but it does predict for a poorer OS without affecting DSS. This suggests that patients with lower pretreatment Hgb may have confounding medical problems that detract from their overall survival.

Mutually exclusive expression patterns of Bcl-2 and Par-4 in human prostate tumors consistent with down-regulation of Bcl-2 by Par-4

Par-4 is a widely expressed protein that sensitizes both prostatic and non-prostatic cells to apoptosis. Constitutive- or regulated- overexpression of Par-4 caused a reduction in the levels of the anti-apoptotic protein Bcl-2. Replenishment of Bcl-2 levels abrogated susceptibility to Par-4-dependent apoptosis, suggesting that Par-4-mediated apoptosis requires downmodulation of Bcl-2 levels. The inverse correlation between Par-4 and Bcl-2 expression was recapitulated in human prostate tumors. Par-4 but not Bcl-2 was detected in the secretory epithelium of benign prostatic tumors and in primary and metastatic prostate cancers that are apt to undergo apoptosis. Moreover, xenografts of human, androgen-dependent CWR22 tumors showed Par-4 but not Bcl-2 expression. By contrast, androgen-independent CWR22R tumors derived from the CWR22 xenografts showed mutually exclusive expression patterns of Par-4 and Bcl-2. These findings suggest a mechanism by which Par-4 may sensitize prostate tumor cells to apoptosis.

Evolving trends in combined modality therapy for pancreatic cancer

Only 5%-15% of patients with pancreatic adenocarcinoma undergo potentially curative resection. Evidence that postoperative adjuvant therapy improves outcome is limited to a single randomized trial utilizing split-course chemoradiation. More aggressive regimens have developed and are associated with, at best, a modest improvement in patient outcome. The potentially significant morbidity associated with pancreaticoduodenectomy, which can compromise the delivery of postoperative chemoradiation, has led to the investigations of preoperative regimens. Although such an approach is feasible, its ultimate impact warrants further evaluation. Among the 4% of patients who present with unresectable or locally advanced disease, combined modality therapy has produced the most promising results. However, only modest improvements in survival have so far been achieved. Combined modality therapy with radioisotope implantation appears to have the greatest potential for improving local control and survival in these patients. Intraoperative radiation therapy (IORT) may be associated with lower morbidity than radioisotope implantation, but its impact may be limited by radiobiological disadvantage associated with single-dose boost therapy. The problem of distant metastasis remains significant. New chemotherapeutic agents have the potential to produce better results than those achieved with 5-fluorouracil. Continued advances in surgery, radiation, and systemic therapy should lead to the increased use of modern combined modality interventions with an associated further improvement in patient outcome.

Second malignant neoplasia in patients with T1 glottic cancer treated with radiation

OBJECTIVE/HYPOTHESIS

To evaluate incidence, site of occurrence and outcome of second malignant neoplasia (SMN) in patients with T1 glottic cancer treated with radiation.

STUDY DESIGN

Retrospective.

METHODS

Between February 1964 and May 1993, 158 patients with T1 squamous carcinoma of the larynx were treated with definitive radiation. Incidence, site (aerodigestive tract or not) and outcome of SMN were analyzed. Median follow-up was 63 months (range, 12-245 mo).

RESULTS

Thirty-four patients developed SMN, for an overall incidence of 22%. Twenty-four (67%) SMNs occurred in an aero-upper-digestive-tract site compared with nine (25%) occurring in a non-aero-upper-digestive tract site. The incidence of SMN observed was higher than would be expected for the general population at risk. The observed-to-expected ratios (OER) for all SMN, aero-upper-digestive SMN and non-aero-upper-digestive SMNs were 1.73, 5.53, and 0.62, respectively. Overall 5- and 10-year survivals were 76% and 57%, respectively, for those who did not develop SMN, as compared with 68% and 26%, for those who developed SMN (P = .003). Overall, 13 patients (8.2%) have died from laryngeal cancer, while 23 (15%) died from SMN (P = .001).

CONCLUSION

This study confirms a higher incidence of SMN in T1 glottic cancer patients, compared with the general population. The majority of cases occur in aero-upper-digestive sites. These patients are more likely to die from their SMN than from glottic cancer. Patients with T1 squamous cell carcinoma of the glottic larynx represent a group of head and neck cancer patients who should be targeted in studies evaluating the potential benefits of chemoprevention, and aggressively counseled for social and/or behavioral modifications.

Adjuvant therapy for pancreatic cancer: current status

Only 5% to 15% of patients with pancreatic adenocarcinoma are candidates for a potentially curative resection. Evidence that postoperative adjuvant therapy improves outcome has been limited to a single randomized trial of a well tolerated split-course, 5-Fluorouracil (5-FU) based, chemoradiation regimen. More aggressive regimens have since been developed and are associated with, at best, a modest improvement in patient outcome. The potentially significant morbidity associated with pancreaticoduodenectomy, which can compromise the delivery of postoperative adjuvant chemoradiation, has led to the development of preoperative (adjuvant/neoadjuvant chemoradiation) regimens in these patients. Although experience suggests that such an approach is feasible, the ultimate impact warrants further evaluation. In addition, despite evolving experiences towards more dose intensive pre or postoperative adjuvant chemoradiation regimens, the problem of distant metastases remains significant. New chemotherapeutic agents, such as gemcitabine, appear to have the potential to produce better results than those achieved over the last quarter century with 5-FU. A cooperative group study has recently been activated and is evaluating its impact in an adjuvant setting when given in addition to 5-FU based chemoradiation. In the meantime, ongoing investigations into optimal integration of different therapeutic modalities, along with advances in surgery, radiation, and systemic therapy, should lead us towards further improvements in outcomes for these patients.

Postoperative radiotherapy in the treatment of single metastases to the brain: a randomized trial

CONTEXT

For the treatment of a single metastasis to the brain, surgical resection combined with postoperative radiotherapy is more effective than treatment with radiotherapy alone. However, the efficacy of postoperative radiotherapy after complete surgical resection has not been established.

OBJECTIVE

To determine if postoperative radiotherapy resulted in improved neurologic control of disease and increased survival.

DESIGN

Multicenter, randomized, parallel group trial.

SETTING

University-affiliated cancer treatment facilities.

PATIENTS

Ninety-five patients who had single metastases to the brain that were treated with complete surgical resections (as verified by postoperative magnetic resonance imaging) between September 1989 and November 1997 were entered into the study.

INTERVENTIONS

Patients were randomly assigned to treatment with postoperative whole-brain radiotherapy (radiotherapy group, 49 patients) or no further treatment (observation group, 46 patients) for the brain metastasis, with median follow-up of 48 weeks and 43 weeks, respectively.

MAIN OUTCOME MEASURES

The primary end point was recurrence of tumor in the brain; secondary end points were length of survival, cause of death, and preservation of ability to function independently.

RESULTS

Recurrence of tumor anywhere in the brain was less frequent in the radiotherapy group than in the observation group (9 [18%] of 49 vs 32 [70%] of 46; P<.001). Postoperative radiotherapy prevented brain recurrence at the site of the original metastasis (5 [10%] of 49 vs 21 [46%] of 46; P<.001) and at other sites in the brain (7 [14%] of 49 vs 17 [37%] of 46; P<.01). Patients in the radiotherapy group were less likely to die of neurologic causes than patients in the observation group (6 [14%] of 43 who died vs 17 [44%] of 39; P=.003). There was no significant difference between the 2 groups in overall length of survival or the length of time that patients remained functionally independent.

CONCLUSIONS

Patients with cancer and single metastases to the brain who receive treatment with surgical resection and postoperative radiotherapy have fewer recurrences of cancer in the brain and are less likely to die of neurologic causes than similar patients treated with surgical resection alone.

Use of rectal cancer position as a prognostic indicator

The hypothesis of this study was that the position of rectal cancer within the circumference of the rectum influences mortality. Tumor position was prospectively documented in 181 patients with rectal carcinoma by two examiners. The results were analyzed for correlation to survival using the Lifetest model and for multivariate correlation using the Cox regression model. An anterior tumor location was present in 43 patients and was found to have a significantly higher survival rate than other positions. Two-thirds of anterior tumors were of pathologically favorable Dukes' stages. Fifty-five patients had posterior tumors with decreased survival rates, two-thirds of which were of unfavorable stages. Circumferential position in 61 patients was most predictive of poorer outcome, with a relative risk of death being increased by 4.6 times (P = 0.014) and a 5-year survival rate of 68.8 per cent; 85 per cent of these tumors were of pathologically unfavorable stages. The 5-year survival rate for the whole group, which included 181 patients with all histopathological stages except those with distant metastases at presentation, was 78.5 per cent. This ranking of survival rates was found to be consistent in each category with the postoperatively determined Dukes' stage, which carried a prognostic significance of P = 0.0001. We conclude that tumor position is a significant indicator of prognosis available before surgery for rectal cancer.

Radical Sphincter preservation surgery with coloanal anastomosis following high-dose external irradiation for the very low lying rectal cancer

High-dose preoperative radiation and specifically designed surgical techniques were used to extend the application of sphincter preservation surgery for cancer of the distal 3 cm of the true rectum. A total of 203 consecutive patients with rectal cancer were treated with external-beam irradiation (45-70 Gy) and radical curative surgery. The cancer was at the level of 0.5-3.0 cm in 65 patients. In these 65 patients treated by radical resection with coloanal anastomosis six suffered recurrence (9%), and the 5-year actuarial survival was 85%. There was a single death. There was no local recurrence among 44 patients in whom the postradiated cancer resided in the rectal wall with or without nodal involvement. With proper selection, high-dose preoperative radiation therapy thus permits extended use of sphincter preservation surgery with coloanal anastomosis for cancers of the distal 3 cm of the true rectum.

Novel mutations in the polyadenine tract of the transforming growth factor beta type II receptor gene are found in a subpopulation of human pancreatic adenocarcinomas

In this study, we determined the incidence of microsatellite instability (MIN) in pancreatic adenocarcinoma and determined whether MIN might target, for mutations, the simple nucleotide repeats of the transforming growth factor beta type II receptor (TGFBR2) gene. Forty-eight surgically resected pancreatic tumor tissue samples and two normal pancreas tissue samples were analyzed in this study. Microsatellite analysis was performed for six loci in 14 of the 48 tumor specimens for which we had matching normal genomic DNA. Only four of the 14 tumors (29%) were MIN-positive as determined by the presence of microsatellite variations in more than one locus. Interestingly, eight of the 14 specimens (57%) showed microsatellite variations or loss of heterozygosity at D18S34, suggesting that this locus may be a critical region of genetic instability in pancreatic tumorigenesis. Of the 48 tumors, only two (4%) showed mutations in the polyA region, one of the MIN-targeted sites of the TGFBR2 gene. DNA sequence analysis of these two specimens showed the presence of a two-base deletion in one tumor specimen and the other tumor specimen showed a base substitution in the polyA tract at codon 128 of the TGFBR2 gene. The fact that these mutations occurred in the polyA tract of some pancreatic tumors suggests that a subpopulation of these tumors may be susceptible to MIN-targeted mutations. The incidence of these mutations are low and similar to that reported for nonhereditary, sporadic colon cancers.

Reproduction of radiologic images on plain paper

Skyrocketing health care costs and pressures from managed care have combined to promote cost-cutting strategies in radiology and radiation oncology departments. A study was conducted to evaluate the use of a high-resolution laser printer for printing plain-paper images as substitutes for both original and duplicate radiologic film images. A variety of radiologic images were used to evaluate the image reproduction capabilities of the printer in terms of linearity, detail, and contrast. In many cases, printed images had a quality comparable to that of the original images. Six computed tomographic (CT) scans and six radiation therapy simulator radiographs were compared with printed reproductions by each of seven board-certified radiation oncologists, who rated the reproductions as acceptable for documentation, acceptable for diagnostic purposes (CT scans only), or unacceptable. Ninety-five percent of printed CT images and 90% of printed simulation images were rated acceptable for documentation. The quality of printed images of radiation therapy port films was not quantitatively measured but was improved by adjusting image contrast and brightness and using various image enhancement techniques. The use of printed images is less expensive than that of processed film and eliminates the environmental, time, storage, and delivery problems associated with film. Technologic advances in imaging, networking, and printing have made possible the inexpensive duplication of medical images.

High-dose preoperative radiation and the challenge of sphincter-preservation surgery for cancer of the distal 2 cm of the rectum

PURPOSE

Sphincter-preserving surgery for the management of distal rectal cancer is gaining recognition as an alternative to abdominoperineal resection and loss of anal function. The use of high-dose preoperative radiation appears to enhance the options for sphincter preservation, even in the most distal segments of the rectum.

MATERIALS AND METHODS

Seventy patients with tumors located in the distal 2 cm of the rectum received a minimum dose of 40 to 45 Gy over 4 1/2 weeks at 1.8 to 2.5 Gy per fraction. Patients with unfavorable tumors were given an additional boost of 10 to 15 Gy. Surgery was performed 5 to 10 weeks following completion of radiation. Radical surgical resection was performed in 48 patients and full thickness local excision in 22. Follow-up ranged from a minimum of 1 year to a maximum of 10 years, with a median of 4 years.

RESULTS

There was one perioperative mortality. Two patients did not have their colostomy closed because of complications. Late diversion was required in 4 patients, primarily for recurrent disease. Sixty patients (86%) maintained long-term satisfactory sphincter function. Local recurrence was observed in 9 patients (13%) and distant metastases in 12 patients (17%). The overall five-year actuarial survival rate was 82%. The 5-year survival and local recurrence for postradiation pathological stage of disease was: T0, T1, T2, N0--95% and 8%, T3, T4, N0--91% and 4%, T(any) N+--50% and 41%, respectively.

CONCLUSION

High-dose preoperative radiation, in properly selected patients with rectal cancers of the distal 2 cm, offers opportunities for sphincter-preserving surgical resection with excellent local control, survival, and enhanced quality of life.

Ionizing radiation-inducible apoptosis in the absence of p53 linked to transcription factor EGR-1

The tumor suppressor protein p53 is a pivotal regulator of apoptosis, and prostate cancer cells that lack p53 protein are moderately resistant to apoptotic death by ionizing radiation. Genes encoding the transcription factor early growth response-1 (EGR-1) and cytokine tumor necrosis factor-alpha (TNF-alpha) were induced upon irradiation of prostate cancer cells, and inhibition of EGR-1 function resulted in abrogation of both TNF-alpha induction and apoptosis. Induction of the TNF-alpha gene by ionizing radiation and EGR-1 was mediated via a GC-rich EGR-1-binding motif in the TNF-alpha promoter. Because TNF-alpha induces apoptosis in prostate cancer cells, these findings suggest that, in the absence of p53, ionizing radiation-inducible apoptosis is mediated by EGR-1 via TNF-alpha transactivation.

Critical issues in the evolving management of rectal cancer

Evolving trends in the management of rectal cancer have focused on organ preservation, improved quality of life, and survival of patients. A significant shift is underway in our thinking about what constitutes the true rectum and defining the "proximal" and "distal" segments of the rectum. Tumor mobility remains a dominant prognostic factor in patient selection and choice of surgery. A clinical staging with tumor location in the rectum provides a logical algorithm for treatment decision making with either chemoradiation therapy or surgery as initial treatment of choice. Current rectal cancer management has largely focused on postoperative adjuvant radiation strategies with improvement reported for T3 and N+ cases. Recent data from Europe suggests that preoperative radiation has a significant advantage over surgery alone or postoperative treatment. This appears to be borne out by institutional studies of high-dose preoperative radiation (>45 Gy) in the United States. Aggressive preoperative combined chemoradiation has also led to significant downstaging of cancer with pathological complete response rates of 20% to 30%. This offers new options for surgical management of residual disease with endocavitary radiation or local excision. The development of new agents Gemcitabine, paclitaxel, and CPT-11 may also prove beneficial. New treatment strategies need to be coordinated with evolving knowledge of the biological behavior of the tumor based on its genetic fingerprints. c-Ki-ras and C-myc mutations have been implicated in tumor initiation and progression. A number of other tumor suppressor genes, APC gene, p53, and DCC have also been implicated in colorectal tumor carcigenesis. The modification of biological behavior by mutations in these genes is currently under study. This may guide new treatment strategies significantly reducing the death rates from rectal cancer and improving functional results of treatment.