The radiotherapy planner, a great step forward in the IORT-based treatment of colorectal cancer

Colorectal cancer is one of the most frequent tumors, its prevalence and incidence growing continually both inside and outside Spain. Prevention measures based on early diagnosis and control of onset risk factors are crucial. Once diagnosed, surgery accompanied with chemotherapy or external or intraoperative radiotherapy is the best way of tackling it.

Clínica Mayo boasts unmatchable experience in dealing with both the primary colorectal cancer and the advanced recurrent carcinoma. This clinic has shown that application of intraoperative radiation therapy (IORT) outperforms external radiotherapy in terms of local control at 3 years and the global survival rate over this same period of time for patients with locally advanced tumors.

In the words of Professor Pedro Lara, chair-holding professor of oncology at the Universidad Fernando Pessoa Canarias, director of the Canary Cancer Research Institute (Instituto Canario de Investigación del Cáncer) and director of the oncology department of Hospitales Universitarios San Roque “administering radiotherapy in the surgical bed after tumor resection represents a huge advance in dealing with this illness. We can now apply the treatment in the exact spot at the right time and in the best dose without harming nearby healthy tissue”.

IORT and planning

Intraoperative radiation therapy is a technique for directing a single high-intensity radiation dose at the tumor bed during surgery, protecting the surrounding radiation-sensitive healthy tissue. The hospital radiation physicist plans the treatment on the basis of the exact application site and dose to be administered; this information is provided by the radiation oncologist. The Radiance™ IORT planner enables them to make the necessary calculations from the ultra-precise algorithms it works with, improving the accuracy of the IORT application and allowing simulated visualization of the treatment result. The clinician can also adjust the parameters to achieve the intended result without having to make these decisions under the pressure of the operating theater. Thanks to Radiance™ the radiation oncologist is now able to provide personalized treatment, adjusting the precise radiotherapy dose for each patient, safeguarding the high-risk organs. The Radiance™ IORT planner, unique in the world, has been developed by the Spanish technology group GMV.

As Doctor Lara points out, “the advantage of these advanced planning systems is twofold: firstly, the extreme precision in treatment administration, and secondly, the possibility of reliably recording the administered treatment, which might be extremely useful in the future.” He goes on, “to be able to carry out a treatment with curative intention of a recurrent colorectal tumor, habitually in zones of difficult access for conventional treatment, represents a huge advance for these patients.”

Intraoperative radiation therapy planned with Radiance™ allows the clinician to take the best possible pre-operation decisions, tailoring the treatment to suit each particular individual while also developing more precise predictive scenarios and avoiding the necessity of taking high-pressure decisions in the operating theater. Last but not least, this technique enhances the disease control rate in diverse tumor locations, including bowel cancer: http://scielo.isciii.es/pdf/onco/v27n6/12.pdf.

Incidence

The figures provided by the Spanish Medical Oncology Society (Sociedad Española de Oncología Médica: SEOM) and the Spanish Cancer Recording Network (Red Española de Registros de Cáncer: REDECAN) show that the number of newly diagnosed colorectal cancer patients in 2020 will top 44,200, or, what comes to the same thing, on average the weekly cases of new diagnoses will added up to 850.

These rising figures are due to many causes; the population’s demographic changes, with increasing life expectancy and the consequent aging and chronicity; bad living habits (fiber-poor, fat-rich diets, smoking, alcohol intake, etc) by some citizens, especially those with risk factors like previous colorectal pathologies (polyps, chronic inflammatory intestinal illnesses, diabetes type II, etc…); while also taking into account that a genetic predisposition to tumors of this type has been clearly demonstrated.

A crucial prevention factor is screening by means of colonoscopies in over 50s (one colonoscopy every 4 years), lowering this cut-off age to 40 in the case of genetic predisposition, previous colorectal pathologies. There are other, less invasive diagnostic tests like virtual colonoscopy, genetic blood testing, fecal occult blood testing, fecal immunochemical testing and other types of genetic determination.

A particularly serious case is locally recurrent rectal cancer, where the results of IORT in addition to surgical resection, in comparison with those of surgery and external radiotherapy, show a much improved 3- to 5-year survival rate.