“Applying lean-six-sigma methodology in radiotherapy: lessons learned by the breast daily repositioning case”: this is the title of the study that will be published in Radiotherapy and Oncology, the European reference magazine for radiotherapy, by Pietro Mancosu, Giorgia Nicolini, Giulia Goretti, Fiorenza De Rose, Davide Franceschini, Chiara Ferrari, Giacomo Reggiori, Stefano Tomatis and Marta Scorsetti.

The study is the result of collaboration between the Lean office of Humanitas and Radiotherapy and in particular the work of Dr. Pietro Mancosu, specialist in Medical Physics and the engineer Giulia Goretti, Lean Manager.


Lean methodology and Lean 6 sigma

Lean methodology was invented by the Japanese engineer Taiichi Ohno and applied for the first time in the Japanese company Toyota, and then spread rapidly in many other sectors and countries. The goal of Lean is to combine efficiency and quality of work done, through the identification and elimination of waste in respect of people.

As engineer Goretti explains: “Humanitas was one of the first structures in Italy to apply the principles of Lean to healthcare, putting continuous improvement of clinical, care and service quality for the benefit of patients at the center of its work. The 6 Sigma, introduced in 1986 in Motorola, pays attention to improving the process, identifying and removing the causes of defects, thus minimizing the variability of the process itself. The Lean 6 Sigma is the combination of the two methodologies of improving quality and creating value for the patient, and is applicable when the standard of a process is already at an excellent level, in an attempt to minimize subjective variability and make the procedure increasingly standardized, to ensure a result replicable with the same excellent quality.


Lean 6 Sigma and Radiotherapy

“This work was born within the Lean champion programme, an advanced course dedicated to continuous improvement that I attended in Humanitas”, explains Dr. Mancosu.

“I thought of applying the Lean 6 Sigma methodology to Radiotherapy with the aim of refining a process in detail that already guarantees high standards for our patients at the moment. The search for higher and higher quality, in a perspective of excellence, has always characterized the Radiotherapy of Humanitas led by Professor Marta Scorsetti, and we were happy to confirm, including through the data extracted from this work, that our modus operandi is excellent, the result of the commitment of all professionals who have been working in Radiotherapy for several years.

The objective of the study with Lean 6 Sigma application was to assess the error in the positioning of the breast cancer patient undergoing imaging for radiotherapy,” continued Dr. Mancosu.


Simulation imaging in view of the treatment plan

Dr. Fiorenza De Rose, reference for breast disease in radiotherapy, explains that “The patient with breast cancer is subjected to a simulation CT scan, in order to define the target volume and identify the surrounding healthy organs; the treatment plan is then optimized by maximizing the ratio between the doses to the target and the surrounding healthy tissues, so as to treat the patient minimizing side effects. The radiotherapy treatment in the breast is divided over fifteen days and the patient is repositioned each time by a TSRM (medical radiology technician) on the basis of the correspondence between the images acquired on the treatment bed and those acquired during the simulation phase”.

“At Humanitas we have 4 accelerators for radiotherapy with volumetric repositioning imaging (similar to CT) and an accelerator with 2D imaging (similar to slab), with which we perform about 80% of treatments in women with breast cancer. We concentrated on this last machine, applying the Lean 6 sigma to reduce the variability of the process and decrease the unlikely occurrences. We calculated the error in the daily movement of the patient and redesigned the process to an even higher quality, even if already of a high level”, underlined Dr. Mancosu.


Process steps and results

“Our study saw the application of the five phases of the Lean 6 sigma: defining, measuring, analyzing, improving and monitoring. We started by retrospectively analyzing the 30-month movements through a complex work of database interrogation that included a phase of raw data remediation, a data mining activity and the creation of a layer of structured data presentation. We analyzed 14,931 shifts from 1,342 patients.

It was found that only 0.8% of patients have median movements of more than 1 centimeter. The absence of high deviations confirms the overall quality of the radiotherapy treatment offered by Humanitas. On the other hand, there has been a considerable variation in the monthly percentage of fractions with movements of less than one millimeter. This has been deepened as a potential aspect of the process that could be improved.

Thanks to the involvement of the entire Radiotherapy team, we have thus redesigned the process, standardizing some steps that had not been carried out systematically before. First, the image of the patient is taken from a certain angle (lung- sine) and the contour of the body, breast and lung is exported in order to help TSRMs match the machine. The computer then automatically matches the images in order to give the TSRM a rough indication. The TSRM proceeds, finally, with a manual “fine tuning”, refining the work of the computer, moving any critical cases manually and signaling them, in order to help the TSRM of the next shift.

We observed the new procedure for six months and managed to reduce the standard deviation of <1mm displacements from 6.1% to 0.6%, further minimizing the displacement error and further improving our technical parameters,” explains Dr. Mancosu.


The publication on Radiotherapy and Oncology

“It is the first time in the world that Lean 6 sigma methodology has been applied to Radiotherapy in a systematic way. It is also the first experience of Lean of Humanitas published in a scientific journal.

We are proud of this result, which shows how applying Lean to healthcare and internal processes is a continuous incentive to improve, in order to ensure greater excellence to our patients, even where the processes are already of the highest quality. This project was really the result of great teamwork, from the analysis phase to the drafting phase of the article to be proposed to Radiotherapy and Oncology, a work in which everyone gave their best to make small but important improvements for the benefit of our patients,” concluded Engineer Goretti and Dr. Mancosu.