COMPOSITIONS AND METHODS FOR USE IN ONCOLOGY
FIELD OF THE การประดิษฐ์
5 The การประดิษฐ์ relates to compositions and methods for use in medical diagnostic and
patient monitoring, typically in the context of therapy, in particular in the context of oncology to optimize tumor bed local irradiation. It more particularly relates to a biocompatible gel ซึ่งประกอบรวมด้วย nanoparticles and/or nanoparticles aggregates, โดยที่ i) the
density of each nanoparticle and of each nanoparticles aggregate is of at least 7 g/cm3, the 10 nanoparticle or nanoparticles aggregate ซึ่งประกอบรวมด้วย an inorganic material ซึ่งประกอบรวมด้วย at
least one metal element having an atomic number Z of at least 25, more preferably of at
least 40, each of said nanoparticle and of said nanoparticles aggregate being covered with a
biocompatible coating; ii) the nanoparticles and/or nanoparticles aggregates concentration
is of at least about 1% (w/w); and iii) the apparent viscosity at 2 s1 of the gel ซึ่งประกอบรวมด้วย 15 nanoparticles and/or nanoparticles aggregates, at is between about 0.1 Pa.s and about 1000
Pa.s when measured between 20°C and 37°C.
The composition of the การประดิษฐ์ typically allows improving the post-surgery tumor bed delineation in order to optimize its irradiation.
20 BACKGROUND
The local control of cancer disease's recurrence or relapse constitutes a crucial step of anti-
cancer treatment following surgery and radiotherapy steps. Post-operative radiotherapy is
used in several indications to treat the tumor bed once tumorectomy has been performed in 25 order to improve rates of local control and thus reduce, ideally avoid, tumor recurrences. A
recent meta-analysis of the Early Breast Cancer Trialists' Collaborative Group stressed the
importance of reducing local breast tumor recurrences, because one breast cancer death
could be avoided for every four local recurrences avoided. According to the authors of
"Customized computed tomography-based boost volumes in breast-conserving therapy: 30 use of three-dimensional histologic information for clinical target volume margins"
[IJROBP 75(3): 757-763 (2009)], one method to improve local control is to increase the
irradiation dose the tumor bed is exposed to (i.e. boost irradiation). The authors add that
2
this effect could be further increased by improving the delineation of the tumor bed (i.e., the target volume the boost irradiation should specifically target).
The International Commission on Radiation Units and Measurements defines the Gross
Tumor Volume (GTV) as the gross demonstrable extent and location of a malignant 5 growth. For the adjuvant breast radiotherapy (the surgical step is followed by a
radiotherapy step), the GTV has been excised with a variable margin of tissue, leaving a
cavity. The cavity is not the GTV, but related to it. The cavity walls is referred to,
somewhat loosely, as the tumor bed ["Target volume definition for external beam partial
breast radiotherapy: clinical, pathological and technical studies informing current 10 approaches" Radiotherapy and Oncology 94 255-263 (2010)].
In clinical practice, accurately identifying the tumor bed is challenging and a high rate of inter-observer variability in tumor bed contouring is frequently reported, especially in poorly visualized resection cavities ["Excised and Irradiated Volumes in Relation to the
Tumor size in Breast-Conserving Therapy" Breast Cancer Res Treat 129:857-865 (2011)]. 15 The irradiated postoperative volume (as delineated on the radiotherapy planning CT-scan
before the start of radiotherapy), in patients treated with breast-conserving therapy is not,
for most of the cases, clearly visible and a cavity visualization score is frequently used to
assess the quality of the irradiated postoperative volume identification.
Likewise, for prostate cancers, the EORTC Radiation Oncology Group has made 20 recommendation for target volume definition in post-operative radiotherapy, presenting
guidelines for standardization of the target volume definition and delineation as well as
standardization of the clinical quality assurance procedures; authors from "Guidelines for
target volume definition in post-operative radiotherapy for prostate cancer, on behalf of
the EORTC Radiation Oncology Group" [Radiotherapy & Oncology 84 121-127 (2007)], 25 in particular referred to a study where a high inter-observer variability of target volume
delineation in postoperative radiotherapy for prostate cancer was observed when performed
by five (5) distinct radiation oncologists for eight (8) distinct patients (The CTV varied
between the physicians from 39 to 53 cm3 for the patient corresponding to the smallest
variation and from 16 to 69 cm3 for the patient corresponding to the largest variation).
30 A study to evaluate the accuracy of a boost technique, reported in "Improving the
definition of the tumor bed boost with the use of surgical clips and image registration in
breast cancer patients" [Int. J. Radiation Oncology Biol. Phys. Vol 78 (5) ; 1352-1355
3
(2010)1 shows that the use of radiopaque clips during tumorectomy, typically the use of 3 or more clips, increases the accuracy of the tumor bed delineation (cf. Figure 1). However, questions over the accuracy of CT/clip-based TB delineation remain. Clips only define
points located on the excision cavity walls such that the remaining tumor tissue-excision 5 cavity interface must be derived by interpolation, taking into account tissue density and
distortion.
Interestingly, a report on the magnitude of volumetric change in the postlumpectomy
tumor bed has demonstrated significant tumor bed volume changes before and during
radiation therapy or radiotherapy (RT) ["The dynamic tumor bed: volumetric changes in 10 the lumpectomy cavity during breast conserving therapy" Int. J. Radiation Oncology Biol.
Phys. 74(3):695-701 (2009)]. Thirty-six (36) patients were enrolled in the study, with Tis
(10), Ti (24) and T2 (2) breast tumors. Thirty (30) patients received a whole breast irradiation after lumpectomy followed by a boost dose of 10 Gy. Six (6) patients were treated with partial breast irradiation. Treatment planning CT scans of the breast were
15 obtained shortly after surgery, before the start of the whole breast irradiation for treatment
planning and before delivery of the tumor bed boost. Patients who were treated with partial
breast irradiation received only a scan postoperatively and a scan before tumor bed
treatment.
During the interval between postoperative scan and second scan (median interval, 3
20 weeks), the tumor bed volume decreased by a median of 49.9%. Between the planning
scan and the boost scan (median interval, 7 weeks), the median tumor bed volume
decreased by 44.6%.
A subgroup of eight (8) patients, who experienced a delay (median interval, 23 weeks)
between surgery and RT because of planned chemotherapy, had a median reduction of the 25 tumor bed volume of 60.3% during the interval between postoperative scan and planning
scan. When this magnitude and rate-of-change data were evaluated in context of the entire
patient set, the observed results suggested that the tumor bed volume decreased more
rapidly in the weeks immediately after surgery and then attained a relative plateau.
According to the authors, the impact of large volumetric change on planning volume, 30 dosimetry, or clinical parameters such as local control or cosmetic outcome, is an
important area for future research as theoretically, if a single planning scan is used to plan
the boost clinical target volume (CTV) in a patient with a tumor bed that shrinks
4
dramatically during the course of RT, the surrounding normal tissues receive unnecessary additional radiation that could yield poorer cosmetic outcomes and more late undesirable effects. Conversely, if a single planning scan is performed long after surgery, the reduced tumor bed volume could actually result in underestimating the true tumor bed or the area of
5 surgical tumor contamination.
WO 2011/084465 relates to stabilizing and visualizing tissues gaps left by surgical removal
of cancerous tissues. According to the inventors, a conformal filling approach is a
considerable improvement over the use of clips, which provide poor resolutions of the 10 site's margin The described implants may be formulated to be stable until no longer
needed, and then biodegrade. According to WO 2011/084465, the implantation of the
hydrogel, leads to an increase of the mean cavity volume. Therefore, when using standard
margins, the hydrogel tends to increase normal tissue radiation doses. A reduced margin
expansion is thus required in order to decrease normal tissue radiation doses.
15
As easily understandable from the above, there remains a clear need to improve the post-
surgery tumor bed delineation in order to optimize irradiation to the tumor bed only.
DETAILED DESCRIPTION
20
Inventors now provide an advantageous composition which considerably improves targeted tissue delineation, in particular tumor bed delineation, without impacting on targeted tissue volume changes, typically when considering a tumor bed, on tumor bed
volumes changes or on post lumpectomy tissue remodeling. In the context of the การประดิษฐ์, 25 the tumor bed is tissue covering the cavity obtained following tumor resection.
The composition of the การประดิษฐ์ further advantageously allows an at least 10% increase of
energy (radiation) dose deposit on the tumor bed, i.e. without increasing the energy dose
deposition in surrounding healthy tissues.
30 A first object relates to a biocompatible gel ซึ่งประกอบรวมด้วย nanoparticles and/or nanoparticles
aggregates, โดยที่ i) the density of each na