How to define the volume of removed fragment of a mammary gland
Local relapse is not only a failure of topical treatment, but also the double
following risk both for development of remote metastases and for increasing of
following lethality. This is the conclusion which the researchers performing
randomized studies of organ-preserving of breast cancer (NSABP-B06-trial,
Millan-III-trial, Uppsalo-Orebro-trial, Scottish Conservation Trial, OntarioClinico-Group) have come to.
As the study of F. Meric et al. (2003) showed, the availability of tumor
element at the edge of resection not only increases the chances of local relapse, but
also increases the possibility of remote metastases (3.7 times) and the possibility of
death from breast cancer (3.9 times).
Having analyzed the factors which can potentially cause the risk of relapses
after organ-preserving treatment M.J. Silverstein (1997, 1999) came to the
conclusion that only three features are statistically significant: histological degree
of malignance, the size of tumour, and width of resection edges. Later, having
analyzed prognostic significance of width of resection edges irrespective of the rest
two features, he established that probability of local relapse lowers with the
increase of resection volume or the distance from “contour” of microscopically
defined tumour to the edge of resection.
V.F. Semiglazov (1992) marks out that increasing of tumour size from 15 to
40 cm is accompanied with doubled number of relapses (25.5 and 57 %,
correspondingly), and the increasing of resection edges from 1 to 10 mm on the
contrary brings to decreased frequency of local relapses (almost in 5 times – from
42 to 8.3 %).
One can logically assume that the width of resection edges should not be
considered as absolute value, and it should be somehow connected with the sizes
of the tumour itself.
That is why there must be some definite criterion to define the volume of
removed tissues at surgical treatment of breast cancer. The volume of removed
tissues should be logically tied with other two volumes – of the mammal gland and
of the tumour.
M.I Davidov and V.P. Letyagin (2006, 2007) proposed to define the index of
correlation of volumes of the tumour and the mammary gland. Not once the
attention was drawn to the fact that existing nowadays classification of breast
cancer and TNM system (of 1997) with all its advantages does not take into
account the size of affected gland. For instance in the small mammary gland even
the small lesion (up to 2 cm) occupies considerable part of the organ.
Knowing the volumes of the tumour and mammary gland it is important to
define optimal volume of removed fragment of the gland since it is necessary to
keep to the verge between oncological safety and maximal preservation of the
organ. This is what the choice of way of the gland reconstruction depends on.
Previously during the study of possibilities of MAC preservation (nippleareolar complex) (read the article “Nipple preservation”) it has been established
that at breast cancer tumour cells locate not further from the pathological nidus that
the distance equal to the diameter of the tumour. That is why the distance from the
contour of defined tumour to the edge of resection of removed fragment is
considered to be the distance equal to the largest size of the tumour.
Formula for calculation of the volume of removed fragment is the following:
Vfr  0,52  (à  2d)  (b  2d)  (c  2d) ,
Vfr – the volume of removed fragment of the mammary gland,
а, b, с – linear dimensions of the tumour,
d – the largest size of the tumour (а, b or с).
Example
With the dimensions of the tumour 2,5 × 1,0 × 1,5 cm the volume of removed
fragment will be
Vfr = 0,52 × (2,5 + 2 × 2,5) × (1 + 2 × 2,5) ×(1,5 + 2 × 2,5) =
= 0,52 × 7,5 × 6,0 × 6,5 = 152,1 cm3.
From the practical point of view it is important to take into account not onlu
the volume of removed tissues and the volume of the breast, but also their
correlation because this correlation helps to understand which part of the gland
should be removed and which one can be safely left. In other words, this
correlation defines the surgical tactics in treatment of breast cancer.
Basing on the study of this correlation we developed oncological (surgical)
tactics of treatment of patients with breast cancer.
Correlation of volumes is calculated with the formula:
Vfr
 100% ,
Vgland
Vfr – the volume of removed fragment of mammary gland, Vgland – volume of
the gland.