Dose-Escalated Radiotherapy Alone or in Combination With Short-Term Androgen Deprivation for Intermediate-Risk Prostate Cancer: Results of a Phase III Multi-Institutional Trial

PURPOSE

It remains unknown whether or not short-term androgen deprivation (STAD) improves survival among men with intermediate-risk prostate cancer (IRPC) treated with dose-escalated radiotherapy (RT).

METHODS

The NRG Oncology/Radiation Therapy Oncology Group 0815 study randomly assigned 1,492 patients with stage T2b-T2c, Gleason score 7, or prostate-specific antigen (PSA) value >10 and ≤20 ng/mL to dose-escalated RT alone (arm 1) or with STAD (arm 2). STAD was 6 months of luteinizing hormone-releasing hormone agonist/antagonist therapy plus antiandrogen. RT modalities were external-beam RT alone to 79.2 Gy or external beam (45 Gy) with brachytherapy boost. The primary end point was overall survival (OS). Secondary end points included prostate cancer-specific mortality (PCSM), non-PCSM, distant metastases (DMs), PSA failure, and rates of salvage therapy.

RESULTS

Median follow-up was 6.3 years. Two hundred nineteen deaths occurred, 119 in arm 1 and 100 in arm 2. Five-year OS estimates were 90% versus 91%, respectively (hazard ratio [HR], 0.85; 95% CI, 0.65 to 1.11]; P = .22). STAD resulted in reduced PSA failure (HR, 0.52; P <.001), DM (HR, 0.25; P <.001), PCSM (HR, 0.10; P = .007), and salvage therapy use (HR, 0.62; P = .025). Other-cause deaths were not significantly different (P = .56). Acute grade ≥3 adverse events (AEs) occurred in 2% of patients in arm 1 and in 12% for arm 2 (P <.001). Cumulative incidence of late grade ≥3 AEs was 14% in arm 1 and 15% in arm 2 (P = .29).

CONCLUSION

STAD did not improve OS rates for men with IRPC treated with dose-escalated RT. Improvements in metastases rates, prostate cancer deaths, and PSA failures should be weighed against the risk of adverse events and the impact of STAD on quality of life.

Outcomes of Rural Men with Breast Cancer: A Multicenter Population Based Retrospective Cohort Study

Background: Breast cancer is rare in men. This population-based study aimed to determine outcomes of male breast cancer in relation to residence and other variables. Methods: In this retrospective cohort study, men diagnosed with breast cancer in Saskatchewan during 2000–2019 were evaluated. Cox proportional multivariable regression analyses were performed to determine the correlation between survival and clinicopathological and contextual factors. Results: One hundred-eight eligible patients with a median age of 69 years were identified. Of them, 16% had WHO performance status ≥ 2 and 61% were rural residents. The stage at diagnosis was as follows: stage 0, 7%; I, 31%; II, 42%; III, 11%; IV, 8%. Ninety-eight percent had hormone receptor-positive breast cancer. The median disease-free survival of urban patients was 97 (95% CI: 50–143) vs. 64 (46–82) months of rural patients (p = 0.29). The median OS of urban patients was 127 (94–159) vs. 93 (32–153) months for rural patients (p = 0.27). On multivariable analysis, performance status ≥ 2, hazard ratio (HR) 2.82 (1.14–6.94), lack of adjuvant systemic therapy, HR 2.47 (1.03–5.92), and node-positive disease, HR 2.32 (1.22–4.40) were significantly correlated with inferior disease-free survival in early-stage invasive breast cancer. Whereas stage IV disease, HR 7.8 (3.1–19.5), performance status ≥ 2, HR 3.25 (1.57–6.71), and age ≥ 65 years, HR 2.37 (1.13–5.0) were correlated with inferior overall survival in all stages. Conclusions: Although residence was not significantly correlated with outcomes, rural men had numerically inferior survival. Poor performance status, node-positive disease, and lack of adjuvant systemic therapy were correlated with inferior disease-free survival.

Development and Validation of Consensus Contouring Guidelines for Adjuvant Radiation Therapy for Bladder Cancer After Radical Cystectomy

PURPOSE

To develop multi-institutional consensus clinical target volumes (CTVs) and organs at risk (OARs) for male and female bladder cancer patients undergoing adjuvant radiation therapy (RT) in clinical trials.

METHODS AND MATERIALS

We convened a multidisciplinary group of bladder cancer specialists from 15 centers and 5 countries. Six radiation oncologists and 7 urologists participated in the development of the initial contours. The group proposed initial language for the CTVs and OARs, and each radiation oncologist contoured them on computed tomography scans of a male and female cystectomy patient with input from ≥1 urologist. On the basis of the initial contouring, the group updated its CTV and OAR descriptions. The cystectomy bed, the area of greatest controversy, was contoured by another 6 radiation oncologists, and the cystectomy bed contouring language was again updated. To determine whether the revised language produced consistent contours, CTVs and OARs were redrawn by 6 additional radiation oncologists. We evaluated their contours for level of agreement using the Landis-Koch interpretation of the κ statistic.

RESULTS

The group proposed that patients at elevated risk for local-regional failure with negative margins should be treated to the pelvic nodes alone (internal/external iliac, distal common iliac, obturator, and presacral), whereas patients with positive margins should be treated to the pelvic nodes and cystectomy bed. Proposed OARs included the rectum, bowel space, bone marrow, and urinary diversion. Consensus language describing the CTVs and OARs was developed and externally validated. The revised instructions were found to produce consistent contours.

CONCLUSIONS

Consensus descriptions of CTVs and OARs were successfully developed and can be used in clinical trials of adjuvant radiation therapy for bladder cancer.

Long-term outcome of breast cancer patients with one to two nodes involved - application of nodal ratio

Nodal ratio (NR) is defined as the number of involved nodes to the number of nodes examined. There is limited information on the application of NR on population data. Previous reports in breast cancer generally analyzed one to three positive axillary nodes as a single group. This study investigates whether one to three positive axillary nodes is a homogeneous group in prognosis by comparing one to two positive nodes to three positive nodes. The population-based registry of a Canadian province from 1981 through 1995 was searched. As the reliability of nodal assessment depends on the number of nodes sampled, we also studied the subgroup of patients with greater than or equal to eight nodes dissected. Of a total of 5,996 breast cancer patients, 1187 had one to three positive axillary nodes. The 263 patients with three positive nodes compared to the 924 patients with one to two nodes fared worse with a significantly reduced cause-specific survival (CSS) and overall survival (OS). Patients with one to two positive nodes had similar CSS (p=0.31) and OS (p=0.63). Among those with greater than or equal to eight nodes dissected, there were 677 patients with one to two positive nodes. CSS and OS were not significantly different between one versus two positive nodes (p=0.16 and 0.34, respectively), but with NR, the corresponding p values were 0.0068 and 0.08, respectively. The cutoff value of NR 0.15 was found to be most useful and confirmed by the validation dataset. NR is able to segregate patients better than the absolute number of positive nodes used in the current staging system. NR should be incorporated into the staging system.

Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markers

Background

Fiducial markers and daily electronic portal imaging (EPI) can reduce the risk of geographic miss in prostate cancer radiotherapy. The purpose of this study was to estimate CTV to PTV margin requirements, without and with the use of this image guidance strategy.

Methods

46 patients underwent placement of 3 radio-opaque fiducial markers prior to prostate RT. Daily pre-treatment EPIs were taken, and isocenter placement errors were corrected if they were ≥ 3 mm along the left-right or superior-inferior axes, and/or ≥ 2 mm along the anterior-posterior axis. During-treatment EPIs were then obtained to estimate intra-fraction motion.

Results

Without image guidance, margins of 0.57 cm, 0.79 cm and 0.77 cm, along the left-right, superior-inferior and anterior-posterior axes respectively, are required to give 95% probability of complete CTV coverage each day. With the above image guidance strategy, these margins can be reduced to 0.36 cm, 0.37 cm and 0.37 cm respectively. Correction of all isocenter placement errors, regardless of size, would permit minimal additional reduction in margins.

Conclusions

Image guidance, using implanted fiducial markers and daily EPI, permits the use of narrower PTV margins without compromising coverage of the target, in the radiotherapy of prostate cancer.

Human dendritic cells engineered to express alpha tumor necrosis factor maintain cellular maturation and T-cell stimulation capacity

Dendritic cell (DC) vaccine has been demonstrated to induce antitumor immunity in animal models. It has been shown that the efficiency of antitumor immunity by DC vaccine is closely correlated with DC maturation status. The mature human DCs generated from peripheral blood mononuclear cells (PBMCs) in the presence of granulocyte macrophage-colony-stimulating factor (GM-CSF), interleukin (IL)-4, and tumor necrosis factor (TNF)-alpha have widely contributed to their growing use in cancer vaccination trials. Although the objective clinical immune responses have been observed, the treatment results have proved to be somewhat disappointing. One question of whether these ex vivo-generated mature DCs can maintain their maturation status in vivo after DC vaccination is unclear. In this study, we investigated the influence of different culture media (RPMI 1640/10% fetal calf serum [FCS] versus serum-free AIM-V medium) on DC maturation and the change of maturation status of these ex vivo generated mature DCs during further culturing in medium without inflammatory cytokine TNF-alpha. We previously constructed a recombinant adenovirus AdV-TNF-alpha expressing the transgene human TNF-alpha. We transfected human DCs with AdV-TNF-alpha at multiplicity of infection of 100, resulting in engineered DCs secreting TNF-alpha (4.6 ng/mL/10(6) cells/24 hours). We also conducted kinetic studies to compare the maturation status and the T-cell stimulation capacity by ex vivo-generated mature DCs and TNF-alpha- transgene-engineered DCs during further culturing in medium without TNF-alpha. Our data show that mature DCs can be generated from PBMCs in both Dulbecco's modified Eagle's medium plus 10% FCS and serum-free AIM-V medium containing GM-CSF (100 ng/mL), IL-4 (100 ng/mL), and TNF-alpha (10 ng/mL). However, these mature DCs gradually lost their maturity and became immature ones when culturing in medium in the absence of TNF-alpha. On the contrary, the human DCs engineered to express TNF-alpha can (i) stably maintain their cellular maturation and (ii) efficiently stimulate T-cell proliferation even during culturing ex vivo in medium without TNF-alpha stimulation. Therefore, DCs engineered to express TNF-alpha may also maintain their maturation status and induce more efficient antitumor immune responses when applied in vivo for vaccination. Thus, our results may be important in designing DC-based cancer vaccines in the future.

HER-2/neu-gene engineered dendritic cell vaccine stimulates stronger HER-2/neu-specific immune responses compared to DNA vaccination

HER-2/neu is a candidate for developing breast cancer-targeted immunotherapeutics. Although DNA-based and HER-2/neu transgene-modified dendritic cell (DC)-based vaccines are potent at eliciting HER-2/neu-specific antitumor immunity, there has been no side-by-side study comparing them directly. The present study utilizes an in vivo murine tumor model expressing HER-2/neu antigen to compare the efficacy between adenovirus (AdVneu)-transfected dendritic cells (DC(neu)) and plasmid DNA (pcDNAneu) vaccine. Our data showed that DC(neu) upregulated the expression of immunologically important molecules and inflammatory cytokines and partially converted regulatory T (Tr)-cell suppression through interleukin-6 (IL-6) secretion. Vaccination of DC(neu) induced stronger HER-2/neu-specific humoral and cellular immune responses than DNA vaccination, which downregulated HER-2/neu expression and lysed HER-2/neu-positive tumor cells in vitro, respectively. In two HER-2/neu-expressing tumor models, DC(neu) completely protected mice from tumor cell challenge compared to partial or no protection observed in DNA-immunized mice. In addition, DC(neu) significantly delayed breast cancer development in transgenic mice in comparison to DNA vaccine (P<0.05). Taken together, we have demonstrated that HER-2/neu-gene-modified DC vaccine is more potent than DNA vaccine in both protective and preventive animal tumor models. Therefore, DCs genetically engineered to express tumor antigens such as HER-2/neu represent a new direction in DC vaccine of breast cancer.

Combined radiation therapy and dendritic cell vaccine for treating solid tumors with liver micro-metastasis

BACKGROUND

Tumor metastasis and relapse are major obstacles in combating human malignant diseases. Neither radiotherapy alone nor injection of dendritic cells (DCs) can successfully overcome this problem. Radiation induces tumor cell apoptosis and necrosis, resulting in the release of tumor antigen and danger signals, which are favorable for DC capturing antigens and maturation. Hence, the strategy of combined irradiation and DC vaccine may be a novel approach for treating human malignancies and early metastasis.

METHODS

To develop an effective combined therapeutic approach, we established a novel concomitant local tumor and liver metastases model through subcutaneous (s.c.) and intravenous (i.v.) injection. We selected the optimal time for DC injection after irradiation and investigated the antitumor effect of combining irradiation with DC intratumoral injection and the related mechanism.

RESULTS

Combined treatment with radiotherapy and DC vaccine could induce a potent antitumor immune response, resulting in a significant decrease in the rate of local tumor relapse and the numbers of liver metastases. The related mechanisms for this strong antitumor immunity of this combined therapy might be associated with the production of apoptotic and necrotic tumor antigens and heat shock proteins after irradiation, phagocytosis, migration and maturation of DCs, and induction of more efficient tumor-specific cytotoxic T lymphocyte activity through a cross-presentation pathway.

CONCLUSIONS

Co-administration of local irradiation and intratumoral DC injection may be a promising strategy for treating radiosensitive tumors and eliminating metastasis in the clinic.