Should low-risk prostate cancer be left to active monitoring?

According to Specialist in Medical Oncology and Radiotherapy Timo Joensuu at Docrates Cancer Center, active treatment of prostate cancer is particularly supported by the fact that the treatment can nowadays be performed using radiotherapy with minimal side effects. The latest radiotherapy techniques have not been found to involve even the risk of secondary cancer.There is currently no consensus on whether localised prostate cancer should be actively treated or not. NCCN (National Comprehensive Cancer Network), EAU (European Association of Urology) and the Finnish Current Care Guidelines, among others, recommend active monitoring without treatment as an option. However, the Current Care Guidelines state that active monitoring is not suitable for everyone.

Active monitoring is generally chosen because the adverse effects of surgery, such as impotence and urinary incontinence, are thought to be too great in relation to the fact that low-risk prostate cancer does not become life-threatening for everyone during their lifetime. In active monitoring, the situation is mainly monitored through annual measurements of PSA levels, repeated MRI scans and biopsies, and treatment is initiated if the situation becomes more serious.

Men in active monitoring had double the likelihood of developing metastatic prostate cancer

According to the results of a ten-year randomised study (Hamdy et al., 2016), however, active monitoring is more likely to lead to cancer progression and metastasis compared to the option of treating the cancer immediately. In the study conducted between 1999 and 2009, 1643 men aged 50–69 who had been diagnosed with localised prostate cancer were randomly divided into three groups: active monitoring (545 men), external radiotherapy (545 men) and surgery (553 men). According to the results, men in active monitoring were twice as likely to develop metastatic prostate cancer as men who had received early external radiotherapy or undergone surgery. The result was statistically significant.

Although the 10-year monitoring period was too short to reveal a statistically significant difference in prostate cancer mortality rates among the different groups, a lower mortality rate among treated men was observed. In any case, the results on active monitoring are significant, if only for the reason that, as the cancer spreads, the patient suffers from the adverse effects of the treatment for the metastatic cancer. These adverse effects, such as sexual dysfunction related to hormone treatment, osteoporosis, bone fractures and metabolic changes are relevant to the patient’s quality of life.

Radiotherapy combined with hormone treatment is a better option than surgery

In an editorial analysing the study, Anthony D’Amico, a leading specialist in the field, suggested that the results also support the notion that external radiotherapy combined with short-term hormone treatment (5–8 months) is a better option than surgery in the treatment of low-risk prostate cancer. Specialist in Oncology and Radiotherapy Timo Joensuu at Docrates Cancer Center says that especially today’s advanced radiotherapy clearly outweighs surgery in the treatment of low-risk prostate cancer.

“At the same time, this is the main reason why prostate cancer should be treated when it is still localised, rather than waiting for the cancer to become aggressive and spread elsewhere in the body. The core of the problem with active monitoring lies precisely in our inability to know with certainty which of the so-called kind cancers will remain moderate and which will spread. There is no point in increasing the number of MRI scans and biopsies, because they increase unnecessary costs, and the latter also increase the risk of infections. Because modern radiotherapy allows localised prostate cancer to be treated immediately and effectively with significantly fewer adverse effects than surgery, there are, in my opinion, no longer any grounds for monitoring,” Joensuu emphasises.

In Finland, it is common practice to refer prostate cancers detected at an early stage (Gleason Score 6, PSA < 10, < T2, cancer in up to 2/12 of biopsies) to active monitoring. However, according to Timo Joensuu, such cancers can be effectively treated with radiotherapy, even without hormone treatment. In this case, the best solution for radiotherapy is almost always interstitial HDR brachytherapy. In HDR brachytherapy, the high radiation dose is strictly limited to the prostate area. Thus, when healthy tissue is saved, the likelihood of maintaining potency is the best and, unlike in surgery, there is no risk of incontinence. Moreover, HDR therapy has not been found to involve the risk of secondary cancer.

In addition to HDR brachytherapy, Docrates uses external radiotherapy in radiotherapy for localised prostate cancer. The technique used in external radiotherapy is called VMAT Rapid Arc, which allows the optimisation of the radiation dose on the target tissue to be as large as possible while minimising radiation on healthy tissue. Thanks to modern image-guided radiotherapy, the treatment can be targeted with millimetre precision. Consequently, the likelihood of healing increases, while adverse effects of treatment are reduced.

To prevent adverse effects in both external and interstitial radiotherapy, Docrates also uses SpaceOAR hydrogel, which is injected between the rectum and the prostate, depending on the situation and at the discretion of the doctor. SpaceOAR reduces the rectal radiation dose by up to 70%, and studies have shown it to reduce the likelihood of adverse effects related to bowel function, urination and sexual quality of life eightfold.

Sources: 

D’Amico AV. Treatment of Monitoring for Early Prostate Cancer. Editorial. N Eng J Med 2016, 375;15, p 1482-1483.

Hamdy F. C., Donovan J. L., Lane J. A., Mason M., Metcalfe C., Holding P., Davis M., Peters T. J., Turner E. L., Martin R. M., Oxley J., Robinson M., Staffurth J., Walsh E., Bollina P., Catto J., Doble A., Doherty A., Gillatt D., Kockelbergh R., Kynaston H., Paul A., Powell P., Prescott S., Rosario D. J., Rowe E., Neal D. E. 2016. 10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer. N Engl J Med 2016; 375: 1415-1424.

Hamstra DA. et al. Of men who had erections sufficient for intercourse at baseline; median 3 years. Sexual quality of life following prostate intensity modulated radiation therapy (IMRT) with a rectal/prostate spacer: Secondary analysis of a phase 3 trial. Pract Radiat Oncol. 2018 Jan – Feb;8(1):e7-e15.

Hamstra DA. et al. Continued benefit to rectal separation for prostate radiation therapy: Final results of a phase III trial. Int J Radiat Oncol Biol Phys. 2017 Apr 1;97(5):976-85.

Mariados N,  et al. Average dose reduction when comparing pre and post spacer treatment plans. Hydrogel spacer prospective multicenter randomized controlled pivotal trial: Dosimetric and clinical effects of perirectal spacer application in men undergoing prostate image guided intensity modulated radiation therapy. Int J Radiat Oncol Biol Phys. 2015 Aug 1;92(5):971-7.