Potential for the NLS Approach In Diagnosing Gastic And Colonic
Cancers
P.A. Svetlova, N.A. Sorokina,
T.G. Kuznetsova, V.I. Nesterova,
L.A. Yankina, N.V. Tatioshev
The non-linear diagnostic method (NLS) has been actively practiced lately at many
medical institutions. The most tangible results were achieved by using the NLS method
as a means of idpensary observation. In the course of its development and advancement
the method has become a foremost tool for diagnosis and monitoring for a number of
widespread digestive organ diseases: it facilitates rapid and detailed information about a
lesion and its pattern and helps in assessing treatment efficacy. This has been found true
in our studies for a range of diseases including gastro-duodenal ulcer, chronic gastritis,
benign and malignant gastric and colonic tumors. The specific character and working
conditions of the therapeutic and clinical institutions in Russia enables the extensive use
of NLS methodology, not only for diagnosis with some symptoms present but also for
medication monitoring. Importantly the speed and low cost enables many patients to avail
themselves of the NLS information. Physicians can now assess patients with latent
changes that can only be verified by means of NLS. Specifically, such patients include
those having precancerous diseases or a mucous disturbance in the upper and/or lower
sections of the digestive tract and patients who developed a tumor, which still remains
latent in a certain phase.
According to the data acquired by some medical specialists, using the device for NLSdiagnosis,
and based on annual research in thousands of cases, the frequency of detecting
local or diffuse changes, typical for chronic atrophic gastritis in patients over 50 years
old, is within 30-40%. The analysis of the spectral examinations of pattern-different
sections of focal changes in stomach mucosa shows that different symptoms of diseases
including intestinal metaplastic and epithelial dysplasia can be detected in them just as
often. During NLS analysis symptoms of gastric ulcer were recorded in about 5% of
cases, polyps in stomach in 7% and polyps in colon in 45% of cases. Thus, just the NLS
analysis results alone (without other risk factors taken into account) indicates that most of
the patients in the respective age group appear to be among those who need dynamic
observation because of potential gastric cancer (GC) or colonic cancer (CC).
According to the cancer register for 1999-2000, the values of gastric and colonic cancer
cases were 80.9 and 53.1 respectively per 100000 patients, and the death rate according to
the mortality statistics was 47.35 and 19.5%. According to the conclusions of the
therapy-diagnosis unit, with around 70% of patients under active medical observation,
pathologies of that kind are likely to be detected as often as in 0.4-0.8% of cases.
Therefore, the NLS screening would allow to detect GC or CC in about every 150th-200th
examinee.
Considering that the emergency of clinical signs is one of the incentives for a patient to
take medical advice and a reason for hardware-based examination, some clinical
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implications and their pattern were evaluated in the cases of the above mentioned
diseases. In 720 patients affected by GC or CC the condition appeared to be symptomfree
in 42% of cases. In 32% of cases there were some signs characteristic of previous
chronic digestive tract diseases. That was the case in 77% and 92% for the 1st phase,
56% and 68% for the 2nd phase, 23% and 32% for the 3rd phase, and 8% for the 4th phase
of the disease. The clinical implications at a gastric cancer are of a pain-dyspepsis
syndrome nature typical for the lesion in the upper section of the digestive tract. Colonic
cancer subgroups were segregated with dominating signs of intestinal hemorrhage,
disturbed evacuation or abdominal pain. A certain interrelationship was proven between
the pattern of the clinical implications and the process localization. In more than 50% of
cases the clinical implications lasted less than 3 months and in 26% of patients the CC
developed acutely within a few days. It should be noted that the so-called “minor sign
syndrome” corresponded to some later phases of the disease. The same was true for lab
examination data where the change became evident during phases III and IV (2).
The results of NLS-diagnosis for the initial phases of gastric cancer in a series of 104
examinations showed that in 72% of cases the physician (on the assumption of a spectral
similarity to the reference standard) regarded the lesion as benign and indicative of focal
mucosa hyperplasia, polyp, an area of local inflammation, wall deformation or a small
ulcer. The probability for detecting signs of malignant change found out in the
elimination mode was under 1%. Of 134 cases of colonic cancer in phase 1 malignant
adenomas were detected in 58% of patients. The rest of the patients were found to have
the so-called “minor” forms of cancer, like polyps, atrophic gastritis or atrophic-hyper
plastic gastritis. The endoscopic verification of GC and CC with reference to the
diacrisis of phases II, III and IV of the diseases completely confirmed the results of the
NLS-investigation.
172 patients were found to have GC or CC discovered by NLS-examination conducted
within a less than a year interval. Among them 62% of patients had an initial phase of
gastric cancer and 38% of the patients during previous observation were found to have
some or other signs of chronic gastritis in the form of focal mucosa hyperplasia, local
inflammation or wall deformation. According to morphological investigation, the
sections were of a benign nature and cancer developed over the last year only. In the rest of
the patients the macroscopic changes corresponding to malignant affection (spectral
similarity to “gastric carcinoma” reference standard D<0.425) occurred in the span
between the last two examinations. The preceding endoscopy detected atrophic gastritis
free of focal changes in the area of the developed tumor. Similar NLS data were acquired for
38 patients who during a year’s observation were diagnosed to have developed a
tumor corresponding to phases II and III.
The NLS of the colon and straight intestine was performed a year before tumors were
diagnosed in 21 patients affected by malignant polyps, of whom 17 had been under active
observation because of polyposis, while no formation of that kind was in evidence during
the initial examination. In addition, within the same time span 13 patients were examined
who were diagnosed with a precancerous condition (spectral similarity to straight
intestine carcinoma, reference standard D>0.7) and minor forms of cancer. In 6 of the
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patients the tumor developed in the area of endoscopic polypectomy after they had a huge
villous adenoma removed. Thus, in 34 (27%) of 121 patients, who were diagnosed to
have a malignant polyp condition in phase 1 or a small size tumor, colonic cancer
developed within a year. 36 patients examined within the same time interval were found
to have the condition in phase II and III just as frequently. 28 of them were subjected to
regular medical check-ups with no clinical signs of the disease in evidence in any of
them. 8 patients, within 3-7 months prior to tumor diagnosis, began to show signs of
growing anemia or progressive stool retention. The medical observation data for these
patients, with the NLS method employed a year before the cancer was detected, had
indicated no tumor.
There are two very essential factors known to be of paramount importance for malignant
disease diagnosis: the quality of clinical and diagnostic techniques and the specific
pattern of the disease progress which actually determine the dynamics of the disease
progression. Considering the capabilities and working conditions in the therapeutic
institutions, the data on gastric and colonic cancer diagnoses may to a certain extent be
regarded as optimum. This implies, that even if all the patients were readily diagnosed
with the disease during the medical observation (actually it is a matter of 60%), the phase 1
condition could have been detected only in 40% of them. The analysis of causes of the late
diagnosis cases suggests that such cases could be prevented by improving
organizational and methodical work.
Furthermore, the focus should be placed on the specific features of the disease progress
which are of great and possibly of vital importance for tumor detection. The analysis of
the available data prompts the assumption that a tumor may develop within a short time
interval reaching the size of either “minor cancer” or extensive lesion. This confirms the
idea that the tumor growth dynamics in different patients and in different phases of the
disease is likely to vary and be of both continuous and discrete patterns. So a possible
scenario of tumor development could be the emergency of “early” gastric cancer against
the background of precancerous gastric diseases with a subsequent prolonged period of
existence in the initial phase which enables its diagnosis after a year or a long time later.
At the same time, this “benign” scenario of disease progress is not typical for some
patients and based on rapid tumor growth we just fail to detect the initial phase of the
condition in advance. Colonic cancer development through the benign phase and then
through a malignant adenoma is not the only possible scenario. Tumors can develop de
novo and here too, a variant of a comparatively slow or fast growth is possible. This
provides an explanation of an “accidental” detection of patients with fairly large tumors
during medical observation and a great number of patients with a short clinical anamnesis and
late phases of the disease.
Thus, NLS can be considered as an adequate method for diagnosing gastric and colonic
cancers. The difficulties in dealing with NLS interpretation largely concern the initial phases
where the frequency of disease detection depends in the long run on how keen the
physicians are on performing a spectral verification of any focal changes in the mucosa in the
case of a chronic gastritis and on keeping the patients under dynamic observation at the
given modes of elimination and NLS-analysis involved.
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The results allow segregation into two principal variants of disease diagnosis. The first
one suggests “accidental” tumor detection during NLS-investigation; neither clinical nor
other familiar signs of disease are in evidence or their intensity is an insufficient reason
for the patient to see a doctor. The second variant occurs when the patient develops
clinical implications which impel the physician to carry out investigations for them. The
results of diacrisis of gastric and colonic cancers indicate that for most patients the
problem of early diagnosis can not be solved, not only because of certain organizational
factors but also and primarily because of the specific pattern of the disease progress and
its manifestations. However, the actual opportunities for improving the well-timed
disease diagnosis in practical public health conditions lie, primarily, in increasing the
number of patients to be examined by means of the NLS-method within the frameworks of
a health survey and also in a timely and complete examination of the patients who are
suspected to have the disease.
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