Future directions in combined modality therapy for rectal cancer: reevaluating the role of total mesorectal excision after chemoradiotherapy

Most patients who develop rectal cancer present with locoregionally advanced (T3 or node-positive) disease. The standard management of locoregionally advanced rectal cancer is neoadjuvant concurrent chemoradiotherapy (nCRT), followed by radical resection (low-anterior resection or abdominoperineal resection with total mesorectal excision). Approximately 15% of patients can have a pathologic complete response (pCR) at the time of surgery, indicating that some patients can have no detectable residual disease after nCRT. The actual benefit of surgery in this group of patients is unclear. It is possible that omission of surgery in these patients, termed selective nonoperative management, can limit the toxicities associated with standard, multimodal combined modality therapy without compromising disease control. In this review, we discuss the clinical experiences to date using selective nonoperative management and various attempts at escalation of nCRT to improve the number of patients who have a pCR. We also explore several clinical, laboratory, imaging, histopathologic, and genetic biomarkers that have been tested as tools to predict which patients are most likely to have a pCR after nCRT.

Herpes zoster and radiation therapy: what radiation oncologists need to know about diagnosing, preventing, and treating herpes zoster

Herpes zoster, a viral disease that is characterized by a painful and blistering eruption in the skin, represents reactivation of latent varicella zoster (chickenpox) virus infection. In high-risk groups such as elderly or immunocompromised patients, the incidence of zoster can be as high as 50%. Radiation oncologists are likely to see zoster because cancer, and cancer therapy, can adversely affect immune function. A few reports suggest that radiation therapy is a risk factor for zoster, and that the skin eruption is often in or near the radiation treatment field. The diagnosis is typically made through clinical history and exam, but several tests are available to confirm the diagnosis and differentiate it from other infections or dermatitis. Effective management consists of prompt antiviral medication, acute pain control, appropriate precautions to limit transmission, and referral to specialists in certain cases. Despite appropriate therapy, up to 18% of patients can develop persistent postherpetic neuralgia, defined as pain more than 4 months after resolution of the rash. Several classes of pain medication are available to treat acute or long-term pain. Vaccination against zoster is recommended for patients aged 60 years or older, as it can reduce the incidence and severity of zoster.

Toxicity after external beam radiotherapy for prostate cancer: an analysis of late morbidity in men with diabetes mellitus

OBJECTIVE

To investigate the influence of diabetes mellitus (DM) on late genitourinary (GU) and gastrointestinal (GI) toxicity in patients treated with external beam radiotherapy (RT) for prostate cancer.

MATERIALS AND METHODS

A total of 626 men were treated with curative-intent RT for prostate cancer from 1988 to 2008. Using the National Comprehensive Cancer Network risk category, the patients were considered to have low-risk (30%), intermediate-risk (42%), or high-risk (28%) prostate cancer. The median radiation dose was 74 Gy; 45% received androgen deprivation therapy for a median of 4 months. Late GU and GI Radiation Therapy Oncology Group toxicity was recorded prospectively at each visit after external beam RT. The median follow-up period was 55 months.

RESULTS

Of the 626 men, 102 (16%) had DM that was controlled by diet (8%), oral medications (52%), or insulin (39%). The patients with DM were more likely to receive intensity-modulated RT and androgen deprivation therapy and to have a shorter follow-up duration (P ≤.05 for all). Univariate analyses demonstrated that greater radiation dose, baseline urinary dysfunction, intensity-modulated RT, and DM were associated with grade 2 or greater GU toxicity, and transurethral resection of the prostate and DM were associated with grade 3 or greater GU toxicity. In addition, androgen deprivation therapy use, age ≥70 years, and anticoagulation were associated with grade 2 or greater GI toxicity, and age ≥70 years and anticoagulation were associated with grade 3 or greater GI toxicity. The multivariate analyses for late toxicity demonstrated a greater risk of grade 2 or greater (relative risk 1.36, P = .10) and grade 3 or greater GU toxicity (relative risk 2.74, P = .04) with DM.

CONCLUSION

A greater incidence of late GU toxicity was seen in patients with DM treated for prostate cancer. This relationship might be useful when considering the treatment of patients with DM, especially those receiving dose-escalated RT or with a history of transurethral resection of the prostate.

New paradigms and future challenges in radiation oncology: an update of biological targets and technology

Radiation oncology exploits the biological interaction of radiation within tissue to promote tumor death while minimizing damage to surrounding normal tissue. The clinical delivery of radiation relies on principles of radiation physics that define how radiation energy is deposited in the body, as well as technology that facilitates accurate tumor targeting. This review will summarize the current landscape of recent biological and technological advances in radiation oncology, describe the challenges that exist, and offer potential avenues for improvement.

Combined-modality therapy for rectal cancer: analysis of potential differences in disease presentation, treatment adherence, and treatment outcome according to race

OBJECTIVES

Population-based studies suggest African Americans (AAs) with rectal cancer have a worse overall outcome compared with non-AAs. This relationship was explored in a cohort of rectal cancer patients treated with preoperative chemoradiation therapy (CRT) and surgery at 2 academic cancer centers.

METHODS

A total of 146 patients (26 AA, 120 non-AA) underwent treatment with curative intent. The median age was 57 years. Median dose was 50.4 Gy, given with 5-fluorouracil-based concurrent chemotherapy. Differences in disease presentation, adherence to recommended therapy, and treatment outcome (freedom from failure) by race were analyzed. Median follow-up was 34 months from completion of CRT.

RESULTS

AAs had longer time from diagnosis to start of therapy (median, 45 vs. 35 d; P<0.01) and from CRT completion to surgery (median, 42 vs. 46 d; P=0.03). AA patients presented with more favorable disease (20% stage I, 33% stage III) compared with non-AA patients (0% stage I, 48% stage III, P<0.01). AA patients were less likely to receive adjuvant chemotherapy (58% vs. 89%, P=0.01). Log-rank analysis showed AAs were not more likely to recur after therapy (freedom from failure at 3 y, 100% for AA patients vs. 81% for non-AA patients, P=0.09). The difference in time from preoperative therapy to surgery and a lower rate of adjuvant therapy in AA patients did not seem to result in inferior disease outcome for this cohort.

CONCLUSIONS

Further study is necessary to explore the reasons underlying the delays in therapy and lower rates of adjuvant chemotherapy for AA patients.

Radiation dose ≥54 Gy and CA 19-9 response are associated with improved survival for unresectable, non-metastatic pancreatic cancer treated with chemoradiation

BACKGROUND

Unresectable pancreatic cancer (UPC) has low survival. With improving staging techniques and systemic therapy, local control in patients without metastatic disease may have increasing importance. We investigated whether the radiation dose used in chemoradiation (CRT) as definitive treatment for UPC and the CA 19-9 response to therapy have an impact on overall survival (OS).

METHODS

From 1997-2009 46 patients were treated with CRT for non-metastatic UPC. Median prescribed RT dose was 54 Gy (range 50.4-59.4 Gy). All patients received concurrent chemotherapy (41: 5-fluorouracil, 5: other) and 24 received adjuvant chemotherapy.

RESULTS

41 patients were inoperable due to T4 disease and 5 patients with T3 disease were medically inoperable. Five patients did not complete CRT due to progressive disease or treatment-related toxicity (median RT dose 43.2 Gy). Overall, 42 patients were dead of disease at the time of last follow-up. The median and 12 month OS were 8.8 months and 35%, respectively. By univariate analysis, minimum CA 19-9 post-CRT <90 U/mL was favorably associated with OS (12.3 versus 8.8 months, p = 0.012). Radiotherapy dose ≥54 Gy trended towards improved OS (11.3 versus 6.8 months, p = 0.089). By multivariable analysis, a delivered RT dose of ≥54 Gy (HR 0.47, p = 0.028) and minimum CA 19-9 post-CRT of <90 U/mL (HR 0.35, p = 0.008) were associated with OS.

CONCLUSIONS

CRT as definitive treatment for UPC had low survival. However, our retrospective data suggest that patients treated to ≥54 Gy or observed to have a minimum post-CRT CA 19-9 <90 U/mL had improved likelihood of long-term survival.

Aspirin use and the risk of prostate cancer mortality in men treated with prostatectomy or radiotherapy

PURPOSE

Experimental evidence suggests that anticoagulants (ACs) may inhibit cancer growth and metastasis, but clinical data have been limited. We investigated whether use of ACs was associated with the risk of death from prostate cancer.

PATIENTS AND METHODS

This study comprised 5,955 men in the Cancer of the Prostate Strategic Urologic Research Endeavor database with localized adenocarcinoma of the prostate treated with radical prostatectomy (RP) or radiotherapy (RT). Of them, 2,175 (37%) were receiving ACs (warfarin, clopidogrel, enoxaparin, and/or aspirin). The risk of prostate cancer-specific mortality (PCSM) was compared between the AC and non-AC groups.

RESULTS

After a median follow-up of 70 months, risk of PCSM was significantly lower in the AC group compared with the non-AC group (3% v 8% at 10 years; P < .01). The risks of disease recurrence and bone metastasis were also significantly lower. In a subgroup analysis by clinical risk category, the reduction in PCSM was most prominent in patients with high-risk disease (4% v 19% at 10 years; P < .01). The benefit from AC was present across treatment modalities (RT or RP). Analysis by type of AC medication suggested that the PCSM reduction was primarily associated with aspirin. Multivariable analysis indicated that aspirin use was independently associated with a lower risk of PCSM (adjusted hazard ratio, 0.43; 95% CI, 0.21 to 0.87; P = .02).

CONCLUSION

AC therapy, particularly aspirin, was associated with a reduced risk of PCSM in men treated with RT or RP for prostate cancer. The association was most prominent in patients with high-risk disease.

Evaluation of the prostate bed for local recurrence after radical prostatectomy using endorectal magnetic resonance imaging

PURPOSE

To summarize the results of a 4-year period in which endorectal magnetic resonance imaging (MRI) was considered for all men referred for salvage radiation therapy (RT) at a single academic center; to describe the incidence and location of locally recurrent disease in a contemporary cohort of men with biochemical failure after radical prostatectomy (RP), and to identify prognostic variables associated with MRI findings in order to define which patients may have the highest yield of the study.

METHODS AND MATERIALS

Between 2007 and 2011, 88 men without clinically palpable disease underwent eMRI for detectable prostate-specific antigen (PSA) after RP. The median interval between RP and eMRI was 32 months (interquartile range, 14-57 months), and the median PSA level was 0.30 ng/mL (interquartile range, 0.19-0.72 ng/mL). Magnetic resonance imaging scans consisting of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging were evaluated for features consistent with local recurrence. The prostate bed was scored from 0-4, whereby 0 was definitely normal, 1 probably normal, 2 indeterminate, 3 probably abnormal, and 4 definitely abnormal. Local recurrence was defined as having a score of 3-4.

RESULTS

Local recurrence was identified in 21 men (24%). Abnormalities were best appreciated on T2-weighted axial images (90%) as focal hypointense lesions. Recurrence locations were perianastomotic (67%) or retrovesical (33%). The only risk factor associated with local recurrence was PSA; recurrence was seen in 37% of men with PSA >0.3 ng/mL vs 13% if PSA ≤0.3 ng/mL (P<.01). The median volume of recurrence was 0.26 cm(3) and was directly associated with PSA (r=0.5, P=.02). The correlation between MRI-based tumor volume and PSA was even stronger in men with positive margins (r=0.8, P<.01).

CONCLUSIONS

Endorectal MRI can define areas of local recurrence after RP in a minority of men without clinical evidence of disease, with yield related to PSA. Further study is necessary to determine whether eMRI can improve patient selection and success of salvage RT.

Combined modality therapy for rectal cancer: the relative value of posttreatment versus pretreatment CEA as a prognostic marker for disease recurrence

PURPOSE

To evaluate the prognostic significance of the first postsurgery carcinoembryonic antigen (CEA) level in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiation (nCRT) and total mesorectal excision.

METHODS

A total of 100 patients underwent nCRT and had baseline and posttreatment CEA levels recorded within 6 months of surgery. The median radiotherapy dose was 50.4 Gy. Eighty-six patients received adjuvant 5-fluorouracil-based chemotherapy. Prognostic factors were analyzed for possible associations with freedom from failure (FFF) by univariate and multivariate analyses. Median follow-up was 30 months.

RESULTS

The median CEA (ng/ml) levels at baseline before nCRT, after nCRT, and after total mesorectal excision were 3.6, 1.7, and 1.3, respectively. Pathologic complete response was observed in 22%. FFF at 36 months was 78%. Local failure and distant failure occurred in 4 and 20% of the patients, respectively. On univariate analysis, pathologic complete response, margin status, and both pretreatment and postsurgery CEA levels were associated with recurrence (all P < 0.05). On multivariate analysis, pathologic complete response (P < 0.007), margin status (P < 0.001), and postsurgery CEA level (P = 0.003), but not baseline CEA level (P = 0.2), were found to be associated with recurrence.

CONCLUSIONS

After nCRT for rectal cancer, postsurgery CEA level may have more prognostic value than pretreatment level. Patients with a postsurgery CEA level of >2.5 ng/ml have higher rates of recurrence and may warrant closer surveillance.

Image-guided radiotherapy using surgical clips as fiducial markers after prostatectomy: a report of total setup error, required PTV expansion, and dosimetric implications

PURPOSE

To determine the total setup error and the required planning target volume (PTV) margin for prostate bed without image guided radiotherapy (IGRT), and to demonstrate the feasibility and dosimetric benefit of IGRT post prostatectomy using surgical clips.

MATERIALS AND METHODS

Seventeen patients were treated with intensity modulated radiotherapy (IMRT) to the prostate bed with a 1cm PTV margin. Three-dimensional shifts of the surgical clips inside the prostate bed were measured with respect to the isocenter from 364 orthogonal kV image pairs, and the total setup error was calculated to determine the required PTV margin. Alternative IMRT plans using 5mm or 1cm PTV expansion were generated and compared for rectal and bladder sparing.

RESULTS

Surgical clips were reproducibly and reliably identified. The mean (standard deviation) shifts in the left-right (LR), superior-inferior (SI), and anterior-posterior (AP), axes were: -0.1 mm (1.7 mm), 0.6 mm (2.4 mm), and -2.1 mm (2.6 mm), respectively. The required PTV margins were calculated to be 6, 8, and 9 mm in the LR, AP, and SI axis, respectively. A PTV expansion of 5mm, compared to 1cm, significantly reduced V65 Gy to the rectum by 10%.

CONCLUSIONS

In the absence of IGRT, a non-uniform PTV margin of 6mm LR, 8mm AP, and 9 mm SI should be considered. Use of clips as fiducial markers can decrease the total setup error, enable a smaller PTV margin, and improve rectal sparing.

Role of HMG-CoA reductase inhibitors with curative radiotherapy in men with prostate cancer

Brachytherapy and external beam radiotherapy are effective and commonly used treatment modalities in men with localized prostate cancer. In this review, we explore the role of radiation therapy in the curative management of prostate cancer, including the use of conformal therapeutic techniques to allow for the escalation of radiation doses to tumor, along with the use of combined radiation and hormonal therapy to enhance disease outcomes in men with aggressive disease. We also review the possible anticancer role of HMG-CoA reductase inhibiting agents (statins) in men with prostate cancer. Laboratory evidence suggests that statins may have antineoplastic effects when used alone and may sensitize cells to radiation therapy when given in combination. We explore the biologic basis for an anticancer effect and the clinical evidence suggesting statins may aid in improving outcomes with radiation therapy for localized prostate cancer.

Late toxicity after intensity-modulated radiation therapy for localized prostate cancer: an exploration of dose-volume histogram parameters to limit genitourinary and gastrointestinal toxicity

PURPOSE

To characterize the late genitourinary (GU) and gastrointestinal (GI) toxicity for prostate cancer patients treated with intensity-modulated radiation therapy (IMRT) and propose dose-volume histogram (DVH) guidelines to limit late treatment-related toxicity.

METHODS AND MATERIALS

In this study 296 consecutive men were treated with IMRT for adenocarcinoma of the prostate. Most patients received treatment to the prostate with or without proximal seminal vesicles (90%), to a median dose of 76 Gy. Concurrent androgen deprivation therapy was given to 150 men (51%) for a median of 4 months. Late toxicity was defined by Common Toxicity Criteria version 3.0 as greater than 3 months after radiation therapy completion. Four groupings of DVH parameters were defined, based on the percentage of rectal or bladder tissue receiving 70 Gy (V(70)), 65 Gy (V(65)), and 40 Gy (V(40)). These DVH groupings, as well as clinical and treatment characteristics, were correlated to maximal Grade 2+ GU and GI toxicity.

RESULTS

With a median follow-up of 41 months, the 4-year freedom from maximal Grade 2+ late toxicity was 81% and 91% for GU and GI systems, respectively, and by last follow-up, the rates of Grade 2+ GU and GI toxicity were 9% and 5%, respectively. On multivariate analysis, whole-pelvic IMRT was associated with Grade 2+ GU toxicity and age was associated with Grade 2+ GI toxicity. Freedom from Grade 2+ GI toxicity at 4 years was 100% for men with rectal V(70) ≤ 10%, V(65) ≤ 20%, and V(40) ≤ 40%; 92% for men with rectal V(70) ≤ 20%, V(65) ≤ 40%, and V(40) ≤ 80%; and 85% for men exceeding these criteria (p = 0.13). These criteria were more highly associated with GI toxicity in men aged ≥70 years (p = 0.07). No bladder dose-volume relationships were associated with the risk of GU toxicity.

CONCLUSIONS

IMRT is associated with low rates of severe GU or GI toxicity after treatment for prostate cancer. Rectal dose constraints may help limit late GI morbidity.

Prolongation of total treatment time because of infrequently missed days of treatment is not associated with inferior biochemical outcome after dose-escalated radiation therapy for prostate cancer

PURPOSE

Prolongation of treatment time with radiation therapy (RT) is associated with inferior disease control for many rapidly proliferating tumors, but it is uncertain whether the same effect is seen in prostate cancer.

METHODS AND MATERIALS

596 patients underwent with curative-intent RT for adenocarcinoma of the prostate. By National Comprehensive Cancer Network criteria, men were classified as having low-risk (30%), medium-risk (40%), or high-risk (30%) disease. The median RT dose was 72 Gy. Androgen-deprivation therapy (ADT) was used in 45%. The idealized treatment time was defined as the total elapsed time (including weekends) to complete treatment if started on a Monday. Missed days of treatment, defined as the number of days beyond the idealized treatment time, was recorded for all patients. Missed days were added to the end of therapy resulting in a longer treatment time. Analysis was conducted for missed days and other standard prognostic variables against freedom from biochemical failure (FFBF).

RESULTS

The median number of missed days was 2 (range, -3 to 22). With a median follow-up of 51 months, men with 5 or more missed days had similar 4-year FFBF rates (79% vs. 83% in men with <5 missed days, p = 0.0809), especially in the subset of men receiving 74 Gy or greater (89% for both groups, p = 0.8008). Analysis of missed days was performed for the subsets of dose, ADT, and risk category. Men without ADT had a lower FFBF rate with more missed days (p = 0.0030), but this association was not seen in men treated to a dose of 74 Gy or greater (p = 0.7425). On multivariate analysis, dose (p = 0.0010), T stage (p = 0.0145), and prostate-specific antigen level (p < 0.0001) were associated with FFBF, but Gleason score (p = 0.1351) and missed days (p = 0.3767) were not.

CONCLUSIONS

Slight prolongation of treatment time (e.g., ≤7 days) was not associated with inferior FFBF, especially in men receiving an RT dose of 74 Gy or greater.

Radiotherapeutic strategies in the management of low-risk prostate cancer

Prostate cancer is the most common nonskin malignancy among men in the United States. Since the introduction of screening with prostate-specific antigen (PSA), most patients are being diagnosed at an early stage with low-risk disease. For men with low-risk prostate cancer, there exists an array of radiotherapeutic strategies that are effective and well tolerated, such as external-beam radiotherapy and brachytherapy. In recent years, there have been tremendous advances in the field of radiation oncology that have transformed the way radiation is used to treat prostate cancer, such as intensity-modulated radiotherapy, image-guided radiotherapy, and stereotactic radiotherapy. It is now feasible to deliver high doses of radiation to the target volume with improved precision and spare more of the neighboring tissues from potentially damaging radiation. Disease outcomes are generally excellent in low-risk prostate cancer. Improvements are expected with further integration of innovative technologies in radiation delivery, tumor imaging, and target localization.

External beam radiotherapy for prostate cancer: urinary outcomes for men with high International Prostate Symptom Scores (IPSS)

PURPOSE

To report the urinary outcome of men treated for prostate cancer with external beam radiotherapy (EBRT) who have pretreatment obstructive urinary symptoms (International Prostate Symptom Score [IPSS] ≥ 15).

METHODS AND MATERIALS

We treated 368 patients with EBRT for localized prostate cancer, and pre- and post-radiotherapy (RT) IPSSs were recorded. In total, 80 men had an IPSS ≥ 15, 48% of whom were taking genitourinary (GU) medications before RT. The IPSS was followed over time and analyzed as a pretreatment factor against Radiation Therapy Oncology Group acute and late GU toxicity.

RESULTS

The median follow-up was 44 months. Among men with a pre-RT IPSS ≥ 15, the median IPSS at baseline, first follow-up, and last follow-up was 18 (range, 15 to 34), 17 (range, 0 to 32), and 13 (range, 0 to 34), respectively. The mean patient declines in IPSS from baseline to first and last follow-up were -3.6 points (p < 0.0004) and -6.9 points (p < 0.0001), respectively. At last follow-up, 43 men (54%) took GU medications. Pre-RT IPSS ≥ 15 vs. ≤ 14 was associated with a higher incidence of Grade ≥ 2 acute GU toxicity (64% vs. 42%, p = 0.0005), and 4-year freedom from Grade ≥ 2 late GU toxicity was 38% vs. 64% (p < 0.0001). There was no greatly increased risk of Grade ≥ 3 late GU toxicity for men with IPSS ≥ 15 (4-year freedom from Grade ≥ 3 late GU toxicity of 90% vs. 96%, p = 0.0964).

CONCLUSIONS

Although the improvement is not immediate, men with moderate to severe obstructive GU symptoms can have improvement in urinary function after EBRT, without significant risk for severe morbidity.

Statin Use and Risk of Prostate Cancer Recurrence in Men Treated With Radiation Therapy

Purpose

There has been growing interest in the potential anticancer activity of statins based on preclinical evidence of their antiproliferative, proapoptotic, and radiosensitizing properties. The primary objective of this study was to determine whether statin use is associated with improved clinical outcomes in patients treated with radiotherapy (RT) for prostate cancer.

Patients and Methods

In total, 691 men with prostate adenocarcinoma treated with curative-intent RT between 1988 and 2006 were retrospectively analyzed. Of those, 189 patients (27%) were using statins, either during initial consultation or during follow-up. Lipid panels were collected (n = 298) a median of 5 months before RT start. Median follow-up was 50 months after RT.

Results

Statin use was associated with improved freedom from biochemical failure (FFBF; P < .001), freedom from salvage androgen deprivation therapy (FFADT; P = .0011), and relapse-free survival (RFS; P < .001). Improved FFBF for statin users was seen in low-, intermediate-, and high-risk groups (P = .0401, P = .0331, and P = .0034, respectively). The improvement in FFBF with statin use was independent of ADT use or radiation dose. On multivariable analysis, statin use was associated with improved FFBF (P < .001) along with pretreatment prostate-specific antigen ≤ 8.4 (P < .001), stage less than T2b (P = .0111), and Gleason score < 7 (P = .0098). On univariate analysis, pretreatment total cholesterol < 187 (89% v 80%; P = .0494) and low-density lipoprotein (LDL) < 110 (96% v 85%; P = .0462) were associated with improved 4-year FFBF.

Conclusion

Statin use was associated with a significant improvement in FFBF, FFADT, and RFS in this cohort of men treated with RT for prostate cancer. The favorable effect of statins may be mediated by direct effect or via the LDL-lowering effect of these medications.

The use of anticoagulants improves biochemical control of localized prostate cancer treated with radiotherapy

BACKGROUND

: Substantial experimental evidence suggests that anticoagulants (ACs) may inhibit cancer growth and metastasis, although the limited data from clinical trials have been inconsistent. The potential antineoplastic effect of ACs was investigated in patients who received radiotherapy for localized prostate cancer.

METHODS

: The study cohort consisted of 662 patients with adenocarcinoma of the prostate who received radiotherapy (RT) with curative intent. Among those 622 men, 243 (37%) were receiving ACs (warfarin, clopidogrel, and/or aspirin). All patients received external-beam RT, permanent seed implantation, or a combination of both. Prostate-specific antigen (PSA) values were monitored for biochemical control of disease.

RESULTS

: At a median follow-up of 49 months, the biochemical control rate at 4-years was significantly better in patients who received ACs at 91% compared with 78% in patients who did not receive ACs (P = .0002). The distant metastasis rate at 4 years also was reduced in the AC group compared with the non-AC group (1% vs 5%; P = .0248). In subgroup analysis, the improvement in biochemical control was significant only for patients with high-risk disease. Along with Gleason score, T classification, and initial PSA, the use of AC therapy was associated independently with improved biochemical control in multivariate analysis.

CONCLUSIONS

: AC therapy was associated with an improvement in biochemical control in patients with prostate cancer who received RT with curative intent. The effect was most prominent in patients who had high-risk disease. Cancer 2010. (c) 2010 American Cancer Society.