Radiotherapy in prostate cancer Dr.Mina Tajvidi Radiation oncologist

indication Radical Radiotherapy Adjuvant Radiotherapy Salvage Radiotherapy palliative Radiotherapy

Radical radiotherapy

clinical T1, T2 The optimal management of localized (clinical T1 or T2) prostate cancer is controversial. Standard options include radiation therapy (external beam and/or brachytherapy, with androgen deprivation therapy [ADT] in selected cases), radical prostatectomy, or active surveillance (also termed watchful waiting) in carefully selected patients at low risk of recurrence. There are no randomized trials that have resolved the question of what constitutes the best treatment for these men The goal of RT for men with localized prostate cancer is the delivery of the planned dose of radiation to the tumor while minimizing radiation to surrounding normal tissues

CONFORMAL RT TECHNIQUES Three-dimensional conformal RT Intensity-modulated RT Image-guided RT Experimental techniques(Stereotactic body RT, Particle irradiation)

Three-dimensional conformal RT Three-dimensional conformal RT (3D-CRT) delivers radiation to a three-dimensional volume using imaging studies and computer software to more precisely target RT delivery by better delineating the prostate gland and its surrounding structures The review concluded that 3D-CRT had a better therapeutic index than conventional EBRT for clinically localized prostate cancer

Intensity-modulated RT IMRT delivers nonuniform beam intensities to the target volume by changing the intensity of the beam, in contrast to 3D-CRT, in which a uniform intensity is administered to a defined field There are no randomized trials comparing IMRT with 3D-CRT. In observational studies, IMRT appears to be less toxic at an equivalent dose

Image-guided RT Image-guided radiation therapy (IGRT) is a technique that acquires two- or three- dimensional images prior to each treatment, thus tracking the location of the tumor and surrounding organs. Commonly used imaging approaches for prostate IGRT include gold marker (fiducial) tracking with megavoltage portal imaging, fluoroscopy, abdominal ultrasound, or CT. IGRT provides accurate localization of the prostate gland, which can vary on a daily basis.

Stereotactic body RT Stereotactic body radiation therapy (SBRT) is an extreme form of hypofractionation, in which the entire dose of radiation is administered in one or a very limited number of fractions. Longer follow-up in larger numbers of patients is required to assess the safety and efficacy of this approach; at present SBRT should only be performed within the context of a clinical trial

Particle irradiation The most data are available for particle beams using protons, and there is more limited, ongoing research with carbon ions Particle beam RT requires adaptation of particle accelerators designed for other purposes or specialized equipment. These techniques are not widely available.

Radiation dose and schedule The incidence of biochemical failure after treatment with 74 to 80 Gy was significantly lower than with doses of 64 to 70 Gy (25 versus 35 percent, odds ratio 0.60, 95% CI ) there was no evidence that mortality was improved with higher doses of RT radiation doses of 72 Gy or higher given with contemporary conformal techniques (Grade 1A)

Hypofractionation 52.5 to 55 Gy in 20 fraction Although hypofractionation has not been shown to be equivalent to a longer course of therapy, it may be appropriate for elderly or handicapped patients who are unwilling or unable to undertake an eight week course of therapy Multiple randomized trials are ongoing, and long-term results are required before hypofractionation can be considered a standard alternative

Brachytherapy for localized prostate cancer For men with low-risk, clinically localized prostate cancer A large prostate gland size (>50 to 60 g) is relative contraindications to prostate brachytherapy For men with intermediate-risk or high-risk localized disease we suggest external beam radiation therapy (EBRT) with or without brachytherapy or radical prostatectomy rather than brachytherapy alone There is no consistent evidence to suggest that androgen deprivation improves the oncologic outcome for men undergoing prostate brachytherapy, and we do not suggest its use

ANDROGEN DEPRIVATION WITH RT Men with intermediate-risk disease (clinical T2 stage and either PSA 10 to 20 ng/mL or Gleason score 7) appear to benefit from four to six months of neoadjuvant and concurrent ADT during RT.(RT (Grade 2B) Those with high-risk disease (Gleason score 8 to 10 or serum PSA >20 ng/mL) should receive neoadjuvant and concurrent ADT with RT and also continue adjuvant ADT for two more years after completing RT

Clinical stage T3 prostate cancer EBRT is more commonly employed than surgery whole pelvis RT rather than prostate only RT use a gonadotropin-releasing hormone agonist for at least two months prior to the initiation of RT, followed by concurrent treatment during RT, and adjuvant treatment for at least two years. Whether the addition of brachytherapy to EBRT provides benefit beyond that achievable with adequate doses of EBRT (≥72 Gy) plus ADT is unclear.

Adjuvant radiotherapy The optimal management of patients with undetectable serum PSA levels who have pT3 disease or positive surgical margins after radical prostatectomy, but randomized clinical trials support the use of adjuvant RT compared to observation. Large randomized clinical trials have demonstrated that adjuvant RT significantly improves biochemical relapse-free survival (RFS) and metastasis RFS Radiation dose:60 to 64 Gy Additional trials will be required before higher doses can be recommended

ADT to adjuvant RT after surgery for pT3 prostate cancer Whether there is benefit from adding ADT to adjuvant RT after surgery for pT3 prostate cancer is unknown ADT should be considered only in the context of a clinical trial. For men with pT3 disease who refuse or are ineligible for a clinical trial, and who understand and accept the risks, concurrent ADT could be considered

Salvage radiotherapy For men who have a PSA-only recurrence following radical prostatectomy and an otherwise favorable life expectancy, we recommend salvage RT Although there are no randomized trials that address this topic, this approach is well tolerated and appears to extend cancer-specific survival compared to management with observation alone. For men receiving salvage RT, we recommend a minimum RT dose of at least 64 Gy Based upon recent historical series that suggest that higher doses may be beneficial, We suggest that outside of a clinical trial setting, RT be limited to the prostate bed and not include the pelvic lymph nodes (Grade 2C).

The benefit of ADT in conjunction with RT The benefit of ADT in conjunction with RT is uncertain we suggest limiting the use of ADT to men with very unfavorable risk factors at the time of radical prostatectomy (eg, Gleason score ≥8 or preoperative PSA >20) (Grade 2C). When we do use hormonal therapy, we use ADT before and during salvage RT (four to six months total).

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