DOC WHAT ARE OCCUPATIONAL CANCERS?

Occupational Cancers

The Human Body -- Cancer (Photo credit: n0cturbulous)

An occupational Cancer is a Cancer caused by carcinogenic agents which fall under Group 1 of the International Agency for Research on Cancer in the work place or IARC.

IARC classify the agents into 5 groups:
Group 1: proven carcinogens based on epidemiological studies among workers with long exposure

Group 2A: probable human carcinogens (based on animal studies which are relevant to human exposure

Group 2B: possible human carcinogens ( based on significant increase in cancer incidence in more than 1 animal species or strains)

Group 3: Agents are not classified as carcinogenic to humans

Group 4: Agents probably not carcinogenic to humans

Well known examples of occupational cancers are :
1.mesothelioma caused by asbestos
2.liver angiosarcoma caused by vinyl chloride and arsenic.
Patients with these 2 cancers can be compensated under WICA.

What are the Signs and symptoms of occupational cancers?
The symptoms and signs of occupational cancers are specific to  the type of cancer whether they are caused by work or not.

Some cancers have a long latency period so they can be difficult to establish the exposure history of the cancer and therefore the causal relationship.

Diagnostic Criteria of Work relatedness:
A good occupational history may be difficult to obtain in view of the long latency of the some cancers. It is however necessary for diagnosis.

Investigation to establish work relationship to Cancers:
A good occupational history may be able to establish if there is exposure to the carcinogens under Group 1 of the IARC:

1.Bladder cancer due to
a.4-aminobiphenyl in rubber and tire manufacturing
b.Arsenic in wood preservation, use of pesticide, manufacture of glass , semiconductors, alloys , pigment and anti-fouling paints
c.Benzidine in manufacture of dyes and pigments

2.Blood cancer (leukemia) from:
a.benzene in petrochemical industry, refinery, laboratory testing of benzene usage, handling of fuels containing benzene(vehicle workshops or petrol stations),bulk storage of petrol and related products
b.ionizing radiation from use of radioactive isotopes or x-ray machines

3.Lung cancer may be due to:
a.Arsenic in wood preservation, use of pesticide, manufacture of glass , semiconductors, alloys , pigment and anti-fouling paints
b.Asbestos  from construction and demolition of buildings containing asbestos roofing and rubbish chutes, ship building and repair where asbestos is used for insulation of boiler and pipes, repair and replacement of asbestos brake linings by car and bus mechanics
c.beryllium in manufacture of nuclear devices, satellite, radar system, aircraft brushing and bearings in the aeronautical industry
d.cadmium in manufacture of nickel-cadmium batteries,jewelery , certain fungicides, dyes and pigments, waste treatment, smelting and refining of ores containing cadmium, cadmium electroplating,plastic industry involving compounding of polyvinyl chloride,automotive and aircraft industries,
e.chromiun in chromium metal plating,
f.nickel in stainless steel production, battery manufacture,
g.BIS (chloromethyl ether) in chemical industry,
h.vinyl chloride in rubber and plastic manufacture,storage and analysis of VCM

4.Liver (angiosarcoma) cancer may be due to :
a.Arsenic in wood preservation, use of pesticide, manufacture of glass , semiconductors, alloys , pigment and anti-fouling paints
b.vinyl chloride in rubber and plastic manufacture,storage and analysis of VCM

6.Pleural mesothelioma is due to :
Asbestos  from construction and demolition of buildings containing asbestos roofing and rubbish chutes, ship building and repair where asbestos is used for insulation of boiler and pipes, repair and replacement of asbestos brake linings done by car and bus mechanics

7.Nose and sinus cancers are due to:
a.chromiun in chromium metal plating,
b.nickel in stainless steel production, battery manufacture,
c.wood dust in wood working

8.Skin cancer may be due to:
a.Arsenic in wood preservation, use of pesticide, manufacture of glass , semiconductors, alloys , pigment and anti-fouling paints
b.UV light radiation from exposure to the sun in construction and ship building industries
c.polycystic hydrocarbons, tar, pitch, bitumen, mineral oil and soot in petrochemical industries and refinery

Correlate the cancer to latency period, minimum exposure and level of exposure in the workplace.    Latency period may be 5 to 30 years depending on the type of cancer.

Management:

1.All cancers must be referred to hospitals for further management.

2.All suspected carcinogenic chemicals should be substituted with non carcinogenic substances whenever possible.

3.Try to reduce exposure of workers to carcinogenic substances as far as possible through engineering means, barriers, Personal Protective Equipment etc

4.Keep a register of all workers exposed to carcinogens for at least 10 years and follow up when possible.

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DOC I HAVE CANCER 2

Be on the alert for: CAUTION
1.Changes in bowel or bladder
2.A sore or an ulcer anywhere on the body, including the mouth, which       does not heal properly.
3.Unusual bleeding from the nose or any other part of the body, and blood in the stools.
4.Thickening lump in breast or elsewhere
 5.Indigestion,
6.Obvious changes in the size, shape or colour of a mole on the skin.
7.Nagging cough, hoarseness,

 Pay attention to problems that won’t go away or get better, like: a persistent cough (with or without phlegm), hoarseness of voice, indigestion or discomfort, loss of weight for no reason, a change in bowel habits (such as persistent diarrhoea or constipation).

Ladies, early detection may save your life.

Examine your breasts once a month. Regular breast self examination (BSE) helps to detect breast cancer at a stage when it can still be treated and even cured. Many women have saved their lives through regular examination of their own breasts. A regular examination by your doctor is also recommended. Mammograms are special X-rays of the breasts to look for lumps. They are usually recommended for women over 50.

Regular Pap Smears. A Pap smear is a simple, quick and painless test that detects cervical cancer at an early stage when it has a good chance of cure. A woman should start having regular Pap smears once she becomes sexually active.

Speak to your doctor about your personal and family medical history. Certain medical conditions may increase your risk of developing some cancers. For example, people who are carriers of the Hepatitis B virus are more likely to develop liver cancer. Women infected with certain sexually transmitted diseases have a higher chance of getting cervical cancer.

Your doctor can advise you how to prevent such conditions. But if you already have them, he can tell you what steps you can take to reduce your risk of developing cancer.

Some cancers (like breast and colorectal cancers) tend to run in families. If your parents, brothers or sisters have had cancer, discuss it with your doctor. He may recommend some screening tests to help determine your risk for developing the same cancer.

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DOC I HAVE CANCER
Cancer is the top killer in Singapore.
About one quarter of all deaths here are caused by cancer.

Normal healthy cells grow and multiply in an orderly, controlled manner. 
Cancer cells on the other hand multiply uncontrollably. They do not function normally and instead form a growth or tumour. These cancerous tumours can spread to nearby tissues and organs as well as to other parts of the body. 

Cancer kills by:
Destroying important organs
Disturbing normal body functions
Blocking important blood vessels or air passages.

Not all cancers are the same
Cancer is really a group of diseases. There are many types of cancer which can arise from the different types of cells in the body.

MOST COMMON TYPES OF CANCER IN SINGAPORE ARE:

Male
Lung
Colon & rectum
(large intestine)
Stomach
Liver
Nasopharynx
(back of the nose)

Female
Breast
Colon & rectum
Lung
Cervix
(neck of the womb)
Stomach

Cancer can be prevented
Cancer is not contagious like the flu or chickenpox. You cannot catch cancer from someone who has it.
Many cancers develop because of lifestyle habits such as smoking, excessive drinking of alcohol or eating too much fat (especially animal fat).

Others are caused by factors in the environment such as sunlight, radiation and some industrial chemicals. By leading a healthy lifestyle and avoiding certain risk factors, about one-third of all cancers can be prevented from occurring.

Cancer can be cured
Many people are afraid of cancer because they think it is incurable. In fact, about one-third of all cancers can be cured if they are detected and treated early enough. Recognizing the early warning signs and going for regular check-ups can save your life if cancer strikes.

Lower your risk of cancer by leading a healthy lifestyle
Stay away from cigarettes and cigarette smoke. Cigarette smoke contains about 40 different cancer-causing substances. Almost all of those who develop lung cancer are smokers. Smoking also causes cancers of the mouth, throat, larynx (voice box), oesophagus (gullet), stomach, pancreas, kidney and bladder. Even if you don’t smoke, breathing in other people’s smoke can increase your risk of developing lung cancer.

If you do not smoke, ask any smokers you live or work with to avoid smoking in your presence.

Take more fresh fruits and vegetables. Fruits and vegetables contain fibre and vitamins which help to reduce your risk of developing colorectal (large intestine) and stomach cancer.

The chemicals used to process foods like ham, bacon, luncheon meat may form cancer-causing substances when they are digested. These substances have also been found in salted or preserved foods (such as salted fish or pickled vegetables) and may lead to cancer of the stomach and nasopharynx. But you don’t have to give up these food items totally. Just eat them less often.

Peanuts, seeds and grains that are not stored properly often become mouldy. Some of these moulds produce substances that can cause liver cancer.

Overweight? Exercise regularly and eat less fatty foods. People who are overweight are more likely to develop cancers of the colon, rectum, breast and prostate. To maintain a healthy weight, take up a regular exercise or sport. Eat less foods high in fat or sugar.

Prevent sunburn and avoid overexposure to the sun. People who have fair skin are more prone to skin cancer. The ultraviolet rays from the sun damage the skin. Frequent sunburn may lead to skin cancer.

Comply with safety regulations if you are exposed to cancer-causing substances at work. Always follow the safety regulations as they are meant to protect you.

Avoid excessive alcohol if you drink
People who frequently drink large amounts of alcohol are likely to develop liver cancer. They are also at risk of developing cancer of the mouth, throat and oesophagus (gullet).

Alternate your drinks with non-alcoholic ones. Drink them slowly so they last longer.

Look out for these early warning signs and let your doctor know. Notice any unusual lumps, sores, moles or bleeding?

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A front page of The Family Doctor from 1889 (Photo credit: Wikipedia)

THE FAMILY DOCTOR

“I WILL FOLLOW that method of treatment which according to my ability and judgment, I consider for the benefit of my patient and abstain from whatever is harmful or mischievous.”
The Hippocratic Oath


When I first started as a family doctor in 1974, the medical doctor was regarded like a fatherly figure to most patients. He was kind, compassionate and caring for his patients and a friend to their family.
It was something I aspire to become.

Not every general practitioner can be a family doctor.
The family doctor knows the family of his patients like the back of his hands.

For example I see the father for his monthly review of  high blood pressure( A Simple Guide to Hypertension), his wife for osteoporosis( A Simple Guide to Osteoporosis), the younger son for weekly injections of vitamin when he was suffering from leukemia( A Simple Guide to Blood Cancer) and undergoing chemotherapy, the oldest son who is married and now worried about finances ( I promised that I will help him out if he does not abort the child) because his wife is confirmed as pregnant. The oldest son now has 2 children of school going age. The younger son whom the father was worried may be infertile as a result of his chemotherapy is now a proud father of a baby boy. The father himself had hoarseness of the voice which after not improving for 2 weeks was sent for biopsy of his vocal cord and found to have cancer of the larynx( A Simple Guide to Laryngeal Cancer). He was treated for this and has been free of cancer for 10 years.

Somehow the family of the patient becomes intertwined with your life and you find yourself asking the patient about his wife, sons and their children each time you meet .That is only one family.

Another patient whose wife was diagnosed with cancer of the breast ( A Simple Guide to Breast Cancer) after routine mammogram found several lumps in her breast (one of which turned up to cancerous on biopsy) consulted me regarding the removal of the breast which her surgeon wanted to do. It was a small lump which showed early cancer. My advice was remove the lump and then do radiation therapy. However her surgeon thought otherwise and opted to remove the breast. The removed breast was found to be free of cancer. Apparently the cancerous cells had been removed during the earlier biopsy. So an unnecessary major operation

was done . The wife asked me not to tell her teenage daughter about the removal of the breast and up to today her daughter who now has a five year daughter still does not know about her mother’s breast removal.
Her husband who had been smoking cigarettes in the toilet for many years subsequently had a bypass operation for his coronary artery blockage( A Simple Guide to Ischemic Heart Disease) . After the operation he asked for me to come to his house to remove all the stitches instead of going to the hospital.
His brother subsequently had cancer of the prostate ( A Simple Guide to Prostate Cancer)and had a catheter inserted into his bladder in order for him to pass urine into a bag. One morning I was called to attend to him because the catheter had slipped out and he was unable to pass urine.
I had to go to the nearest pharmacy to get a similar catheter which can be inserted into his bladder and can be retained inside the bladder. The extent that the family doctor goes out his way to make sure his patient is well showed his commitment to the family and their trust in him.

These are just another example of the trust between the family doctor and the patients. There are many many other families whose trust in their family doctor make us go all out to help and treat them like part of a family.
The family doctor not only diagnose the pregnancy for a newly married couple. He also see pregnant woman for antenatal monthly reviews up to the 5th month of her pregnancy before sending to a obstetrician in a private or public hospital for her further checkup and delivery.

He sees the baby as early as 5 days after their birth for treatment of the baby’s jaundice or infection of the navel.

He teaches the mother breastfeeding methods through pregnancy and baby guides published by milk companies and advises on how to feed the child  and burping of the child.
He also follows up with the necessary childhood vaccinations and medical checkups.

As the child grows older, treatment of infectious diseases like influenza, common cold, measles , rubella and mumps follows.

Once in a while you will have a child with high fever having fits coming to the clinic. These are attended to immediately because of the danger of damage to the brain.

Parents of the children will come to see you occasionally for cold, cough and diarrhea and sometimes conjunctivitis.

Grandparents will see you for old age illness like rheumatism pains, diarrhea or incontinence.

I remember frequent cases where I will have to catherize the patient in order to relieve them of their urine blockage and bloated bladders. Then there are the chronic cases of diabetes, hypertension and strokes.I was often called for house calls sometimes in the middle of the night to attend to febrile fits in children, asthma, strokes, heart attacks and severe infections which prevent them from coming to the clinic.

In the past the family doctor was like a friend to the family. He treats the baby, the older children, the pregnant mothers, working fathers and their grandparents. Even now there are families who still bring their grandchildren to consult me.
Most of  the family know how to contact me during an emergency.

I know their names and the children’s names and also their family situation.

In many cases the patients who are poor are charged a token amount otherwise they will not see you due to their pride.
They however do not have to pay their medical fees or medicines.

During our recent relocation of our clinic while going through the medical record cards in order to discard those patients who have not seen me for at least 10 years. I found that there were patients still owing money since 1974 when I first started the clinic. I do not believe in chasing patients for their money.

There was this Indian foreman who was in charge of our estate rubbish removal. He was poor but he brought his family to see me asking the money to be owed. For 10 years he brought his family for treatment . Knowing that he was poor I did not expect any payment for all these treatments. Yet at the age of 55 years ( the retirement age at that time) he was able to withdraw funds from the government Central Provident Fund( A compulsory saving scheme meant for retirement). To my surprise he asked my nurses to calculate all the medical bills over the years to added up so that he can pay the whole sum. It was a pleasant surprise for me.

At that time a family doctor was really a family doctor looking after babies, children, pregnant mothers, working fathers and grandparents.

Times have changed since the 1990s. Pregnant women goes to their obstetrician.

Babies and children are treated by their pediatricians.

Working parents are treated by their company doctors.

Grandparents may be treated by geriatricians.

In spite of all these changes there are still many families who still remember their family doctors and come back to us when the other doctor’s medicines do not work.
They know that they can depend on us and can come to us for advice.
That is the essence of a family doctor whose duty is to guide, treat and educate a full generation of patients.

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A TALE OF 2 CANCERS
———————————————


NASOPHAYNGEAL CANCER (A Simple Guide to Nasophayngeal Cancer)


The Ear Nose and Throat Department treats all cancers of the ear nose and throat.
Some of the throat and mouth cancers are treated together with the Dental Surgery Department.
In the 1970s one of the most common and deadly cancer was the Nasopharyngeal Cancer which  now is known to be linked with Epstein-Barr virus.
Treatment was difficult because of the closeness of the nose cancer to the brain and the frequently late diagnosis.
Surgical treatment is usually not considered unless it was at an early stage.
The treatment of choice was deep X-ray radiation to the affected area followed by chemotherapy in all cases spread of the cancer to other organs.
The mortality rate was high compared to the present modern treatment today of gamma knife treatment.
At the time of my assignment, there was a woman patient in the ward who was in the advanced stage of nasopharyngeal cancer and undergoing chemotherapy.
She was a teacher of 32 years of age who was mostly sick during the time there.
She was emaciated with vomiting during her chemotherapy and loss of appetite.
She was always in pain because the cancer has spread to the brain.
We had to give painkillers and anti-vomiting injections every now and then in order to relieve her symptoms.
Because of the injections, she was also in a sleepy state most of the time.
She has quite a few visitors including her family and her students, most of whom were dejected at the state of her condition.
I tried talking to her on several occasions but she was most too tired to answer except in short sentences.
One morning her bed was cleared and we know that she has succumbed to her illness in the night.


It was sad but quite a lot of nasopharyngeal cancer patients had succumbed in this way including my father-in-law during my medical student days.


LARYNGEAL CANCER (A Simple Guide to Laryngeal Cancer)


In contrast to the dangerous nasopharyngeal cancer (which was usually detected late), the Laryngeal Cancer is usually detected much earlier .
The symptom of hoarseness of voice was one of the easily symptom which prompts the patient to see a doctor.
Even then, some patient then to delay their checkup by a ENT surgeon preferring to see Chinese Sinsehs (Traditional Chinese healers) for treatment hoping to be cured of their condition.
We had a elderly female patient of 70 years who had an advanced stage of Laryngeal cancer which fortunately grow very much slower than the nasophayngeal cancer.
Although it had spread just outside of her larynx or vocal box, surgical removal of her cancer was successful.
A tracheostomy(hole in her windpipe) was done in order that she could breathe through the hole.
Her vocal box was completely removed and closed so her only way of breathing was through the hole.
By covering the hole partially ,she was able to utter some gutterial sounds which required a speech therapist to teach her to talk again.
Nowadays there are mechanical and electronic devices which can placed in the vocal box area to help the patient to talk
In the meantime she was recovering from her surgery in the ward.
Strict instructions was given to made sure the tracheostomy hole was not blocked and free of infection.
In the meantime I used to communicate with her through hand gestures and some written words.
She was cheerful in spite of her illness and I used to try to ‘talk’ to her with hand gestures and written words to keep her in good spirits.
Her relatives were also helpful and kind to her.
Once her condition was well enough to return home, she was discharged.


She even send me a thank you card for taking good care of her.
This was the one of the satisfying things about being a doctor.
It is always important to treat a patient well as another human being rather than a medical case.
When you treat a patient well and kindly , even other patients, nursing staff ,and hospital ‘amahs’(helpers or assistants) also know about it and treat you just as well.

In all, the ENT department was one of the satisfying department to work in and very essential to learn about managing a patient in the family practice.

Not many family doctors know how to remove a fish bone from the throat, a small marble from the nose of a child, remove wax from the ears, bleeding from the nose or treat peritonsillar abscess

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THE ENT DEPARTMENT


The Ear Nose Throat  (ENT) Department of

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Singapore General Hospital is one of the smallest department with 4 consultant ENT Surgeons, 2 medical officers and 1 houseman.


It is however one of the most essential department of the hospital as 80% of cases are generally  the ear nose and throat conditions.


However 90% of the cases can be seen as outpatients or by experienced Accident and Emergency Doctors and General Practitioners.


Our job is to handle those ENT conditions which the Accident and Emergency Doctors could not handle.


Typical conditions are:


1.Foreign bodies in the ear and nose such as small marbles, small parts of toys, cotton buds in the nose of children, which can be removed with a nasal forceps or sucked out with suction tubes


2. Fish bones or chicken bones stuck  in the throat which can be removed by crocodile forceps.
If further down the throat an endoscope may be required to remove the bones sometimes under general anesthesia.


3.Severe infections of the ear with pussy discharge which require drainage of the pus.


4.Severe blockage of the ear by wax which my required syringing of the ear with warm water to remove the wax.


5.Peritonsillar  abscess or quinsy ( A Simple Guide to Tonsillitis)which is an abscess or bag of pus surrounding the tonsil causing blockage to food, swallowing and even breathing.
A cut just above the tonsil will usually drain the pus and relieve the blockage. However the patient will normally have to stay in hospital for one or two days to make sure the bleeding stop and he or she is able to swallow and breathe properly.
He or she is then scheduled for a future operation to remove his tonsils.


6.Bleeding from the nose(A Simple Guide to Epistaxis)  is an emergency which has to be attended quickly because of the danger of loss of blood.
Most mild bleeding of the nose comes from bursting of blood vessel of the septum and can be stopped easily by coagulating the blood vessel with silver nitrate or cautery (electrical burning) under local anesthesia.
In severe cases packing the nose with gauze packs anteriorly from the front or posteriorly from the back to plug the bleeding can be done with great discomfort to the patient.


7.Vertigo (A Simple Guide to Vertigo) or severe dizziness may be treated with an injection of stemetil with temporary relief. Recurrence especially in cases of Meniere’s Disease (A Simple Guide to Meniere’s Disease)  is quite common.


8.The cancer patients of the nose and throat are particular in danger of bleeding of the nose, breathing difficulty and spread of the cancer to the rest of the body. The most common cancer seen here is Nasopharyngeal Cancer (A Simple Guide to Nasopharygngal Cancer).
Other cancers are Cancer of the Larynx, Tongue, Salivary glands.
These will be talked about in the next blog.

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THE NEW DOCTOR
It was the first day of my life as a new doctor.

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It was exhilarating. It was exciting.

It was quickly brought down to earth or hospital ward.
The head of Ear Nose Throat Department of Singapore
General Hospital spent little time to introduce his
consultants  and medical officers to me
(the only houseman and the most junior doctor
around to do all the ward work).

We then make a ward round of all the inpatients
to update the latest information on their medical
conditions and also which patient will be fit for
discharge on that day.

The houseman (me) doctor was of course supposed to do
these (so called red tape) as well as to take blood
tests and fill out all the information on new
patients admitted to the ward.

After the ward round I got around to do all the
paper work and blood tests.
It was a small department which was why only 1
houseman doctor was attached to it.

The patients were generally post-surgical recovery
cases who of course may need pain killers and
constant monitoring for post operation complications.

Of course there were also the odd nasopharyngeal cancer
(A Simple Guide to Nasopharyngeal Cancer) patient
who were on chemotherapy because their cancer was
fairly advanced.

So it was work and work and work again as new cases
come and old cases had the usual pain and bleeding
after operations.

I had never like the word “cases” because it was so
impersonal.

I would try to know my patient’s name, what sort of
work they were in.

I also believe in helping the nurses and nursing aides in their work as I do not consider myself superior to them.
After all I had just started on my medical journey while they had so much more experience in their many years in nursing.

One of the many disadvantage of being a doctor was the long hours we are expected to work.
When there is a night duty, a doctor has to work from
8am in the morning up to 1pm the next day.
Of course the main work was from 8am to 5pm.
From 5.01pm onwards we have to attend to the
new cases admitted to the ward as well as the
inpatients in the wards who has complications
like bleeding postoperatively or had severe pain
or unable to sleep.


Because the Ear Nose Throat Department has less
emergencies, life at night was not too bad and
usually there was some time to sleep.

However because there were fewer medical officers and houseman in the ENT dept, night duty happened about every 3 days including Sundays and public holidays.
Meals such as dinner and breakfast were served by the ward assistants.

For me , I was allowed to see some outpatients when
I had finished my ward work.

In addition I was allowed to assist in some operations.
I was lucky enough to be able to do  a tonsillectomy
operation (A Simple Guide to Tonsillitis) with
a trainee medical doctor guiding me with instructions.

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