Secondary cancer

Carcinogenic agents include chemicals in the environment, such as aniline and benzene, which are associated with the development of bladder cancer and leukemia, respectively. Environmental factors, such as excessive sun exposure, also may result in cancer. Viruses, including the human papilloma virus and hepatitis B, maybe associated with the development of cancer. Some of the chemotherapy agents cause secondary cancers after therapy has been completed. Numerous factors may contribute to the development of cancer. 

There is an increased risk of secondary cancers in the form of acute leukemia, and the carcinogenic potential of procarbazine is thought to be higher than that of most other alkylating agents. 

As stated in a recent review [53], the development of efficient cisplatin chemotherapy has brought an unexpected challenge as many patients survive longer, they find themselves at risk of late complication in their anti-neoplasic therapy. Indeed, although unambiguous data on the capacity of cisplatin to induce secondary cancers in humans is still lacking, its carcinogenic properties in rats and mice has been reported [53] [54], Treatment-... 

Oncolytic agents intended for treatment of advanced disease (if treatment is successful, there may be later concerns regarding secondary cancers)... 

Cancer patients given conventional treatment are not told that both radiation and chemotherapy can cause secondary cancer. 

The risk of secondary cancer has been assessed in 412 children treated with etoposide and anthracyclines for acute lymphoblastic leukemia, 99 of whom also received G-CSF and 58 of whom received cranial irradiation (91). Overall, 20 children developed myeloid leukemia and myelodysplastic syndrome at a median of 2.3 years after treatment. The 6-year cumulative incidence of these secondary cancers was 11% among patients who received G-CSF, close to that observed in those who received cranial irradiation (12%), but significantly higher than in those who received neither irradiation nor G-CSF (2.7%). 

The distributions of immune function parameters were compared across treatment groups via t-test. Kaplan Meier estimates were used to summarize overall survival (OS) and event free survival (EPS). Survival was calculated from PBSC infusion until death or date of last contact. EPS is defined as the absence of death, relapse, disease progression and de novo secondary cancer. Cox regression models were fitted for the outcomes of OS and EPS. P values associated with regression models were derived from the Wald test. The last possible day of contact was Pebruary 21,2006. 

The concept of pleomorphism may very well tie in with the fact that nearly 600 different kinds of cancer cells reportedly have been identified. And that one kind of cancer may lead to another, or secondary, cancer. That is, cancer may not only metastasize or spread as the same kind of cancer, but a new kind may occur (that is, in different kinds of cells). If, say, viruses are involved in cancer formation, and can change from one kind to another, then the different kinds of cancer-causing viruses could be legion. And this, of course, may be an obstruction to the development of a general vaccine, as is in the case of AIDS. (It may be reemphasized that the work of Dr. Livingston was aimed at autogenous vaccines, specific to the particular patient.)... 

Surgery has long had the reputation for sometimes causing the cancer to metastasize or spread, and it now turns out that radiation and chemotherapy are also suspect, either causing new or secondary cancers, or the primary cancer to reappear more aggressively and virulently than before. 

Figure 1 False-color scintigram of the human spine and ribs, revealing secondary cancers (metastases) in the vertebrae arising from a primary cancer of the prostate gland. A scintigram (y-camera scan) is a record of radioactive emissions from an isotope (in this case, " Tc) that is selectively absorbed by bone when injected into the body, y-ray scintigraphy is frequently used to screen cancer patients for signs of secondary disease, often after their primary cancer has been treated. Here, the metastases appear as the pink and white hot spots in the thoracic spine. (Reproduced from CNRI/Science Photo Library.)...

Cancer cells may spread and seed themselves elsewhere in the body. From these new sites further secondary cancerous growths may develop, hastening the destructive process which may well end in the victim s death. Neoplasms may spread via the blood stream or along lymph vessels. 

Topoisomerase inhibitors topotecan and irinotecan (CPT-11), etoposide (VP-16), teniposide Increased risk of secondary cancer or relapses... 

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