Focal or Subtotal Therapy for Early Stage Prostate Cancer

Abstract

Focal treatment for prostate cancer is highly intriguing, but poorly supported by the published literature. Further studies, preferably randomized controlled trials, are needed before this can be considered standard therapy. Focal treatment should be reserved for patients with focal disease. Even "clinically insignificant" synchronous tumors are malignant, and carry risk of progression if not treated with the index lesion. Whether these are likely to progress in this setting compared to those managed with active surveillance is unknown. The limited data regarding subtotal or focal cryotherapy suggest that patients properly evaluated for presence of satellite tumors have a low risk of having large unknown satellite tumors. The author requires office-based saturation biopsy prior to considering focal cryotherapy. Observation of prostatic intraepithelial neoplasia (PIN), atypical findings (ASAP), or cancer on the contralateral biopsy cores excludes the patient from consideration of subtotal therapy. MRI offers a potential additional ability to detect occult contralateral tumors. Younger men paradoxically seem to have greater interest in focal therapy while having a higher risk of future malignancy in the untreated areas based on the years of potential risk. However, no age cutoff is established. Without published data to support its use, lumpectomy or freezing only the focus where cancer is believed to exist, will remain limited. Hemispheric or subtotal treatment decreases the amount of untreated tissue. As a result, the local failure rate would be predicted to be lower but is unknown. When performing subtotal treatment, the author freezes almost the entire gland, sparing only the aspect adjacent to the contralateral neurovascular bundle, and has found this practice to be of highly limited utility based on the issues described. Biopsy should be performed following any treatment that fails to target the entire gland. A positive biopsy should be dealt with based on clinical factors as if the patient had not been treated, and a positive biopsy should not preclude active surveillance if deemed appropriate.

Comparison of outcomes of salvage robot‐assisted laparoscopic prostatectomy for post‐primary radiation vs focal therapy

“…For example, patients who underwent focal ablation had better erectile function before surgery. This was an expected finding as focal therapies aim to spare at least one NVB to preserve erectile function .…”

Tumor focality in prostate cancer: implications for focal therapy

“…Thus, patients harboring a bilateral prostate cancer should not be excluded from non-surgical focal treatment, even with the current controversy that smaller secondary foci may remain untreated. 35 Genetic basis of focality Multifocality can be explained by either uniclonal or multiclonal expansion of tumor cells. The former hypothesis suggests that a single transforming event occurs in one cell with the spread of this clone through the prostate resulting in topographically distinct but genetically related tumors.…”

“…Therefore, advocacy of subtotal treatment with the knowledge that smaller secondary foci remain untreated continues to be controversial at present despite there being two phase ii prospective ethics committee approved trials assessing this in MD Anderson and university College london and are currently recruiting patients (nCT00987675, nCT00877682). 35 Furthermore, although the goal of focal therapy for prostate cancer is to selectively ablate known disease, it should be remembered that a field effect might occur in prostate cancer, that is neoplastic or paraneoplastic cells exist in the apparently histologically normal field adjacent to the tumor. Genetic alteration and molecular changes have been found in normal appearing prostate tissue adjacent to tumor, consistent with the possibility of a field effect.…”

Contemporary Results of Focal Therapy for Prostate Cancer Using Cryoablation

“…Focal therapy is intended to be a tailored treatment, thereby avoiding overtreatment while cautiously providing awareness of potential undertreatment. 35,[39][40][41][42][43] In the absence of image-guided therapy, at present, a practical approach is hemiablation of the prostate leaving untreated an intact lobe that will be able to facilitate an acceptable level of QoL, including potency and urinary continence. Retrospective analysis of a few large prostatectomy databases demonstrated that some proportion of the patients (up to 20%) with low-risk PCa could be selected for hemiablation.…”