Accession Agreement

Exhibit 4.11

Accession Agreement

August 20, 2004

Pursuant to Section 5(n) of the Purchase Agreement (the “Purchase Agreement”) dated August 4, 2004, among Oiler Acquisition Corp., a Delaware corporation (the “Issuer”), and Citigroup Global Markets Inc., X.X. Xxxxxx Securities Inc., Wachovia Capital Markets, LLC and Deutsche Bank Securities Inc., as representatives of the initial purchasers (the “Initial Purchasers”) named in Schedule I thereto, such Section 5(n) being an inducement to the Initial Purchasers to enter into the Purchase Agreement and the Registration Rights Agreement (the “Registration Rights Agreement”) dated August 4, 2004, among the Issuer, and Citigroup Global Markets Inc., X.X. Xxxxxx Securities Inc., Wachovia Capital Markets, LLC and Deutsche Bank Securities Inc., as representatives of the Initial Purchasers, each of the subsidiary guarantors set forth on the signature pages hereto (each a “Subsidiary Guarantor” and, collectively the “Subsidiary Guarantors”) does hereby agree, on a joint and several basis, to accede to the terms of the Purchase Agreement and the Registration Rights Agreement as guarantors, and hereby undertakes to perform, on a joint and several basis, each of the obligations of the Issuer set forth in the Purchase Agreement or the Registration Rights Agreement as though it had entered into the Purchase Agreement and the Registration Rights Agreement on August 4, 2004. Such performance obligations referenced in the preceding sentence are in addition to the performance obligations of US Oncology, Inc. under the Purchase Agreement and Registration Rights Agreement, whose performance obligations shall occur by operation of law.

[Signature Pages Follow.]

IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental Indenture to be duly executed, all as of the date first above written.

	US ONCOLOGY, INC.
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Chief Financial Officer
	ALABAMA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	AOR HOLDING COMPANY OF INDIANA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President

	AOR MANAGEMENT COMPANY OF ARIZONA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR MANAGEMENT COMPANY OF INDIANA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR MANAGEMENT COMPANY OF MISSOURI, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR MANAGEMENT COMPANY OF OKLAHOMA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President

	AOR MANAGEMENT COMPANY OF PENNSYLVANIA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR MANAGEMENT COMPANY OF TEXAS, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR MANAGEMENT COMPANY OF VIRGINIA, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AOR REAL ESTATE, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President

	AOR OF INDIANA MANAGEMENT PARTNERSHIP, as a Subsidiary Guarantor
		By:	AOR MANAGEMENT COMPANY OF INDIANA, INC.
		Its:	General Partner
		By:	/s/ Xxxxx Xxxxxxxxx
		Name:	Xxxxx Xxxxxxxxx
		Title:	Vice President
		and
		By:	AOR HOLDING COMPANY OF INDIANA, INC.
		Its:	General Partner
		By:	/s/ Xxxxx Xxxxxxxxx
		Name:	Xxxxx Xxxxxxxxx
		Title:	Vice President
	AOR OF TEXAS MANAGEMENT LIMITED PARTNERSHIP, as a Subsidiary Guarantor
		By:	AOR MANAGEMENT COMPANY OF TEXAS, INC.
		Its:	General Partner
		By:	/s/ Xxxxx Xxxxxxxxx
		Name:	Xxxxx Xxxxxxxxx
		Title:	Vice President

	AOR SYNTHETIC REAL ESTATE, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	AORT HOLDING COMPANY, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	CALIFORNIA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	FLORIDA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	GREENVILLE RADIATION CARE, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	IOWA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	MICHIGAN PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	NEBRASKA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	NEW MEXICO PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	NORTH CAROLINA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	PENNSYLVANIA PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	PHYSICIAN RELIANCE HOLDINGS, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	PHYSICIAN RELIANCE NETWORK, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	RMCC CANCER CENTER, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	SELECTPLUS ONCOLOGY, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	ST. LOUIS PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	TEXAS PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager
	TOPS PHARMACY SERVICES, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	US ONCOLOGY CORPORATE, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	US ONCOLOGY PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	US ONCOLOGY RESEARCH, INC., as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Vice President
	WASHINGTON PHARMACEUTICAL SERVICES, LLC, as a Subsidiary Guarantor
	By:	/s/ Xxxxx Xxxxxxxxx
	Name:	Xxxxx Xxxxxxxxx
	Title:	Manager

	PHYSICIAN RELIANCE, L.P., as a Subsidiary Guarantor
		By:	PRN Physician Reliance, LLC
		Its:	General Partner
		By:	/s/ Xxxxx Xxxxxxxxx
		Name:	Xxxxx Xxxxxxxxx
		Title:	Manager
	PRN PHYSICIAN RELIANCE, LLC, as a Subsidiary Guarantor
		By:	/s/ Xxxxx Xxxxxxxxx
		Name:	Xxxxx Xxxxxxxxx
		Title:	Manager